Glomerulonephritis Disease

BASICS

DESCRIPTION

An immunologic response to an infection (usually streptococcal) which damages the renal glomeruli. It can be initiated by other bacterial and viral infections. This is an immune complex, hypocomplementemic glomerulonephritis. Most common in children. Characterized by diffuse inflammatory changes in the glomeruli and clinically by the abrupt onset of hematuria with red blood cell casts, and mild proteinuria. Accompanied in many cases by hypertension, edema, and azotemia.

System(s) affected: Renal/Urologic
Genetics: No known genetic pattern
Incidence/Prevalence in USA: 20/100,000/year (1-2% of pyodermas and 8% of streptococcal infections in children; occurs with impetigo in the late summer and with streptococcal pharyngitis in the winter)
Predominant age:
- 60% of cases in children 2-12 years old
- Only 10% older than 40 years of age
Predominant sex: Male > Female (60:40)

SIGNS AND SYMPTOMS

Classic findings of acute nephritis
- Hematuria (100%)
- Oliguria or anuria (52%)
- Edema (85%)
- Hypertension (82%)
- Hypocomplementemia (C3) (83%)
- Gross hematuria (30%), tea-colored urine
- Edema of face and eyes in the am and feet and ankles in the afternoons and evenings
- Fever (rare)
Other signs and symptoms
- Pharyngitis
- Respiratory infection
- Scarlet fever
- Dark urine
- Weight gain
- Abdominal pain
- Anorexia
- Back pain
- Pallor
- Impetigo

CAUSES

Follows group A beta-hemolytic streptococcus infection
"Nephritogenic" strains of strep - groups 1, 4, 11, 12, 49 "Red Lake", 55, 60
Unusual to have a second attack - protective immunity to nephritogenic antigen
Cases of "postinfective" glomerulonephritis have also been reported from pneumococcus, staphylococcus, meningococcus, chickenpox, and hepatitis
Streptococcal infection precedes renal lesions by 1-3 weeks
Pharyngitis precedes renal lesions by 1-2 weeks (types 1, 2, 4, 12)
Impetigo (types 49, 55, 57) usually precedes throat or otitis media infection by 2-4 weeks

RISK FACTORS

15% occurrence rate after infection with nephritogenic strain
Endemic with cyclic epidemics
Subclinical cases 20 times more common
Streptococcal infection (e.g., scarlet fever or erysipelas) can be associated with rheumatic fever or acute glomerulonephritis, rarely both

DIAGNOSIS

LABORATORY

Streptococcal tests (Streptozyme) that include many antigens are most sensitive (+ or -) for screening but not quantitative
Antistreptolysin O (ASO) - quantitative titer. Increased in 60-80% of cases. Increase begins 1-3 weeks, is highest 3-5 weeks, normal in 6 months. ASO titer is unrelated to severity, duration or prognosis of renal disease.
Red blood cells casts on urinalysis:
- destroyed by centrifugation
- disintegrate in urine, particularly alkaline urine
Characteristically, red blood cells from glomerular bleeding are distorted while those from lower urinary tract have normal morphology
U/P creatinine > 40, decreased renin
Culture throat and skin lesions for streptococcus
C3 and C4 complements are best for evaluation
Streptozyme
Hypertriglyceridemia
Proteinuria
Decreased glomerular filtration rate
Uremia
Increased serum creatinine
Anemia
ANA to rule out systemic lupus erythematosus

Drugs that may alter lab results: N/A
Disorders that may alter lab results: N/A

PATHOLOGICAL FINDINGS

On renal biopsy
- Diffuse proliferative and exudative glomerulonephritis
- Electron microscopy - subepithelial deposits
- Immunofluorescence - C3 in almost all cases, some with IgG and IgM

SPECIAL TESTS

N/A

IMAGING

X-rays and/or ultrasound are not necessary to make the diagnosis

DIAGNOSTIC PROCEDURES

If progressive, consider renal biopsy. Biopsy usually not indicated.

TREATMENT

APPROPRIATE HEALTH CARE

Most patients can be safely followed as outpatients
Inpatient usually until blood pressure and creatinine normalized and edema begins to recede

GENERAL MEASURES

Decrease salt: no-added salt diet until edema and hypertension clear
Decrease fluids to insensible losses plus 2/3 of the urine output until diuresis
Control hypertension with diuretics
Dialysis: peritoneal dialysis or hemodialysis for symptomatic azotemia, unresponsive hyperkalemia, intractable acidosis, diuretic resistant pulmonary edema

SURGICAL MEASURES

N/A

ACTIVITY

Can return to full activity after clinically improved. May have increased hematuria after exercise for up to two years.

DIET

"No-added" salt diet until edema, hypertension, and azotemia clear
Restrict protein in presence of azotemia and metabolic acidosis
Avoid high potassium foods

PATIENT EDUCATION

National Kidney Foundation, 30 E. 33rd Street, Suite 1100, New York, NY 10016, (212)889-2210
Web site - www.healthanswers.com

FOLLOW UP

PREVENTION/AVOIDANCE

Treat streptococcal infections aggressively

POSSIBLE COMPLICATIONS

Hypertensive retinopathy
Hypertensive encephalopathy
Rapidly progressive glomerulonephritis
Abnormal urinalysis may persist for years (microhematuria)
Chronic renal failure (rare)
Nephrotic syndrome (approximately 10%)
Marked decline in glomerular filtration rate (rare)

EXPECTED COURSE AND PROGNOSIS

Usually self-limited to 2-3 weeks
Immediate mortality < 0.5%
Long-term: excellent in children; almost all patients recover completely
May have more morbidity in adults or in those with pre-existing renal lesions
Microscopic hematuria may persist for 24 months (or longer with complete recovery)
Proteinuria persists for up to 3 months
Symptoms can be exacerbated by an intercurrent illness but rarely after 12 months
Urine may be darker (microscopic hematuria) after strenuous exercise

MISCELLANEOUS

ASSOCIATED CONDITIONS

N/A

AGE-RELATED FACTORS

Pediatric: Common in children ages 2-16
Geriatric: N/A
Others: N/A

PREGNANCY

N/A

OTHER NOTES

N/A

ABBREVIATIONS

N/A

Clinical Investigations

ROLE OF HOMOEOPATHY

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