Pellagra is a systemic pathology of the human body, manifested in the appearance of symptoms of the defeat of the digestive and nervous system, as well as the apparent changes in the skin that are caused by the pronounced insufficiency of vitamins of all subgroups B and nicotinic acid.
A number of pathological conditions are present, which are background conditions for the development of signs of pellagra, but the development of this pathology is most often formed with an alimentary deficiency of vitamins of subgroups B, nicotinic acid, and also with organic pathologies of severe degree of abdominal cavity organs.
Currently, the frequency of the classic variant of pellagra has decreased significantly, and the pallagra in children is more likely a historical fact.
In the development of signs of pellagra, as the main manifestation of the insufficient content of nicotinic acid and the main groups of vitamin B, the greatest pathogenetic significance is the defeat of the digestive tract, due to the fact that most of the diseases of the gastroenterological profile is accompanied by vitamin deficiency. More often, the pathology of the small intestine becomes the cause of the manifestation of the patient's signs of pellagra, as in this section of the digestive tract is absorption of vitamins B, as well as nicotinic acid, like most other groups of vitamins and vitamin-like substances. Background diseases that trigger the development of pellagra are: resection of the small intestine, chronic enteritis and the formation of gastrointestinal fistula.
In addition, the severe form of pellagra accompanies the course of acute infectious diseases localized in the intestine, the most common forms of which are intestinal tuberculosis and dysentery . With prolonged alcohol abuse, conditions are also created for suppressing the absorption capacity of the small intestine, which inevitably leads to the development of vitamin deficiencies in certain categories of vitamins.
As with any form of vitamin deficiency, pellagra can develop not because of a lack of vitamins B, but at excessive consumption, which occurs even in the normal course of pregnancy and the period of breastfeeding, and against the background of increased physical activity, combined with starvation.
If we consider the pathogenetic mechanisms of the development of pellagra, the main role in the formation of lesions of internal organs, structures of the nervous system and skin is impaired metabolism of vital elements, especially carbohydrates, occurring at the cellular level. However, the trigger mechanism in the pathogenesis of the development of typical clinical manifestations of pellagra is the insufficient content of the amino acid tryptophan in the human body.
With the progression of the disease, the patient develops irreversible processes in the skin and nervous system structures that are degenerative. In a situation where a pellagra develops in an absolutely healthy person against a disturbed diet, the primary variant of the disease should be understood. If the development of signs of pellagra is provoked by pathological changes in internal organs of a chronic nature, then a diagnosis of a secondary variant of pellagra is established.
Due to the fact that the pellagra is accompanied by severe metabolic disturbances in the patient's body, its pathomorphological manifestations are quite wide. Changes in the degenerative nature are noted in tissues of various origins (skin, endocrine organs, skeletal muscles, nervous system structures and organs of the digestive tract).
With the development of a detailed clinical picture, patients suffering from pellagra note the appearance of a wide range of symptoms. In connection with a large list of patient complaints, with primary contact with the patient it is difficult to establish a correct diagnosis, however, detailed anamnestic data suggest the presence of a given pathology in humans. As a rule, the patient's primary treatment for medical care is formed in the presence of various signs of a dyspepsia symptom-complex (complete absence of appetite, and sometimes even aversion to food intake, a feeling of dryness and burning in the mouth, distortion of taste preferences), and with the progression of the disease patient complains of a violation of the functioning of the intestine in the form of alternating periods of relaxation of stool and constipation.
With the increase of toxic syndrome, the patient notes progressive weakness, inability to perform habitual physical activity, dizziness and lack of interest in life. Most often, patients with pellagra occupy the passive position of "lying on their backs."
In the diagnosis of pellagra, the primary objective examination of the patient is of great importance, which is accompanied by the detection of a whole spectrum of pathognomonic symptoms that allow the diagnosis to be correctly established. When visual examination of the oral cavity, the patient is marked by a pronounced hyperemia not only of the tongue, but also of the mucous cheeks, gums with the presence of small ulcers, which in some situations may have signs of hemorrhagic impregnation. Similar changes in the mucous membranes are observed in the projection of the esophagus and stomach, but for their visualization the patient needs to perform esophagogastroscopy.
With the prolonged course of the pellagra, many small bleeding erosions appear in the thick and thin sections of the intestine, which can be accompanied by the appearance of an admixture of blood in the feces found in the analysis of feces for "hidden blood".
Anemia syndrome with pellagra, as a rule, is quite pronounced and is accompanied by all the clinical manifestations characterizing this pathological condition.
The primary criterion for damage to the structures of the nervous system in pellagra is the appearance of signs of polyneuritis of different localization, which, in the first place, is accompanied by a violation of all types of sensitivity without a pronounced pain component. With the progression of pellagra degenerative processes affect the structure of the brain, in connection with which, the patient develops cerebral and focal neurological symptoms ( headache , impaired coordination, vomiting, impaired vision, memory, hearing, etc.).
When the endocrine structures are affected, the patient develops polyglandular insufficiency in the form of a tendency to arterial hypotension , adynamia, progressive muscle weakness, polyuria and osteoporotic lesion of bone tissue of a widespread nature.
Violation of protein and vitamin metabolism is more reflected in laboratory indicators and is accompanied by the development of pronounced hypoproteinemia due to a decrease in the albumin fraction.
It should be borne in mind that pellagra can occur in both acute and prolonged clinical variant, each of which has its own characteristic features. For the development of the acute form of pellagra, the trigger mechanism must be expressed alimentary deficiency of exogenous nature. The debut of the disease in this situation is a sharp increase in frequency and relaxation of the stool, the frequency of urging for an act of defecation can reach 20 times a day. After a few days, the patient develops severe psychoneurological disorders (delirium), significantly aggravating the patient's condition. With the continuing vitamin deficiency, the patient exhibits typical skin signs of pellagra.
The prolonged course of pellagra is difficult for early diagnosis, since for a long time this category of patients has been observed in neurologists about sluggish polyneuritis. Subsequently, symptoms of a psycho-neurological nature that also do not differ in specificity are added. And only after the appearance of skin symptoms develops a classical version of the flow of pellagra.
The primary lesion of the skin with pellagra is their increased dryness and discoloration towards the gray shade. Most of the above manifestations are localized along the lateral surfaces of the abdomen and back, as well as on the extensor surface of the extremities. Against the backdrop of these changes, the reddening of the skin of the upper body and distal limbs, resulting from exposure to ultraviolet irradiation, is quite contrasting. A characteristic feature of erythema in this case is its clear contours, which are the boundary between the affected and unchanged skin areas. If the patient has an acute clinical variant of pellagra, the above changes in the skin are supplemented by the phenomena of exudative inflammation, manifested as the appearance of blisters with hemorrhagic contents. The healing process of the inflammatory skin elements is characterized by a long period and is accompanied by the development of massive cicatricial deformities.
Changes in the skin on the face with pellagra are accompanied by characteristic pathognomonic changes in the form of the formation of "pellagrotic glasses" (brown hyperpigmentation of the eyelids with peeling) and "the collar of Kasal" ( erythema stripe on the neck and chest).
With pellagra, the appearance of secondary skin elements in the form of follicular papules, localized in the projection of the shin and thigh, having a clear even hemorrhagic rim, is possible.
Complications of pellagra consist in the transition of the disease into an acute form, often resulting in a fatal outcome. In this situation, the diagnosis of the disease is extremely difficult, since the patient is marked by a lightening increase in the phenomena of a neurological nature, sometimes not differing from other intracerebral pathologies (increased tendon reflexes, convulsive readiness, severe degree of impaired consciousness, rigidity of the limbs, visual hallucinations, vomiting and triasm of the masticatory muscles ). In this case, a reliable diagnosis can be made only when examining the sectional material.
Patients with diagnosed pellagra must be treated in a hospital in compliance with the conditions of complete physical and psycho-emotional rest. The only pathogenetically justified direction of drug treatment is substitution therapy with the use of the drug Amide Nicotinic acid in parenteral or oral form. A saturated daily dose of the drug should be 0.3 g for at least six weeks, after which it should be switched to a maintenance dosage of 50 mg, mainly by oral administration.
Parenteral (intramuscular) administration of nicotinic acid amide is limited to a mass of adverse reactions in the form of a painful sensation of heat, reddening of the upper half of the trunk and itching of the skin , although this method of administering the drug is much more effective.
Given the pathogenetic mechanisms of the development of pellagra, it is advisable to supplement the substitution therapy with B vitamins in the parenteral form (Thiamine in a daily dose of 20 mg, Riboflavin 10 mg and Pyridoxine 50 mg). Indication for the appointment of vitamin B12 is the presence of signs of macrocytosis, glossitis and hyperchromia. The presence of severe anemic syndrome should be cured by fractional blood transfusions of 100 ml once every five days.
In the period of elimination of acute manifestations of pellagra and against the background of the applied substitution therapy, it is necessary to conduct a conversation with the patient on the topic of correction of eating behavior. The main criterion for a proper diet in this situation is saturation of the daily menu with products with a high concentration of B vitamins, ascorbic and nicotinic acid, and also protein foods.