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NBME 23 Answers

Block 1/Question#1
An asymptomatic 30-year-old woman comes to the physician for ...
Anovulation

Block 1/Question#2
A 56-year-old woman comes to the physician for a health ...
Microbial oncoprotein that interferes with tumor suppressor proteins

Block 1/Question#3
A 52-year-old man comes to the physician because of severe ...
Triglyceride

Block 1/Question#4
A male newborn has a myelomeningocele that involves the ...
Closure of the caudal neuropore

Block 1/Question#5
A study is conducted to examine the effectiveness of a newly ...
Phase 2

Block 1/Question#6
A 32-year-old woman comes to the emergency department after ...
Borderline

Block 1/Question#7
Which of the following is present in integral plasma ...
Transmembrane region

Block 1/Question#8
A 30-year-old man with HIV infection comes to the office for ...
It increases plasma concentrations of other PIs also metabolized by cytochrome P450

Block 1/Question#9
A 45-year-old man is brought to the physician by his parents ...
Schizotypal

Block 1/Question#10
A 13-year-old girl is brought to the office because of a ...
Staphylococcus aureus

Block 1/Question#11
A 55-year-old man who has a 10-year history of type 2 ...
Impotence

Block 1/Question#12
A 48-year-old man who is a farmer in a remote area of India ...
Blockade of postsynaptic inhibition of spinal motor reflexes

Block 1/Question#13
A researcher is asked to prospectively investigate the ...
Prevalence: above the standard; Incidence: above the standard

Block 1/Question#14
A 65-year-old woman develops deep venous thrombosis of the ...
Heparin-induced thrombocytopenia

Block 1/Question#15
A 26-year-old man who is a Peace Corps volunteer comes to the ...
0.9% Saline

Block 1/Question#16
Physical analysis of the isolated genomic DNA from a mutant ...
Methylase

Block 1/Question#17
A 54-year-old woman comes to the physician because of a ...
Supraspinatus

Block 1/Question#18
A 15-year-old boy has nasal polyps and develops bronchospasms ...
Enzyme B

Block 1/Question#19
Unlike the DNA polymerases found in Escherichia coli, RNA ...
Mistakes in transcription are not transmitted to progeny

Block 1/Question#20
A 22-year-old woman at 12 weeks' gestation comes to the ...
Hydropic villi with central cisterns

Block 1/Question#21
A 40-year-old woman with a history of low-grade follicular ...
Bacterial pneumonia

Block 1/Question#22
An investigator is studying the adverse effects of a ...
Presentation of antigens to CD8+ T lymphocytes

Block 1/Question#23
A 35-year-old man comes to the physician because of a tremor ...
Anticholinergic agent

Block 1/Question#24
A 39-year-old man comes to the physician because of darkening ...
Ferritin

Block 1/Question#25
A 5-year-old boy who is undergoing induction chemotherapy for ...
Varicella-zoster virus

Block 1/Question#26
A couple comes to the physician for counseling prior to ...
1/150

Block 1/Question#27
An 11-year-old boy is brought to the physician by his mother ...
Sexual abuse

Block 1/Question#28
An otherwise healthy 82-year-old man is brought to the ...
Posterior cord syndrome

Block 1/Question#29
A 34-year-old woman with a 5-year history of hepatitis C ...
Infiltration of lymphocytes, plasma cells, and macrophages

Block 1/Question#30
A 52-year-old man comes to the physician because of inability ...
Pelvic splanchnics

Block 1/Question#31
A 16-month-old boy is brought to the physician for a ...
Absence of germinal centers in lymph nodes

Block 1/Question#32
Which of the following sets of serum findings is most likely ...
Phosphate: increased;
Ca2+: decreased;
Parathyroid hormone: increased


Block 1/Question#33
A 25-year-old woman and her 25-year-old husband come to the ...
α-Thalassemia trait

Block 1/Question#34
A 64-year-old woman is found dead at the foot of her basement ...
Metastatic breast cancer

Block 1/Question#35
A 42-year-old woman comes to the physician because of a ...
Binding of permeable ligand to nuclear transcription factor

Block 1/Question#36
A medical student is caring for a 72-year-old man who has ...
Let me get the resident physician so we can go over the results.

Block 1/Question#37
A 47-year-old woman with multiple sclerosis is brought to the ...
Fasciculus gracilis

Block 1/Question#38
A 43-year-old woman sustains multiple fractures and ...
Hyaline membranes

Block 1/Question#39
A 65-year-old man who is a farmer comes to the physician ...
Disruption of DNA strands secondary to ionization effect

Block 1/Question#40
Which of the following properties of integral membrane ...
Extensive hydrophobic interactions between the amino acid side chains of the protein and the membrane phospholipid tails

Block 1/Question#41
A 62-year-old woman is brought to the emergency department 30 ...
Pons

Block 1/Question#42
A 68-year-old woman comes to the office because of a 3-month ...
Retroperitoneal fibrosis

Block 1/Question#43
A 65-year-old woman has the recent appearance of a lesion at ...
Adenocarcinoma

Block 1/Question#44
A 34-year-old woman is brought to the emergency department 30 ...
Area labeled ‘D’ (Spinothalamic tract, right)

Block 1/Question#45
A 56-year-old woman comes to the physician because of a ...
Presynaptic release of acetylcholine

Block 1/Question#46
A 31-year-old primigravid woman at 28 weeks' gestation comes ...
Bone

Block 1/Question#47
A 61-year-old man comes to the emergency department because ...
Budd-Chiari syndrome

Block 1/Question#48
A 20-year-old man is brought to the emergency department by ...
3,4-Methylenedioxymethamphetamine (MDMA)

Block 1/Question#49
Electrical stimulation of the stellate ganglion is most ...
Heart rate

Block 1/Question#50
A 45-year-old woman with coronary artery disease and anemia ...
4.5

Block 2/Question#1
A 26-year-old woman comes to the physician because of a ...
Tinea corporis

Block 2/Question#2
Cyclophosphamide and some other chemotherapeutic agents kill ...
Granulocytes

Block 2/Question#3
A prospective study is done to assess the relative efficacy ...
Include the outcome for each participant in the group to which he or she was randomized

Block 2/Question#4
An 18-year-old woman comes to the physician because of a ...
Maximum oxygen consumption (VO2max): decreased;
Venous blood lactate: increased;
Energy production by glycolysis: increased


Block 2/Question#5
A female newborn develops respiratory distress. Her ...
Osteogenesis imperfecta, type I

Block 2/Question#6
A 6-month-old girl is brought to the office for a well-child ...
Hepatitis B

Block 2/Question#7
A 45-year-old man is brought to the emergency department ...
Hypovolemic shock

Block 2/Question#8
An 8-year-old boy is brought to the physician by his mother 6 ...
Serum calcitonin concentration

Block 2/Question#9
A 60-year-old man has had easy fatigability, loss of ...
Lung

Block 2/Question#10
A 50-year-old man who lives in eastern Minnesota comes to the ...
Babesia microti and Borrelia burgdorferi

Block 2/Question#11
An antiserum is elicited by immunization with protein X, and ...
Proteins X and Y have no epitopes in common

Block 2/Question#12
A 75-year-old woman has stress urinary incontinence with ...
Stimulation of α-adrenoreceptors

Block 2/Question#13
A 45-year-old man comes to the office for a health ...
Invasion of the submucosa

Block 2/Question#14
A 65-year-old woman with diabetic ketoacidosis has had a ...
Mucormycosis

Block 2/Question#15
A child with septicemia has an antibiotic clearance (Cl) of ...
28.8

Block 2/Question#16
Which of the following best explains impaired action ...
Increase in axonal capacitance

Block 2/Question#17
A 21-year-old man comes to the physician because of a 1-month ...
Leishmania

Block 2/Question#18
A 48-year-old man comes to the physician because of a 24-hour ...
Perforated peptic ulcer

Block 2/Question#19
A 70-year-old man with severe congestive heart failure has ...
Serum BUN: 40;
Serum creatinine: 2;
Urine Na+: 5;
Urine specific gravity: 1.025


Block 2/Question#20
A 47-year-old woman has had a goiter for 10 months. She has ...
Replacement of thyroid parenchyma by lymphoid cells

Block 2/Question#21
A 55-year-old man comes to the physician because of a 1-year ...
FEV1/FVC: normal;
FVC: decreased;
Diffusing capacity of the lung for carbon monoxide: decreased


Block 2/Question#22
A 42-year-old man comes to the physician because of a 1-month ...
Sand fly

Block 2/Question#23
A 75-year-old man with prostate cancer has metastases to the ...
Prostatic venous plexus to the vertebral venous plexus

Block 2/Question#24
A 46-year-old woman has a 1-day history of high-grade fever, ...
Leukocyte alkaline phosphatase activity greater than 250 U/L

Block 2/Question#25
A 44-year-old man with invasive pancreatic cancer is brought ...
Area labeled ‘H’

Block 2/Question#26
A 36-year-old woman comes to the physician for a follow-up ...
Fibromuscular dysplasia

Block 2/Question#27
A 3-month-old girl is brought to the physician by her parents ...
Densely packed capillaries

Block 2/Question#28
A cohort study is conducted to examine the association ...
200

Block 2/Question#29
Which of the following pairs of drugs interferes with DNA ...
Lomustine and cyclophosphamide

Block 2/Question#30
A 21-year-old man is brought to the emergency department 30 ...
Liver

Block 2/Question#31
A 40-year-old man has had enlarging breast tissue for the ...
Spironolactone

Block 2/Question#32
A 2-year-old girl is brought to the physician because she is ...
N-methyl-d-aspartate (NMDA)

Block 2/Question#33
A 68-year-old man who has been treated for the past 4 weeks ...
Area labeled ‘B’

Block 2/Question#34
A 35-year-old woman comes to the physician because of a ...
Synthesis of viral DNA

Block 2/Question#35
A 42-year-old man with a history of recurrent pyelonephritis ...
Magnesium ammonium phosphate

Block 2/Question#36
A newborn has external genitalia that appear to be male. ...
Hyperplastic fetal adrenal glands

Block 2/Question#37
A 62-year-old woman is brought to the physician because her ...
Embolus to the femoral artery with left leg ischemia

Block 2/Question#38
A 78-year-old man is found unresponsive in his yard by a ...
"Thank you for telling me this. Your friend's previous statements to you can be helpful in making decisions for him."

Block 2/Question#39
A 39-year-old woman with obesity and recently diagnosed ...
Gemfibrozil

Block 2/Question#40
A 22-year-old man is brought to the emergency department 30 ...
Peak inspiratory pressure (alveolar): positive;
End-tidal pressure (alveolar): positive;
Peak inspiratory pressure (intrapleural): positive;
End-tidal pressure (intrapleural): positive


Block 2/Question#41
A 44-year-old woman, gravida 2, para 2, comes to the ...
Cervical canal

Block 2/Question#42
A 63-year-old woman comes to the physician because of a ...
FVC: decreased;
FEV1/FVC: decreased;
Peak expiratory flow rate: decreased;
Peak inspiratory flow rate: decreased


Block 2/Question#43
A 2-week-old girl is brought to the physician by her parents ...
Iris

Block 2/Question#44
A 4-year-old boy is brought to the physician by his parents ...
Dietary change

Block 2/Question#45
A 61-year-old man is prescribed fluoxetine for major ...
Raphe nuclei

Block 2/Question#46
Which of the following types of vaccine is most appropriate ...
Live attenuated virus

Block 2/Question#47
A 65-year-old man is scheduled for physical therapy 3 days ...
Medial (internal) rotation

Block 2/Question#48
A 45-year-old woman is brought to the emergency department ...
Inspiratory pause on right upper quadrant palpation

Block 2/Question#49
A 56-year-old man comes to the physician because of severe ...
Colchicine

Block 2/Question#50
A 65-year-old man recovering from a cerebral infarction due ...
Preventing ADP-stimulated platelet activation

Block 3/Question#1
A 32-year-old woman comes to the physician after the result ...
Yolk sac

Block 3/Question#2
A 35-year-old man comes to a new physician for a health ...
Liver

Block 3/Question#3
An 18-hour-old male newborn is 61 cm (24 in) long and weighs ...
Decreased gluconeogenesis

Block 3/Question#4
A 31-year-old primigravid woman at 32 weeks' gestation comes ...
Hypoglycemia

Block 3/Question#5
A 68-year-old woman has a 6-month history of weakness, ...
Na+: decreased;
K+: increased;
pH: decreased


Block 3/Question#6
A 25-year-old man has an orchiectomy for a recently detected ...
Germ cells

Block 3/Question#7
A male newborn is delivered at 39 weeks' gestation after an ...
Gastroschisis

Block 3/Question#8
A 62-year-old man with a blood pressure of 220/160 mm Hg ...
Labetalol

Block 3/Question#9
A male newborn is delivered at term to a 30-year-old woman. ...
Ask the mother and sister to leave the room and inform the parents of the abnormality

Block 3/Question#10
An investigator is studying two drugs, Drugs X and Y, to ...
Area under the curve

Block 3/Question#11
A 50-year-old woman with idiopathic cardiomyopathy is ...
Penetration of larvae from soil into the skin

Block 3/Question#12
A 39-year-old man comes to the physician for a routine health ...
β-Myosin

Block 3/Question#13
A 65-year-old man with a history of gout comes to the ...
I will authorize the permit, but I recommend that you continue with regular exercise and only use the permit when you are having severe pain.

Block 3/Question#14
A 3-day-old male infant with Down syndrome has had repeated ...
Duodenal atresia

Block 3/Question#15
A 45-year-old woman comes to the physician for a follow-up ...
Myopathy

Block 3/Question#16
A 40-year-old woman comes to the physician because of a ...
Pituitary gland

Block 3/Question#17
A 24-year-old woman comes to the physician because of a ...
Accessory spleen

Block 3/Question#18
A patient with a 20-year history of type 1 diabetes mellitus ...
Impaired release of glucagon

Block 3/Question#19
A previously healthy 32-year-old man is brought to the ...
Toxicology screening

Block 3/Question#20
An 82-year-old woman is brought to the physician by her ...
Decreased function of the puborectalis muscle

Block 3/Question#21
A 60-year-old woman comes to the physician 1 week after she ...
Amplification

Block 3/Question#22
A 54-year-old woman with rheumatic heart disease is brought ...
Intra-alveolar transudates

Block 3/Question#23
A pregnant 28-year-old woman is found to have symmetrical ...
Lactotrope

Block 3/Question#24
A 25-year-old man is brought to the emergency department 30 ...
Fractional excretion of sodium greater than 2%

Block 3/Question#25
A 43-year-old woman undergoing chemotherapy for acute ...
Preformed IgM antibodies

Block 3/Question#26
A 27-year-old woman has headaches and blurred vision. She ...
Angiotensin

Block 3/Question#27
A 30-year-old man reports increasing fatigue and dyspnea on ...
Atrial septal defect

Block 3/Question#28
A 10-year-old boy sustains an abrasion on his left knee. One ...
Labile cells

Block 3/Question#29
A 50-kg (110-lb) experimental animal receives 1 L of 5% ...
Intracellular volume: decreased;
Intracellular osmolality: increased;
Extracellular volume: increased;
Extracellular osmolality: increased


Block 3/Question#30
A 20-year-old woman comes to the physician because of a ...
C1q

Block 3/Question#31
The parents of a 1-year-old boy with a bilateral cleft palate ...
Multifactorial

Block 3/Question#32
A 70-year-old man comes to the physician because of decreased ...
Inhibition of prostaglandin synthesis

Block 3/Question#33
A 78-year-old man has had progressive loss of hearing in his ...
Otosclerosis

Block 3/Question#34
A 34-year-old woman with a long-standing history of ...
Fat

Block 3/Question#35
A 31-year-old woman comes to the emergency department because ...
Tell the patient's husband that he is not allowed in the treatment area, and that he must remain in the waiting area

Block 3/Question#36
A 70-year-old woman comes to the physician because of a ...
Serum sickness

Block 3/Question#37
A 48-year-old man is referred for evaluation of possible ...
108 to 118

Block 3/Question#38
A 5-year-old boy who has recently recovered from an upper ...
Immune destruction of platelets

Block 3/Question#39
A 44-year-old woman comes to the physician because of a ...
Decreased CSF production by the choroid plexus

Block 3/Question#40
A 38-year-old woman with hypercalcemia, hypophosphatemia, and ...
Area labeled ‘B’ (Proximal convoluted tubule)

Block 3/Question#41
A previously healthy 45-year-old man comes to the physician ...
Infraspinatus

Block 3/Question#42
A 48-year-old woman has severe gastroesophageal reflux. ...
Inhibition of gastric H+–K+ ATPase

Block 3/Question#43
A 65-year-old man has had increasing shortness of breath over ...
Osteitis deformans (Paget disease)

Block 3/Question#44
A 23-year-old woman comes to the physician for advice ...
Because irradiated food is not radioactive, you will not be exposed to ionizing radiation by consuming it.

Block 3/Question#45
A 44-year-old woman comes to the physician because of a ...
Decreased arterial Pco2

Block 3/Question#46
A 19-year-old woman is severely burned over 35% of her total ...
Increased metabolic rate

Block 3/Question#47
A 14-year-old boy with a tibial fracture is fitted with a leg ...
Neck of the fibula

Block 3/Question#48
A 20-year-old woman comes to the physician because of a ...
Inhibition of the cytochrome P450-dependent demethylation reaction

Block 3/Question#49
Genetic analyses of cells obtained on amniocentesis confirm ...
Epinephrine

Block 3/Question#50
A 32-year-old woman, gravida 2, para 1, at 39 weeks' ...
Increased fetal systemic vascular resistance

Block 4/Question#1
A 65-year-old man is brought to the emergency department ...
Thromboxane A2

Block 4/Question#2
A 60-year-old woman with type 2 diabetes mellitus comes to ...
Subacromial bursitis

Block 4/Question#3
A 33-year-old woman comes to the physician for a routine ...
Inorganic phosphorus: decreased;
Parathyroid hormone: increased;
Calcitriol: decreased


Block 4/Question#4
A 76-year-old woman is brought to the physician by her son ...
She expresses clear and consistent values

Block 4/Question#5
Transmission of a bacterial agent by person-to-person contact ...
Meningococcal meningitis

Block 4/Question#6
A 35-year-old woman, gravida 2, para 1, undergoes vaginal ...
External anal sphincter

Block 4/Question#7
A 3-day-old female newborn delivered at term is brought to ...
Increased conversion of bilirubin to water-soluble isomers

Block 4/Question#8
A 36-year-old nulligravid woman and her 40-year-old husband ...
1 of 50

Block 4/Question#9
A 35-year-old man who is a veterinarian in a rural area comes ...
Coxiella burnetii

Block 4/Question#10
A study was conducted to investigate the mean age at onset in ...
99%

Block 4/Question#11
A 40-year-old man comes to the physician for a routine health ...
Finasteride

Block 4/Question#12
Investigators conduct a prospective, community-based study to ...
Strength of association, temporal relationship, dose-response gradient

Block 4/Question#13
A 65-year-old man comes to the physician because of a 1-year ...
Smooth muscle cells of the deep artery

Block 4/Question#14
A 61-year-old woman comes to the physician for a health ...
Closure of the mitral valve

Block 4/Question#15
A 35-year-old man comes to the physician because of a 4-month ...
Arachidonic acid

Block 4/Question#16
In a study of the use of ultrasonography for the early ...
80%

Block 4/Question#17
A 24-year-old man has a grade 3/6 systolic murmur. Cardiac ...
Aortic stenosis

Block 4/Question#18
An investigator is conducting a study to determine the cause ...
Enveloped

Block 4/Question#19
A 6-month-old male infant is brought to the physician because ...
Regulatory T lymphocytes

Block 4/Question#20
A 7-year-old boy is brought to the physician by his mother ...
Release of interferon gamma by TH1 cells

Block 4/Question#21
An otherwise healthy 26-year-old scuba diver has difficulty ...
Hyperresonance over most of the left side of the chest

Block 4/Question#22
A 40-year-old man with terminal small cell carcinoma of the ...
Demeclocycline

Block 4/Question#23
A 74-year-old woman comes to the physician because of a ...
Ipratropium

Block 4/Question#24
A 60-year-old man comes to the physician because of a 1-month ...
Erythropoietin

Block 4/Question#25
An 85-year-old woman is brought to the physician by her ...
Donepezil

Block 4/Question#26
A 28-year-old man has hypertriglyceridemia that has not ...
Aspirin

Block 4/Question#27
A man accidentally touches the surface of a hot stove; 20 ...
Histamine

Block 4/Question#28
An 18-month-old girl is brought to the physician because of ...
Decreased sodium bicarbonate reabsorption in the proximal tubule

Block 4/Question#29
A 2-week-old male newborn is brought to the physician by his ...
Galactose-1-phosphate uridyltransferase

Block 4/Question#30
A study is planned to assess differences in hypertension ...
Cross-sectional study

Block 4/Question#31
A 32-year-old man who lives at sea level travels to a ...
Normoblasts

Block 4/Question#32
A 42-year-old woman comes to the office because of a 1-year ...
Spontaneous regression

Block 4/Question#33
A 16-year-old girl with bulimia nervosa is brought to the ...
Potassium: decreased;
Chloride: increased;
Bicarbonate: decreased


Block 4/Question#34
A 44-year-old man who is a farmer and has been spraying his ...
Area labeled ‘D’

Block 4/Question#35
A 17-year-old girl with type 1 diabetes mellitus comes to the ...
Acknowledge the patient's reasons for missing insulin injections

Block 4/Question#36
A 40-year-old man comes to the physician because of a 3-month ...
Postcentral

Block 4/Question#37
A 2-year-old boy is brought to the emergency department ...
Lipoprotein lipase

Block 4/Question#38
A 45-year-old woman is scheduled to undergo a lymph node ...
Accompany the resident while the resident obtains signed consent

Block 4/Question#39
A 44-year-old woman comes to the physician because of ...
Celiac sprue

Block 4/Question#40
A 16-year-old girl is brought to the emergency department 30 ...
Tail of the pancreas

Block 4/Question#41
Electrophysiology of the heart is studied in an anesthetized ...
Ablation of the atrioventricular node

Block 4/Question#42
A 12-year-old girl is admitted to the hospital for treatment ...
Methionine

Block 4/Question#43
A 65-year-old man develops a progressive ataxia with gait ...
Right cerebellar hemisphere

Block 4/Question#44
A 44-year-old man is brought to the emergency department by ...
Entrapment of the inferior rectus muscle

Block 4/Question#45
A 32-year-old man has a diastolic blood pressure that ...
Precapillary resistance

Block 4/Question#46
A female neonate is delivered at 38 weeks' gestation by ...
Rough endoplasmic reticulum

Block 4/Question#47
A 43-year-old woman comes to the physician because she has ...
Left atrial myxoma

Block 4/Question#48
A 2-week-old female newborn of Mexican descent is brought to ...
Why don't you continue with what you're doing, and let's try changing her to a different formula.

Block 4/Question#49
A 15-year-old boy is brought to the physician for a ...
Testosterone

Block 4/Question#50
A 48-year-old man has complete loss of hearing in his right ...
Area labeled ‘C’ (Cranial nerve 8: vestibulocochlear)

Recent comments ...

... welpdedelp made a comment on nbme23/block1/q#1 (An asymptomatic 30-year-old woman comes to the...)
 +7  upvote downvote
submitted by welpdedelp(77)

when a follicle doesn't rupture (aka anovulation) then it will form a cyst.

uslme123  n premenopausal women, simple adnexal cysts (image 1) that are <3 cm in diameter typically represent normal follicles or may be a corpus luteal cyst (these may appear simple or complex) and may be considered a normal finding. Even when up to 5 cm in diameter, these simple cysts are so commonly due to normal menstrual physiology that the Society of Radiologists in Ultrasound (SRU) does not recommend follow-up when asymptomatic
... ber1ber1 made a comment on nbme23/block1/q#1 (An asymptomatic 30-year-old woman comes to the...)
 +0  upvote downvote
submitted by ber1ber1(0)

for anyone who thought it was endometriosis its not because endometriosis of the ovary would have multiple blood filled "chocolate cysts" and presents bilaterally and patient would typically have pelvic pain as well FA 2019:p634

... charcot_bouchard made a comment on nbme23/block1/q#1 (An asymptomatic 30-year-old woman comes to the...)
 -1  upvote downvote
submitted by charcot_bouchard(90)

After everything its jjust an epidem ques. Below 55 vs Above 55 years

ls3076  can you elaborate please?
... osgoodschlatter10 made a comment on nbme23/block1/q#1 (An asymptomatic 30-year-old woman comes to the...)
 +0  upvote downvote
submitted by osgoodschlatter10(0)

The most common cyst in a young female is Follicular cyst; this is a cystic dilatation of an unruptured Graffian follicle.

Failure of Graffian follicle to rupture --> Anovulation

Ref FA2019 Pg 631-632

... lfsuarez made a comment on nbme23/block1/q#2 (A 56-year-old woman comes to the physician for a...)
 +3  upvote downvote
submitted by lfsuarez(66)

Patient presents with cervical intraepithelial neoplasia, with the most likely culprit being HPV. HPV causes this neoplasia though the creation of E6/E7 oncoproteins which inhibit p53 and Rb tumor suppressor proteins respectively.

... sne made a comment on nbme23/block1/q#3 (A 52-year-old man comes to the physician because of...)
 +18  upvote downvote
submitted by sne(17)

Alcoholic = pancreatic insufficiency. Linoleic, oleic, and palmitic acid can be absorbed without pancreatic lipases since they're just free fatty acids. Triglycerides need to be broken down by lipases before absorption.

Bile acids are the main method for eliminating cholesterol, not pancreatic enzymes

... mousie made a comment on nbme23/block1/q#4 (A male newborn has a myelomeningocele that involves...)
mousie  Caudal = Bottom of the SC = failure to close = spina bifida and Rostral = top of SC = failure to close = Anencephaly
... sweetmed made a comment on nbme23/block1/q#4 (A male newborn has a myelomeningocele that involves...)
 +0  upvote downvote
submitted by sweetmed(44)

Dont get confused with club feet. Clubfoot is a birth defect where one or both feet are rotated inward and downward.[1][4] The affected foot and leg may be smaller than the other.[1] In about half of those affected, both feet are involved.[1] Most cases are not associated with other problems.[1] Without treatment, people walk on the sides of their feet, which causes problems with walking.[2] The exact cause is usually unclear.[1] A few cases are associated with distal arthrogryposis or myelomeningocele.[2]

... lfsuarez made a comment on nbme23/block1/q#5 (A study is conducted to examine the effectiveness of...)
 +2  upvote downvote
submitted by lfsuarez(66)

Phase II studies test the efficacy of a drug. This second phase of testing can last from several months to two years, and involves up to several hundred affected patients.

... sajaqua1 made a comment on nbme23/block1/q#6 (A 32-year-old woman comes to the emergency...)
 +5  upvote downvote
submitted by sajaqua1(228)

Borderline personality disorder- feelings of "emptiness," suicidality, self-mutilation, unstable relationships, and more common in women than in men. A common defense mechanism in this disorder is "splitting" in which people are seen as entirely good or entirely bad. Borderline personality disorder is also part of the Cluster B personality disorders, which are associated with substance abuse.

imnotarobotbut  Suicide attempts are also commonly seen with Borderline
... step420 made a comment on nbme23/block1/q#7 (Which of the following is present in integral plasma...)
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submitted by step420(18)

Integral membrane proteins are found within the plasma membrane and span the whole length across. The inside of the membrane is very hydrophobic due to the long carbon chains. Extensive hydrophobic interactions between the protein side chain and the lipid tails will help anchor the protein in the membrane.

yb_26  O-linked glycosylation of secreted and membrane bound proteins is a post-translational event that takes place in the cis-Golgi compartment after N-glycosylation and folding of the protein
... yb_26 made a comment on nbme23/block1/q#7 (Which of the following is present in integral plasma...)
 +0  upvote downvote
submitted by yb_26(51)

O-linked glycosylation of secreted and membrane bound proteins is a post-translational event that takes place in the cis-Golgi compartment after N-glycosylation and folding of the protein

... step420 made a comment on nbme23/block1/q#8 (A 30-year-old man with HIV infection comes to the...)
 +5  upvote downvote
submitted by step420(18)

Ritonavir inhibits CYP450! So you can use it to boost the concentration of the other Protease inhibitors by preventing their metabolism by CYP450!

mousie  who knew
sympathetikey  Right on (thanks sketchy)
mguan1993  MAGIC RACKS is a good mnemonic ive heard for 450 inhibitors (macrolides, amiodarone, grapefruit, cimetidine, RITONAVIR, alcohol (chronic), cipro, ketoconazole, sulfa
criovoly  "CRACK AMIGOS" Cimetidine Ritonavir Amiodarone Ciprofloxacion Ketoconazole Acute alcoholism Macrolides Isoniasid Grapefruit juice Omeprazole Sulfonamides
... sajaqua1 made a comment on nbme23/block1/q#9 (A 45-year-old man is brought to the physician by his...)
 +2  upvote downvote
submitted by sajaqua1(228)

From First Aid- schizotypal personalities exhibit eccentric appearance, odd beliefs or magical thinking, and interpersonal awkwardness. These describe the several layers of clothes, belief in psychic abilities and crystals, and poor eye contact.

A) Borderline- unstable moods with impulsivity, self-mutilation, suicidality, and a sense of emptiness, along with a greater likelihood in women B) Dependent- those with an excess need for support and low self-confidence C)Histrionic- excessively emotional, seeks attention, sexually provocative, concerned with appearance ("actor's disease") D) Narcissistic- grandiosity, entitled, lacks empathy, demands 'the best' E) Schizoid- voluntary social withdrawal, limited emotional expression, content to be on their own

... welpdedelp made a comment on nbme23/block1/q#10 (A 13-year-old girl is brought to the office because...)
 +2  upvote downvote
submitted by welpdedelp(77)

I chose this b/c its the most common pathogen for skin infections

seagull  same here
sympathetikey  Some bowlsheet
... mcl made a comment on nbme23/block1/q#10 (A 13-year-old girl is brought to the office because...)
 +3  upvote downvote
submitted by mcl(228)

So if you didn't h8 bedbugs enough, they can apparently also serve as vectors for drug-resistant bacteria including MRSA HOW FUN IS THAT

spacepogie  SO FUN
... chris07 made a comment on nbme23/block1/q#10 (A 13-year-old girl is brought to the office because...)
 +3  upvote downvote
submitted by chris07(15)

Bed bugs themselves are not known to be carriers of illness, but they can leave itchy bites. The girl is likely to scratch these bites, abrade the skin, and thus increase the risk of a staph skin infection (since staph aureus is the most common skin infection pathogen)

mcl  Oh! The article I found said that MRSA has been shown to colonize the saliva of bed bugs for up to like 15 days, and that they isolated MRSA from several specimens. Is it just more likely that the patient scratches it in since staph is e v e r y w h e r e ?
chris07  I mean it’s possible. The last review course I took said that it wasn’t associated with anything. It may be, but either way...same answer :)
... hayayah made a comment on nbme23/block1/q#11 (A 55-year-old man who has a 10-year history of type...)
 +13  upvote downvote
submitted by hayayah(447)

He has fecal incontinence so his external sphincter is damaged, which is innervated by the pudendal n. (S2-S4). The pelvic splanchnic nerves, which mediate the erection process, are also S2-S4.

thomasburton  Why could this not be dysuria?
lilyo  I think that you are thinking about urinary incontinence. If we damage the pudendal nerve S2-S4, you can exhibit urinary and fecal incontinence since this nerve innervates both the urethral and the external anal sphincters. However since the pelvic splanchnic nerves also have roots that originate in S2-S4 a patient with pudendal nerve damage will also have impotence since these control the erection reflex. He wouldn't have dysuria which is painful urination. Most likely caused by a urethral infection or a blockade of the urinary tract. He would have urinary incontinence. I hope this helps.
... lfsuarez made a comment on nbme23/block1/q#12 (A 48-year-old man who is a farmer in a remote area...)
 +3  upvote downvote
submitted by lfsuarez(66)

Patient present to the clinic with classical symptoms of tetanus. Tetanus toxin work via inhibition of GABA/glycine release from Renshaw inhibitory cells. Without these inhibitory signals on the postsynaptic neuron, they are continuously activated causing muscle tetany.

... yb_26 made a comment on nbme23/block1/q#12 (A 48-year-old man who is a farmer in a remote area...)
 +6  upvote downvote
submitted by yb_26(51)
  • binding to the MHC class II receptor and triggering the release of cytokines - superantigens

  • binding to the neuromuscular junction and prevention of ACh release - botulinum toxin

  • blockage of a GTP-binding protein resulting gin the accumulation of cAMP - pertussis toxin

  • blockage of presynaptic inhibition of spinal motor reflexes - tetanus toxin

  • prevention of protein synthesis by blocking elongation of the polypeptide chain - diphtheria toxin, Pseudomonas aeruginosa exotoxin A

thomasburton  Not sure I agree with the second one, M.O.A for botulinum is cleave of SNARE protein preventing pre-synaptic ACH release. Think the second one almost describes something like sux or some other deporalising nicotinic drug.
humble_station  You are right but to get the muscle spasms, trismus & seizures it has to inhibit GABA & Glycine release from Renshaw cells Cleaving the snare proteins will cause paralysis
... aladar50 made a comment on nbme23/block1/q#13 (A researcher is asked to prospectively investigate...)
 +3  upvote downvote
submitted by aladar50(18)

So there’s 100 residents, and the prevalence after 2 years is =10 at the beginning, +5 in the first year, +10 second year, and -3 that healed, for a total prevalence of 22 residents or 22/100=22 percent. Thus, prevalence = above the standard. For incidence, it’s 15 new cases out of 90 residents over the 2 years (100 total residents – 10 that already had ulcers), or 15 new ulcers per 180 patient⋅years. This would be 83.3 new ulcers per 1000 patient⋅years if you extrapolated it out -- basically (1000/180) * 15 -- thus, incidence = above the standard.

zelderonmorningstar  Okay I feel like an idiot cause I thought: Above the Standard = Doing a good job keeping old people from getting ulcers. Thumbs up. Below the Standard = I wouldn’t let my worst enemy into your ulcer ridden elder abuse shack.
aladar50  @zelderon Ohh damn. I could totally see how one could view the answer choices that way. I think it is important to read how they are phrased - they are asking if the center is above THE standard or below THE standard. The “standard” is an arbitrary set point, and the results of the study are either above or below that cut off. Maybe if it was “above/below standards” that would work. Also, being above the standard could either be a good thing or bad thing. If say you were talking about qualifying for a competition and you have to do 50 push ups in a minute, then being above=good and below=bad. In this case, having more ulcers than the standard = bad.
saynomore  @aladar Thank you!!! but how did you get the 15 new ulcers per 180 patient⋅years? I mean I understand the 15 part, but not the second part ... hence why I messed this up, lol :|
aladar50  @saysomore Because the study is looking at 100 residents over a period of 2 years. Since 10 already had the disease at the start, when looking at incidence you only include the subjects that have /the potential/ of developing the disease, so 90 patients over 2 years. This would be 90 patient⋅years per year, or a total of 180 patient⋅years over the course of the study.
sympathetikey  @zelderonmorningstar I thought the same exact thing. Had the right logic, but then just put the backwards answer.
kai  I wonder if they chose this wording on purpose just to fuck with us or if this was accidental. My guess is there's some evil doctor twirling his thumbs somewhere thinking you guys are below the standard.
... keshvi made a comment on nbme23/block1/q#13 (A researcher is asked to prospectively investigate...)
 +2  upvote downvote
submitted by keshvi(4)

i counted both the prevalence and incidence using patient - years. Is it incorrect to use patient years for prevalence?

... jigyasa made a comment on nbme23/block1/q#13 (A researcher is asked to prospectively investigate...)
 +0  upvote downvote
submitted by jigyasa(0)

Why have you taken 180 as patient years? Isn't patient years calculated as no of patients multiplied by the number of years they suffer?

... sajaqua1 made a comment on nbme23/block1/q#14 (A 65-year-old woman develops deep venous thrombosis...)
 +3  upvote downvote
submitted by sajaqua1(228)

The patient started receiving post-surgical subcutaneous anticoagulation therapy, so most likely either unfractionated heparin or low molecular weight (LMW) heparin. Unfractionated heparin's primary anticoagulation ability comes from working with antithrombin III to block coagulations factors II and X.

However, heparin can also bind to a platelet protein called Platelet Factor 4 (PF4), found in alpha-granules. When it binds PF4, the new heparin-PF4 molecule is immunogenic. The immune response to this generates anti-heparin-PF4 Ig. Platelets already have Ig receptors on their surfaces, so when these anti-heparin-Pf4 Ig trigger the receptors on the platelets, these platelets degranulate. The degranulation kicks off further clotting, leading to a drop (often more than 50%) in platelet count.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2600013/

... yb_26 made a comment on nbme23/block1/q#14 (A 65-year-old woman develops deep venous thrombosis...)
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submitted by yb_26(51)

More simple from FA 2019: Heparin-induced thrombocytopenia is due to development of IgG antibodies against heparin-bound platelet factor 4 (PF4) Antibody-heparin-PF4 complex activates platelets => thrombosis and thrombocytopenia

  • highest risk with unfractionated heparin
... imnotarobotbut made a comment on nbme23/block1/q#15 (A 26-year-old man who is a Peace Corps volunteer...)
 +1  upvote downvote
submitted by imnotarobotbut(39)

The treatment of cholera is mostly supportive - you want to rehydrate the patient by giving them an isotonic saline since they're losing a lot of fluids.

... criovoly made a comment on nbme23/block1/q#15 (A 26-year-old man who is a Peace Corps volunteer...)
 +0  upvote downvote
submitted by criovoly(4)

This patient is giving symptoms of hypovolemic shock, mainly due of dehydration. The HYPOTENSION is an example of severe dehydration and hypovolemic shock. You need to expand the vessels rehydrating the patient in order to avoid further shock and dehydration.

... consistentwrongdoer3 made a comment on nbme23/block1/q#16 (Physical analysis of the isolated genomic DNA from a...)
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submitted by consistentwrongdoer3(6)

Why does methylation cause loss of resistance to GATC restriction endonuclease? Does this have to do with methylation of U to T?

methylased  GATC related to methylase --> https://en.wikipedia.org/wiki/Dam_methylase
sympathetikey  Dam methylase, alright
... thomasalterman made a comment on nbme23/block1/q#16 (Physical analysis of the isolated genomic DNA from a...)
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submitted by thomasalterman(77)

Methylase methylates DNA, making the DNA resistant to restriction endonucleases

*https://d2jmvrsizmvf4x.cloudfront.net/7Pf4zZ3TuGwLTRKvUGYL_methylatedrestriction.jpg

... defalty98 made a comment on nbme23/block1/q#16 (Physical analysis of the isolated genomic DNA from a...)
 +0  upvote downvote
submitted by defalty98(0)

Why are we complicating things? Change in the bases will destroy the palindromic sequence required for any restriction endonuclease to work. Methylation is the only option that makes sense.

... imgdoc made a comment on nbme23/block1/q#16 (Physical analysis of the isolated genomic DNA from a...)
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submitted by imgdoc(33)

Explanations for this are too complicated. Think of it like this:

You've got a piece of mutated DNA that is able to be digested by a restriction endonuclease, that means the DNA was transcriptionally available to begin with. AKA it was not methylated, because as we know, methylation = heterochromatin which is transcriptionally inactive. that means methylase was mutated

Only other plausible answer was DNase, and if it was mutated it would be inactive, not overactive.

... stinkysulfaeggs made a comment on nbme23/block1/q#16 (Physical analysis of the isolated genomic DNA from a...)
 +2  upvote downvote
submitted by stinkysulfaeggs(17)

Me reading this question stem: .....do you mean which of the following ENZYMES?

... thomasalterman made a comment on nbme23/block1/q#17 (A 54-year-old woman comes to the physician because...)
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submitted by thomasalterman(77)

The most important hints to the question are as follows, with #2 being the most specific:

1) patient reports pain with overhead motion and reports recurrent overhead motion during work. Overhead motion can damage the supraspinatus muscle due to impingement by the acromion.

2) Pain is worst with internal rotation of the shoulder - this is consistent with the findings of the empty-can test, which indicates a supraspinatus injury.

mousie  I was thinking along the lines of overhead motion - damage to the subacromial bursa which is between the acromion and the supraspinatus ... also its the most commonly injured rotator cuff m. so could have guessed this one right
sympathetikey  Thanks for the explanation. I was scratching my head as to why this is correct, since supraspinatus only does 15 degrees of abduction, but you make a lot of sense.
charcot_bouchard  IDK WTF i picked Trapezius
ls3076  why would injury to supraspinatus cause weakness with internal rotation though?
targetusmle  yeah coz of that i picked subscapularis
maddy1994  ya the whole question pointed to supraspinatus ...but last line internal rotation made me pick subscapularis
darthskywalker306  I went for Trapezius. That shoulder flexion thing was a big distraction. Silly me.
... sajaqua1 made a comment on nbme23/block1/q#18 (A 15-year-old boy has nasal polyps and develops...)
 +12  upvote downvote
submitted by sajaqua1(228)

Enzyme A stands in for Phospholipase A2, turning phospholipids in the cell membrane into arachidonic acids. From there, Enzyme B stands for Cyclooxygenase (COX), while Enzyme C stands for 5-Lipoxygenase (5-LO). 5-LO produces 5-HPETE, which is turned into leukotrienes. Leukotrienes play a double role in events like asthma, because they cause bronchoconstriction (seen in this patient) and by acting as chemical attractants for inflammatory cells, whose activity will close the airway further. By blocking COX (presumably with an NSAID), we leave more of the substrate arachidonic acid for 5-LOX to ultimately convert into leukotrienes. This is the basis for aspirin-intolerant-asthma, which is frequently associated with nasal polyps. (Samter's triad).

https://www.karger.com/article/FullText/355949

D) Prostacyclin synthase . E) Thromboxane synthase

... keycompany made a comment on nbme23/block1/q#19 (Unlike the DNA polymerases found in Escherichia...)
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submitted by keycompany(127)

This question is disguised. What they are really asking is "what is the sole determinant of species survival"? The only answer is the ability to procreate. Because DNA Polymerase has proof-reading activity, progeny will be unaffected by RNA Polymerases lack of proof-reading activity.

ls3076  the phrasing of this explanation doesnt make sense to me.
ls3076  oh wait sorry i just read it again. So instead of proofreading how are errors handled with RNA?
thomasburton  Think the point is basically although errors with RNA polymerase make make the bacterium not very good at infecting or killing or whatever it does not affect replication as it is not used during replication!
... seagull made a comment on nbme23/block1/q#19 (Unlike the DNA polymerases found in Escherichia...)
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submitted by seagull(461)

https://en.wikipedia.org/wiki/Proofreading_(biology)

Here is a little bit on proofreading.Hope it helps

... krewfoo99 made a comment on nbme23/block1/q#19 (Unlike the DNA polymerases found in Escherichia...)
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submitted by krewfoo99(10)

So basically what this is saying that DNA will be transmitted to the progeny not RNA. So DNA will replicate in the G2 phase and transfer of DNA material to progeny will occur in the M phase. The RNA may be mutated and making defective products, but this will not transmit into the progeny, thus not affecting species survival based on RNA mutations.

... wonderboyg made a comment on nbme23/block1/q#20 (A 22-year-old woman at 12 weeks' gestation comes to...)
 +6  upvote downvote
submitted by wonderboyg(6)

this patient's uterus was increased in size compared to a 12 week uterus. she had grape like structures and no fetus. this would indicate a hydatidiform mole. this patient also had no fetal parts so it would be a complete mole.

according to pathoma, a hydatidiform mole is an "abnormal conception characterized by swollen and edematous villi with proliferation of trophoblasts"

also in a complete mole, most villi are hydropic and trophoblasts will proliferate diffusely around these hydronic villi.

the sheetlike masses of syncytiotrophoblasts would indicate a choriocarcinoma.

nwinkelmann  Also, ball like masses of proliferating decidua, I think, means ectopic decidua, which can be seen in endometriosis, deciduocervicitis, and in the lymph nodes. Markedly dilated fetal blood vessels can be seen in rare complication of placentomegaly which could potentially lead to IUGR but could also result in a normal neonate.
yb_26  @nwinkelmann no, ball-like masses of proliferating decidua are seen in endometrial papillary syncytial change
... thomasalterman made a comment on nbme23/block1/q#21 (A 40-year-old woman with a history of low-grade...)
 +9  upvote downvote
submitted by thomasalterman(77)

She just completed the course of rituximab, which targets CD20 receptors. B-cell deficiency can predispose to bacterial infections.

b) BM failure is not associated with rituximab c) wrong d) wrong e) this occurs w/in 7-10 days of starting treatment, and would not occur after completing a 4-month course of rituximab.

meningitis  Forgot the time frame for Serum sickness and got it wrong.. thanks @thomasalterman
stinkysulfaeggs  Same. Crap.
... sajaqua1 made a comment on nbme23/block1/q#22 (An investigator is studying the adverse effects of a...)
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submitted by sajaqua1(228)

MHC I function is integral to cancer suppression. MHC I displays endogenously synthesized proteins and presents them to CD8+ T cells. The failure to display MHC I, or MHC I display of non-self (and by extension cancerous) proteins triggers a cellular immune response, leading to destruction of the cell.

The proteasome is used for the degradation of worn out, senescent, or malformed proteins. As cancer develops, more mutations lead to increased wrong proteins. Only by expression of the proteasome, or its over-expression, can these mutant proteins be degraded fast enough to not be displayed by MHC I and lead to the cell being killed. Bortezomib blocks the proteasome, so the mutant proteins are displayed on the surface, allowing the immune system to recognize and kill pathological cells.

catch-22  Another way to approach it is to think about MHC class I processing. Basically, if you inhibit the proteasome, peptides will not be generated and nothing is available to be loaded onto MHC I (remember MHC I has to be loaded before it's transported to the cell surface). Cells that don't express MHC I get killed by the natural killers. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2214736/
kai  "In conclusion, we have demonstrated that the proteasome inhibitor bortezomib down-regulates class I and enhances the sensitivity of myeloma to NK cell–mediated lysis" from the conclusion of the NIH paper
maddy1994  another mechanism is by blocking proteosome u even decrease degration of proapoptotic proteins...so it enchances apoptosis(from uworld)
... krewfoo99 made a comment on nbme23/block1/q#22 (An investigator is studying the adverse effects of a...)
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submitted by krewfoo99(10)

Why would perforins be the wrong answer? Wouldnt accumulation of toxic proteins cause the cell to undergo apoptosis ?

ergogenic22  Bortezomib does not directly activate perforin. It directly inhibits the proteasome which → enables CD8+ T cells to initiate apoptosis → via perforin release (in essence a downstream effect).
... tinydoc made a comment on nbme23/block1/q#22 (An investigator is studying the adverse effects of a...)
 +1  upvote downvote
submitted by tinydoc(62)

https://youtu.be/HIRz5hJf3mU

MOA of proteosome inhibitors for MM. TLDR: is that they basically block the proteosome from functioning so that myeloma cells can't recycle protiens (they make a ton of them) and when they can't be recycled they build up and thats toxic to the cell and it dies.

beyond that the question is basically asking if the inhibition of proteosomes isnt specific to the Myeloma cells and it inhibited other cells' proteosomes what would be effected?

MHC class I is present on all nucleated cells (all cells in the body except RBC) and function to present endogenous antigens to CD8+ t cells to be destroyed (for example Viral DNA in an infected cell). The way they do this is by taking the protien it needs to present and breaking it down into much smaller peptide chains (so it can fit on the MHCI. If this step was inhibited in other cells then the the Presentation of MHC I wouldnt be able to present their antigens to CD8+ T cells and Natural killer cells. as the question implies.

The question was super tricky because if you don't know how proteosome inhibitors work then you start looking for an answer that would explain how they would kill tumor cells as well. I got it wrong too. It required knowledge of the way MHC I presents peptides.

... thomasalterman made a comment on nbme23/block1/q#23 (A 35-year-old man comes to the physician because of...)
 +2  upvote downvote
submitted by thomasalterman(77)

Trihexphenidyl and Benztropine are antimuscarinics that can treat the resting tremor and rigidity of parkinsonism.

mousie  haloperidol induced Parkinson's... ? adding a anticholinergic can counter these adverse effects of the antipsychotic .. ?
fulminant_life  @mousie yeah it balances the dopamine-cholinergic imbalance caused by the antipsychotics
kai  +So antipsychotics induce Extrapyramidal side effects which is drug induced Parkinson = low Dopamine High Ach, and you would treat this with anticholinergic (Benztropine).This is neurologic. +Antipsychotics also produce non-neurologic, systemic anti-cholinergic effects like dry mouth, sedation, hypotension etc
... mcl made a comment on nbme23/block1/q#23 (A 35-year-old man comes to the physician because of...)
 +2  upvote downvote
submitted by mcl(228)

To expand on this, what we think happens with Parkinson's disease (and parkinsonianism) is an imbalance between dopamine and acetylcholine. It makes more sense if you look at this diagram, paying particular attention to the indirect pathway. Loss of dopaminergic (DA) neurons from the substantia nigra (SNc) results in constant activation of those ACh secreting neurons, which ultimately results in inhibition of thalamus from initiating movements. Therefore, using anticholinergics help with parkinsonianism secondary to haldol.

mcl  Also, you don't wanna use sinemet since that would be counterproductive
... welpdedelp made a comment on nbme23/block1/q#24 (A 39-year-old man comes to the physician because of...)
 +3  upvote downvote
submitted by welpdedelp(77)

Hemochromatosis, aka "bronze diabetes". Cannot be Addison due to the hyperglycemia and normal BP

alexb  I missed this bc didn't notice it was a middle-aged guy w/ just 3 year hx of Type 1 DM.
tinydoc  I got it mixed up with primary adrenal insufficiency and the acth ⇒ hyperpigmentation.
maddy1994  testicular atrophy &hepatomegaly helped me out to eliminate the options..when i was left with ferritin and saw pigmentation it clicked that it is hemochromatosis
krewfoo99  Symptoms of Darkening of skin, liver dysfunction, diabetes, with testicular atrophy will always be hemochromatosis
... seagull made a comment on nbme23/block1/q#25 (A 5-year-old boy who is undergoing induction...)
 +0  upvote downvote
submitted by seagull(461)

Did anyone think that influenza was right? I understand that Herpes-Z can cause pneumonia but why is this answer better over influenza?

jrod77  I believe it's the vesicular rash that gives it away. I thought it was influenza too, but i re-read the questions and I realized they included a rash which disqualifies influenza.
charcot_bouchard  Also h/o of immunsupression, disseminated VZV. Influenza itself doesnt cause severe disease. secondary PNA does. which u will see in elderly. usually
... sajaqua1 made a comment on nbme23/block1/q#25 (A 5-year-old boy who is undergoing induction...)
 +14  upvote downvote
submitted by sajaqua1(228)

Critical points for this question: 5 year old boy, immunosuppressed because of chemotherapy, 2 day history of fever, cough, shortness of breath, febrile (101.8 F), respirations 46/min, with cyanosis and generalized vesicular rash. Extensive nodular infiltration.

Of the options listed only measles and VZV give a rash. A rash from measles usually starts rostrally and descends caudally, and is flat and erythematous. By contrast, VZV (chickenpox) presents with generalized rash that quickly transitions from macular to papular then to vesicular.

sympathetikey  Good call.
imnotarobotbut  Also, VZV causes pneumonia (what this patient probably had) and encephalopathy in the immunocompromised.
nwinkelmann  What threw me off was that it didn't mention the synchronicity of the rash. I stupidly took failure to mention to mean that the rash was synchronous, which doesn't fit VZV because chickenpox rash is characterized as a dyssynchronous rash (i.e. all stages of the macule to papule to vesicle to ulceration are seen at the same time). MUST REMEMBER: don't add information not given!
jboud86  If anyone wants to refresh info on Vaicella-Zoster virus, page 165 in FA 2019.
... welpdedelp made a comment on nbme23/block1/q#26 (A couple comes to the physician for counseling prior...)
 +5  upvote downvote
submitted by welpdedelp(77)

2/3 1/25 1/4

He has a 2/3 chance of being heterozygous (not 2/4 b/c we know he for sure doesn't have CF)

1/25 chance in the population

1/4 chance of a heterozygous couple having a child with CF

welpdedelp  ok, so it messed up the formatting 0.66667 x 1/25 x 0.25
nwinkelmann  ugh... I ALWAYS forget about changing the carrier status to 2/3. Chance of affected individual = chance of father passing allele * chance of mother passing allele = 2/31/21/25*1/2 = 2/300 = 1/150.
zpatel  2/3(chance of heterozygous) * 1/25(meet carrier) * 1/2(chance of male to transfer affected gen) * 1/2(female to transfer affected gen) = 1/150
... yotsubato made a comment on nbme23/block1/q#27 (An 11-year-old boy is brought to the physician by...)
 +0  upvote downvote
submitted by yotsubato(309)

"Children exhibit behavior incongruent with their age and development" in sexual abuse.

... yb_26 made a comment on nbme23/block1/q#27 (An 11-year-old boy is brought to the physician by...)
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submitted by yb_26(51)
  • children often exhibit sexual knowledge or behavior incongruent with their age.

  • abuser is known to victim, usually male

  • peak incidence 9-12 years

... seagull made a comment on nbme23/block1/q#28 (An otherwise healthy 82-year-old man is brought to...)
 +2  upvote downvote
submitted by seagull(461)

B12 deficiency leads to demylination of the DCML and ALS pathways (i.e. posterior cord syndrome).

... sajaqua1 made a comment on nbme23/block1/q#28 (An otherwise healthy 82-year-old man is brought to...)
 +5  upvote downvote
submitted by sajaqua1(228)

Posterior cord syndrome occurs due to infarction of the posterior half of the spinal cord, from occlusion of the posterior spinal artery. Our patient presents with decreased sensation to pinprick below the level of the knees as well as walking with a wide-based gait, likely indicating loss of proprioception. The patient is also anemic with hyper-segmented neutrophils.

Hypersegmented neutrophils are typically caused by an inability to make enough DNA, caused by a lack of necessary precursors and vitamins including B9 (folate) and B12 (cobalamin). If the patient is folate deficient, we see elevated homocysteine deficiency. If the patient is B12 deficient, we see elevated methylmalonic acid and homocysteine levels. Hyperhomocysteinemia can increase thrombosis. Thrombosis in the posterior spinal artery can cause posterior cord syndrome. In addition, lack of vitamin B12 impairs myelin formation and leads to Subacute Combined Degeneration, which affects the Spinothalamic tract (accounting for decreased pinprick sensation), Corticospinal Tract, and Dorsal Column-Medial Lemniscus Tract (accounting for the reduced proprioception.

A) Anterior cord syndrome- loss of motor command, as well as bilateral loss of heat and pain, the patient has not lost motor function, so it cannot be this. B) Central cord syndrome- presents as a combination of motor and sensory loss, usually with bladder dysfunction. This patient does not display motor loss or bladder dysfunction. C) Hemicord syndrome- Also called Brown-Sequard, this is complete injury to either the left or right side of the spinal cord. It presents with motor dysfunction and reflex dysfunction ipsilaterally at the level of the lesion; loss of upper motor command below the lesion ipsilaterally (spastic paresis); loss of dorsal column-carried sensation ipsilaterally at and below the lesion; and loss of pain and temperature sensation contralaterally 2 to 3 vertebra below the lesion. E) Segmentary syndrome- a congenital failure to develop part of the spinal cord. The new onset of symptoms at 82 years old makes this an unlikely diagnosis,.

yb_26  amazing, thank you!
... masonkingcobra made a comment on nbme23/block1/q#28 (An otherwise healthy 82-year-old man is brought to...)
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submitted by masonkingcobra(84)

Personally my issue with this question is that I though B12 causes demyelination in both the LCST and the DCML (SCD) but they are testing the mechanism here really with the whole methylamonic acid bit and the impaired myelin synthesis

If you're curious

https://www.nature.com/articles/scsandc20166

... titanesxvi made a comment on nbme23/block1/q#28 (An otherwise healthy 82-year-old man is brought to...)
... krewfoo99 made a comment on nbme23/block1/q#28 (An otherwise healthy 82-year-old man is brought to...)
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submitted by krewfoo99(10)

Can someone explain what the picture is supposed to show? Is it supposed to be segmented neutrophils?

titanesxvi  yes do to B12 deficiency
... amarousis made a comment on nbme23/block1/q#28 (An otherwise healthy 82-year-old man is brought to...)
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submitted by amarousis(10)

But doesn't subacute combined degeneration lead to impairment in DCML, spinocerebellar and corticospinal tract? I get the ataxic gait - DCML/spinocerebellar. But the sensation to pinprick, wouldn't that be the spinothalamic tract? That is not usually affected in subacute combined degeneration.

krewfoo99  It would affect the dorsal column tract and the spinothalamic tract. It wont affect the spinocerebellar tract (Thus Rombergs sign in B12 deficiency will be positive) All three of the tracts are affected in Friedrichs Ataxia
krewfoo99  Sorry. Just checked on FA. It will also affect the spinocerebellar tract
... docred123 made a comment on nbme23/block1/q#29 (A 34-year-old woman with a 5-year history of...)
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submitted by docred123(3)

Can anyone further explain this?! I could eliminate a few item choices and I guessed correctly, just need more information! Thanks

wired-in  Patient has 5 yr h/o hep C, so it is chronic. Chronic inflammation is characterized by presence of lymphocytes & plasma cells while neutrophils is more characteristic of acute inflammation (Pathoma Ch. 2). AFP is within reference range so probably not HCC. Choice D, palisading lymphocytes & giant cells suggests granuloma which isn't typical of hep C.
... sajaqua1 made a comment on nbme23/block1/q#30 (A 52-year-old man comes to the physician because of...)
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submitted by sajaqua1(228)

The patient underwent removal of a rectal tumor which had involvement with the prostate. The prostatic capsule is rich with nerves including the pelvic splanchnic nerves, a set of parasympathetic nerves responsible for PNS autonomic regulation. Erections are a parasympathetic function.

A) Gray rami from the sympathetic chain- erections are a parasympathetic function, not sympathetic. Emission of sperm is a sympathetic function, and is directed by the inferior hypogastric nerve. C) Pudendal- the pudendal nerve is a somatic nerve that receives sensation from the penis, posterior scrotum, clitoris, and labia, as well as being responsible for some movement of the pelvic floor, and ejaculation. D) Superior hypogastric nerve- a sympathetic nerve, this contributes to the hypogastric plexus and may also contribute to sympathetic control of emission. E) Ventral ramie of S2-S4- These rami contribute to the pudendal nerve.

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