What are the characteristics of Gastrointestinal (GI) beriberi?

Characteristics of Gastrointestinal Beriberi

Gastrointestinal beriberi is a distinct clinical presentation of thiamine deficiency characterized by severe abdominal pain, intractable nausea and vomiting, lactic acidosis, and potential cardiovascular collapse that can mimic a surgical emergency but responds dramatically to intravenous thiamine within hours. 1

Core Clinical Features

Primary Gastrointestinal Manifestations

• Severe, persistent abdominal pain that may mimic acute surgical conditions requiring emergency intervention 1
• Intractable nausea and vomiting lasting weeks to months, refractory to standard antiemetic therapies 2, 3
• Anorexia as a prominent early symptom that contributes to progressive nutritional decline 3
• These gastrointestinal symptoms may be the sole presenting features in mild thiamine deficiency, occurring before classic neurological or cardiac manifestations develop 3

Systemic Complications

• Profound lactic acidosis without other clear metabolic explanation, often accompanied by anion gap metabolic acidosis 1, 2
• Hemodynamic instability including hypotension and cardiogenic shock requiring vasopressor support 1
• Cardiac hypokinesis representing overlap with "wet beriberi" cardiovascular involvement 1
• Altered mental status ranging from lethargy to confusion, which may progress rapidly 1, 2
• Bilateral lower extremity weakness indicating concurrent peripheral neuropathy ("dry beriberi" features) 2

High-Risk Clinical Contexts

Predisposing Conditions

• Chronic gastrointestinal illness with malabsorption, particularly Crohn's disease or other inflammatory bowel conditions 4
• Total parenteral nutrition (TPN) without adequate thiamine supplementation, especially when multivitamin infusions are discontinued 4
• Prolonged vomiting from any cause leading to poor oral intake and thiamine depletion 2
• Post-bariatric surgery patients with persistent vomiting, rapid weight loss, or poor dietary compliance 5

Important Clinical Pitfall

• Gastrointestinal beriberi can occur in well-nourished, non-alcoholic patients without traditional risk factors, making the diagnosis easily missed 1
• Oral multivitamin supplementation may be inadequate in patients with malabsorption, even when prescribed as replacement for intravenous formulations 4

Diagnostic Approach

Clinical Recognition

• Suspect gastrointestinal beriberi when gastrointestinal symptoms (abdominal pain, nausea, vomiting) are refractory to usual therapies and no other cause is identified 3
• The combination of unexplained abdominal symptoms, cardiogenic shock, and lactic acidosis should immediately raise suspicion 1
• Classic Wernicke's encephalopathy triad (ophthalmoplegia, ataxia, confusion) may be absent or incomplete, particularly in early or predominantly gastrointestinal presentations 3

Laboratory and Imaging Considerations

• Thiamine level measurement has cost and time limitations; diagnosis based on clinical presentation and therapeutic response is often more practical 6
• MRI may show characteristic abnormalities in brainstem, thalamus, and mammillary bodies if neurological involvement is present 4
• Rule out other causes of lactic acidosis, shock, and abdominal pain through standard workup 1, 2

Treatment Response

Immediate Therapeutic Intervention

• Administer intravenous thiamine immediately (100-300 mg daily) when clinical manifestations suggest beriberi, without waiting for laboratory confirmation 6, 5
• For patients with predisposing factors (persistent vomiting, malabsorption, TPN), prophylactic thiamine should be given 5
• Never administer glucose before thiamine repletion due to risk of precipitating or worsening thiamine deficiency 5

Expected Clinical Course

• Dramatic improvement occurs within hours of intravenous thiamine administration 1, 3
• Hypotension and cardiovascular instability typically resolve first, often within hours 1
• Gastrointestinal symptoms (nausea, vomiting, abdominal pain) improve rapidly, usually within 24 hours 3
• Mental status and neurological deficits recover over days to weeks with continued supplementation 2, 4
• This rapid therapeutic response serves as both diagnostic confirmation and life-saving treatment 1

Critical Clinical Pearls

• Gastrointestinal beriberi represents a forme fruste (incomplete form) of Wernicke's encephalopathy where GI symptoms predominate 3
• The condition is potentially fatal if unrecognized but completely reversible with prompt thiamine replacement 6, 1
• Consider small intestinal bacterial overgrowth (SIBO) if oral thiamine supplementation fails, as this may impair thiamine absorption 5
• In bariatric surgery patients, thiamine deficiency symptoms (ataxia, confusion, coma, neuropathy, cardiac insufficiency with tachycardia) warrant immediate treatment without delay for test results 5