Yes, You Should Be Concerned and Act Promptly
In an 18-year-old with MELAS syndrome who develops a cold, you must treat this as a potentially serious metabolic crisis trigger that requires aggressive supportive care and close monitoring for stroke-like episodes, seizures, and metabolic decompensation. 1
Why This Matters in MELAS
Infections—even seemingly minor ones like a common cold—can precipitate life-threatening complications in MELAS patients through several mechanisms:
- Metabolic stress from infection increases cellular energy demands that dysfunctional mitochondria cannot meet, potentially triggering stroke-like episodes, seizures, or encephalopathy 1, 2
- Fever and dehydration worsen the underlying metabolic acidosis characteristic of MELAS, creating a dangerous cascade 1
- Respiratory infections can lead to inadequate ventilation, compounding the metabolic acidosis that MELAS patients already struggle with 1
Immediate Management Steps
Supportive Care (Start Now)
- Aggressive hydration with intravenous or oral fluids to prevent dehydration and support cellular metabolism 1
- Antipyretics for fever control (avoid aspirin due to Reye's syndrome risk) 3, 1
- Enforce strict rest and avoid all physical exertion, as exercise intolerance is a cardinal feature of MELAS and exertion during illness can trigger stroke-like episodes 1, 4
Monitoring Requirements
- Watch closely for warning signs of stroke-like episodes: sudden vision changes, confusion, focal neurological deficits, severe headache, or altered consciousness 1, 2
- Monitor for seizure activity, which can occur at any age in MELAS and may be the first sign of metabolic decompensation 1
- Assess for respiratory distress or inadequate ventilation, particularly if fever is high or the patient appears lethargic 1
Laboratory Evaluation
- Check serum lactate levels if symptoms worsen, as elevated lactate is the hallmark metabolic derangement in MELAS and indicates worsening mitochondrial dysfunction 1
- Consider prophylactic antibiotics if high fever and respiratory symptoms develop, as bacterial superinfection (particularly otitis media in younger patients) complicates influenza in 25% of cases under age 5 3, 1
L-Arginine Therapy Considerations
If your son is already on prophylactic L-arginine (600 mg/kg/day for patients under 20 kg or 12 g/m² for those over 20 kg), ensure compliance during this illness. 1 If not currently on L-arginine:
- L-arginine is the primary treatment for preventing and managing stroke-like episodes in MELAS by improving endothelial function through nitric oxide-mediated vasodilation 1, 4, 2
- Consider initiating or increasing L-arginine during acute illness in consultation with your mitochondrial disease specialist 1
When to Seek Emergency Care
Go to the emergency department immediately if your son develops:
- Any focal neurological symptoms (weakness, vision loss, speech difficulty, confusion) 1, 2
- Seizures 1
- Severe headache with altered consciousness 1
- Respiratory distress or significantly increased work of breathing 1
- Persistent vomiting or inability to maintain hydration 1
Critical Pitfall to Avoid
Do not assume this is "just a cold" that will resolve on its own. 1 The metabolic stress from even minor infections can trigger catastrophic complications in MELAS, including stroke-like episodes that may cause permanent neurological damage or require decompressive craniectomy in severe cases 5. Early aggressive supportive care and close monitoring can prevent these outcomes.
Oxygen Therapy Note
If hypoxemia develops, provide adequate oxygen without hesitation. 1 Unlike COPD patients where oxygen can worsen CO2 retention, the mechanism of respiratory compromise in MELAS is fundamentally different—these patients need oxygen to support their already-compromised cellular metabolism 1.