Thiamine deficiency is a medical condition of low levels of thiamine (vitamin B1). A severe and chronic form is known as beriberi. There are two main types in adults: wet beriberi, and dry beriberi. Wet beriberi affects the cardiovascular system resulting in a fast heart rate, shortness of breath, and leg swelling. Dry beriberi affects the nervous system resulting in numbness of the hands and feet, confusion, trouble moving the legs, and pain. A form with loss of appetite and constipation may also occur. Another type, acute beriberi, is found mostly in babies and presents with loss of appetite, vomiting, lactic acidosis, changes in heart rate, and enlargement of the heart. Thiamine deficiency is a medical condition of low levels of thiamine (vitamin B1). A severe and chronic form is known as beriberi. There are two main types in adults: wet beriberi, and dry beriberi. Wet beriberi affects the cardiovascular system resulting in a fast heart rate, shortness of breath, and leg swelling. Dry beriberi affects the nervous system resulting in numbness of the hands and feet, confusion, trouble moving the legs, and pain. A form with loss of appetite and constipation may also occur. Another type, acute beriberi, is found mostly in babies and presents with loss of appetite, vomiting, lactic acidosis, changes in heart rate, and enlargement of the heart. Risk factors include a diet of mostly white rice, as well as alcoholism, dialysis, chronic diarrhea, and taking high doses of diuretics. Rarely it may be due to a genetic condition which results in difficulties absorbing thiamine found in food. Wernicke encephalopathy and Korsakoff syndrome are forms of dry beriberi. Diagnosis is based on symptoms, low levels of thiamine in the urine, high blood lactate, and improvement with treatment. Treatment is by thiamine supplementation, either by mouth or by injection. With treatment symptoms generally resolve in a couple of weeks. The disease may be prevented at the population level through the fortification of food. Thiamine deficiency is rare in the United States. It remains relatively common in sub-Saharan Africa. Outbreaks have been seen in refugee camps. Thiamine deficiency has been described for thousands of years in Asia and became more common in the late 1800s with the increased processing of rice. 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.