NBME 18 Exam Questions With 100% Correct Answers

NBME 18 Exam Questions With 100% Correct Answers A deficiency in what causes infantile neonatal RDS? - ANSWER- - lethicin - aka dipalmitoylphosphatidylcholine L/S has to be greater than 2 Patient with long history of type 1 diabetes has loose stools for 1 year. Stool shows no abnormalities. Pathophysiologic mechanism most likely for cause of diarrhea? - ANSWER- Diabetic diarrhea - type of autonomic neuropathy - occurs usually at night, is watery and painless, and can be associated with fecal incontinence - Bouts of diarrhea can be episodic, along with intermittently normal bowel habits or even alternating with periods of constipation. Ciprofloxacin use would be contraindicated if taking? - ANSWER- - calcium carbonate *Multivalent (calcium, iron, magnesium) cations decrease absorption same with doxycycline Most likely cause of primary pericarditis? - ANSWER- - Viral *more likely due to picornavirus Virus with viral particles with a wheel-like shape - ANSWER- Rotavirus Is a type of Reovirus which is: double-stranded RNA, segmented, naked, icosahedral Red pulp of spleen - ANSWER- - composed of connective tissue known as cords of Billroth and many splenic sinuses that are engorged with blood - *primary function is to filter the blood antigens, microorganisms, and defective or worn-out red blood cells* -Somone who underwent splenectomy and had a blood count showing target erythrocytes indicates a loss of function of the red pulp of the spleen greening reaction on blood agar - ANSWER- - indicates alpha hemolysis aka strep pneumo, viridans, mutans, mitts *beta hemolysis is clear on blood agar and gamma shows no hemolysis Indole test is used to differentiate between - ANSWER- - E. coli and Klebsiella - adding tryptophan to the culture, *E. coli* will split indole from tryptophan but Klebsiella won't E. coli (+)= pink Klebsiella (-)= yellow They are both gram - rods, fast lactose fermenters, and both can cause nosocomial UTIs When giving a drug that causes myelosuppression, it is most appropriate to include monitoring of what? - ANSWER- - neutrophil count When we talk about drugs that cause bone marrow suppression (Clozapine, Carbamazepine, PTU/Methimazole, Colchicine), we're mostly worried about neutropenia, leading to infections. Person will hypovolemia will have? - ANSWER- - increased sympathetic nerve traffic to the SA node via the baroreceptor reflex *Hypotension --> decreased arterial pressure --> decreased stretch --> decreased afferent baroreceptor firing --> increased efferent sympathetic firing and decreased efferent parasympathetic stimulation --> vasoconstriction, increased HR, increased contractility and increased BP* Baroreceptor is important in the response to severe hemorrhage Chemoreceptors - ANSWER- respond to changes in O2, CO2, and blood pH - *Peripheral:* carotid and aortic bodies are stimulated decreased PO2(<60 mmHg), increased PCO2 and decreased pH of blood - *Central:* are stimulated by changes in pH and PCO2 of brain interstitial fluid, which in turn are influenced by arterial CO2 Man comes in with a 6 month history of progressive SOB with exertion. History of frequent nosebleeds since adolescence. Physical exam shows petechiae and finger clubbing. Most likely cause of patient's condition? - ANSWER- - Pulmonary arteriovenous shunting Hereditary hemorrhagic telangiectasia (aka *Osler-Weber-Rendu syndrome* ) - inherited disorder (A.D.) of blood vessels - sx: blanching skin lesions (telangiectasias), recurrent epitaxis, skin discolorations, arteriovenous malformations, GI bleeding, hematuria Large vascular malformations in the lung allow oxygen-depleted blood from the right ventricle to bypass the alveoli, meaning that this blood does not have an opportunity to absorb fresh oxygen. This may lead to breathlessness. Very large AVMs cause a marked inability to absorb oxygen, which may be noted by cyanosis (bluish discoloration of the lips and skin), clubbing of the fingernails (often encountered in chronically low oxygen levels) Embryonic periods weeks 3-8 - ANSWER- - neural tube formed by neuroectoderm and closes by week 4 *Extremely susceptible to teratogens* Person is administered Heparin for treatment of DVT and a few days (usually 5-14) later has a decreased platelet count - ANSWER- Heparin induced thrombocytopenia - drug related antibodies *development of IgG antibodies against heparin bound platelet factor 4* - Antibody-heparin-PF4 complex activates platelets --> thrombosis and thrombocytopenia *If someone receiving heparin develops new or worsening thrombosis, or if the platelet count falls -->HIT* Obstructive(absorptive) atelectasis - ANSWER- - results from airway obstruction - ex: mucus, tumors, foreign bodies 0 the air within the lungs distal to the obstruction is absorbed, the lung collapses and the *mediastinum shifts toward the collapsed lung* Compression atelectasis - ANSWER- - fluid within the pleural cavity, such as seen with CHF, causes increased pleural pressure which collapses lung tissue - *mediastinum shifts away from collapsed lung* Contraction atelectasis - ANSWER- - fibrosis causes collapse of lung I- t occurs when either local or generalized fibrotic changes in the lung or pleura hamper expansion and increase elastic recoil during expiration.