UWorld Block 2 Flashcards
Clonidine mechanism
å-2 adrenoreceptor in brainstem resulting in reduced sympathetic. outflow from CNS leading to decrease in peripheral vascular resistance, heart rate and BP.
Eastern USA and central america mycosis
Blastomyces
Filtered load ,excretion rate , reabsorption rate, secretion rate
Filtered load : GFR X [plasma]
Excretion rate: V X [urine]
Reabsorption rate= filtered load- excretion rate
Secretion rate: excretion rate- filtered load.
Postoperative urinary retention
Anasthesia and analgesia contribute to :
-over distention of bladder, decreased micturition reflex
-decreased contractility of detrusor muscle and incomplete empyting.
Contraction of detrusor is stimulated by muscharinic cholinergic agonist (eg bethanecol)
Large friable vagitations on valve cusps along with destruction of valve leaflets
Mitral stenosis due to infective endocarditis.
Acyclovir mechanism of action
In infected host cells, acyclovir (a neucleoside analogue) is converted into acyclovir monophosphate —> acyclovir triphosphate –> competes with deoxygunanosine triphosphate for DNA polymerase.—> acyclovir triphosphate incoporated into replicating viral DNA—> DNA synthesis stops.
Hepatitis B serological markers
- HBsAG: detectable during acute infection, persistence implies chronic infection.
- Anti-HBs: appearance indicates resolution of acute infectionor vaccination. (Long term immunity)
- Anti HBc IgM: present during windows phase when both HBsAg and anti-HBs are absent,
- Anti HBc IgG: not present after vaccination. Present in both acute and chronic.
- HBeAg: marker of high viral replication in chronic infection
- Anti-HBe: presence in chronic infection indicates low viral replication and infectivity.
Phenylpherine effect on bladder
It encourages the trigone and sphincter to contract. –> urinary retention .
Endocarditis with intact valve, etiology
S.aureus
Doest vasectomy affect the volume of ejaculation
Semen is composed primarily of fluid secreted from the seminal vesicles and prostate, spermatozoa consists onlt of 2-5% of semen by volume.
Fungal cell wall- target for which antifungal
Major polysacharide component of fungal cell wall is 1,3 beta D glucan.
Caspofungin and other “fungin” anti fungals blocks glucan synthesis.
They are especially effective against candida and aspergillus.
What is the most common cause of mitral stenosis
Rheumatic fever
Celiac disease presentation
Diarrhea, weight loss , and abdominal pain. Some patients presents with constipation.
Paraclinical : elevated serum transglutaminase
Microglia in post-stroke
As neurons disintegrate their fragments begin to be phagocytosed by microglia. The abundance of lipids seen in the cytoplams of the microglia results from extensive phagocytosis of myelin breakdown products.
Ependymal cells are
Cilliated glial cells that lines the ventricles of the brain and the central canal of the spinal cord.
Urge incontinence drugs
Anticholinergic such as oxybutyinin
Case: Paroxysmal hypertension, flushing, diaphoresis, and episodic headache
Pheochromocytoma
Coccidiosis immitis :clinical
- pulmonary form : flu-like illness, cough ,erythema nodosum.
- disseminated: affects skin, bones, and lungs.
Subflacine herniation
Cingulate gyrus herniates under the falx cerebri, potentially compressing the ACA.
Galactosemia: enzyme affected
Glactose 1 phosphate uridyl transferase defeciancy (galt)
Normal :galactose –> galactose 1 phosphate –> glucose 1 phosphate .
Galactosemia: galactose 1 phoshpate __X__ —> glucose 1 phosphate.
This means accumulation of galactose 1 phosphate.
Cat scratch disease
Bartonella henselae (bacillary angiomatosis) (pic)
In case of portal hypertension signs with normal liver in biopsy the most likely cause would be
Portal vein thrombosis
Reduced ß-globin synthesis results in
- microcytic microchromic anemia
- precipitation of unpaired å chain within red cell precursors in the bone marrow (ineffective erythropoiesis) and lysis of circulating erythrocytes (extravascular hemolysis)
Blastomyces
Culture 25˙ : branching hyphae,
biopsy: large round yeast with doubly refractile wall and single broad based bud.