britesky89

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Apr 6, 2015
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Hi guys! I need some help with NBME 7 questions. Thanks in advance!

1. 37 yo M- progressive weakness over the last 5 days, began at his ankles, then went on to involve the proximal muscles of the lower extemitites, hands, forearms, and face. Mild tingling of fingers and feet. Had an URI 2 weeks ago which is not present now. On exam: moderate weakness of facial muscles, proximal muscles of extremities, and marked weakness of distal muscles of extremities. DTRs are absent. Hypotonia of knees and ankles. Sensation to light touch and vibration is mildly decreased over the feet. Most likely cause?
A. Decreased acetylcholine receptors
B. Decreased release of acetylcholine from motor nerve terminals
C. Degeneration of muscle fibers
D. Demyelination of axons
E. Loss of motor neurons (WRONG)

I thought this was Gullian barre. Is it D? But I thought demyelination of axons was MS? Maybe loss of motor nuerons corresponds better to ALS? Can someone please explain?

2. 75 yo M brought to the ER with confusion and lethargy for two days. The day before the onset of symptoms the was gardening, and the temperature was 100 F. He has a hx of DM2 treated with glyburide, and HTN treated with HCTZ. Six weeks ago he had a laprascopic cholecystectomy. He smokes one pack of cigerattes daily and drinks two martinis every night. He traveled to Hawaii 2 mo. ago. His temp is 106.7 F, HR 120, BP 90/60. Skin is hot and dry but not erythematous. He has decreased muscle tone. Creatinine kinase is 8000, AST is 400. Cause of patient's condition?
A. Anticholinergic poisoning (WRONG)
B. Delerium Tremens
C. Heat Stroke (correct? but what's the explanation?)
D. Malaria
E. Malignant Hyperthermia

This question is really confusing. He had cholecystectomy 6 weeks ago so it could be malignant hyperthermia from the anesthetic. He was gardening so I was even thinking Jimson weed (gardener's pupil) which is seen in anticholinergic toxicity.

3. 15 yo B brought by mother who is concerned about her son's change in behavior after he transferred to a new school 4 mo ago. He has become withdrawn and has been sleeping poorly, which has resulted in daytime fatigue. He has lost 10 lbs during this period. His academic performance has deteriorated; he failing all of his classes and is often late to school. Mother says boy's maternal uncle and grandmother have been treated for depression. Most likely explanation for this patient's behavior?
A. Learning disorder
B. Major depressive disorder (correct - explantion please)
C. Malingering
D. Substance Abuse (WRONG)
E. Age appropriate behavior

Don't amphetamine stimulants cause insomnia and weight loss?

4. 7 yo B has as a routine dental cleaning. One yr ago he underwent aortic valve replacement for congenital aortic stenosis. He has normal heart sounds without any murmur. He is at risk for bacterial endocarditis from which organism?
A. Candida Albicans
B. Haemophilus Influenzae
C. Moraxella cataralis
D. Staph Aureus (WRONG)
E. Viridans strep (correct- please explain)

I was thinking that since he has a prosthetic valve the answer is staph aureus. Why is it viridans strep?

5. 42 yo M with 3 day hx of temps 38.4 C (101.1 F), left sided chest pain, malaise, loss of appetitie, & cough productive of yellow phlegm and a 36 hr hx of increasing SOB. Appears ill. Has smoked 2 packs of cigerettes daily for 25 yrs. His vitals: 38.8 C (101.8 F), resp 22/min, HR 112/min, BP 118/72. Crackles and wheezes are heard at the left lung base; breath sounds are decreased. There is dullness to percussion at the left lung base and left tactile fremitus. Exam is otherwise normal. Xrays of the chest are shown. Gram stain of sputum shows small gram negative bacilli and leukocytes. Most likely Dx is pnuemonia caused by which of the following organisms?
A. E. coli (WRONG)
B. H. influenzae (correct - can someone explain why it's H. influenzae and not E.coli?)
C. N. meningitidis
D. Psuedomonas aueriginosa
E. Strep Pneumoniae

6. 37 yo F with sickle cell disease- 24 hr hx of fever, RUQ pain after eating, and nausea. 4 months ago she had a sickle cell crises. Her only medication is folic acid. BMI is 23; temp 100.8 F, HR 90. Exam shows mild icterus, Her abdomen is distended. Bowel sounds are decreased and Murphy's sign is present. Labs:
Leukocyte Count: 12,000
Serum:
Billirubin total 3
Alkaline phospate 60
Amylase 90
Lipase 40 (N: 14-280)
U/S abd shows cholelithiasis, pericholecystic fluid, and a normal sized common bile duct. Dx?
A. Acute cholecystitis (correct)
B. Acute pancreatitis
C. Acute viral hepatitis
D. Cholangitis (WRONG)
E. Sickle cell disease
Why isn't it acute cholangitis? She has the charcot's triad of Jaundice (mild icterus), Fever (100.8 F), and RUQ pain?

7. 22 yo M college student brought to student health clinic by his friend due 1 mo. hx of increasing paranoia and difficulty sleeping. Patient has become suspicious of his roommates and has voiced out concerns about the effect of dormitory food on his health. He remains awake till 3 am watching for strangers in the vicinity of his building. He has become socially withdrawn. His school performance has deteriorated. He uses marijuana occasionally. He appears restless & tense. No abnormalities on physical exam. MSE shows anxious mood with auditory hallucinations. Urine toxi screen is negative. Next step in management?
A. Biofeedback
B. Carbamezapine therapy
C. Clonzepam therapy
D. Clonidine
E. EEG
F. Exposure therapy
G. Lithium carbonate therapy (WRONG)
H. Midazolam therapy
I. Olanzapine therapy (correct--- Can someone explain reasoning?)
J. Phenobarbital therapy
K. Sertraline therapy

I was thinking he had bipolar but I guess the auditory hallucinations make schizophrenia more accurate. However, he must have schizophreniform since he has a hx of 1 month of symptoms. Do we treat schizophreniform the same way as shizophrenia?

8. Newborn male has bilateral clubfoot deformity. He was a term infant born from an uncomplicated preg and delivery. Immediately after birth he did not move his lower extremities. He did not cry when he received a needle stick to his heel. On exam: he is vigorous; moves his upper extremities but not his lower extremities. Bladder is palpable and full. Dx?
A. Cerebral Palsy (WRONG)
B. Congenital hip dysplasia
C. Gullian barre syndrome
D. Muscular dystrophy
E. Spinal dysraphism (correct - please explain why?)

Can someone please tell me the features that make this a spinal dysraphism scenario vs a cerebral palsy vignette?

9. Unconscious 22 yo M ER- 5 min after having a 10 min generalized tonic clonic seizure. He was running a marathon when he became disoriented and had a seizure. Temp 105 F, HR 120, resp 22, BP 90/50. Dry hot skin is seen on exam. Insertion of Foley catheter shows red brown urine; urinanalysis shows 4+ hemoglobin, 4+ myoglobin, 2+ RBCS. Most appropriate next step to prevent acute nephrotoxic renal failure in this patient?
A. N-Acetylcysteine therapy
B. Allopurinol
C. IV 0.9% saline (correct -please explain why?)
D. Low dose dopamine therapy
E. Mannitol therapy (WRONG)
F. No preventive measures are indicated

Isn't mannitol used to prevent rhabdomyolysis by increasing urine flow rate and decreasing the duration of contact between myoglobin and the renal tubular cells?

10. 32 yo F ER- 2 day hx of vomiting, diarrhea, right sided pelvic pain. LMP was 3 weeks ago. Temp 102.2 F, HR 100, resp 20, BP 120/70. RLQ tenderness with rebound on abd exam with decreased bowel sounds. Pelvic exam shows right adnexal tenderness. Pregnancy test is negative. Labs:
Hb 12, leukocyte ct 15,000, segmented neutrophils 80%, bands 10%, lymphocytes 5%, monocytes 5%.
U/S shows no adnexal mass. Dx?
A. Adnexal torsion (WRONG)
B. Appendicites (correct - can someone please explain why it is appendicitis and not adnexal torsion?)
C. Bowel obstruction
D. Corpus luteum cyst
E. Degenerating leiomyoma uteri
F. Ovarian cancer
G. Ovarian hyperstimulation syndrome
H. Tubo-ovarian abscess
I. Urinary tract infection
 

Nabin

7+ Year Member
Jun 8, 2012
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My two cents on the questions. I may be wrong regarding my explanations.

1. MS = demyelination of CNS axons involving oligodendrocytes, GBS: demyelination of peripheral axons involving Schwann cells
2. Elderly patient. has comorbidites, had a recent surgery, a good candidate for heat stroke even with minor exertions. Malignant hyperthermia from anesthetic use would occur immediately after the surgery. CK would not be elevated so much in anticholinergic toxicity.
3. Amphetamine toxicity would present with a lot of sympathetic activation features. Nothing is given here. F/H/O depression in two relatives, I think this clue should not be overlooked. He has depressive features too.
4. Dental cleaning: Viridans strep IE
5. Don't think E. coli cause pneumonia that too often. Always look for S. pneumoniae first. Since this dude is gram -ve H. influenzae would be the next best bet.
6. Presentation of cholangitis would be much more severe even requiring emergency decompression, with high fever, chills, leukocytosis. Mild icterus probably stems from the pigmented gallstones in this patient with Sickle cell.
 

Nabin

7+ Year Member
Jun 8, 2012
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Status
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7. In bipolar look for goal-directed activity. Similar treatment of both schizophreniform disorder and schizophrenia.
8. Usually cerebral palsy is diagnosed with insidious developmental milestones over time in early childhood. So, here best bet would be a congenital deformity.
9. Giving fluid first is always a safe option in any patient provided there is no very good indication for something else. More so here when you want to prevent ischemic (edit: nephrotoxic) ATN resulting from myoglobinuria. Give some fluids and keep up the renal perfusion as the best initial thing here.
10. U/S shows nothing here.
 
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Nabin

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Jun 8, 2012
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Edit: I realized after reading again in question number 6. The slight increase seen in bilirubin is due to breakdown of abnormal RBCs in the RE system.
 

britesky89

2+ Year Member
Apr 6, 2015
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Thanks Nabin!! Really appreciate your explanations!

I have a question about number 2 though. Someone explained this patient as developing post viral pneumonia superimposed on the flu. Is this a good explanation? Flu symptoms include athralgias/myalgias, cough, fever, headache & sore throat, nausea/voming/diarrhea. Out of those this patient only has fever and cough. Is that enough to conclude that this patient had the flu?
 

Nabin

7+ Year Member
Jun 8, 2012
138
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Status
  1. Medical Student
Thanks Nabin!! Really appreciate your explanations!

I have a question about number 2 though. Someone explained this patient as developing post viral pneumonia superimposed on the flu. Is this a good explanation? Flu symptoms include athralgias/myalgias, cough, fever, headache & sore throat, nausea/voming/diarrhea. Out of those this patient only has fever and cough. Is that enough to conclude that this patient had the flu?

Not really, I think. Temperatures more than 106 F is a medical emergency and suggests heat stroke, probably non-exertional in this frail elderly patient with comorbidities and other physiological stresses. A temperature of 100 F before symptom onset could have been a cold. This is also a stressor and aggravated the situation for the guy. Non-exertional heat strokes should be suspected in elderly patients with chronic illnesses. The elevated CK is a very important clue to use here.

About the flu, look for sudden onset high fevers around 102/103 with myalgias, headache etc. If an elderly had the flu and his temperature reads >105 F, its still a heat stroke, non-exertional type.
 

britesky89

2+ Year Member
Apr 6, 2015
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  1. Medical Student
I'm sorry I meant number 5. The one with H. influenzae as the answer. Can you tell me if that is a post influenza pneumonia. Post viral pneumonia is usually caused by strep pneumo, staph aureus, or H.influenzae.
 
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Nabin

7+ Year Member
Jun 8, 2012
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I'm sorry I meant number 5. The one with H. influenzae as the answer. Can you tell me if that is a post influenza pneumonia. Post viral pneumonia is usually caused by strep pneumo, staph aureus, or H.influenzae.

I was wondering why the flu came in here!

In a post-viral pneumonia case, you'd find a history beginning with a viral symptoms going on for a few days and then the patient starts to deteriorate with productive cough, dyspnea and chest pain. In this case, there is a history of chest pain to note from the beginning itself of his given 3 day history. So, its pneumonia from the beginning.
 
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britesky89

2+ Year Member
Apr 6, 2015
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I was wondering why the flu came in here!

In a post-viral pneumonia case, you'd find a history beginning with a viral symptoms going on for a few days and then the patient starts to deteriorate with productive cough, dyspnea and chest pain. In this case, there is a history of chest pain to note from the beginning itself of his given 3 day history. So, its pneumonia from the beginning.


Thanks Nabin!! That really helps !
 
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