14-year-old male with sudden left-sided weakness

Cardiology

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Case Presentation

A 14 years old boy is referred with sudden-onset left-sided hemiparesis that began 6 hours ago. His mother reports a 3-year history of progressive exertional dyspnea and easy fatigability, for which he was repeatedly treated with salbutamol inhalers at a local clinic under a diagnosis of refractory asthma. Two weeks ago, he had a mild diarrheal illness and has since been poorly hydrated. On examination, he is afebrile but has marked central cyanosis and Grade 3 digital clubbing. Oxygen saturation is 76% on room air, rising only to 79% on high-flow oxygen. Neurological exam confirms left-sided hemiplegia (power 1/5). Cardiovascular exam reveals a prominent left parasternal heave and a palpable, loud, single second heart sound (P2). No murmurs are audible. Complete blood count shows a hemoglobin of 21.8 g/dL and a hematocrit of 66%. Mild conjunctival icterus is noted.

Question

What is the most likely underlying cardiovascular syndrome explaining both his chronic hypoxia and acute neurological deficit, how do you reconcile the absent murmur with this diagnosis, and what common therapeutic misstep must be strictly avoided during his acute stabilization?

Answer

The patient has Eisenmenger syndrome (likely secondary to a large congenital systemic-to-pulmonary shunt like a VSD or PDA) complicated by an acute ischemic stroke. The stroke is driven by a combination of hyperviscosity from reactive polycythemia (Hb 21.8 g/dL) and paradoxical embolism, where a venous clot crossed directly into the systemic circulation through the reversed shunt. The absence of a murmur is a classic finding; as pulmonary vascular resistance rises to equal or exceed systemic resistance, the pressure gradient across the defect disappears, eliminating the turbulent flow that generates a murmur. The mild icterus is a red herring caused by increased bilirubin turnover from the massive red cell mass. During acute stabilization, routine therapeutic phlebotomy (venesection) must be strictly avoided despite the high hematocrit, especially since he is dehydrated; abrupt volume depletion will worsen hyperviscosity, compromise systemic perfusion, and increase the stroke volume deficit. The immediate priority is meticulous intravenous hydration with normal saline to correct dehydration while monitoring for fluid overload.

Clinical Pearl

In cyanotic congenital heart disease, the disappearance of a murmur is a sign of clinical worsening (Eisenmenger syndrome), not improvement. Never perform phlebotomy for reactive polycythemia in a dehydrated patient, as this precipitously increases the risk of stroke; prioritize volume-for-volume fluid resuscitation first.