Niacin deficiency in children

Introduction to niacin deficiency in children Nicotinic acid deficiency ( nicotinic acid deficiency), also known as ecdysis, or Pellagra (Italian translation, meaning rough skin), is due to the lack of niacin (commonly known as vitamin PP) or niacin in the body, rash The digestive system and the nervous system are the main manifestations of diseases. As early as the eighteenth century, the clinical manifestations of the disease were described in more detail, but it was not until 1917 that Goldberger confirmed that the disease was related to dietary factors. In 1937, the use of niacin to treat pellagra of human body achieved significant results. In 1945, it was found that treatment with tryptophan also had the same effect. Niacin and nicotinamide constituted the coenzyme system required for cellular respiration in vivo. Niacin is a heat-resistant and alkali-resistant water-soluble vitamin that is the most stable of all kinds of vitamins. basic knowledge The proportion of illness: the incidence rate of infants and young children is about 0.04%-0.06% Susceptible people: children Mode of infection: non-infectious Complications: epilepsy schizophrenia peripheral neuritis anemia amenorrhea libido

Causes of niacin deficiency in children

(1) Causes of the disease

Common causes of niacin deficiency or rough skin are:

1. Insufficient intake: Mainly found in corn-based food, because most of the niacin contained in corn is a combination type, which can not be used by the body without decomposition. The corn protein lacks tryptophan, which is the precursor of niacin. .

2. Absorption disorders: such as chronic malnutrition, long-term diarrhea, pyloric obstruction, chronic intestinal obstruction, intestinal tuberculosis, etc. can affect the absorption of niacin.

3. Disease factors: Many pathogenic bacteria such as Salmonella, Shigella, Staphylococcus aureus, Pneumococcal, B. pertussis can not make niacin for breeding, and must take niacin from infected human tissue, so these children are easy Concurrent niacin deficiency.

4. Drugs: refers to drugs that can interfere with the metabolism of niacin, the common is isoniazid, the latter can interfere with the action of pyridol, while pyridol is the tryptophan through the uridine, the metabolism of nicotinamide Important coenzymes, therefore, the various causes of vitamin B6 deficiency can also cause the disease, and some anticancer drugs, especially 6-thioguanidine can also cause this disease.

5. Congenital genetic disease: Hartnups disease can cause the disease due to defects in the small intestine and renal tubules transporting tryptophan and other amino acids.

(two) pathogenesis

Niacin or nicotinamide, also known as niacin or nicotinamide, is two coenzymes, nicotinamide adenine dinucleotide (coenzyme I, NAD) and nicotinamide adenine dinucleotide phosphate (coenzyme II, NADP). The precursor, niacin absorbed by the tissue, constitutes the important coenzymes NAD and NADP in the cell, which are involved in many redox reactions in the body, including glucose glycolysis, pyruvate metabolism, pentose biosynthesis and fat, amino acids, The metabolism of protein and strontium, the large dose of niacin has the effect of lowering blood cholesterol, triacylglycerol and -lipoprotein concentration and dilating blood vessels.

The main lesions are manifested in the skin, digestive tract and nervous system, edema and lesions in the dermis of the dermis, papillary vasodilatation and hyperemia, lymphocytic infiltration around the blood vessels, hyperkeratosis of the epidermis, subsequent atrophy, erythema on the skin, infiltration Liquid, can form herpes and bullae, after crusting, atrophy and coloration, severe rash spread throughout the body, sebaceous glands and hair follicles withered, digestive tract manifested as intraoral and tongue mucosa redness, congestion, long-term disease, tongue stagnation, often accompanied Infection, ulceration, colonic intestinal wall thickening, inflammation, small piece of pseudomembrane formation, followed by intestinal mucosal atrophy, intestinal gland reduction, fatty infiltration in the liver, neurological lesions including demyelinating and ganglion cells Degeneration, demyelination can also occur in the lateral and posterior cords of the spinal cord.

Prevention of niacin deficiency in children

Balanced diets containing meat, eggs, milk and vegetables can meet the recommended daily niacin requirements. Infant niacin needs 8mg per day, and children and adolescents need 10-20mg per day (according to Chinese DRIs, infants are 2 ~ 3mgNE / d; children 6 ~ 7mgNE / d; pregnant women and lactating mothers 15 ~ 18mgNE / d.

Niacin can tolerate the highest intake: 10 mg NE/d for 1 year old, 15 mg NE/d for 4 years old, 20 mg NE/d for 7 years old, and 30 to 35 mg NE/d for 14 to 18 years old.

The content of niacin in food is calculated per 100g. Pig liver contains 16.2mg, beef 5.4mg, pork 4.2mg, milk 0.2mg, soybean, rice content is about 2.5mg, but the refined processing honing will lose most of it. It is necessary to actively treat chronic wasting diseases and timely supplement and adjust dietary varieties.

Pediatric niacin deficiency complications Complications, epilepsy, schizophrenia, peripheral neuritis, anemia, amenorrhea, loss of libido

1. Central nervous system: This disease affects the central nervous system, causing neurological disorders, disorientation, seizures, tension schizophrenia, hallucinations, confusion, paralysis, and even death.

2. Peripheral neuritis: There may be peripheral neuritis.

3. Anemia: Large cell or positive cell hypochromic anemia can occur.

4. Urinary and reproductive system: Women may have vaginitis and menstrual disorders, amenorrhea; males have a burning sensation when urinating, and have decreased libido.

Symptoms of niacin deficiency in children Common symptoms Sunburn causes skin allergies Loss of appetite, nausea, diarrhea, glossitis, lethargy, peeling, loss of vision, insomnia

Early symptoms are not obvious, there may be anorexia, drowsiness and dizziness, burning and numbness in the limbs, skin, digestive tract, and nervous system symptoms may occur in the course of the disease, thus having a 3"D" characteristic; Diarrhea, dermatitis ( Dermatitis), Dementia, if it has other chronic diseases, the clinical symptoms are particularly serious. Typical symptoms often occur during strong sunlight in summer and autumn, and sometimes can be induced by thermal radiation and physical damage to the skin.

Skin symptoms

It can occur slowly or suddenly. The rash occurs after being stimulated by strong sunlight or friction. First, there is symmetrical erythema at the exposed area. This erythema is very similar to sunburn. In mild cases, it is easy to miss diagnosis. The erythema gradually Turn reddish brown, after 2 weeks, the skin becomes thicker and desquamation and pigmentation deepens. There is a sharp boundary between the wrist skin and the surrounding healthy skin, much like a pair of gloves, suede gloves, the same change can occur in The feet and lower limbs are mostly symmetrical, or around the neck, the baby is mostly in the contact between the buttocks and the diaper. The erythema, the labia and the perianal area may also have erythema. In some cases, vesicles are formed, which are like burns, and are susceptible to secondary infection after rupture. In some cases, skin infections may occur, followed by desquamation. When the condition improves, the edema and red color gradually recede. After healing, there may be a large piece of peeling, and gradually become a new pink skin. In chronic cases or repeated authors, the skin becomes thicker and excessive. It is keratinized and has fissures, and some produce sputum, which is common in the knees, elbows, and heel.

2. Gastrointestinal symptoms

Common appetite loss, stomatitis, glossitis, nausea, vomiting, diarrhea and other symptoms, early tongue tip and bilateral edge swelling, tongue papilla enlargement, after the whole tongue reddish like fresh beef color, and finally shrink, tongue epithelium if it falls off It is a map tongue, ulcers in the oral mucosa, swelling of the gums, diarrhea is the most common symptom, stool is watery or mushy, the amount is large, there is stench, sometimes even blood, most patients' stomach juice lacks stomach acid and pepsin, thus digestive function affected.

3. Nervous system symptoms

Seeing irritability, restless sleep, gradually developing into mental depression, inattention, mood change, loss of orientation, insomnia, paralysis, even complete mental disorder or dementia, occasional or limb weakness and lethargy, sensory system also changed Such as photophobia and color, the noise is unbearable, the taste is abnormal, the hands and feet can have burning sensation, numbness and paralysis and other symptoms of peripheral nerve inflammation, sputum reflexes early hyperthyroidism, late disappearance, neurological symptoms do not necessarily exist with skin symptoms.

Most patients have large cell or normal cell hypochromic anemia (due to decreased gastric acid), which is effective with iron or niacin. This disease is often associated with other B vitamin deficiency or other signs of nutritional deficiencies.

Pediatric niacin deficiency examination

1. Analysis of gastric acid: often shows a lack of stomach acid.

2. Decreased urinary nicotinic acid metabolites: N-methylnicotinamide and dipyridone, the normal metabolites of niacin in urine, were significantly reduced, and the latter were more sensitive and had decreased before clinical symptoms appeared.

3. Lack of niacin in the body: The content of coenzyme I (NAD) in red blood cells is reduced, which reflects the lack of niacin in vivo. The ratio of red blood cell NAD and NADP (coenzyme II) <1.0 mostly indicates niacin deficiency.

If there is diarrhea, it is generally suitable for X-ray examination of the gastrointestinal tract to determine whether there is any cause. The gastrointestinal X-ray examination can find changes in intestinal function and mucosal morphology, similar to other gastrointestinal abnormalities caused by other nutritional deficiencies.

Diagnosis and identification of niacin deficiency in children

diagnosis

1. History: Long-term eating diet lacking niacin, the type of dietary intake, the food variety is corn-based food.

2. Clinical manifestations: Typical clinical symptoms and signs of glossitis and stomatitis occur earlier, suspicious people should be vigilant, and typical skin symptoms, mental symptoms and irregular diarrhea, the diagnosis can be basically clear.

3. Laboratory examination features: Prompt niacin deficiency.

4. Therapeutic response: Timely administration of a large amount of niacin or nicotinamide and improvement of the diet, the symptoms are relieved.

Differential diagnosis

1. Rash: Atypical rash can be mistaken for polymorphous erythema, limb pain, sunburn, toxic dermatitis, lupus erythematosus, abscess, eczema, contact dermatitis, solar dermatitis and allergic purpura.

2. Gastrointestinal symptoms: It must be differentiated from enteritis, except for other causes of chronic diarrhea, especially intestinal tuberculosis, localized enteritis and "primary" malabsorption syndrome.

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