How do you test an adult with intoxication-like symptoms after carbohydrate‑rich meals and no alcohol use for auto‑brewery syndrome?

Testing for Auto-Brewery Syndrome

The confirmatory test for auto-brewery syndrome is a supervised carbohydrate challenge test with serial blood or breath ethanol measurements, performed in a monitored setting where exogenous alcohol intake is impossible. 1, 2, 3

Diagnostic Protocol

Step 1: Controlled Environment Testing

• Admit the patient to a supervised inpatient unit with visitor restrictions to ensure no external alcohol access 4
• Measure baseline blood alcohol level at admission 4
• Administer a carbohydrate-rich meal or glucose load (specific amounts vary, but typically a high-carbohydrate challenge) 1, 2, 3
• Obtain serial blood or breath ethanol measurements at 2-hour intervals for up to 24 hours 4
• Positive test: elevated blood/breath ethanol levels (often >100 mg/dL) developing after carbohydrate intake without any alcohol consumption 1, 4

Step 2: Identify the Source

• Perform upper and lower endoscopy to obtain intestinal secretions for fungal culture 3
• Send samples for fungal speciation and antifungal sensitivity testing 3
• Look specifically for yeast overgrowth (commonly Candida species or Saccharomyces cerevisiae) in the gastrointestinal tract 2, 3, 5

Step 3: Assess Predisposing Factors

• Document history of prolonged antibiotic use, which disrupts normal gut flora and allows fungal overgrowth 3, 4
• Identify gastrointestinal abnormalities such as prior gastrectomy, laparotomy, intestinal obstruction, or hypomotility disorders 5, 4
• Check for conditions causing gut dysbiosis that permits pathological yeast colonization 5

Key Clinical Pearls

Timing of Symptoms

• Symptoms typically occur 30 minutes to several hours after carbohydrate-rich meals 1, 2
• Blood alcohol levels can reach 160-322 mg/dL in documented cases without any exogenous alcohol intake 4

Differential Considerations

• Rule out covert alcohol use first through the controlled monitoring protocol 4
• Consider that patients may skip meals to avoid symptoms, leading to nutritional deficiencies 2
• Be aware of medicolegal implications: patients may face DUI arrests despite genuine medical condition 2, 4

Common Pitfalls to Avoid

• Do not rely on patient history alone – patients are often disbelieved by healthcare providers and may have visited multiple centers without diagnosis 2
• Do not perform testing in an uncontrolled environment – the diagnosis requires absolute certainty that no exogenous alcohol was consumed 4
• Do not skip the endoscopic evaluation – identifying and speciating the causative organism guides appropriate antifungal therapy 3
• Do not overlook the condition in patients with positive alcohol levels who deny drinking – this is a genuine, though rare, medical syndrome 1, 5

Confirmatory Criteria

The diagnosis is confirmed when:

1. Elevated blood/breath ethanol develops after supervised carbohydrate challenge 1, 3
2. Fungal organisms are identified in gastrointestinal samples 3
3. Symptoms resolve with antifungal therapy and carbohydrate restriction 2, 3