Renal & Acid-Base confusion pairs
26 Renal & Acid-Base topics students commonly mix up on Step 1, each with the fastest separator, a side-by-side comparison, and a free practice question.
- Nephritic syndrome vs Nephrotic syndromeBlood/RBC casts and hypertension point nephritic; massive protein and lipiduria point nephrotic.Video
- Acute interstitial nephritis vs Acute tubular necrosisAIN: WBC casts, eosinophils, and a recent drug; ATN: muddy brown granular casts after ischemia or a toxin.Video
- Prerenal azotemia vs Intrinsic AKIPrerenal: FeNa under 1 percent, BUN to creatinine above 20:1, bland sediment; intrinsic AKI: FeNa above 2 percent with active sediment.Video
- SIADH vs Diabetes insipidusSIADH: hyponatremia with inappropriately concentrated urine; diabetes insipidus: hypernatremia with dilute urine and polyuria.Video
- Atherosclerotic renal artery stenosis vs Fibromuscular dysplasiaOlder vascular-risk patient means atherosclerosis; young woman with string-of-beads means fibromuscular dysplasia.Video
- IgA nephropathy vs Poststreptococcal GNIgA nephropathy: hematuria during the infection with normal C3; PSGN: hematuria 1 to 3 weeks after infection with low C3.Video
- Goodpasture syndrome vs Granulomatosis with polyangiitisGoodpasture: pulmonary-renal with anti-GBM and no ENT disease; GPA: adds sinusitis and saddle nose with c-ANCA/PR3.Video
- Minimal change disease vs FSGSMinimal change is steroid-responsive child with normal LM; FSGS is segmental sclerosis and often resistant.Video
- Membranous nephropathy vs Membranoproliferative GNMembranous is subepithelial spike-and-dome nephrotic disease; MPGN is subendothelial/mesangial tram-track mixed disease.Video
- Postrenal AKI vs Intrinsic AKIPostrenal AKI: outflow obstruction with hydronephrosis on ultrasound; intrinsic AKI: parenchymal injury with active urine sediment.Video
- Acute kidney injury vs Chronic kidney diseaseAKI is rapid and recent; CKD is persistent for months with chronic adaptation and scarring clues.Video
- Autosomal dominant polycystic kidney disease vs Autosomal recessive polycystic kidney diseaseADPKD is adult cystic kidney disease with aneurysm/liver cyst clues; ARPKD is infantile kidney-liver fibrocystic disease.Video
- Alport syndrome vs Thin basement membrane disease / IgA nephropathyAlport is hematuria plus ear/eye/progression; thin basement membrane is benign isolated hematuria; IgA is synpharyngitic hematuria.Video
- Diabetic nephropathy vs Renal amyloidosisDiabetic nephropathy is diabetes-duration nodular sclerosis; amyloidosis is Congo red-positive systemic protein deposition.Video
- Proliferative lupus nephritis vs Membranous / sclerosing lupus nephritisClasses III/IV are proliferative nephritic activity; Class V is membranous nephrotic disease; Class VI is advanced sclerosis.Video
- Hyperkalemia ECG vs Hypokalemia ECGHyperkalemia: peaked T waves progressing to a widened QRS; hypokalemia: flattened T waves with prominent U waves.Video
- Hypovolemic hyponatremia vs Euvolemic / hypervolemic hyponatremiaFirst prove hypotonicity, then use volume exam: dry is hypovolemic, normal is SIADH-type euvolemic, swollen is hypervolemic.Video
- High anion gap metabolic acidosis vs Normal anion gap metabolic acidosisHigh-gap means added acid; normal-gap means bicarbonate loss or renal acid-handling failure with chloride replacement.Video
- Respiratory acidosis vs Metabolic acidosisRespiratory acidosis is CO2 retention; metabolic acidosis is bicarbonate loss or acid gain.Video
- Distal / proximal renal tubular acidosis vs Type 4 renal tubular acidosisType 1 and type 2 RTA are hypokalemic; type 4 RTA is the hyperkalemic one, from aldosterone deficiency or resistance.Video
- Calcium oxalate / uric acid stones vs Cystine / struvite stonesEnvelope/radiopaque is calcium oxalate; acidic/radiolucent is uric acid; hexagonal is cystine; infection/alkaline/staghorn is struvite.Video
- Renal cell carcinoma vs Urothelial carcinoma of renal pelvisRenal cortical parenchymal mass means RCC; renal pelvis or collecting-system urothelial lining means urothelial carcinoma.Video
- Urothelial bladder cancer vs Squamous bladder cancerUrothelial is smoking/aromatic amine and most common; squamous is chronic irritation or Schistosoma-associated.Video
- Benign prostatic hyperplasia vs Prostate cancerBPH is smooth transition-zone obstruction; prostate cancer is hard peripheral-zone malignancy with metastatic potential.
- Lower UTI (acute cystitis) vs Upper UTI (acute pyelonephritis)Cystitis is lower tract dysuria/frequency; pyelonephritis is fever plus flank/CVA kidney involvement.Video
- Drug-induced acute interstitial nephritis vs Autoimmune acute interstitial nephritisDrug-induced AIN follows a culprit medication; autoimmune AIN follows systemic immune clues or uveitis without drug timing.Video
Renal & Acid-Base rapid reviews
Several confusion pairs per video, with chapters for each pair.