Acute post-streptococcalGN- Pediatrics

Question 1

DD of hematuria (A++)

Answer 1

Pathological (Hem positive) :
- Haemoglobinuria; due to destruction of
RBCs as in case of acute haemolysis like
favism
-Myoglobinuria; In case of muscle injury as myositis or crush injury

Non-pathological (Hem negative)
-Foods colourings e.g beet roots
-Drugs e.g Rifampicin
-Urate crystals
-pink nappies in infants
-Fictitious; consider if no cause was found

Question 2

Defintion of PSGN (C)

Answer 2

An immunologic response of the kidney to infection with nephritogenic strain of group A-β haemolytic streptococci.

Question 3

pathogenesis of PSGN (C)

Answer 3

Streptococcal infection after a latent period → produce antibodies → antigen plus antibodies in the presence of complement (C3) → produce an immune complex that are trapped in the glomeruli and induce acute glomerular inflammation which cause the followings:
* Glomerular endothelial damage → loss of RBCs in urine ± proteins.
* Proliferation of mesangial and endothelial cells → obstruction of glomerular capillaries → ↓↓ glomerular blood flow → which ↓↓ GFR resulting in oliguria and fluid retention → hypervolemia (oedema) → hypertension

Other cause of hypertension is that ↓↓ GFR → activates the juxtaglomerular apparatus → activates renin angiotensin system → hypertension

Question 4

Clinical presentations of acute PSGN (A++)

Answer 4

• Microscopic haematuria
• Macroscopic haematuria
• Classical triad of oliguria, haematuria and hypertension
• Classical presentation plus one of the complications
• One of the complications

Question 5

Classical clinical presentation of PSGN (A++)

Answer 5

• Non-specific: headache, vomiting, and abdominal pain.
• Specific
  o Haematuria: usually mild, painless, range from weak tea to cola coloured, and rarely growth haematuria.
  o Oliguria: urine output < 1 ml/kg/hour or < 400 ml/m2
  /day.
  o Hypertension: transient, mild to severe.
  o Oedema: mild periorbital puffiness (↑↑ in the morning) and pretibial oedema.
• Manifestations of complications
  o Heart Failure due to hypertension or hypervolemia.
  o Hypertensive encephalopathy due to acute hypertension → punctate cerebral haemorrhage & oedema
  o Acute renal failure: due to rapidly progressive (crescentic) GN.

Question 6

Diagnosis of PSGN (A)

Answer 6

1. Urine analysis:
   * Colour: cola coloured or gross haematuria.
   * Volume: Oliguria.
   * Specific gravity: High
   * Proteinuria: mild (< 1gm/dl), if severe → nephritic nephrosis (10 -20%)
   * Microscopic examination: RBCs casts (pathognomonic to glomerular bleeding)
2. Blood analysis: -
   * Low serum complement 3.
   * Evidence of recent streptococcal infection:
   o Throat or skin lesion swab culture
   o Positive ASOT (may be negative after skin infection)
   o Anti-Deoxyribonuclease B titre (Anti- DNase B).
   * CBC: showed dilutional anaemia.
   * Renal function test → (may be impaired)
   * Electrolytes: may be hyperkalaemia & dilutional hyponatremia.
3. Renal biopsy: is indicated
   * Severe renal failure requiring dialysis
   * Severe hypertension
   * Features of systemic illness.
   * Unresolving Acute GN:
   o Abnormal renal function > 2 weeks
   o Hypertension, haematuria or massive proteinuria > 4 weeks
   o Low C3 > 8 weeks

Question 7

Treatment of PSGN (A++)

Answer 7

• Bed rest plus course of penicillin→ For 10 days.
• Diet →
  o Salt restriction
  o Fluid restriction: in oliguria to avoid hypervolemia and the intake = urine out-put + insensible loss (400m/m2/d)
  o Potassium & protein restriction: only with renal failure.
• Hypertension:
  o Mild to moderate:
  Fluid restriction, frusemide, plus one of captopril (ACE inhibitors) or amlodipine or nifedipine.
  o Severe hypertension:
  ▪ IV frusemide, plus one of
  ▪ Hydralazine, or IV Diazoxide or IV infusion of Na nitroprusside
• Treatment of complications:
  o Heart failure: according to the cause → control of blood pressure in hypertensive HF and give diuretics ± dialysis in hypervolemic HF.
  o Acute renal failure; conservative and dialysis if indicated.
• The patient can be discharged to home if there is no gross haematuria, normal renal function and controlled blood pressure

Question 8

Causes of generalized edema in children (A)

Answer 8

-Cardiac:
e.g heart failure
History of heart disease, dyspnea and tachycardia

-Hepatic:
e.g liver cell failure
Jaundice, ascites and abdominal pain

-Nutritional edema:
History of chronic diarrhoea, feature of malnutrition, skin changes

-Renal; nephrotic syndrome:
History of renal problem, frothy urine and decreased urine output

-Angioneurotic edema:
History of drug intake or ingestions