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Endocrinology

Insufficiency of niacin

Insufficiency of niacin (Niacinum, RR vitamin, B3 vitamin) — the morbid condition caused by deficit of this vitamin B an organism. At the expressed deficit the pellagra, in less hard cases — RR hypovitaminosis which is shown dysfunctions of a nervous system, intestines, dystrophic changes of skin develops.

Epidemiology
The pellagra is observed in some countries of Asia and Africa where inhabitants eat mainly corn. Endogenous forms of a hypovitaminosis of RR are more often, develop against diseases of the digestive system, neuritis, poisonings with lead, benzene, thallium.

Pathogeny
Niacin is a part of many dehydrogenases and influences many types of an exchange. Niacinum in a small amount is synthesized in an organism from tryptophane. The organism needs continuous intake of RR vitamin with food.

Classification
There is no standard classification of insufficiency of RR vitamin. The pellagra is subdivided on easy, moderately severe and severe forms. Carry forms with limited dermatitis, an infrequent diarrhea and a moderate adynamy to lungs; to heavy — forms with the cachexia, prolonged psychoses extended by damages of skin; between these extreme options — moderately severe forms.

Approximate formulation of the diagnosis:
1. A pellagra (easy degree), erythematic (limited) dermatitis in a neck and hands, enteritis, a pellagrichesky neurasthenia.
2. Chronic ulcer colitis, often recurrent, in an aggravation phase.
Secondary pellagra: damage of face skin, neck, brushes and feet, the expressed asthenic syndrome.
3. RR hypovitaminosis: limited erythematic dermatitis in the field of brushes, functional disorder of intestines, a moderate asthenic syndrome.

Preliminary diagnosis
At a pellagra first of all around lips, a nose, on cheeks, a forehead, a neck, on brushes and feet the dark red erythema appears; in a zone of an erythema blisters which then burst are possible; on a mucous membrane of lips cracks are observed. The mucous membrane of a mouth is hyperemic, on gingivas there are ulcerations. Language is bright red edematous, gains character of "polished". Due to the development of a glossitis and stomatitis patients complain of mouth pain, burning in the field of language. A chair of watery 3 — 5 times a day and more without tenezm and blood. Signs of asthenic, delirious syndromes develop. In hard cases there are spasms, an ataxy, weak-mindedness sometimes develops.
In the spring under the influence of solar radiation the exacerbation of an illness, especially skin manifestations is usually observed.

The hypovitaminosis of RR can proceed with moderate, weakness, deterioration in appetite, small weight loss in combination with a limited erythema on a face, hands and an unstable chair.

Verification of the diagnosis
For confirmation of the diagnosis of a pellagra and especially a hypovitaminosis of RR it is necessary to determine the content of vitamin and its metabolites in blood and urine (see the table).

The differential diagnosis is carried out with a system lupus erythematosus, to a spr, dysentery, an ariboflavinosis. It is necessary to consider a combination at a pellagra of three main syndromes (dermatitis, diarrhea, defeat of TsNS).

Treatment and prevention
Prevention basis — a balanced diet. Daily need for niacin of 20 — 25 mg. If necessary in addition appoint it on 15 — 25 mg a day inside.
The patient with for the first time the revealed pellagra or a palindromia is subject to hospitalization. Niacin is appointed inside on 50 mg by 2 — 4 times a day. For injections use 1% niacin solution which is entered on 1 ml or in a muscle (injections are painful) or in a vein (to enter slowly). Nikotinamid inside appoint 50 — 100 mg 3 — 4 times a day (tablets on 25 mg). Solutions of a nikotinamid (1%, 2,5%, 5%) on 1 — 2 ml can be entered into a muscle, under skin and into a vein. Nikotinamid does not give vascular reactions. Course of treatment of 2 — 4 weeks. The patient in addition appoint ascorbic acid, thiamin, Riboflavinum.

 
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