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Endocrinology

Insufficiency of B1 vitamin

Insufficiency of B1 vitamin (thiamin) — the morbid condition caused by deficit of this vitamin B an organism and which is shown disturbances mainly from a nervous system, heart and intestines in hard cases in the form of beriberi.

Epidemiology
In the countries East and Southeast Asia where the polished rice, B1 avitaminosis including beriberi remains a key product of food, it is quite widespread. B1 hypovitaminosis in the developed countries meets quite often and is observed generally at patients with chronic diseases of a digestive tract, an alcoholism, polyneurites, endocrine diseases (a diabetes mellitus, a toxic craw), etc. Insufficiency of thiamin is often combined with deficit of other vitamins of group B.

Pathogeny
B1 vitamin is well dissolved in water; the coenzyme tiamindifosfat (cocarboxylase) plays an essential role in carbohydrate metabolism. Along with it thiamin participates in an exchange of amino acids, nucleotides, acetylcholine and cholinesterase. At deficit of B1 vitamin in fabrics and blood nedookislenny products collect: pyruvic acid, lactic acid, etc. At the same time activity of various parts of the nervous system (especially peripheral nervous system), skeletal muscles and a myocardium, and also function of a digestive tract is broken. At patients with an alcoholism partly owing to insufficiency of thiamin, and also a pyridoxine Gayet's encephalopathy — Vernike develops.

Classification
During beriberi distinguish 3 forms:
a) paralytic (polyneuritic),
b) cordial and
c) edematous.

Approximate formulation of the diagnosis:
1. Hypovitaminosis B 1 (exogenous), neurocirculatory dystonia of cardial type.
2. Diffusion toxic craw, thyrotoxicosis of the I—II stage, hypovitaminosis B 1 (endogenous), polyneuropathy of the lower extremities.
3. Beriberi mainly cardial form, a circulatory unefficiency (on right ventricular type) the II stages.

Preliminary diagnosis
Deterioration in appetite, nausea, bent to locks, paresthesia in legs, gastrocnemius muscle pain are characteristic when walking, deterioration in a dream, irritability, tearfulness, decrease in physical and mental effeciency. Sometimes moderate weight loss, lability of pulse against the general psychoemotional lability. Language is dryish, the stomach is blown unsharply up, painful and deep sensitivity in the field of feet and shins is moderately reduced, tendon jerks are unsharply weakened (more standing). Deficit of thiamin is often combined with a lack of other vitamins of group B (Riboflavinum, a pyridoxine, niacin, etc.) therefore the symptomatology can be various.

At a paralytic form of beriberi of a pas the forefront the expressed weight loss and symptoms of the progressing polyneuritis of the lower extremities proceeding without pain syndrome. Various paresthesias, decrease in the beginning in painful, and then deep sensitivity, weakening of tendon jerks, the atactic phenomena, muscular weakness, a hypotrophy of muscles, their paresis and paralyzes on peripheral type are characteristic. These neuromuscular frustration develop on the lower extremities in the beginning, extending then to hands and a trunk. In hard cases also cranial nerves are surprised.

Damage of heart, mainly right ventricle therefore patients have no cyanosis is characteristic of a cordial form of beriberi. Patients complain of an asthma, heartbeat, is frequent on hypostases. Reveal tachycardia, swelling of cervical veins, expansion of borders of heart to the right, not rough systolic noise at a top, increase in a liver, often ascites, hypostases standing. Disturbances of a hemodynamics usually develop gradually.

Early emergence of the hypostases advancing polyneuritis symptoms is characteristic of an edematous form unlike "Sukhoi". In the beginning they are marked out over anklebones, then they extend up to shins, hips; later ascites joins.

Hard proceeding malignant options are typical for a final phase of an illness. The expressed pain in epigastric area with distribution on a breast, short wind, tachycardia, increase of right ventricular insufficiency are characteristic. According to literature, from the moment of development of this symptom complex to death there pass 3 — 5 days, sometimes even 6 — 12 h.

Verification of the diagnosis
The diagnosis of a hypovitaminosis of Bi is confirmed by reduction of content of thiamin in blood (in serum lower than 5 mkg/l, in erythrocytes is lower than 30 mkg/l), sharp increase of concentration of pyruvic acid in blood (it is higher than 0,01 g/l) and urine (higher than 30 mg/days), increase of content in blood of lactic acid (it is higher than 200 mg/l). Recently for this purpose use also a number of more difficult modern methods.

The differential diagnosis is carried out with infectious polyneurites, chronic intoxication alcohol or lead. To reveal intoxication lead, except the anamnesis, help a characteristic border on gingivas, anemia with a basphilic punctuation of erythrocytes, release of lead with urine. At infectious polyneurites accurate communication with an infection is observed. To identify a polyneuritic or polyneuralgic syndrome at patients with an alcoholism quite difficult as it is quite often connected with deficit of food.

Treatment and prevention
Treatment of patients is usually carried out on an outpatient basis. The diet rich with thiamin, in combination with thiamin drugs in (50 — 100 mg/days) or parenterally is recommended (30 — 60 mg/days).
Patients with the expressed illness forms often need hospitalization. Parenterally enter thiamin on 1 ml and cocarboxylase. At the same time appoint other vitamins of group B (inosine, a pyridoxine, niacin) and ascorbic acid.

 
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