Signs and symptoms
Symptoms of beriberi include weight loss, emotional disturbances, impaired sensory perception, weakness and pain in the limbs, and periods of irregular heart rate. Edema (swelling of bodily tissues) is common. It may increase the amount of lactic acid and pyruvic acid within the blood. In advanced cases, the disease may cause high-output cardiac failure and death.
Symptoms may occur concurrently with those of Wernicke's encephalopathy, a primarily neurological thiamine-deficiency related condition.
Beriberi is divided into four categories as follows. The first three are historical and the fourth, gastrointestinal beriberi, was recognized in 2004:
- Dry beriberi specially affects the peripheral nervous system.
- Wet beriberi specially affects the cardiovascular system and other bodily systems.
- Infantile beriberi affects the babies of malnourished mothers.
- Gastrointestinal beriberi affects the digestive system and other bodily systems.
Dry beriberi causes wasting and partial paralysis resulting from damaged peripheral nerves. It is also referred to as endemic neuritis. It is characterized by:
- Difficulty in walking
- Tingling or loss of sensation (numbness) in hands and feet
- Loss of tendon reflexes
- Loss of muscle function or paralysis of the lower legs
- Mental confusion/speech difficulties
- Involuntary eye movements (nystagmus)
A selective impairment of the large proprioceptive sensory fibers without motor impairment can occur and present as a prominent sensory ataxia, which is a loss of balance and coordination due to loss of the proprioceptive inputs from the periphery and loss of position sense.
Wernicke's encephalopathy (WE), Korsakoff's syndrome (alcohol amnestic disorder), Wernicke–Korsakoff syndrome are forms of dry beriberi.
Wernicke's encephalopathy is the most frequently encountered manifestation of thiamine deficiency in Western society, though it may also occur in patients with impaired nutrition from other causes, such as gastrointestinal disease, those with HIV/AIDS, and with the injudicious administration of parenteral glucose or hyperalimentation without adequate B-vitamin supplementation. This is a striking neuro-psychiatric disorder characterized by paralysis of eye movements, abnormal stance and gait, and markedly deranged mental function.
Korsakoff's syndrome is, in general, considered to occur with deterioration of brain function in patients initially diagnosed with WE. This is an amnestic-confabulatory syndrome characterized by retrograde and anterograde amnesia, impairment of conceptual functions, and decreased spontaneity and initiative.
Alcoholics may have thiamine deficiency because of the following:
- Inadequate nutritional intake: Alcoholics tend to intake less than the recommended amount of thiamine.
- Decreased uptake of thiamine from the GI tract: Active transport of thiamine into enterocytes is disturbed during acute alcohol exposure.
- Liver thiamine stores are reduced due to hepatic steatosis or fibrosis.
- Impaired thiamine utilization: Magnesium, which is required for the binding of thiamine to thiamine-using enzymes within the cell, is also deficient due to chronic alcohol consumption. The inefficient utilization of any thiamine that does reach the cells will further exacerbate the thiamine deficiency.
- Ethanol per se inhibits thiamine transport in the gastrointestinal system and blocks phosphorylation of thiamine to its cofactor form (ThDP).
Following improved nutrition and the removal of alcohol consumption, some impairments linked with thiamine deficiency are reversed, in particular poor brain functionality, although in more severe cases, Wernicke–Korsakoff syndrome leaves permanent damage. (See delirium tremens.)
Wet beriberi affects the heart and circulatory system. It is sometimes fatal, as it causes a combination of heart failure and weakening of the capillary walls, which causes the peripheral tissues to become edematous. Wet beriberi is characterized by:
Gastrointestinal beriberi causes abdominal pain. Gastrointestinal beriberi is characterized by:
- Abdominal pain
- Lactic acidosis
Infantile beriberi usually occurs between two and six months of age in children whose mothers have inadequate thiamine intake. It may present as either wet or dry beriberi.
In the acute form, the baby develops dyspnea and cyanosis and soon dies of heart failure. These symptoms may be described in infantile beriberi:
- Hoarseness, where the child makes moves to moan but emits no sound or just faint moans caused by nerve paralysis
- Weight loss, becoming thinner and then marasmic as the disease progresses
- Pale skin
- Ill temper
- Alterations of the cardiovascular system, especially tachycardia (rapid heart rate)
- Convulsions occasionally observed in the terminal stages