Post-Streptococcal Glomerulonephritis
Description Diagnostic criteria General and supportive measures Medicine treatment Referral ICD-10 code: N00.9 DESCRIPTION Acute post-streptococcal glomerulonephritis (APSGN) is a disorder of the kidneys caused by an immunological response of the kidney to nephritogenic strains of streptococci. It develops one to three weeks after a streptococcal throat or skin infection. Immune complexes a
General and supportive measures
ICD-10 code: N00.9
DESCRIPTION
Acute post-streptococcal glomerulonephritis (APSGN) is a disorder of the kidneys caused by an immunological response of the kidney to nephritogenic strains of streptococci. It develops one to three weeks after a streptococcal throat or skin infection. Immune complexes are deposited in the glomerular basement membrane and/or mesangium of the glomeruli.
DIAGNOSTIC CRITERIA
Clinical
- Occurs predominantly in children 3–12 years old.
- Presents approximately 1 week after streptococcal pharyngitis OR approximately 3 weeks after skin infection (impetigo).
- Characteristic features include:
- facial or generalised oedema,
- painless macroscopic haematuria (smoky or tea coloured urine),
- oliguria, and
- hypertension.
Special investigations to confirm APSGN
| Urine analysis | |
| Macroscopic appearance | smoky, brown, bloody |
| Urine test strips | 1+ to 3+ haematuria; ~ trace to 2+ proteinuria |
| Microscopic examination | dysmorphic red blood cells; red blood cell and granular casts |
| Blood investigations | |
| Streptococcus serology ASO or Anti-DNAse B titre |
positive in the absence of prior antibiotic treatment (ASO often negative in preceding skin infections) |
| Complement study C3 C4 |
decreased normal |
| Serum biochemistry | |
| Serum electrolytes | dilutional hyponatraemia, hyperchloraemic hyperkalaemic metabolic acidosis is common |
| Serum Urea & Creatinine | mildly elevated in the acute phase |
| Full blood count | dilutional anaemia; thrombocyte count is normal |
GENERAL AND SUPPORTIVE MEASURES
- Bed rest is necessary in children with severe hypertension or pulmonary oedema.
- Monitor fluid balance and prescribe fluid on a daily basis:
- Weigh daily and record fluid intake and output strictly.
- Allowed fluid intake should be calculated based on previous day’s urine output and insensible losses.
- In small children, fluid balance is best monitored with regular weighing.
- Never use a potassium-containing solution in an anuric patient.
- Do not use parenteral fluids if oral intake is possible.
- Ensure daily fluid calculations are performed using insensible losses and previous day’s output. Fluid management according to fluid status:
- Pulmonary oedema plus oliguria/anuria: Do not give fluid.
- Hydrated anuric patient without extra-renal fluid losses: Oral fluid to replace insensible water losses only.
- Normally hydrated plus oliguria: Oral fluid intake to replace insensible water loss and urine output of previous 24 hours.
- Normally hydrated plus normal urine output: Give normal fluid intake.
IMPORTANT:
Insensible water loss is calculated as:
- Older children: 25 mL/kg/day (400 mL/m2/day)
- Dietary measures:
- Restrict sodium intake in all patients.
- Restrict potassium intake until result of serum electrolytes is available.
- Restrict protein intake to 0.5 g/kg/day.
MEDICINE TREATMENT
Eradication of streptococci:
- Phenoxymethylpenicillin, oral, 50 mg/kg/24 hours in 4 divided doses (6 hourly) for 10 days.
OR
If unable to take oral medication:
- Benzathine benzylpenicillin (depot formulation), IM, 30 000 units/kg/dose, 2 doses given 5 days apart.
- Maximum dose: 1.2 million units.
For severe penicillin allergy:
- Refer to Drug Allergy, Allergies to Penicillins.
Hypertension
Hypertension usually develops acutely due to fluid overload and presents as hypertension emergency (crisis), hypertension urgency or persistent significant hypertension. See: Cardiovascular System, Hypertension in Children.
If hypertensive emergency/crisis: Patient with signs of hypertensive encephalopathy, i.e. convulsions, retinal haemorrhages, visual loss and end organ disease e.g. left heart failure.
Management for acute hypertensive emergency/crisis due to post-streptococcal glomerulonephritis:
- Furosemide, IV, 1–2 mg/kg/dose.
If oliguric:
- Furosemide, IV, 5 mg/kg/dose.
- Administer IV bolus slowly over 5 minutes due to risk of ototoxicity.
AND
- Labetalol, IV, 0.2–1.0 mg/kg/dose as a bolus.
- Maximum bolus dose: 40 mg.
- Continue infusion: 0.25–3.0 mg/kg/hour.
- Monitor blood pressure frequently (every 30 minutes).
- Taper infusion rate up or down according to response.
If hypertensive urgency: Symptomatic patients with significant elevation of blood pressure with complaints of headache, blurred vision and nausea but lack the above clinical manifestations or persistent significant hypertension:
- Propranolol, oral, 1-2 mg/kg/dose, 6 hourly.
- Maximum dose: 8 mg/kg/24 hours.
If blood pressure is not adequately controlled:
ADD
- Amlodipine, oral, 0.2 mg/kg/dose.
- May be repeated 6 hours later, thereafter once every 24 hours.
- Maximum dose: 5 mg.
- Crush 5 mg tablet and disperse in 5 mL water: amlodipine 1 mg/mL.
Once blood pressure has normalised, taper and stop antihypertensive treatment. Monitor blood pressure over the next 48 hours to exclude rebound hypertension.
If volume overloaded:
See fluid management in general and supportive measures.
- Furosemide, slow IV, 2 mg/kg/dose.
- Maximum dose: 5 mg/kg/dose.
- Maximum cumulative daily dose: 8 mg/kg/24 hours.
If pulmonary oedema:
See fluid management in general and supportive measures.
- Morphine, IV, repeat after 4 hours if required
- < 6 months of age: 0.025–0.1 mg/kg/dose.
- ≥ 6 months of age: 0.05–0.2 mg/kg/dose.
- Oxygen, 100%, 2–3 L/minute by nasal cannula.
REFERRAL
Urgent (as soon as possible)
- Anuric patient with acute volume overload and unresponsive to furosemide.
- Uncontrolled hypertension.
- Oliguric and progressive renal failure.
- Cardiac failure or pulmonary oedema not responding to treatment.
For specialist advice
- Macroscopic haematuria persisting for more than 4 weeks or persistent proteinuria.
- Family history of renal disease.
- Streptococcal aetiology unproven (ASOT and anti-DNAse B negative, normal C3 levels, decreased C4 levels).
- Decreased complement levels which persist for more than 6 weeks.
- Persistent renal failure after initial recovery.
- Persistent hypertension.
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Standard Treatment Guidelines and Essential Medicines List for South Africa Paediatric Hospital _Chapter 6: Nephrological/Urological Disorders; 2023, 5th edition