What is the best course of treatment for a patient with G6PD deficiency, presenting with cough, colds, watery diarrhea, and vomiting after eating corn?

Management of Acute Gastroenteritis with G6PD Deficiency

This patient requires supportive care with oral rehydration therapy, symptomatic treatment for cough and cold, and strict avoidance of oxidative stressors that could trigger hemolytic crisis in G6PD deficiency. 1, 2

Immediate Management Priorities

Gastroenteritis Treatment

• Provide oral rehydration solution for the 4 episodes of watery diarrhea to prevent dehydration, which is critical as metabolic stress can precipitate hemolysis in G6PD-deficient patients 1, 2
• Test stool for Giardia antigen or PCR, as Giardia is a common cause of watery diarrhea with excellent test performance (>95% sensitivity and specificity) 3
• Avoid routine ova and parasites testing unless there is travel history to high-risk areas, as yield is extremely low in chronic diarrhea without travel 3
• Monitor for signs of dehydration including decreased urine output, lethargy, and dry mucous membranes, as dehydration itself can stress red blood cells 3

Upper Respiratory Symptoms

• Treat cough symptomatically with supportive measures including hydration and humidified air 3
• Consider viral upper respiratory infection as the most likely cause given the 4-day duration without fever 3
• Avoid empiric antibiotics unless bacterial infection is strongly suspected, as many antibiotics can trigger hemolysis in G6PD deficiency 4

Critical G6PD-Specific Precautions

Medications to ABSOLUTELY AVOID

The following seven medications have solid evidence for causing hemolysis and must be strictly prohibited: 4

• Dapsone
• Methylthioninium chloride (methylene blue)
• Nitrofurantoin
• Phenazopyridine
• Primaquine
• Rasburicase
• Tolonium chloride (toluidine blue)

Safe Medications for Symptom Management

For pain, fever, or anxiety management, the following are safe in normal therapeutic doses: 2, 4

• Benzodiazepines for anxiety
• Codeine and codeine derivatives for cough suppression
• Acetaminophen for fever (if develops)
• Ibuprofen in standard doses
• Fentanyl if severe pain

Food Protein-Induced Enterocolitis Syndrome (FPIES) Consideration

The vomiting after eating corn raises concern for FPIES, which requires specific diagnostic criteria: 3

• Major criterion: Vomiting 1-4 hours after corn ingestion without IgE-mediated symptoms (no urticaria, wheezing, or angioedema) 3
• Minor criteria needed (at least 3 of 9): repetitive vomiting episodes, extreme lethargy, marked pallor, need for emergency care, need for IV fluids, diarrhea within 24 hours, hypotension, or hypothermia 3
• If only single episode, viral gastroenteritis is more likely, and oral food challenge should be considered to confirm FPIES diagnosis 3
• If FPIES confirmed, eliminate corn from diet completely and monitor for resolution of symptoms 3

Monitoring Requirements

Watch for Hemolytic Crisis Signs

G6PD-deficient patients can develop acute hemolysis triggered by infections, even without drug exposure: 1, 5

• Monitor for dark urine (hemoglobinuria)
• Watch for increasing pallor or jaundice
• Assess for extreme fatigue or lethargy
• Check for tachycardia or tachypnea

Infection-Related Considerations

Severe G6PD deficiency can cause recurrent infections due to impaired neutrophil function and decreased reactive oxygen species production 5

• This patient's respiratory symptoms may reflect underlying immunodeficiency associated with severe G6PD deficiency 5
• Consider DHR (dihydrorhodamine) assay if infections become recurrent to evaluate neutrophil function 5

Common Pitfalls to Avoid

Do not assume all medications are unsafe - many drugs have been wrongly cited as causing hemolysis because they were given during infection-related hemolytic episodes 4

Do not overlook infection as a hemolysis trigger - the current viral illness itself poses oxidative stress risk, independent of medications 1, 2

Do not dismiss the corn-vomiting association - while single episodes are often viral, FPIES should remain on differential, especially if pattern repeats 3

Do not use proton pump inhibitors empirically for vomiting in this acute setting, as this appears to be acute gastroenteritis rather than GERD-related chronic symptoms 3