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7 Renal: RF-Glomer D
Step Up to Medicine, Chap 5: Renal Failure, Proteinuria/Hematuria, Golmerular Dz
Question | Answer |
---|---|
Definition of acute renal failure (ARF). | Rapid decline in renal f'n with an increase in serum Cr (relative increase of 50% or absolute of 0.5-1.0). |
What is azotemia? | Elevated BUN and Cr. |
MCC of ARF? | Prerenal failure |
Etiology of prerenal failure? | Decrease in systemic arterial blood volume or renal perfusion (e.g., hypovolemia, CHF, peripheral vasodilation, obstruction of renal aa) |
Classic BUN: serum Cr ratio in prerenal failure? | >20:1 (kidney is able to reabsorb urea) |
Urinary findings in prerenal failure? | Oliguria is ALWAYS present to conserve volume |
Urine osmolality in prerenal failure? | >500mOsm (increased b/c kidney is able to reabsorb water) |
Urine sodium findings in prerenal failure? | Decreased urine Na <20mEq/L with FENa <1% (Na is avidly reabsorbed) |
Classic BUN: serum Cr ratio in intrinsic renal failure? | <20:1 (kidney not able to absorb urea as well as in prerenal failure) |
Urine osmolality findings in intrinsic renal failure? | Decreased <350mOsm (b/c renal water reabsorption is impaired) |
Urine sodium findings in intrinsic renal failure? | Increased urine Na (>40mEq with FENa >2%) b/c kidneys unable to retain sodium for volume retention |
Pathophysiology of postrenal failure? | Obstruction of urinary tract causing increased tubular pressure (urine can't be excreted) which leads to decreased GFR. |
3 basic tests for postrenal failure. | 1. Physical exam (palpate bladder) 2. US (look for obstruction and hydronephrosis) 3. Catheter (look for urine) |
Hyaline casts on UA suggest which type of renal failure? | Prerenal |
MCC of postrenal failure? | Urethral obstruction secondary to enlarged prostate (BPH) |
A dipstick + for protein (3+) suggests which type of renal failure? | Intrinsic due to glomerular insult |
What do RBC casts on UA indicate? | Glomerular disease |
What do WBC casts on UA indicate? | Renal parenchymal inflammation |
What do fatty casts on UA indicate? | Nephrotic syndrome |
What imaging study should be ordered on all pts presenting with ARF? | Renal US (look for obstruction; both diagnostic and therapeutic) |
MC mortal complications in pt presenting with ARF? | Hyperkalemic cardiac arrest and pulmonary edema. |
What does this urine sediment indicate?: benign sediment with few hyaline casts | Prerenal |
What does this urine sediment indicate?: "muddy brown" cases, renal tubular cells/casts, granular casts with trace protein | ATN (intrarenal) |
What does this urine sediment indicate?: dysmorphic RBCs, RBCs with casts, WBCs with casts, fatty casts with 4+ protein and 3+ blood | Acute glomerulonephritis |
What does this urine sediment indicate?: RBCs, WBCs, WBCs with casts, eosinophils, 1+ protein, 2+ blood | Acute interstitial nephritis |
Name 4 reasons for ordering dialysis in a pt with ARF. | 1. Symptomatic uremia 2. Intractable acidemia 3. Hyperkalemia 4. Volume overload |
MCC chronic renal failure? | Diabetes |
What does this urine sediment indicate?: broad casts (more than 2-3 WBCs in diameter) | Chronic Renal Failure |
What role do ACE-i play in the treatment of chronic renal failure? | Dilate efferent arteriole and reduce risk of progression to ESRD b/c they slow progression of proteinuria (when used early). Use very carefully b/c they can cause hyperkalemia. |
What tx is used to correct hyperphosphatemia in CRF? | Calcium citrate (binds Ph) |
What tx is used to correct anemia in CRF? | Erythropoeitin |
Tx for pruritus in CRF? | Capsaicin cream or cholestyramine and UV light |
Absolute indications for dialysis? | Acidosis (metabolic), Electrolytes (hyperkalemia), Intoxication (methanol, ethylene glycol, aspirin, lithium), Overload (hypervolemia), Uremia (clinical; uremic pericarditis) (AEIOU) |
Is Cr level an absolute indication for dialysis? | NO! |
What is first use syndrome? | Chest pain, back pain, and rarely, anaphylaxis, which may occur immediately after a pt uses a new dialysis machine |
Definition of proteinuria. | Urinary excretion of >150mg protein/24h |
Urine protein in nephrotic syndrome? | >3.5g/day |
MCC of nephrotic syndrome in children? | Minimal change disease |
3 key features of nephrotic syndrome? | 1. Proteinuria 2. Hypoalbuminemia (liver can't keep up with urinary loss of proteins) 3. Hyperlipidemia (increased hepatic synthesis of LDL and VLDL in attempt to make more protein to replace what's being lost) |
Role of ACE-i in treating symptomatic proteinuria? | Decrease urinary albumin loss |
What vaccinations should be given to pts with proteinuria? Why? | Influenza and pneumovax. Increased risk of infection due to loss of Ig in urine |
Gross painless hematuria is a sign of what? | Bladder or kidney cancer (until proven otherwise) |
Name 4 medications which can cause hematuria. | 1. Cyclophosphamide, 2. Anticoagulants, 3. Salicylates, 4. Sulfonamides |
If suspicion for malignancy is high in case of hematuria, what should you order? | Cytoscopy to evaluate bladder, regardless of cytology results |
MC glomerular cause of recurrent hematuria? | IgA nephropathy (most commonly diagnosed in young men) |
MCC of nephritic syndrome? | Poststreptococcal glomerulonephritis |
HTN is associated with which syndrome-- nephritic or nephrotic? | Nephritic |
MCC of nephrotic syndrome in adults? | Membranous glomerulonephritis |
Hypercoagulable state and hyperlipidemia are associated with which syndrome-- nephritic or nephrotic? | Nephrotic |
Tx for glomerular disease? | Steroids and cytotoxic agents |
Fusion of foot processes on electron microscopy. Dz? Tx? | Minimal change disease (nephrotic). Steroid therapy. |
Thickening of glomerular capillary walls. Secondary form due to infection, drugs, neoplasm, or lupus. | Membranous glomerulonephritis |
MCC of glomerular hematuria. Dz? Findings on EM? | IgA nephropathy (Berger's disease). Mesangial deposition of IgA and C3 seen on EM. |
Membranoproliferative glomerulonephritis is usually due to what type of infection? | Hep C |
MCC of nephritic syndrome? | Poststreptococcal glomerulonephritis; commonly occurs after infection with group A beta-hemolytic strep infection of upper respiratory tract or impetigo |
Classic triad seen in Goodpasture's syndrome? | Proliferative glomerulonephritis (usually crescentic), pulmonary hemorrhage, and IgG anti-glomerular basement membrane antibody |
Clinical features: fever, myalgia, rapidly progressive renal failure, hemoptysis, cough, and dyspnea. Dz? | Goodpasture's syndrome |
MCC acute interstial nephritis? | Acute allergic reaction to medication (penicillins, NSAIDs, diurectics, anticoags, phenytoin, sulfonamides) |
Which infections tend to cause AIN, especially in children? | Strep and legionella pneumophilia |
What finding in urine suggests AIN? | Eosinophilia |
What is the nature of the acidosis in renal tubular acidosis? | Non-anion gap hyperchloremic metabolic acidosis. GLomerular f'n is normal |
Which type of renal tubular acidosis should not have bicarb as a treatment? | Type 2/proximal (problem is that proximal tubules can't reabsorb bicarb, so it will just get excreted in urine). Only use bicarb in type 1 (distal). |
Which type of renal tubular acidosis results in hyperkalemia? | Type 4 only (other types have hypOkalemia) |
Rash, fever, acute renal insufficiency, and eosinophilia. Dx? | Acute interstitial nephritis |
AR disease with defective amino acid transporter leading to decreased reabsorbtion of neutral AA like tryptophan--> nicotinamide deficiency. Disease? Clinical findings? | Hartnup syndrome. Pellagra: dermatitis, dementia, diarrhea. Also ataxia and psych disturbances. |
Hereditary or acquired proximal tubule dysfucntion that leads to defective transport of glucose, AA, sodium, potassium, phosphate, uric acid, and bicarb. | Fanconi's syndrome |
Fanconi's syndrome is associated with which type of renal tubular acidosis? | Type 2 |