Question | Answer |
First sign tubule cell dysfunction | inability to concentrate urine |
Fixed specific gravity | chronic renal failure; cannot concentrate or dilute urine |
Negative urine bilirubin + trace urobilinogen | normal urine |
Positive urine bilirubin, absent urobilinogen | obstructive jaundice |
Positive urine bilirubin + increased urobilinogen | hepatitis |
Negative urine bilirubin + increased urobilinogen | extravascular hemolytic anemia |
Positive urine nitrite + positive urine leukocyte esterase | urinary tract infection |
Sterile pyuria | positive urine leukocyte esterase but negative standard culture; TB, C. trachomatis |
Prerenal azotemia | ↑ BUN and creatinine; ↓ renal blood flow (e.g. heart failure, hypovolemia) |
Renal azotemia | ↑ BUN and creatinine due to intrinsic renal disease (acute tubular necrosis) |
Postrenal azotemia | ↑ BUN and creatinine due to obstruction to urine flow |
Serum BUN:creatinine ratio | <15:1 (renal failure); >15:1 (prerenal or postrenal azotemia) |
BUN 80 mg/dL:creatinine 8 mg/dL | ratio 10/1 - renal failure |
BUN 80 mg/dL:creatinine 2 mg/dL | ratio 40/1 - prerenal azotemia or postrenal azotemia |
Creatinine clearance | measures GFR |
Proteinuria | important sign of renal dysfunction |
RBC casts | nephritic type of glomerulonephritis |
WBC casts | acute pyelonephritis, acute tubulointerstitial nephritis |
Fatty casts with Maltese crosses | nephrotic syndrome |
Hyaline casts | normal unless associated with proteinuria |
Renal tubular cell casts | acute tubular necrosis |
Waxy or broad casts | chronic renal failure |
Cystinuria | hexagonal crystals |
Horseshoe kidney | Turner’s syndrome; lower poles fused |
Renal dysplasia | MC childhood cystic disease; abnormal development; flank mass |
Maternal oligohydramnios | fetal juvenile polycystic kidney disease; Potter’s facies in newborn |
Adult polycystic kidney disease | AD; hypertension MC sign; cerebral berry aneurysms |
Visceral epithelial cells | synthesize basement membrane |
Glomerular BM | negative charge due to heparan sulfate |
Nephritic syndrome | oliguria; RBC casts; hypertension; mild to moderate proteinuria |
Nephrotic syndrome | proteinuria >3.5 g/day; ascites and pitting edema; fatty casts; fusion of podocytes |
Immunofluorescence | linear (anti-glomerular BM antibodies); granular (IC deposition) |
IgA GN | MC GN; usually nephritic; episodic hematuria; mesangial IC (lgA-anti-IgA) deposits |
Post-streptococcal GN | nephritic; subepithelial deposits; skin/pharyngeal infections; anti-DNAase B |
SLE type IV GN | nephritic; subendothelial deposits; anti-DNA antibodies |
Crescentic GN | crescents from parietal cell proliferation; worst GN; Goodpasture’s, Wegener’s |
Goodpasture’s | nephritic; anti-BM antibodies (glomerular + pulmonary capillary); crescentic GN |
S/S | young male with hemoptysis progressing to renal failure |
Minimal change disease (lipoid nephrosis) | MCC childhood nephrotic syndrome |
Lipoid nephrosis | podocyte fusion; loss of negative charge in glomerular BM |
Focal segmental glomerulosclerosis | nephrotic syndrome; AIDS and IV heroin abuse |
Membranous GN | MCC adult nephrotic syndrome; subepithelial deposits; epimembranous spikes |
Causes membranous GN | HBV, ACE inhibitors, cancer |
Type I MPGN | nephrotic; subepithelial deposits; HCV association; tram tracks |
Type II MPGN | nephrotic; C3 nephritic factor; intramembranous ICs (dense deposit disease) |
DM nodular glomerulosclerosis | microalbuminuria first sign |
DM glomerulosclerosis | nodules with collagen in mesangium; hyaline arteriolosclerosis of arterioles |
ACE inhibitors | inhibit angiotensin II vasoconstriction of efferent arterioles |
Alport’s syndrome | XD hereditary nephritis with sensorineural hearing loss |
Ischemic ATN | prerenal azotemia MCC; renal tubular cell casts; BUN:creatinine ratio <15:1 |
Ischemic ATN | disruption of BM in proximal tubule and thick ascending limb |
Nephrotoxic ATN | aminoglycosides, IVP dye, Pb/mercury poisoning |
Nephrotoxic ATN | proximal tubule dysfunction; intact BM |
Oliguria | prerenal azotemia, ATN, glomerulonephritis, postrenal azotemia |
Acute pyelonephritis | vesicoureteral reflux with ascending infection; WBC casts, fever, flank pain |
Chronic pyelonephritis | U-shaped scars overlying blunt calyces |
Drug-induced tubulointerstitial nephritis | type I/IV reaction; e.g., penicillin |
S/S | ARF, fever, rash, eosinophilia, eosinophiluria, WBC casts |
Analgesic nephropathy | aspirin plus acetaminophen; renal papillary necrosis; IVP with ring defect |
Myeloma kidney | BJ protein produces foreign body reaction in tubules |
Urate nephropathy | prevent by giving allopurinol prior to chemotherapy |
CRF | fixed specific gravity; BUN:creatinine <15:1; waxy and broad casts |
Renal osteodystrophy CRF | hypovitaminosis D (no 1-α-hydroxylase); produces osteomalacia |
Renal osteodystrophy CRF | osteoporosis from metabolic acidosis |
Renal osteodystrophy CRF | secondary HPTH with increased osteoclastic activity |
S/S CRF | pericarditis, prolonged bleeding time, normocytic anemia, pathologic fractures |
Benign nephrosclerosis | kidney of hypertension; shrunken kidneys due to hyaline arteriolosclerosis |
Malignant hypertension | renal failure; encephalopathy; BP >210/120 mm Hg; IV nitroprusside |
Renal findings | necrotizing arteriolitis; “flea bitten” kidney; hyperplastic arteriolosclerosis |
Renal infarction | pale infarcts; hematuria; common in polyarteritis nodosa |
Hydronephrosis | renal stone MCC; atrophy of cortex/medulla; postrenal azotemia |
Renal stones | most contain calcium (calcium oxalate/phosphate); hypercalciuria MC risk factor |
S/S | colicky pain radiating into groin, hematuria; x-ray usually shows stone |
Staghorn calculus | due to urease producing organisms (Proteus); alkaline urine pH; ammonia smell |
Angiomyolipoma | hamartoma; associated with tuberous sclerosis |
Renal cell carcinoma | smoking MCC; invasion renal vein/vena cava; lung, bone mets; yellow colored |
S/S | flank mass, hematuria; ectopic hormones (EPO, PTH related peptide), left-sided varicocele |
Renal pelvis transitional cell carcinoma | smoking MCC, phenacetin, aniline dyes, cyclophosphamide |
Wilm’s tumor | hypertension, unilateral abdominal mass in child; aniridia/hemihypertrophy in AD types |
Urine draining from umbilicus | persistent urachus |
Retroperitoneal fibrosis | produces hydronephrosis |
Bladder extrophy | abdominal wall defect + epispadias |
Bladder diverticula | most commonly due to prostatic hyperplasia with urethral obstruction |
Acute cystitis | E. coli; females > males; no fever, flank pain, or WBC casts |
Bladder transitional cell carcinoma | smoking MCC, aniline dyes, cyclophosphamide; papillary |
S/S | hematuria; hydronephrosis |
Bladder adenocarcinoma | risk factors persistent urachus, extrophy |
Bladder squamous cell carcinoma | Schistosoma hematobium infection |