Vitamin B1 (Thiamine) Deficiency (Wet Beriberi)

Overview


Plain-Language Overview

Vitamin B1 (Thiamine) Deficiency (Wet Beriberi) is a condition caused by a lack of the essential vitamin thiamine, which is important for energy production in the body. This deficiency mainly affects the cardiovascular system, leading to problems with the heart and blood vessels. People with this condition often experience symptoms like swelling in the legs, fast heart rate, and difficulty breathing due to fluid buildup. The deficiency impairs the body's ability to convert food into energy, which is critical for heart muscle function. If untreated, it can cause serious heart failure and other complications. This condition is most common in people with poor nutrition or chronic alcoholism. Early recognition is important because the symptoms can worsen quickly.

Clinical Definition

Vitamin B1 (Thiamine) Deficiency (Wet Beriberi) is a clinical syndrome resulting from inadequate thiamine intake or absorption, leading to impaired activity of thiamine-dependent enzymes such as pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase. This causes decreased aerobic metabolism and accumulation of lactate, primarily affecting the cardiovascular system. The hallmark of wet beriberi is high-output heart failure characterized by peripheral vasodilation, tachycardia, and fluid retention with resultant edema. It is most commonly seen in malnourished individuals, chronic alcoholics, or those with malabsorption syndromes. The condition is distinguished from dry beriberi by its predominant cardiac involvement. If untreated, it can progress to severe heart failure and death.

Inciting Event

  • Dietary thiamine deficiency due to poor intake or malabsorption.

  • Excessive alcohol consumption impairing thiamine absorption and utilization.

  • Acute illness or infection increasing metabolic demand for thiamine.

  • Administration of intravenous glucose without thiamine supplementation.

Latency Period

  • Symptoms typically develop within weeks to months of thiamine depletion.

  • Rapid onset of cardiac symptoms can occur within days after glucose administration in deficient patients.

  • Chronic deficiency may cause gradual progression over several weeks.

Diagnostic Delay

  • Symptoms are often nonspecific and mimic other causes of heart failure or neuropathy.

  • Lack of awareness of nutritional deficiencies in developed countries delays diagnosis.

  • Failure to recognize alcohol use disorder or malnutrition as risk factors.

  • Overlap with other conditions such as cardiomyopathy or sepsis leads to misattribution.

Clinical Presentation


Signs & Symptoms

  • Exertional dyspnea from congestive heart failure

  • Orthopnea and paroxysmal nocturnal dyspnea due to pulmonary edema

  • Fatigue and weakness from impaired energy metabolism

  • Peripheral edema especially in lower extremities

  • Palpitations from compensatory tachycardia

History of Present Illness

  • Initial presentation includes fatigue, dyspnea on exertion, and palpitations due to heart failure.

  • Progression to peripheral edema, tachycardia, and warm extremities from high-output cardiac failure.

  • Patients may report orthopnea and paroxysmal nocturnal dyspnea.

  • Neurologic symptoms such as paresthesias or muscle weakness may be present but less prominent.

Past Medical History

  • Chronic alcohol use disorder is a common antecedent condition.

  • Malnutrition or recent weight loss from illness or surgery.

  • Gastrointestinal surgeries such as gastric bypass.

  • History of prolonged vomiting or diarrhea causing nutrient loss.

Family History

  • There are no known heritable genetic syndromes directly causing wet beriberi.

  • Family history may reveal nutritional deficiencies in populations with poor diet.

  • Rarely, genetic defects in thiamine transporters can predispose to deficiency but are not typical for wet beriberi.

Physical Exam Findings

  • Tachycardia with bounding pulses due to high-output cardiac failure

  • Peripheral edema often symmetric and dependent

  • Warm extremities with flushed skin from vasodilation

  • Elevated jugular venous pressure indicating volume overload

  • S3 gallop reflecting dilated cardiomyopathy

Diagnostic Workup


Diagnostic Criteria

Diagnosis of wet beriberi is primarily clinical, based on the presence of signs of high-output heart failure such as tachycardia, warm extremities, and peripheral edema in the context of risk factors for thiamine deficiency. Laboratory confirmation includes measuring low blood thiamine levels or reduced activity of erythrocyte transketolase. Response to thiamine administration with rapid symptom improvement supports the diagnosis. Cardiac imaging may show dilated cardiomyopathy with preserved ejection fraction. Exclusion of other causes of heart failure is essential.

Pathophysiology


Key Mechanisms

  • Thiamine (Vitamin B1) deficiency impairs activity of thiamine-dependent enzymes such as pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, and transketolase, leading to decreased ATP production.

  • Reduced ATP availability causes impaired myocardial energy metabolism, resulting in cardiac dysfunction and high-output heart failure.

  • Peripheral vasodilation occurs due to accumulation of vasodilatory metabolites, contributing to wet beriberi symptoms.

  • Increased venous return and fluid retention lead to volume overload and edema.

  • Impaired nerve conduction and neuropathy may coexist but are more prominent in dry beriberi.

InvolvementDetails
Organs

Heart is primarily affected in wet beriberi, presenting with high-output heart failure and edema.

Brain involvement can occur in Wernicke encephalopathy, a related thiamine deficiency syndrome.

Tissues

Myocardial tissue is damaged by energy depletion and oxidative stress, causing dilated cardiomyopathy in wet beriberi.

Peripheral nerves may be involved in mixed beriberi forms, leading to neuropathy.

Cells

Cardiomyocytes are affected due to impaired energy metabolism leading to heart failure in wet beriberi.

Neurons are vulnerable to thiamine deficiency causing neurological symptoms in beriberi syndromes.

Chemical Mediators

Thiamine pyrophosphate (TPP) is the active coenzyme form essential for mitochondrial energy metabolism.

Lactic acid accumulates due to impaired pyruvate dehydrogenase activity, contributing to metabolic acidosis.

Treatments


Pharmacological Treatments

  • Thiamine (Vitamin B1) supplementation

    • Mechanism:
      • Repletes thiamine, a critical cofactor for enzymes in carbohydrate metabolism, restoring energy production and preventing lactic acidosis.

    • Side effects:
      • Allergic reactions

      • Injection site pain

      • Rare anaphylaxis

    • Clinical role:
      • First-line

Non-pharmacological Treatments

  • Correction of underlying malnutrition with a balanced diet rich in thiamine.

  • Management of heart failure symptoms with salt restriction and fluid management.

  • Avoidance of alcohol to prevent further thiamine depletion.

Prevention


Pharmacological Prevention

  • Oral or parenteral thiamine supplementation in at-risk populations

  • Multivitamin preparations containing thiamine for chronic alcoholics

  • Intravenous thiamine administration prior to glucose in malnourished patients

  • Prophylactic thiamine in bariatric surgery patients

  • Vitamin B complex supplementation in malabsorption syndromes

Non-pharmacological Prevention

  • Nutritional counseling to ensure adequate dietary thiamine intake

  • Alcohol cessation programs to reduce risk of deficiency

  • Screening for malnutrition in high-risk groups such as homeless or elderly

  • Management of underlying malabsorption disorders

  • Education on balanced diet including whole grains and legumes

Outcome & Complications


Complications

  • High-output congestive heart failure causing pulmonary edema

  • Cardiogenic shock in severe cases

  • Arrhythmias due to myocardial dysfunction

  • Wernicke encephalopathy if thiamine deficiency affects the CNS

  • Death from untreated cardiac failure

Short-term Sequelae Long-term Sequelae
  • Rapid onset heart failure symptoms including dyspnea and edema

  • Hypotension and tachycardia from decreased cardiac output

  • Metabolic acidosis due to impaired pyruvate dehydrogenase activity

  • Neurological symptoms if concurrent Wernicke encephalopathy develops

  • Fluid retention and weight gain from volume overload

  • Chronic dilated cardiomyopathy with persistent heart failure

  • Irreversible myocardial damage if untreated

  • Peripheral neuropathy from prolonged thiamine deficiency

  • Cognitive impairment related to chronic CNS involvement

  • Increased mortality risk from progressive cardiac dysfunction

Differential Diagnoses


Vitamin B1 (Thiamine) Deficiency (Wet Beriberi) versus Congestive Heart Failure

Vitamin B1 (Thiamine) Deficiency (Wet Beriberi)

Congestive Heart Failure

History of chronic alcoholism or malnutrition

History of ischemic heart disease or chronic hypertension

Normal BNP with lactic acidosis due to impaired pyruvate dehydrogenase activity

Elevated brain natriuretic peptide (BNP) and evidence of volume overload

Rapid onset of high-output heart failure with peripheral edema and warm extremities

Progressive dyspnea with pulmonary edema and peripheral edema

Vitamin B1 (Thiamine) Deficiency (Wet Beriberi) versus Wet Beriberi vs Dry Beriberi

Vitamin B1 (Thiamine) Deficiency (Wet Beriberi)

Wet Beriberi vs Dry Beriberi

Predominantly high-output cardiac failure with edema

Predominantly peripheral neuropathy without cardiac symptoms

Elevated lactate and signs of cardiac dysfunction

Normal cardiac enzymes and no signs of heart failure

Acute or subacute heart failure symptoms

Chronic progressive neurological symptoms

Vitamin B1 (Thiamine) Deficiency (Wet Beriberi) versus Alcoholic Cardiomyopathy

Vitamin B1 (Thiamine) Deficiency (Wet Beriberi)

Alcoholic Cardiomyopathy

Thiamine deficiency due to malnutrition or alcoholism causing high-output failure

Long-term heavy alcohol use with dilated cardiomyopathy features

High-output heart failure with normal or hyperdynamic ejection fraction

Dilated left ventricle with reduced ejection fraction on echocardiogram

Rapidly reversible symptoms with thiamine supplementation

Chronic progressive systolic heart failure

Vitamin B1 (Thiamine) Deficiency (Wet Beriberi) versus Hypothyroidism

Vitamin B1 (Thiamine) Deficiency (Wet Beriberi)

Hypothyroidism

Normal thyroid function tests

Elevated TSH and low free T4

Rapid onset of edema and heart failure symptoms

Slow onset fatigue, weight gain, cold intolerance

Pitting edema due to fluid overload

Myxedema with non-pitting edema

Vitamin B1 (Thiamine) Deficiency (Wet Beriberi) versus Nephrotic Syndrome

Vitamin B1 (Thiamine) Deficiency (Wet Beriberi)

Nephrotic Syndrome

No significant proteinuria or hypoalbuminemia

Massive proteinuria with hypoalbuminemia

Edema develops rapidly with cardiac symptoms

Edema develops gradually with foamy urine

Edema with cardiomegaly and signs of high-output heart failure

Edema primarily in dependent areas without cardiac enlargement

Medical Disclaimer: The content on this site is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. If you think you may be experiencing a medical emergency, call 911 or your local emergency number immediately. Always consult a licensed healthcare professional with questions about a medical condition.

Artificial Intelligence Use: Portions of this site’s content were generated or assisted by AI and reviewed by Erik Romano, MD; however, errors or omissions may occur.

USMLE® is a registered trademark of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). Doctogenic and Roscoe & Romano are not affiliated with, sponsored by, or endorsed by the USMLE, FSMB, or NBME. Neither FSMB nor NBME has reviewed or approved this content. "USMLE Step 1" and "USMLE Step 2 CK" are used only to identify the relevant examinations.