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USMLE
Goljan Renal Path 2
Question | Answer |
---|---|
BUN:Cr ~ 10:1 with oliguria and renal tubular casts | acute tubular necrosis |
Why does acute tubular necrosis have such a bad diagnosis? | FAST. ischemic cause destroys GBM -> loss of polarity -> detachment -> necrosis. can't regenerate renal tubular cell w/o BM -> RF. Death usually during initial oliguric phase. |
What parts of nephron is most susceptible to ischemia? | straight portion of proximal tubule and thick ascending limb (medullary part). Affects Na/K/Cl co-transport |
Nephrotoxic drugs...what are they and where do they affect? prognosis? | gentamicin (aminoglycocides), dye from IV pyelograms; damages proximal tubule. prognosis good because they don't damage BM. |
How do you separate pyelonephritis from low UTIs? | acute pyelonephritis is infection of kidney proper and has fever with flank pain (CVA tenderness) and WBC casts |
what is the mechanism of all UTIs | ascending infection from introitus of urethra. |
scarred kidney with blunted calyces (beneath scarring) | chronic pyelonephritis |
fever with rash, oliguria, eosinophiluria after starting drug | acute drug-induced interstitial nephritis (methicillin) |
what kinds of hypersensitivity are associated with acute drug-induced interstitial nephritis? | combination of type I and type IV hypersensitivities |
empty space on IV pyelogram | analgesic nephropathy from acetaminophen and aspirin combo therapy long-term |
what is the mechanism of analgesic nephropathy? | acetaminophen --> produces free radicals that damage tubular cells of medulla aspirin blocks PGE2 so Angiotensin II is unopposed and peritubular capillaries have decreased blood flow causing ischemia in renal papillaries |
causes of renal papillary necrosis | aspirin/acetaminophen long-term, diabetes, sickle-cell disease, acute pyelonephritis (from abscess formation) |
BUN/Cr >10 for more than 3 months. what is the diagnosis? | Chronic renal failure |
results of chronic renal failure | anemia, anion-gap metabolic acidosis, osteoporosis, osteomalacia, secondary hyperparathyroidism |
uncontrolled essential hypertension (over ten years) causes what? | nephrosclerosis --> hyaline arteriolosclerosis (cobblestone appearance of kidney) |
person with uncontrolled HTN, wakes up with bad HA, dizzy, blurred vision, BP 240/140, papilledema and flamed hemorrhages, hard and soft exudates, BUN/Cr 80/8. what is diagnosis? | malignant hypertension (shows petechia visible on surface of kidney) |
Treatment of malignant hypertension? | IV nitroprusside |
pale, depressed-looking lesions on gross examination of kidney. what do you see on LM? | pale infarction --> coagulation necrosis |
causes of pale infarcts in kidneys in a patient with irregular irregular pulse? | A-fib, causes thromboemboli |
little white dots and microabscesses on gross exam of kidneys probably caused by what? | pyelonephritis |
hydronephrosis and increased pressure have what affect on renal cortex and medulla? | compression atrophy |
staghorn calculi, alkaline urine and smells of ammonia, what is the cause? | urease (+) bacteria: proteus, klebsiella, staph |
most common cause of compression atrophy? | stone |
what is the composition of staghorn calculi | magnesium ammonium phosphate |
mass in kidney adult what is it? | renal adenocarcinoma |
mass in kidney in kid with hypertension? | wilm's tumor |
cause of renal adenocarcinoma? | derived from proximal tubule; most common cause is smoking |
what are results of renal adenocarcinoma? | produce ectopic EPO, PTH-like peptide, and like to invade renal vein |
why hypertension in kid with Wilm's tumor? | the tumor makes renin |
findings in Wilm's tumor? | embryonic kidney structures; aniridia and hemi-hypertrophy of an extremity --> sign that Wilm's tumor has genetic basis |
genetic abnormality in Wilm's tumor? | WT-1 tumor-suppressor gene on chrom 11. AD |
most common organism in cystitis? | E. coli |