Inflammation of multiple nerves (polyneuritis), heart disease (cardiopathy), and edema (swelling) due to a deficiency of thiamine (vitamin B1) in the diet.
There are two major types of beriberi:
- Wet beriberi affects the cardiovascular system.
- Dry beriberi and Wernicke-Korsakoff syndrome affect the nervous system.
Beriberi is rare in the United States because most foods are now vitamin enriched. If you eat a normal, healthy diet, you should get enough thiamine. Today, beriberi occurs mostly in patients who abuse alcohol. Drinking heavily can lead to poor nutrition. Excess alcohol makes it harder for the body to absorb and store thiamine.
A rare condition known as genetic beriberi is inherited (passed down through families). People with genetic beriberi lose the ability to absorb thiamine from foods. This can happen slowly over time and symptoms occur when the person is an adult. However, because health care providers may not consider beriberi in nonalcoholics, this diagnosis is often missed.
Beriberi can occur in breastfed infants when the mother’s body is lacking in thiamine. The condition can also affect infants who are fed unusual formulas that don’t have enough thiamine.
Getting dialysis and taking high doses of diuretics raise your risk of beriberi.
When healthy individuals are deprived of thiamine, thiamine stores are depleted within 1 month. However, within a week after thiamine intake stops, healthy people develop a resting tachycardia, weakness, and decreased deep tendon reflexes; some people develop a peripheral neuropathy.
Thiamine deficiency with nervous system involvement is termed dry beriberi. This presentation usually occurs when poor caloric intake and relative physical inactivity are present. The neurologic findings can be peripheral neuropathy characterized by symmetrical impairment of sensory, motor, and reflex functions of the extremities, especially in the distal lower limbs. Histologic analysis has shown that the lesions arise from a degeneration of the myelin in the muscular sheaths without inflammation.
Another presentation of neurologic involvement is Wernicke encephalopathy, in which an orderly sequence of symptoms occurs, including vomiting, horizontal nystagmus, palsies of the eye movements, fever, ataxia, and progressive mental impairment leading to Korsakoff syndrome. Improvement can be achieved at any stage by the addition of thiamine, unless the patient is in frank Korsakoff syndrome. Only half of the patients treated at this stage recover significantly.
Wet beriberi is the term used for thiamine deficiency with cardiovascular involvement. The chronic form of wet beriberi consists of 3 stages. In the first stage, peripheral vasodilation occurs, leading to a high cardiac output state. This leads to salt and water retention mediated through the renin-angiotensin-aldosterone system in the kidneys. As the vasodilation progresses, the kidneys detect a relative loss of volume and respond by conserving salt. With the salt retention, fluid is also absorbed into the circulatory system. The resulting fluid overload leads to edema of the dependent extremities.
By the time significant edema occurs, the heart has been exposed to a severely high workload in order to pump the required cardiac output needed to satisfy end organ requirements. Parts of the heart muscle undergo overuse injury, which results in the physical symptoms of tachycardia, edema, and high arterial and venous pressures. These changes can lead to myocardial injury, expressed as chest pain.
A more rapid form of wet beriberi is termed acute fulminant cardiovascular beriberi, or Shoshin beriberi. The predominant injury is to the heart, and rapid deterioration follows the inability of the heart muscle to satisfy the body’s demands because of its own injury. In this case, edema may not be present. Instead, cyanosis of the hands and feet, tachycardia, distended neck veins, restlessness, and anxiety occur. Treatment with thiamine causes low-output cardiac failure, because systemic vasoconstriction is reinstated before the heart muscle recovers. Support of heart function is an added requirement at this stage, and recovery is usually fairly quick and complete if treatment is initiated promptly. However, if no treatment is available, death occurs just as rapidly (within hours or days).
Symptoms of dry beriberi include:
- Difficulty walking
- Loss of feeling (sensation) in hands and feet
- Loss of muscle function or paralysis of the lower legs
- Mental confusion/speech difficulties
- Strange eye movements (nystagmus)
Symptoms of wet beriberi include:
- Awakening at night short of breath
- Increased heart rate
- Shortness of breath with activity
- Swelling of the lower legs
A physical examination may show signs of congestive heart failure, including:
- Difficulty breathing with neck veins that stick out
- Enlarged heart
- Fluid in the lungs
- Rapid heartbeat
- Swelling in both lower legs
A person with late-stage beriberi may be confused or have memory loss and delusions. The person may be less able to sense vibrations.
A neurological exam may show signs of:
- Changes in the walk
- Coordination problems
- Decreased reflexes
- Drooping of the eyelids
The following tests may be done:
- Blood tests to measure the amount of thiamine in the blood
- Urine tests to see if thiamine is passing through the urine
Treatment for beriberi should be supervised by a health care professional. The basic treatment for beriberi is to bring thiamine levels in the body back to within normal range. This is accomplished through the administration of oral or injectable thiamine supplements. Additional vitamin supplements may also be recommended. If beriberi is treated promptly, most symptoms of the disease will be reversed.