Beriberi

Disease caused by vitamin B1 (thiamine) deficiency, classically divided into dry beriberi (neurologic form with peripheral neuropathy) and wet beriberi (cardiac form with high-output heart failure). Severe thiamine deficiency can also lead to Wernicke–Korsakoff syndrome (CNS complications).

• Thiamine is an essential cofactor in glucose metabolism (pyruvate dehydrogenase, TCA cycle), so deficiency leads to energy failure (especially in brain and heart) and buildup of lactate. Beriberi is life-threatening but preventable: untreated B1 deficiency causes irreversible neurologic damage (e.g., Korsakoff psychosis) or fatal heart failure, yet it can be rapidly cured with thiamine. It frequently appears on exams in malnourished patients (e.g., chronic alcoholics or famine victims) who show dramatic improvement after thiamine therapy.

• Dry beriberi: symmetric peripheral neuropathy (legs > arms) with numbness, tingling, burning sensation, loss of reflexes, weakness, and muscle wasting (no edema). Patients may have difficulty rising from a squat or walking (e.g., foot drop).
• Wet beriberi: neuropathy plus cardiovascular involvement. Presents as a dilated cardiomyopathy leading to high-output heart failure (tachycardia, warm extremities, bounding pulses, wide pulse pressure) with edema, distended neck veins, and cardiomegaly. Can progress to circulatory collapse (fulminant Shoshin beriberi).
• Wernicke–Korsakoff syndrome: in severe B1 deficiency (especially in alcoholics), Wernicke encephalopathy manifests with acute confusion, ataxic gait, and ophthalmoplegia (eye movement palsies, nystagmus). Untreated, it can lead to Korsakoff syndrome – chronic irreversible memory loss, confabulation, and personality change.
• Infantile beriberi: occurs in young infants (2–4 months) breastfed by a thiamine-deficient mother. Babies present with fulminant heart failure (tachycardia, cyanosis, labored breathing), a weak or absent cry (aphonia), and vomiting. Fatal unless thiamine is given promptly.
• At-risk groups: Chronic alcoholics (poor intake plus malabsorption), populations eating mostly polished rice or highly processed grains, patients after bariatric surgery or prolonged hyperemesis, and those on prolonged TPN (IV nutrition) without thiamine. Deficiency can develop within weeks to a few months of inadequate intake.

1. Maintain a high index of suspicion: in any malnourished or alcoholic patient with neuropathy, heart failure, or unexplained neurologic symptoms, consider thiamine deficiency (beriberi). Do not wait for tests—treat empirically if suspected.
2. Diagnosis is clinical. Laboratory confirmation (if needed) can be done by measuring blood thiamine levels or erythrocyte transketolase activity (low in B1 deficiency and increases after adding thiamine). Often, a rapid improvement after thiamine administration essentially confirms the diagnosis.
3. If Wernicke encephalopathy is suspected (e.g., an alcoholic with confusion/ataxia), give IV thiamine immediately – before any glucose infusion – to prevent precipitating or worsening acute neurologic damage. Never give IV glucose first in a thiamine-deficient patient.
4. Manage associated problems: support cardiac function (oxygen, blood pressure support, diuretics if needed for pulmonary edema) while thiamine takes effect. Evaluate for other concurrent deficiencies (malnourished patients often lack multiple vitamins/electrolytes) and correct them.

1. Replenish thiamine: administer high-dose thiamine (e.g., 100 mg IV daily for days) as soon as deficiency is suspected. IV route is used for acute cases (Wernicke's or severe beriberi); oral supplements for milder chronic cases. Always give thiamine before or with any glucose in at-risk patients.
2. Provide supportive care: for cardiac failure, use appropriate measures (e.g., diuretics for edema, oxygen) while awaiting thiamine's effects. In infantile beriberi, prompt thiamine often produces dramatic improvement within hours. Monitor inpatients closely (e.g., ICU if heart failure or encephalopathy is severe).
3. Address the cause and prevent recurrence: improve nutrition (balanced diet, vitamin supplements), treat alcoholism (rehab, vitamins), and ensure any IV nutrition is fortified with B1. Prognosis: cardiac function usually recovers fully if treated early; neuropathy improves over time. However, if deficiency has led to Korsakoff psychosis (memory loss), that aspect is often permanent.

• Beri-beri comes from Sinhalese for 'I cannot, I cannot', describing the profound weakness caused by this disease.
• Wet vs. Dry: Wet beriberi = fluid overload (edema, heart failure); Dry beriberi = no fluid overload (neuropathy without edema).
• Wernicke's encephalopathy can be remembered by CAN of beer – Confusion, Ataxia, Nystagmus in an alcoholic. Korsakoff syndrome is the permanent amnesia with confabulation that often follows Wernicke's.
• Thiamine (B1) is needed for ATP production (enzymes: Alpha-ketoglutarate dehydrogenase, Pyruvate dehydrogenase, Transketolase). No B1 → no ATP, especially damaging to high-energy organs like brain and heart.

• Any suggestion of Wernicke's encephalopathy (even mild confusion or ataxia in an at-risk patient) is a medical emergency – give IV thiamine immediately. Delaying treatment can lead to coma or permanent brain injury.
• Do not administer glucose without thiamine in a severely malnourished or alcoholic patient—this can precipitate acute beriberi or Wernicke's. Always provide thiamine supplementation first when refeeding.
• Breastfed infants of thiamine-deficient mothers can deteriorate rapidly. A floppy, tachycardic infant with heart failure signs should receive empiric thiamine while diagnostic evaluation is underway.

1. At-risk patient (alcohol use disorder, severe malnutrition, etc.) with symptoms of neuropathy or heart failure → suspect thiamine deficiency (beriberi).
2. If neurologic signs like confusion, ataxia, or ocular palsies are present, act fast: administer IV thiamine (before glucose) for possible Wernicke's encephalopathy.
3. Draw labs (thiamine level, lactate, etc.) if possible, but do not wait for results; start treatment based on clinical presentation.
4. Continue daily thiamine replacement (IV or high-dose oral) and monitor for improvement. Neurologic symptoms may start improving within days; cardiac failure improves rapidly with thiamine.
5. Once acute issues are addressed, ensure nutritional rehabilitation: a balanced diet (or supplements) to prevent recurrence; correct other deficiencies; address underlying causes (e.g., alcohol cessation, food fortification).

• Malnourished individual (e.g., refugee relying on polished rice) with progressive leg numbness/weakness, difficulty walking, plus tachycardia, dyspnea, and bilateral leg edema → wet beriberi (thiamine deficiency).
• Chronic alcoholic with confusion, unsteady gait, and nystagmus → Wernicke encephalopathy from thiamine deficiency (treat immediately with IV thiamine before glucose).
• An infant (3 months old) exclusively breastfed by a malnourished mother, presenting with irritability, cyanosis, tachycardia, an enlarged heart, and a barely audible cry → infantile beriberi (thiamine deficiency).