Question

A 7-year-old boy presents with periorbital puffiness, cola-colored urine, and elevated blood pressure. He develops altered sensorium and seizures. What is the most likely cause of his encephalopathy?

• A. Hypertensive encephalopathy
• B. Uremic encephalopathy
• C. Hypoglycemia
• D. Hypernatremia

Hint:

Seizures + Cola-colored urine + High Blood Pressure in a school-aged child = Hypertensive Encephalopathy PRES secondary to PSGN. First-line therapy: IV Labetalol + IV Furosemide!

Answer 1

The Correct Option is A

Concept:
Post-streptococcal glomerulonephritis (PSGN) causes acute nephritic syndrome characterized by a sudden reduction in glomerular filtration rate (GFR), causing sodium and fluid retention and acute volume overload.
Acute severe hypertension in this setting can rapidly exceed the autoregulatory capacity of the cerebral circulation, precipitating acute neurological crisis.
Explanation:
• The child exhibits classic features of acute post-infectious glomerulonephritis: periorbital edema, gross hematuria (cola-colored urine), and fluid overload-induced systemic hypertension.

• When systemic blood pressure rises acutely above the upper limit of cerebral autoregulation (typically mean arterial pressures $>120\text{--}140\text{ mmHg}$), cerebral hyperperfusion occurs.

• This overcomes the blood-brain barrier, leading to fluid extravasation into the cerebral interstitium, vasogenic cerebral edema (Posterior Reversible Encephalopathy Syndrome, PRES), and acute hypertensive encephalopathy.

• Clinically, hypertensive encephalopathy presents with severe throbbing headache, visual disturbances (blurring, cortical blindness), altered consciousness, and generalized tonic-clonic seizures.

• Uremic encephalopathy occurs in advanced, end-stage chronic uremia (blood urea nitrogen $>100\text{ mg/dL}$) with metabolic flapping tremor (asterixis) rather than sudden-onset acute seizures during early nephritic presentation.

• Immediate treatment involves parenteral antihypertensive therapy (e.g., labetalol, nicardipine, or sodium nitroprusside) and IV loop diuretics (furosemide) to reduce fluid overload.
Final Answer:
The development of seizures and altered sensorium in an acutely hypertensive child with acute nephritic syndrome is due to hypertensive encephalopathy.