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Neurology
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EDUCATION
Emory Pediatric Neurology Teaching Syllabus
Emory University School of Medicine
Atlanta, Georgia U.S.A, 404-727-5756
Acute Renal Problems
Leonard C. Hymes, M.D.
Division of Nephrology
Department of Pediatrics-Emory
- Acute Renal Failure
Definition: Sudden decrease in GFR as demonstrated by a rise in serum creatinine and BUN
Pathogenesis Diagnosis Management
- Acute Renal Failure Pathogenesis
- Pre Renal Azotemia
- Renal parenchymal injury and acute renal failure have not occurred
- Physiologic response to reduced renal perfusion: Dehydration, heart failure, septic shock
- Mediated by ADH, aldosterone and prostaglandins
- Obstructive Uropathies
- Hydronephrosis by imaging studies
- Frequently associated with U.T.I.
- Examples: Posterior urethral valves, ureterocele, VUR, urolithias, tumors
- Tubular-Interstital Disease
- Injury to renal interstitium and tubules
- Ischemic: ATN, vasomotor
- Infiltration: Leukemia
- Toxic: Myoglobinuria, antibiotics
- Glomerular-Vascular
- Usually associated with hematuria and hypertension
- Acute Glomerulonephritis: PSAGN, SLE, Henoch-Schonlein Purpura
- Vascular: HUS, DIC
- Acute Renal Failure Management
- Hypervolemia
- Fluid restriction to IWL
- IWL = 400 cc/meter sq
- Electrolyte free
- Diuretics: Usually ineffective
- Nutrition
- Acute renal failure is a catabolic event
- Daily restrictions: Na and K = 2 grams and Protein = 2 grams / kg
- Renal supplements: Suplena ; Low Na, K and P; high caloric density 500 cal/8oz
- Ca Carbonate or Ca Acetate
- Cacitriol (Rocatrol or Calcijex IV)
- Infection
- Primary infections: Post-strep AGN, hemolytic uremic syndrome, pyelonephritis
- Secondary infections: In-dwelling catheters- bladder, central venous, peritoneal: Staph aureas, fungal
- Antibiotics should be chosen very carefully
- Dose modification for renal failure
Monitor peak and trough levels
- Removal by dialysis
- Uremia
- Symptomatic azotemia
- Encephalopathy
- Platelet dysfunction and bleeding
- Peripheral neuropathy
- Pericarditis
- Absolute indication for dialysis
- Peritoneal
- Hemodialysis
- CVVH (ICU)
- Electrolyte Disturbances
Hyonatremia Hypernatremia Hyperkalemia Hypocalcemia
- Hyponatremia
Dilution: Acute renal failure, nephrotic syndrome, SIADH
Depletion: AGE, Na wasting nephropathy
Spurious: Hyperlipidemia, hyperglycemia
- Dilutional Hyponatremia
- Fluid restriction
- Nephrotic Syndrome - 25% albumin + furosemide
- SIADH - Furosemide + replace 1/2 urine output with 3% saline
- Renal failure: dialysis
- Hyponatremic Dehydration
- Calculation of Na deficit = (140-Na) * TBW where TBW = 0.6 * kg
- Isotonic losses = 140 meq/L
- Example: Na 125 meq/L, weight 5 kg with 5% dehydration (.250 L)
- Na deficit = (140-125) * 0.6 * 5= 45meq
- Isotonic losses .250 * 140 = 35 meq
- Total Na needs = 35 + 45 = 80 meq
- Fluids = maintenance + deficit = 500 + 250 cc
- Totals: 750 cc + Na 80 meq
- Hyponatremia: Seizures
- Seizures may occur when Na < 120 meq/L
- Emergency management: 3% Saline 10cc/kg will raise serum Na by 13 meq/L
- Example: Na 110 meq/L, weight 3 kg Raise serum Na to 130 meq/L= 76 cc of 3% saline
- Hypernatremia
- Calculation of free water deficit (L) = Na - 150 * TBW/150 (TBW=0.60*kg)
- or 4 cc/kg to lower Na by 1 meq/L
- Example: Weight 5 kg, Na 160 meq/L
- Correct to Na 150 meq/L, free water deficit = 4cc*5kg*(160-150) = 200cc
- Correct water deficit over 48 hrs
- Hyperkalemia
- Hyperkalemia: Etiology
- Renal failure
- Primary hypoaldosterone
- Congenital adrenal hyperplasia
- Hyperkalemia: Nonurgent
- Nonurgent: Normal ECG - Kayexalate (Sodium polystyrene resin)
- Dose 0.5 to 1.0 gram/kg q 6-12 h po/pr
- May cause hyperNa
- Cardiac monitoring +/-
- May require elective dialysis
- Hyperkalemia: Urgent
- Urgent: ECG widened qrs and peaked T waves: Cardiac monitoring essential
- NaBicarbonate 1-3 meq/kg IV
- CaGluconate 10% 0.2-0.5 cc/kg IV
- Glucose 25% 2cc (0.5gm) per kg IV + insulin 0.3u per gm glucose
- Must follow with Kayexalate or dialysis
- Hypocalcemia
- Clinical findings: tetany, carpal pedal spasms, + Chevostek sign
- Treatment: IV Ca Gluconate 9% 1cc/ kg: Very dangerous drug
- Oral Ca Carbonate or Acetate
- Vit D: Calcitriol
- Hypertension
- Malignant hypertension
- Malignant hypertension: seizure, coma, cerebral infarction
- Treatment: Diazoxide 2-5 mg/kg IV or Sodium Nitroprusside continuous IV infusion
- Cranial MRI or CT
- Mild to Moderate Hypertension: Step-wise approach
- 1st Ca Channel blockers: procardia, norvasc or Diuretics: lasix, zaroxolyn
- 2nd ACE inhibitors: enalapril, prinivil, captopril
- 3rd Beta blockers: labetalol, atenalol
- 4th Angiotensin receptor blocker: losartan or Vasodilators: minoxidil
- Nephrotic Syndrome
Definition: hypoalbunemia, proteinuria, hyperlipidemia, edema
Urgent problems: anasarca and infections
- Infection
- Strep pneumonia peritonitis and pneumonia. Also gram neg rods
- Antibiotics: Cefotaxime or Vancomycin and Aminoglycoside
- Risk for infections related to multiple factors: Ascitic fluid, hypo IgG, immunosuppreesion, decreased macrophage activity
- Anasarca
- 25% Albumin 0.5 to 1.0 grams/kg q8h
- Lasix 1.0 mg/kg IV q 8h
- Monitor Na and K
- Other indication for albumin: Vascular contraction - hypotension, tachycadia, hemoconcentration, azotemia
- Gross Hematuria
- Urgent
- Trauma
- AGN with hypertension or renal failure
- Bleeding disorders
- Pain (stones, U.T.I)
- Nonurgent
- Isolated: Normal BP, renal function
- Asymptomatic: Painless, no edema
- Examples: IgAN, idiopathic hypercalciuria, thin membrane disease
- Evaluation of Gross Hematuria
- Serum electrolytes, C3C4, ASO, ANA, renal US, Urine Ca/creat
- Urinalysis with microscopic: Hematuria vs Myoglobinuria,RBC morphology
- Renal biopsy for renal failure, HBP, proteinuria, or family history.
- Urinary Tract Infections
- Cystitis vs Pyelonephritis
- Cystitis: Suprapubic pain, dysuria, afebrile, gross hematuria (Adenovirus)
- Pyelonephritis: Septic, flank pain, WBC casts , gram neg enteric organisms
- Criteria for admission based on symptoms
- Urinary Tract Infections: Evaluation
- Imaging studies in all preadolescent children after first infection:
- Renal US, VCUG
- Adolescent female: Sexual activity, pregnancy test, STD
- Adolescent male: Very rare infection, accounting for only 0. 3% of all U.T.I.
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