Pellagra is a
vitamin deficiency disease most commonly caused by a chronic lack of
niacin (vitamin B
3) in the diet. It can be caused by decreased intake of niacin or
tryptophan,
and possibly by excessive intake of
leucine.
It may also result from alterations in protein metabolism in disorders such as
carcinoid syndrome. A deficiency of the
amino acid lysine can lead to a deficiency of niacin as well.
Epidemiologi
Pellagra can be common in people who obtain most of their
food energy from
maize (often called "corn"), notably rural
South America where maize is a
staple food. If maize is not
nixtamalized, it is a
poor source of tryptophan as well as niacin. Nixtamalization of the corn corrects the niacin deficiency, and is a common practice in
Native American cultures that grow corn. Following the corn cycle, the symptoms usually appear during spring, increase in the summer due to greater sun exposure, and return the following spring. Indeed, pellagra was once
endemic in the poorer states of the U.S. South, like Mississippi and Alabama, as well as among the inmates of jails and orphanages as studied by Dr.
Joseph Goldberger.
Pellagra is common in
Africa,
Indonesia, and
China. In affluent societies, a majority of patients with clinical pellagra are poor, homeless, alcohol-dependent, or psychiatric patients who refuse food.
Pellagra was common among prisoners of Soviet labor camps, the
Gulag. It can be found in cases of chronic
alcoholism. In addition, pellagra is a micronutrient deficiency disease that frequently affects populations of refugees and other displaced people due to their unique, long-term residential circumstances and dependence on food aid. Refugees typically rely on limited sources of niacin provided to them, such as groundnuts; the instability in the nutritional content and distribution of food aid can be the cause of pellagra in displaced populations.
Gejala
Pellagra is classically described by "the four D's": diarrhea,
dermatitis,
dementia and death.
A more comprehensive list of symptoms includes:
Frostig and Spies (acc. to Cleary and Cleary) described more specific psychological symptoms of pellagra as
- Psycho-sensory disturbances (impressions as being painful, annoying bright lights, odours intolerance causing nausea and vomiting, dizziness after sudden movements)
- Psycho-motor disturbances (restlessness, tense and a desire to quarrel, increased preparedness for motor action)
Patofisiologi
Pellagra can develop according to several mechanisms, all of which ultimately revolve around niacin deficiency. The first is simple dietary lack of niacin. Second, it may result from deficiency of
tryptophan,
an
essential amino acid found in soybeans, meat, poultry, fish, and eggs
that the body
converts into niacin. Third, it may be caused by excess
leucine, though the relationship is unclear.
Alterations in protein metabolism may also produce pellagra-like symptoms. An example of this is
carcinoid syndrome, a disease in which
carcinoid tumors produce excessive
serotonin. In normal patients, only one percent of dietary tryptophan is converted to serotonin; however, in patients with carcinoid syndrome this value may increase to 70 percent. The diversion of tryptophan to making serotonin in patients with metastatic tumors can result in tryptophan deficiency. Carcinoid syndrome thus may produce decreased protein synthesis, niacin deficiency, and clinical manifestations of pellagra.
sumber : Wikipedia
