What is the initial treatment approach for acute glomerulonephritis?

Initial Treatment Approach for Acute Glomerulonephritis

The initial treatment for acute glomerulonephritis is primarily supportive care focused on managing hypertension, fluid overload, and edema, with antibiotics (penicillin or erythromycin) added specifically for post-streptococcal cases to reduce antigenic load, even without active infection. 1, 2

Immediate Assessment and Stabilization

Determine the Underlying Cause

• Post-streptococcal glomerulonephritis (PSGN) is the most common form in children and requires specific antibiotic therapy 1, 3
• Look for history of pharyngitis (1-2 weeks prior) or impetigo (4-6 weeks prior) 1
• Check complement levels: low C3 with normal C4 strongly suggests PSGN 1
• Consider kidney biopsy if diagnosis is uncertain, presentation is atypical, or C3 remains low beyond 12 weeks 1

Antibiotic Therapy (For PSGN Only)

• Administer penicillin regardless of whether active infection is present to decrease streptococcal antigenic load 1, 2
• Use erythromycin if the patient is penicillin-allergic 1
• First-generation cephalosporins (like cephalexin) are appropriate alternatives for non-anaphylactic penicillin allergies 1
• During outbreaks, use systemic antimicrobials to eliminate nephritogenic strains from the community 1

Supportive Care Measures (All Forms of Acute GN)

Fluid and Sodium Management

• Restrict sodium intake to <2.0 g/day to control hypertension and fluid retention 1
• Monitor fluid status closely and adjust intake based on edema and blood pressure 1, 2

Hypertension Control

• Use diuretics as first-line agents for both hypertension and fluid overload 1, 2
• Add additional antihypertensive medications as needed to achieve target blood pressure 1
• Monitor for diuretic-related complications including hyponatremia, hypokalemia, GFR reduction, and volume depletion 1

Metabolic Management

• Treat metabolic acidosis if serum bicarbonate is <22 mmol/L 1
• Consider treating dyslipidemia in patients with nephrotic syndrome, particularly those with cardiovascular risk factors 1

Monitoring Requirements

Laboratory Surveillance

• Regular assessment of kidney function (serum creatinine, eGFR) 1, 2
• Monitor blood pressure closely 1
• Track proteinuria using albumin-creatinine ratio or protein-creatinine ratio 1
• Follow hematuria resolution 1
• Recheck C3 complement levels at 8-12 weeks in PSGN cases; persistently low C3 beyond 12 weeks warrants kidney biopsy to exclude C3 glomerulonephritis 1

Escalation of Care

Indications for Dialysis

• Severe acute kidney injury unresponsive to medical management 1, 2
• Life-threatening fluid overload or pulmonary edema 2
• Severe uremia 4

Immunosuppressive Therapy

• Reserve corticosteroids and immunosuppression for crescentic PSGN or rapidly progressive glomerulonephritis only 1, 2
• This approach is based on anecdotal evidence and should be considered only in severe cases with extensive crescent formation 1
• For most patients with idiopathic immune complex glomerulonephritis presenting with eGFR <30 mL/min per 1.73 m², supportive care alone is recommended 1

When to Perform Kidney Biopsy

• Diagnostic uncertainty 1
• Atypical presentation 1
• Persistently low C3 beyond 12 weeks 1
• Rapidly progressive glomerulonephritis 1, 3
• Severe azotemia or unresolving disease 2

Common Pitfalls to Avoid

• Do not withhold antibiotics in PSGN even if no active infection is detected; the goal is to reduce antigenic load 1, 2
• Do not use immunosuppression routinely; it is reserved only for crescentic or rapidly progressive disease 1, 2
• Do not assume all acute GN is post-streptococcal; consider IgA nephropathy, lupus nephritis, IgA vasculitis, and ANCA-associated vasculitis in the differential 5, 2
• Do not delay kidney biopsy when presentation is atypical or when C3 remains low beyond 12 weeks 1
• Do not overlook life-threatening complications including hypertensive encephalopathy, heart failure from volume overload, and severe acute kidney injury requiring dialysis 2, 3