Thiamine deficiency; Vitamin B1 deficiency
Beriberi is a vitamin deficiency disease caused by inadequate bodily stores of thiamine (vitamin B1). It can damage the heart and nervous system.
Causes, incidence, and risk factors
There are two major manifestations of thiamine deficiency: cardiovascular disease (wet beriberi) and nervous system disease (“dry beriberi” and Wernicke-Korsakoff syndrome). Both types are most often caused by excessive alcohol consumption.
Symptoms of dry beriberi include pain, tingling, or loss of sensation in hands and feet (peripheral neuropathy), muscle wasting with loss of function or paralysis of the lower extremities, and potential brain damage and death.
Wet beriberi is characterized by swelling, increased heart rate, lung congestion, and enlarged heart related to congestive heart failure.
Beriberi has become rare in the United States because most foods are now vitamin-enriched, which means that a normal diet contains adequate amounts of thiamine.
As a result, beriberi now occurs primarily in patients who abuse alcohol, because drinking heavily can lead to malnutrition and poor absorption and storage of thiamine. This is the cause of Wernicke-Korsakoff syndrome, which is alcohol-related brain damage affecting language and thinking.
Beriberi can also occur in breast-fed infants when the mother has an inadequate intake of thiamine. It can also affect infants fed unusual formulas with inadequate thiamine supplements.
Others at risk for beriberi include patients undergoing dialysis, patients receiving high doses of diuretics, and people in developing countries with limited diets who consume milled rice.
In addition, there is a rare condition known as genetic beriberi. This is an inherited condition in which affected people lose the ability to absorb thiamine from foods. This can happen slowly over time and manifest as an adult. Since beriberi may not be considered in nonalcoholics, this diagnosis is often missed.
Nervous system symptoms are caused by the degeneration of nerve fibers and their insulation (myelin sheath). Heart failure is the most common cause of death in people with beriberi.
Early neurologic symptoms include:
- Complaints of symmetric tingling or burning pain in the extremities
- Numbness in the extremities
- Strange eye movements (nystagmus)
Later neurologic symptoms (Wernicke’s encephalopathy) include:
- Mental confusion/speech difficulties
- Difficulty walking
If a patient with Wernicke’s encephalopathy receives thiamine replacement, language problems, unusual eye movements, and walking difficulties may subside, but may be replaced by Korsakoff’s syndrome, which includes memory loss, impaired ability to learn, and confabulation (making up stories to explain behavior that have little relation to reality).
Heart Failure Symptoms:
- Shortness of breath with exertion
- Symmetric swelling of the lower legs
- Awakening at night short of breath
Signs and tests
A physical examination may show signs of congestive heart failure, including symmetrically swollen lower legs, fluid in the lungs, and elevated neck veins with labored breathing, a rapid heartbeat, and an enlarged heart.
The person with late-stage beriberi may be confused or have memory loss and delusions. Neurological examination may show a loss of vibratory sensation (the person is less able to sense vibration), decreased reflexes, loss of coordination, gait changes, nystagmus, drooping of the eyelids, and inability to move the eye outwards.
- Measurement of blood thiamine and whole-blood or erythrocyte transketolase activity
- Measurement of urinary thiamine excretion
- Clinical response to administered thiamine (symptoms improve after the person is given thiamine supplements)
Thiamine can be administered by injection and with pills. Patients should also receive therapeutic doses of other water-soluble vitamins.
Following thiamine treatment, the symptoms should improve rapidly. Cardiac damage is usually reversible and is not permanent. Full recovery is expected. However, if acute heart failure has already occurred, the outlook is poor.
Nervous system damage is also reversible, if caught early. If not, some symptoms (such as memory loss) may not be completely recovered with treatment.
Untreated, beriberi is often fatal.
- Congestive heart failure
Calling your health care provider
Beriberi is extremely rare in the United States. However, if you feel your family’s diet is inadequate or poorly balanced and you or your children have any of the described symptoms, call your health care provider.
Adequate intake of thiamine will prevent beriberi. Nursing mothers should make sure that their diet is adequate in all vitamins and be sure that infant formulas contain thiamine. People who drink heavily should try to cut down or quit and supplement their diets with B-vitamins to ensure appropriate intake of thiamine.
by David A. Scott, M.D.
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.