8. nephrology Flashcards
how does IV contrast cause renal failure?
vasospasm of afferent arteriole (decrease perfusion to glomeruli)
How long after an infection does post-stre glomerulonephritis occur?
1-2 weeks after infection
renal toxicity of a medication is due to the ….. of the medication
trough (space interval of medications to decrease toxicity of medication)
What is the side effect of aminoglycosides (gentamicin)?
- renal toxic
2. ototoxicity
what is the difference between azotemia and uremia?
azotemia: renal insufficiency but no need for dialysis
uremia: renal insufficiency resulting in need for dialysis
What are complications of uremia? (9)
- need for dialysis
- anemia (decrease epo production)
- hyperrkalemia
- pericarditis
- hypocalcemia (decrease active vit D)
- infections (wbc cant degranulate)
- metabolic acidosis and fluid overload (b/c cant get rid of organic)
- altered mental status
- bleeding (platelets cant degranulate)
What is the treatment for uremia induced bleeding?
DDAVP (desmospressin causes release of subendothelial stores of vWf and factor 8)
What are causes of pre-renal azotemia?
- dehydration/shock/ blood loss
- renal artery stenosis
- hepatorenal syndrome
- ACE inhibitor effect on kidney
- low albumin states (nephrotic and liver disease)
what are causes of post- renal azotemia?
- bladder stone/clot
- bladder cancer
- prostate hypertrophy/cancer
- bilateral ureteral disease (retroperitoneal fibrosis, strictures bilateral)
What is the driving force of GFR in kidney?
hydrostatic pressure in the glomeruli capillary
what is the initial clue to pre-renal azotemia?
BUN: creatinine ratio >20
b/c more time for urea to be reabsorbed b/c slow flow
What can falsely elevate BUN?
- increased protein in diet
2. GI bleeding (protein release)
what happens to urine sodium in pre-renal azotemia?
urine sodium <10 (low b/c body reabsorbs sodium to increase intravascular volume)
what happens to the urine osmolality in pre-renal azotemia?
urine osmolality is high (>500); concentrated urine
high specific gravity >1.010
A pt. presenting with hypertension with renal insufficciency most likely suffers from ……
- primary hyperaldosteronism
- renal artery stenosis
(distinguish w/ aldosterone/renin ratio)
A pt. with liver disease who develops renal insufficiency that does not respond to 1.5 litres of colloid (albumin) most likely suffers from …..
hepatorenal syndrome
What dilates the afferent arteriole of the glomeruli?
Angiotension 2
how do ACE inhibitors result in pre-renal azotemia?
inhibit conversion of angiotensin 1 to angiotensin 2 preventing constriction of efferent arteriole (results in delation of efferent arteriole)
Why is it that ACE inhibitors diminish the rate of prgression to renal failure and uremia in pts with diabetes, HTN, multiple myeloma?
dilation of efferen….> decreased hydrosttatic pressure in glomeruli..> decrease intraglomerular HTN (neverr withold ACE inhibitor)
What is the best blood pressure medication for pt with diabetes?
ACE inhibitors
What is orthodeoxia?
Change positions (sitting up) cause oxygen desaturation
What disease is associated with orthodeoxia?
hepatopulmonary syndrome
what medications can cause retroperitoneal fibrosis (leading to post - renal azotemia)?
- bleomycin (along with pulmonary fibrosis)
2. methotrexate
what chemo medication results in hemorrhagic cystitis?
cyclophosphamide
what are the most common causes of neurogenic bladder?
- diabetes
2. MS
what is the normal post-voidingg residual volume?
50ml of urine (if elevated, implies obstructtion to flow out of bladder)
what are causes of interrstitial renal insufficiency?
- allergic
- toxic
- pigments (hemoglobin/myoglobin)
- proteins (bence jones)
- crystals
A pt. with a BUN/cr of 10, high urine sodium, urine osmolarity (similar to serum osmolarity; isothenuria), and FeNa>1% most likely sufferrs from…..
acute tubular necrosis
How does NSAIDs result in pre-renal azotemia?
inhibit prostaglandins which prevent afferent arteriole dilation (results in constriction of arteriole)
What constricts the efferent arteriole of the glomeruli?
Angiotensin 2
What type of casts/ sediment is associated with acute tubular necrosis?
granular, muddy brown, pigmented cast
dead tubular cells sloughed off
What drugs can result in allergic interstitial nephritis, drug induced hemolysis, and/ or rash?
- penicillins
- cephalosporins
- sulfa drugs
- allopurinol
- rifampin
- quinolones
(1 dose can cause problem)
What medications can result in acute tubular necrosis?
- aminoglycosides (gentamicin)
2. amphotericin
A pt presents with renal insufficiency with associated fever, rash, and eosinophils most likely suffers from …
Allergic interstitial nephritis
What is the most accurate test for eosinophils in the urine?
Hansel stain (or Wright stain)
What are causes of myoglobinuria (rhabdomyloysis)?
- severe crush injury
- seizures
- statins
4, severe exertion
vere crush injury - seizures
- statins
4, severe exertion
What is the initial best step in management of a pt with severe crush injury or seizure?
EKG or potassium level (hyperkalemia causes peaked t waves)
What is the initial best test for rhabdomyolysis?
urinalysis (dipstick positive for blood but no RBCs seen)
What is treatment for rhabdomyolysis?
- hydration (decrease contact time)
- mannitol (osmotic diuretic-> decrease contact time)
- alkalinize urine w/ bicarb
What is confirmatory test for rhabdomyolysis?
elevated CPK (>10,000)
What is treatment for hyperkalemia without EKG changes?
- insulin with glucose
2. bicarbonate
What is the treatment for ethylene glycol intoxication?
- ethanol or fomepizole (prevents formation of oxalate)
2. dialysis
A pt with Crohn disease develops renal insufficiency due to …
oxalate crystals (calcium bound to fat in gut instead of w/ oxalate)
What treatment should pt with cancer being treated with chemotherapy be given to prevent urate crystal associated renal insufficiency?
allopurinol and hydration
What is the most common cause of hypercalcemia?
primary hyperparathyroidism
A pt who underwent a vascular catheter procedure (angioplasty) who develops renal failure, bluish discoloration of extremities and livedo reticularis most likely suffers from …
atheroembolic disease
