05.21.2015 UWorld Notes Flashcards
MS=autoimmune disease that causes demyelination, inflammation, gliosis in CNS. How does this affect bladder?
Loss of CNS control of micturition leads to detrusor hyperreflexia/overactivity and urge incontinence.
As disease progresses, bladder because atonic and dilated leading to overflow incontinence (involuntary continuous urinary leakage and incomplete emptying).
Blood sugar >250 would cause osmotic diuresis due to hyperglycemia. Glycosuria would be present too.
Rhonci and wheezing are signs of tubulent airflow secondary to airway obstruction (asthma/bronchiolitis).
Atopic asthma or viral bronchiolitis. Treat with?
Ribavirin (nucleoside analog that inhibit synthesis of guanine nucleotides and is active against RSV and hepatitis C virus.
Oseltamivir=Inhibitor of influenza A and B viral neuraminidases.
Ganciclovir=anti-herpesvirus guanine nucleoside analgoue that is similiar to acyclovir. Great activity against CMV DNA polymerase.
Lamivudine=anti-retroviral nucleoside reverse transcriptase inhibitor used to treat HIV
Amantadine=impiared uncoting of influenza A after host cell endocytosis.
Interferon alpha released by eukaryotic cells naturally. Pharm use: Hep B and C viruses.
Tonsillectomy, Great Lakes outdoor trip, KOH prep reveals large yeast cell with single bud. When incubated at 24C, grows multicellular structure with branching, tubular cells. Difference between dimorphic and yeasts?
Dimorphic form hyphae in ambient temperatures (25-30C) and yeasts are single cells at body temperature (37C).
Blastomyces dermatitidis: Ohio and MS River valleys, Great lakes region. Found in soil. Pneumonia. Biopsy: Large round yeasts with doubly refractile wall and single broad based bud. Branching hyphae at 25C.
Sporothrix schenckii: Gardening, thorn prick, pustules ulcers, nodules along lymphatics. Branching hyphae at 25C. Round or cigar shaped budding yeasts.
Cooccidioides immmitis: Southwest US; mold in soil. Pulmonary: Flu like illness, cough, erythema nodosum. Disseminated: Skin, bone, lungs. At 37 forms thick walled spherules filled with endospores.
Histoplasma capsulatum: Ohio and MS River valley. Soil, bird, bat droppings, chicken coops, caves. Pulmonary: Granulomas with calcificiations; like TB. Disseminated: Lungs, spleen, liver. Biopsy: Oval yeast cells in macrophages.
Paracoccidioides brasiliensis: Central and South America. Mucocutaneous: Chronic ulcers can progress to lymph nodes and lungs. Biopsy: Cells covered in budding blastoconidia.
Other no dimorphic fungi:
Aspergillus: Immunocompromised patients
Candida: Budding yeast/pseudohyphae. Immunocompromised.
Cryptococcus neoformans: Meningitis in AIDs patients. India ink stain of CSF reveals encapsulated yeast.
Malassezia furfur: Cutaneous mycosis (hypopigmented skin patches). KOH shows short hyphae and spores (spaghetti and meatballs).
Rhizopus, mucor, absidia: Saprophytic fungi that cause mucormycosis in immunosuppressed. Paranasal infection in DKA patients.
Hypocalcemia, hyperactive jaw jerk reflex. Chvostek’s sign (facial muscle contraction elicited by tapping on facial nerve anterior to ear).
Serum calcium levels
HIV polyprotein precursors (gag, pol, env)
Env is glycosylated to become gp160 which is proteolytically cleaved in endoplasmic reticulum and Golgi apparatus to form gp120 and gp41. gp120 mediates viral absorption by binding to CD4 receptor of susceptible cells.
Cortisol doesn’t have direct effect on vascular reactivity. It augments vasoconstrictive effects of catecholamines. Admin of NE alone produced some vascular reactivity however when cortisol was added, vascular reactivity markedly increased.
Effect is permissive.
Administration of cortisol allows NE to achieve full vasoconstrictive potential. Cortisol increases transcription of several genes which play a role in modifying NE vascular activity.
Additive: When combined effect of two drugs is equal to sum of effects expected from individual drugs. When combined effect exceeds sum of individual drug effects: Synergistic.
Reactive arthritis. Classic triad: Conjunctivitis, nongonococcal urethritis, arthritis.
HLA-B27; 1-4 weeks after primary infection cause urethritis or enteritis and caused by autoimmune reaction.
Skin findings: Keratoderma, blennorrhagicum (hyperkeratotic vesicles on palms/soles) and circinate blanitis (annular dermatitis of glans penis). Sacroilitis can occur in 20% of cases.
Hep B lab findings
HBsAg appears before onset of sx and peaks when patient is most ill. Undectable in 3-6 months.
HBeAg and HBV DNA can be detected in serum and are markers of active viral replication. HBeAg predicts infectivity.
Anti-HBcIgM appear shortly after sx.
Anti-HBe and Anti-HBs are IgG.
Chronic HepB=no anti-HBe and persistent levels of HBsAg, HBeAg, and HBV DNA.
Vaccination: anti-Hbs; no anti-HBc, anti-HBe, or viral Ag.
Thalamic syndrome
Vascular lesion of thalamus results in damage to VPL and VPM causing complete contralateral sensory loss. Severe proprioceptive defects that lead to unsteady gait and falls. Incomplete/partial lesions=abnormal painful sensations on affected side of body.
Internal capsule lesion would cause motor deficit.
Ischemic events in pons: Coma, bilateral paralysis, decerebrate rigiditiy, pinpoint pupils, death.
Damage to caudate nucleus: Transient hemiparesis and fontral lobe symptoms like forgetfulness, agitation, psychosis, coreoathetosis, dyskinesia.
Small vessel lipohyalinosis
Small cavities in basal ganglia, posterior limb of internal capsule, pons and cerebellum are lacunar infarctions. Occlusion of small penetrating arteries that aupply these structures. Happens in uncontrolled HTN and DM.
Lipohyalinosis and microatheromas are the primary cause of lacunar infarcts. Lipo=loss of arterial architecture, foam cells, fibrinoid vessel necrosis. Microatheromas=lipid laden macrophages in intima of vessel.
Malignant cell infiltration would cause space-occupying lesion rather than small cavity. Center of large tumor may form cavity due to insufficient perfusion with resultant necrosis.
Oligodendrocyte apoptosis=Multiple sclerosis. Pink patches in white matter tracts.
Common peroneal nerve
Lateral neck of fibula. Divides into deep peroneal and superficial peroneal. Damage to common peroneal occurs via compression or leg fracture: Inability to dorsiflex foot.
Femoral nerve: Largest nerve in lumbar plexus and innervates muscles of anterior and medial thigh. Damage to femoral nerve results in loss of knee jerk.
Tibial nerve: Popliteus and flexors of foot. Difficulty with plantar flexion.
Radial nerve: Wrist drop.
Pudendal nerve: Pelvic floor muscles.
Lateral sural cutaneous: Cutaneous branch of tibial that supplies sensation to calf.
Fenoldopam
Manage hypertensive emergency: Requires immediate but gradual blood pressure reduction over minutes to hours to minimize target organ damage. Selective dopamin receptor agonist with no effect on alpha or beta receptors. Activates adenyly cyclase and raises intraceullar cAMP resulting in vasodilation of arterial beds. Significant reduction in SVR. Stimulation of dopamine receptors in kidneys not only improves renal blood flow but leads to increased sodium and water excretion. Improves renal perfusion while lowering bp.
IV therapy necessary to allow immediate effects.
Hydralazine and diazoxide: Arterial vasodilators. Do not improve renal perfusion. Cause reflex sympathetic activation which increases HR and CTY and sodium and fluid retention.
Nitroprusside is most effective agent for most cases of hypertensive emergency. Slight reflex sympathetic activation and modest tachycardia/sodium/fluid retention. Risk of cyanide toxicity with prolonged use, high doses, and renal insufficiency. Cannot be used in pregnancy.
Pyrazinamide: Works best against intracellular organisms and requires acidic environment.
Most bactericidal to M. TB that is engulfed by macrophages. Other first line agents for MTB (isoniazid, rifampin, ethambutol) have better activity against extracellular MTB than PZA.
Isoniazid inhibits synthesis of mycolic acid. Cell walls.
Ethambutol inhibits cell wall synthesis.
Rifampin inhibits DNA-dep RNA polymerase
Thiazide diuretics
Associated with hypercalcemia, hyperglycemia, hypercholesterolemia, hyperuricemia, hypoonatremia, hypokalemia.
Familial hypocalciuric hypercalcemia: Defective Ca sensing by PT and renal tubule cells. Hypercalcemia with normal to high serum PTH. FHH will have low urinary Ca excretion.
Primary hyperparathyroidism: Increased Ca and elevated PTH levels.
Secondary hyperparathyroidism: Due to chronic renal failure and malabsorption of vitamin D. Hypocalcemia and elevated PTH levels.
Eastern Europe, night sweats, cough, low grade fever
TB
Candida in sputum indicates that oral cavity is colonized. Common contaminant of sputum cultures.
