week 10- renal 2 Flashcards
• Acute renal failure (ARF):
o Aka acute kidney injury (AKI)
o =GRF abruptly ↓ (w/i 48hrs) →sudden retention of normally cleared endogenous and exogenous metabolites (urea, K, PO4, SO4, creatinine, drugs)
o High risk: DM2, HTN, geriatrics
o General presentation (variable): Azotemia (N&/V, malaise, altered sensorium), Arrythmias from hyperkalemia, Ecchymoses dt plt dysfxn, Pericardial effusion, cardiac tamponade, Sz dt electrolyte imbalance, Fasciculations and mm cramps, Perioral paresthesias dt hypocalcemia, Peripheral edema (↑wt), Skin pallor, Hyper/hypovolemia
• Pre-renal ARF, causes, ssx:
o MC (60% community-acquired): inadequate perfusion to KD dt inadequate circulation or volume o ↓intravascular vol= Hemorrhage, dehydration, ↑diuresis, extravascular space sequestration, pancreatitis, burns, trauma, peritonitis o Change in vascular resistance= Sepsis, anaphylaxis, drugs (ACE inhibitors, NSAIDs, epi, norepi, cyclosporine), RAS o ↓CO= CHF, pulm emb, pericardial tamponade o SSX: Dehydration, thirst, dizziness, mental status change, Poor skin turgor, collapsed neck veins, dry mucous membranes, orthostatic BP
• Pre-renal ARF work-up:
o Oliguria (↓400ml/d), emergency! If ↓100 mL (anuria), SG >1.018
o Normal urine osm (>500 mOsm/kg), Urine Na ↓10 mEq/L, FENa ↓1%
o BUN/creatinine >20:1 (azotemia)
o UA: No changes in urine sediment, no protein, cells or casts
o MRI or doppler US: Locate and assess vascular abnormality
o CXR: to evaluate CHF
• Renal (intrinsic) ARF, causes:
o Dt injury in renal tubules, interstitium, vasculature or glomeruli
o mc ATN (80%), ischemic or toxic
o ATIN (10-15%)
o Acute GN (eg PIGN, RPGN)
o Acute PN
o Vascular dzs: vasculitis, polyarteritis nodosa
o Nephrotic syndrome (mult causes)
• Renal ARF ssx, work-up:
o Ssx: vary w cause: Hx URI, diarrhea, use of Abx or IV drugs; Back pain, gross hematuria, fever (PN), Maculopapular rash (interstitial nephritis), Dehydration and shock
o UA: SG ↓1.012, Urine osm ↓350 mOsm/kg, Urine Na >40 mEq/L, FENa >1%
o Variables: Granular casts=ATN, GN, ATIN; WBC casts=PN; RBC casts=PIGN; Eosinophiluria=ATIN
o CBC: ssx anemia, infx
o CMP: ↑ BUN, Creatinine, ratio ↓10:1
o Cystatin C: ↑ when creatinine is still N (early in course)
o ↓serum complement, circulating immune complexes
o Renal bx shows characteristic changes
• Post-renal ARF, causes, ssx:
o urinary flow from both KDs obstructed → ↑nephron intraluminal back pressure, ↓GFR o Causes: BPH, tumors of bladder, prostate, cervix or pelvic area, urolithiasis, renal V stenosis, neurogenic bladder; post-surgical or trauma; anticholinergic drugs o SSX(depend on cause): Renal pain and tenderness, lo abd pain, post-surgery urine leak, edema, ileus w abd distention, enlarged prostate on DRE, distended bladder
• Post-renal ARF work-up, management:
o Lab: normal urine osm, ↑BUN and creatinine, crystals or hematuria
o US: mb hydronephrosis
o Cystoscopy: mb utereral obstruction
o CT or MRI: mb mass causing obstruction
o Manage: mb Refer for dialysis; Find and treat cause, assess pt vitality; Monitor Vitals, input/outputs, electrolytes, BUN/creatinine
• Chronic renal failure, ssx:
o Aka ESRD or “chronic kidney dz” CKD
o = ↓ KD clearance of certain solutes → retain fluids/toxins, progress over mos-yrs. Difficult to identify onset and predict course
o ARF may →irreversible CRF
o General SSX: HTN, edema, osteodystrophy, anemia of chronic dz, uremia
• Causes of CRF:
o Glomerulopathies: Primary: FSGS, IgA nephropathy, membranous nephropathy; Secondary: diabetic nephropathy, amyloidosis, heroin abuse, PIGN, SLE
o Tubulointerstitial nephritis: Drug hypersensitivity, heavy metals, analgesic nephropathy, chronic PN
o Heredity: PKD, Alport syndrome
o Obstructive nephropathy: Prostate dz, nephrolithiasis, retroperitoneal tumor, congenital
o Vascular: Hypertensive nephropathy, RAS
• Ssx of uremia (CRF):
o General: Fatigue, weakness; Sallow-appearing
o Skin: Pruritis, easy bruising; Pallor, ecchymosis, edema
o ENT: Metallic taste, epistaxis; Urinous breath
o Eye: Pale conjunctiva
o Pulm: SOB; Crackles, pleural effusion
o CV: DOE, retrosternal pn on inspiration; HTN, cardiomegaly, friction rub
o GI: Anorexia, N/V, hiccup
o GU: Nocturia, impotence; Isosthenuria
o Neuromuscular: Restless legs, numbness, cramps in legs
o Neuro/MSE: Irritability, poor concentration, depression; Stupor, asterixis, myoclonus, peripheral neuropathy
• Labs for CRF:
o Microalbuminuria (N = ↓20 mg/L, abN >50), WBCs, waxy casts,
o Proteinuria: magnitude predicts rate of progression of ESRD
o Blood: total protein, electrolytes, BUN /creatinine, reticulocytes; Spot check Alb/creatinine (want ↓30)
o Hypercholesterolemia (>400 mg/dl); Anemia, met acidosis, ↓Ca, ↑K, ↑P
o ANA (SLE), Cystatin C (cysteine proteinase inhib) (filtered, not secreted)
o Estimate GFR with serum creatinine
• Imaging for CFR:
o US: BL small kidney, cortical thickness
o Xray: slow bone growth, osteomalacia, renal osteodystrophy
o Avoid contrast dyes
• Staging of CRF:
o 0: Risk factors for CRF (HTN, DM), GFR ≥90 w/o albuminuria; Every 6 mos: check BP, microalbumin, creatinine, HbAIC
o 1: KD damage w N GFR (≥ 90 w albuminuria); tx cormorbid dz
o 2: Ki damage w mild ↓GFR (60-89); Estimate progression
o 3: Mod ↓GFR (30-59); Tx complications
o 4: severe ↓ GFR (15-29); prep for replacement
o 4: KD failure, GFR ↓15, replacement, dialysis
• Renovascular dos:
o Benign hypertensive arteriolar nephrosclerosis
o Renal artery stenosis/occlusion
o Renal vein thrombosis
• Benign hypertensive arteriolar nephrosclerosis
o Chronic HTN damages microvasculature, glomeruli, tubules, interstitial tissues → nephrosclerosis. Over years may → ESRD (common!)
o Risk factors: aging, poorly controlled HTN, DM, African-Americans
• Renal artery stenosis/occlusion
o stenosis of one or both renal a (atherosclerosis): → refractory HTN, abd bruit o occlusion (thromboembolism): → flank pain, abd pain, fever, N/V, hematuria. Mb ARF; Seen on CT angiography
