THIAMIN   VITAMIN  B1

فيتامين  B1

1-من الفيتامينات التي تدوب في الماء .

2- يحول  البيروفيت  الي اسيتايلكوانزايمA  -وهدا المركب ضروري للعمليات الميتابوليزم وخاصة للجهاز العصبي ولعضلات القلب .

3-نقص الثيامين يسبب امراض عضلات القلب وامراض الاعصاب والدماغ :

     - البيري-بيري  الجاف  والرطب .

    - بيري-بيري  الاطفال .

    - Wernicke,s encephalitis .

# البيري- بيري  BERI-BERI

1-     مرض بسبب سوء التغدية .

2-     الاسم من الاصل  Singhalese language  وهي بمعنى   لا  استطيع .

3-      عدم القدرة على فعل أي شيء .

4-     تزداد الاعراض عند الاصابة بالتهاب جرثومي او عند الاجهاد او الحمل والرضاعة .

5-     الكحوليات .

# الباثولوجي  :

1-     نقص في الاستفادة من الكربوهيدرات .

2-      تراكم البيروفيت واللاكتيت .

3-      تراكم هدة المواد  تسبب  اتساع الاوعية الدموية بشكل كبير وبالتالي تترسب السوائل في الانسجة فتتورم الاطراف .

4-     يسبب هدا فشل القلب وبالتالي يتسع القلب .

5-     تزداد تورمات الاطراف مع فشل القلب .

6-     زيادة احتمالية الموت المفاجيء .

7-     ضعف  وفشل العضلات بشكل عام .

8-     في الدماغ يتكون بؤر نزيف في الدماغ الاوسط والهيبوطلموس وجدران  التجويفات الدماغية ..

# الاعراض :

1-     تبداء الاعراض تدريجيا وغالبا بعد بدل مجهود  او اصابة بمرض جرثومي .

2-      فقد الشهية والارهاق وثقل وفشل القدمين .

3-     تورم القدمين والوجه .

4-     تنمل القدمين .

5-     ضعف عضلات الساقين واوجاع عند الضغط .

6-     خدر الساقين .

7-     في الاطفال : تكون الحالة خطيرة وتصيب الاطفال في سن 2-6 اشهر وتسبب:

-         فشل القلب الحاد  وغالبا ما يفقد الطفل.

8-     في الحالة  الناتجة من الكحوليات :

-         تفقد حركة العينين .

-         فقدان الاتزان .

-         دهول وفقد الداكرة .

-         الموت المفاجيء .

# العلاج :

يعطى حقنة في العضل 50 ملج لمدة ثلات ايام ثم  10 ملج حبوب ثلات مرات يوميا الى ان  تتحسن الحالة .

الاستجابة تكون سريعة جداً مثل السحر وتعود العضلات والاعصاب الى سابق حالها .

د. ناصر

 Beriberi

thiamin deficiency; vitamin B1 deficiency

Definition

A vitamin deficiency disease, caused by a lack of vitamin B1 (thiamin); the most significant manifestations are damage to the heart and nervous system.

Causes, incidence, and risk factors

Beriberi has become almost nonexistent in the United States since the discovery of its cause, thiamin deficiency. Most foods are now vitamin enriched, which means that a normal diet contains adequate amounts of thiamin.

·        Beriberi, although uncommon, can be found among alcoholics. Alcohol-related thiamin deficiency is caused by inadequate intakes of thiamin as well as impaired absorption and storage.

·        Beriberi can also appear, in breast-fed infants when the mother has an inadequate intake of thiamin or if the infant is fed unusual formulas without thiamin supplements. Deficiencies may also be found in people whose diet includes certain types of fish that produce an enzyme that inactivates thiamin.

·        Early symptoms of beriberi are nonspecific and include fatigue, irritability, restlessness, loss of appetite, and vague abdominal discomfort.

·        As the disease progresses, patients develop burning sensations, tingling in the extremities, and changes in sensation such as numbness. Patients may develop mental confusion and psychosis. Heart manifestations are caused by degeneration of the heart muscle and include heart failure with shortness of breath (dyspnea) and cyanosis (bluish tinged skin). Neurologic symptoms are caused by degeneration of the nerve fiber and its insulation (myelin). Death is generally a result of heart failure.

There are two kinds of beriberi: dry; and wet. Dry beriberi is associated with energy deprivation and inactivity characterized by mental confusion, peripheral neuropathy, muscular wasting with loss of function or paralysis of the lower extremities. Wet beriberi is resultant of high carbohydrate intake along with strenuous exercise characterized by edema, tachycardia, pulmonary congestion, and enlarged heart.

Beriberi around the World

Vitamin B1 occurs widely in food but may be lost in the course of processing, particularly in the milling of grains. In East Asian countries, where polished white rice is a dietary staple, beriberi has been known for over 1,000 years. The history of the recognition, the cause, and the cure of beriberi is dramatic and is well documented in medical literature. In the 1870s the Japanese navy reported that beriberi had been eradicated among its sailors as a result of adding extra meat, fish, and vegetables to their regular diet. Before that time, almost half of the sailors were likely to develop beriberi, and many died of it.

In 1897 Christiaan Eijkman, working in the Dutch East Indies (now Indonesia), showed that a beriberi-like disease could be produced in chickens by a diet of polished rice. That beriberi in humans was also related to the ingestion of white rice was confirmed by British researchers in Malaysia. There, W. Fletcher in 1907 and Henry Fraser and A.T. Stanton in 1909 showed that in selected groups under close observation beriberi occurred in persons who were eating a polished-rice diet whereas those eating parboiled orbrown rice did not develop the disease. In 1912 Casimir Funk demonstrated that beriberi could be cured in pigeons by feeding them a concentrate made from rice polishings. Following this discovery he proposed that this, as well as several other conditions, were due to the ingestion of diets that were deficient in specific factors which he termed vitamines.

The incidence of beriberi in Asia has markedly decreased, partly because an improved standard of living has allowed a more varied diet and partly because of the gradual popular acceptance of partially dehusked, parboiled, and enriched rice-forms that contain higher concentrations of thiamine. The prevention of beriberi is accomplished by eating a well-balanced diet, since thiamine is present in most raw and untreated foods. In Western countries, thiamine deficiency is encountered almost solely in casesof chronic alcoholism.

Symptoms

Early symptoms:

·        irritability

·        fatigue

·        restlessness

·        decreased appetite

Later symptoms:

·        complaints of tingling or burning in the extremities

·        numbness in the extremities

·        shortness of breath (dyspnea)

·        bluish coloration to the skin (cyanosis)

·        decreased mental ability

·        unusual behavior

·        seizures

·        loss of consciousness

Signs and tests

Physical examination may show signs ofcongestive heart failure, including difficulty breathing, bluish skin(cyanosis), and others. The person with late-stage beriberi may be confused orpsychotic. Neurological examination shows a loss of vibratory sensation (theperson is less able to sense vibration), loss of coordination, gait changes(ataxia), and other changes. The liver may be enlarged (hepatomegaly).

Tests include:

·        ECG (to rule out other causes of seizures and neurologic changes)

·        clinical response to administered thiamine (symptoms improve after the person is given thiamine supplements)

Treatment

Administration of thiamin reverses the deficiency andsymptoms improve rapidly. Because most patients suffer from multipledeficiencies a vitamin B-complex is often given.

·        Neuropathic-thiamine, 10mg TID

·        Cardiac- thiamine 25mg IM BIDx4; then 10mg PO TID

·        Infantile; Rx both mother and infant

·        Wernicke's encephalopathy

·        MEDICAL EMERGENCY

·        thiamine IV 200mg BIDx3

Expectations(prognosis)

Cardiac damage is reversible and is not permanent. Full recovery is expected after treatment. Untreated, beriberi is often fatal.

If acute heart failure has occurred outlook is poor. If damage to the nervous system is not too great response to treatment is usually good.

Complications

·        seizures and subsequent injuries

·        psychosis

·        congestive heart failure

Prevention

Adequate intake of thiamin will prevent beriberi. Nursing mothers should insure that their diet is adequate in all vitamins and be sure that infant formulas contain thiamin. Alcoholics, the elderly, people in stress, and elite athletes also need to focus on well-balanced diet and may require B-vitamin supplementation to ensure appropriate intake and utilization of thiamin.

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