vitamin B2 deficiency
Introduction
Introduction to vitamin B2 deficiency Vitamin B2, also known as riboflavin, is present in tissues in the form of free riboflavin, flavin mononucleotide (FMN) and flavanadenine dinucleotide (FAD). Vitamin B2 deficiency is mainly manifested in the clinical changes of skin mucosal damage. basic knowledge The proportion of illness: 0.025% Susceptible people: no special people Mode of infection: non-infectious Complications: spontaneous abortion anemia
Cause
Vitamin B2 deficiency
(1) Causes of the disease
1. Insufficient intake: Insufficient intake of vitamin B2-rich animal foods (such as milk, meat, eggs, etc.) and fresh vegetables due to economic conditions, supply difficulties and partial eclipse, such as low daily intake At 0.55 mg, symptoms can appear after a few months.
2. Need to increase: women's pregnancy and lactation, puberty of infants and adolescents, heavy physical labor or mental stress, the demand for vitamin B2 in surgery or post-traumatic recovery period is significantly increased, if not timely supplementation is easy to lead to lack of .
3. Absorption and utilization disorders: Vitamin B2 is mainly absorbed in the upper part of the small intestine, diarrhea, segmental ileitis, chronic ulcerative colitis and cirrhosis of patients with vitamin B2 absorption and utilization will be affected.
(two) pathogenesis
There are more than 40 kinds of flavoproteins produced by vitamin B2, which have a great influence on human physiological functions. Some luteinases act as hydrogen donors in biooxidation, and their lack of tissue can cause various dehydrogenation. Decreased enzyme activity, while flavoprotein is also a catalyst and coenzyme of many oxidases, so vitamin B2 deficiency can significantly affect the metabolism of sugar and fat in tissue cells, leading to insufficiency of oxidation, reduced energy utilization, and ultrastructure of cell mitochondria. Changes, animal experiments and clinical studies have shown that vitamin B2 is closely related to protein metabolism, and the amount of vitamin B2 excreted in urine is significantly affected by nitrogen balance. When tissue growth is strong, the excretion of vitamin B2 in urine is reduced, and the discharge is increased when negative nitrogen is balanced. The lack of vitamin B2 can lead to a decrease in the activity of lysyl oxidase, which affects the formation of collagen cross-linking, resulting in weakened collagen support between cells, which may be an important cause of skin damage.
Prevention
Vitamin B2 deficiency prevention
Usually pay attention to the selection of foods rich in vitamin B2, so that the dietary intake can reach the standard of reference intake, educate the nutrition science knowledge, correct the partial eclipse habits is an effective preventive measure, and strengthen the food for the special population that is easy to lack. .
Complication
Vitamin B2 deficiency complications Complications, spontaneous abortion, anemia
Neela et al reported a group of poor women with high incidence of spontaneous abortion, 84% of whom had vitamin B2 deficiency, 15% had anemia and 24.5% had folic acid deficiency. Although the cause of spontaneous abortion is multifaceted, nutrition is an important factor. One, therefore, whether women's spontaneous abortion is one of the clinical manifestations of vitamin B2 deficiency remains to be confirmed by further research.
Symptom
Vitamin B2 deficiency symptoms Common symptoms Oral angle sores Lip dry scrotum pruritus Corneal opacity Photophobia Vitamin B deficiency Lump papules Tongue tongue Conjunctival hyperemia
The clinical symptoms of vitamin B2 deficiency are mostly non-specific, but the symptoms caused by vitamin B2 deficiency often have the characteristics of group disease. Common clinical symptoms include scrotal dermatitis, sputum erosion, seborrheic dermatitis, conjunctival hyperemia and fear of light. Tears, etc., caused by vitamin B2 deficiency, the mechanism of mucosal damage may be because riboflavin deficiency can cause B6 deficiency under certain conditions. Both vitamin deficiency can cause skin and mucous membrane to be affected by skin collagen ripening process. Loss, in fact, lack of iron, zinc deficiency and niacin and other nutritional deficiencies or other diseases can also have the same changes, so relying entirely on clinical symptoms to diagnose vitamin B2 deficiency is often unreliable, some people have studied the clinical symptoms of vitamin B2 deficiency The relationship between vitamin B2 biochemical tests, only about 25% of patients with the above symptoms found abnormal biochemical examination of vitamin B2, showing that the clinical symptoms are not specific for the diagnosis of vitamin B2 deficiency, vitamin B2 deficiency can indeed cause Many clinical symptoms, but this will only occur after the vitamin B2 deficiency reaches a certain level, and the slight vitamin B2 deficiency Lack of any clinical symptoms, which determines the diagnosis of vitamin B2 deficiency based on clinical symptoms is also less sensitive, although the clinical symptoms of vitamin B2 deficiency diagnosis specificity and sensitivity are poor, but because of its simple and easy method Therefore, it is commonly used in epidemiological investigation of vitamin B2 deficiency, and is briefly introduced.
Scrotal symptoms
Itching of the scrotum is a symptom of initial onset, especially at night, and severe affects sleep. The scrotal skin lesions are roughly divided into three types.
(1) erythema type: manifested as symmetrical flaky erythema on both sides of the scrotum, varying in size, diameter is above 2 ~ 3cm, erythema is bright, sticky gray scales, suede, no wrinkles, no infiltration, slightly higher The skin is peeled off, so the boundary with the surrounding skin is clear. The erythema is dark red in the longer course of the disease. The same lesion can be seen at the end of the foreskin. That is, there is brownish black on the foreskin at the glans and thick and thick, and the edges are obvious and tidy. Change about 2/3 of patients with scrotal dermatitis.
(2) Eczema type: its symptoms can not be distinguished from general eczema. The skin lesions are characterized by dryness, desquamation, scarring and infiltration, hypertrophy, deep wrinkles, heavy exudate, erosion, fissure or suppuration. Its hardness is like rubber, the edge is diffuse or limited, and the skin lesions only account for 1/3 of the scrotum, and some involve the scrotum and perineum.
(3) Papular type: The skin lesions are characterized by scattered or densely integrated mung bean to soybean red flat papules, which are asymmetrically distributed on both sides of the scrotum, covered with bright phosphorous, and a few are mossy lesions.
2. Oral symptoms
Including lip dry crack, angular cheilitis, glossitis, etc., the early lip is red and swollen, the longitudinal crack is deepened, then the dry, wrinkled and pigmented, mainly found in the lower lip, some lip mucosa has potential ulcers, the mouth is smashed, The fissures and wet white spots are mostly bilaterally symmetrical. Because of the cracks, the mouth is painful, the severe ones have bleeding, the scars and small pustules often occur, and the tongue is painful, especially eating sour, spicy, hot food. Very, the whole tongue is purple or red, the map of the purple phase changes, the nipple nipple is hypertrophied, first in the tip of the tongue, the posterior wave and other parts, the filamentous nipple congestion is rare, the severe is accompanied by pharyngitis, laryngitis , hoarseness or difficulty swallowing.
3. Eye symptoms
There is conjunctival hyperemia, blood vessels around the cornea and invade the cornea, horns, blisters can occur at the junction of the conjunctiva, severe riboflavin deficiency, ulceration in the lower part of the cornea, erosion of the eyelid edge and corneal opacity, consciously afraid of light, tears, burning sensation , blurred vision and easy to fatigue.
4. Seborrheic dermatitis
More common in sebum secretion, such as the nasolabial fold, the lower jaw, between the two eyebrows, the outer eyelids and the back of the ear, it can be seen that the fatty deposits are located on the dark red base.
Vitamin B2 deficiency is often accompanied by the lack of other vitamin B family. According to the history of dietary deficiency, clinical manifestations and laboratory tests, the diagnosis is not difficult. When the oral-genital syndrome occurs collectively, special attention should be paid to the disease.
Examine
Vitamin B2 deficiency check
Free riboflavin, FAD and FMN in plasma are relatively constant, and the measurement has no diagnostic value. It is often used to determine the amount of vitamin B2 excretion in urine. As the collection of 24h urine is difficult, urine riboflavin/creatinine is often used. And urinary excretion load test two methods, in addition, erythrocyte glutathione reductase (EGR) activity coefficient (AC) measurement has been widely used in clinical because of its sensitivity, accuracy and simplicity.
1. Determination of urinary riboflavin/creatinine: Collect any urine sample, and use the relative amount of creatinine per gram to express the amount of vitamin B2 in the urine. The result is <27g/g creatinine is lacking, and 27-79g/g creatinine is insufficient.
2. Urinary excretion load test: After taking 5 mg of riboflavin orally, the urine output was collected for 4 hours, and the result was <400 g/4h urine is lacking, and 400-799 g/4h urine is insufficient.
3. Determination of the activity coefficient of erythrocyte glutathione reductase (EGR): EGR is a flavin-protected flavin protein. When vitamin B2 is deficient, its activity is decreased. For example, FDA is added to erythrocyte-soluble blood containing EGR in vitro. The activity can be recovered, and the ratio of the activity to the original activity after the rebound is the activity coefficient AC of EGR, and the AC value is >1.
Auxiliary inspection
1. Can do local skin cytology examination.
2. Perform skin tissue biopsy if necessary.
Diagnosis
Diagnosis and identification of vitamin B2 deficiency
Inspection diagnosis
Diagnostic treatment
Because the clinical symptoms of vitamin B2 lack specificity, it is difficult to diagnose the disease from the experiment. However, in some primary medical units lacking experimental conditions, individuals or groups suspected of having vitamin B2 deficiency can be tested for vitamin B2 for diagnosis. Treatment, effective can be diagnosed, oral vitamin B2 dose of 15 ~ 30mg / d, scrotal dermatitis symptoms can generally be relieved or disappeared within 1 to 2 weeks, and oral symptoms improved by 2 to 4 weeks.
2. Diagnostic criteria
Clinically, there is no unified diagnosis standard of 2 deficiency disease target=_blank>vitamin B2 deficiency disease. There are only vitamin B2 deficiency epidemiological investigation and diagnosis standards in China, and 2 lack of disease target=_blank> vitamin B2 deficiency disease diagnosis criteria are as follows.
(1) Signs: including: 1 sacral blepharitis; 2 mouth redness, mouth rupture, mouth smashing; 3 lips redness, lip cracking, lip erosion; 4 tongue purple, tongue ulcer, tongue nipple hypertrophy, tongue nipple atrophy; Scrotal redness, scrotal desquamation, scrotal erosion, scrotal scarring; 6 oily dermatitis.
(2) Experimental examination: load 4h urinary riboflavin <400g, can be diagnosed if the following conditions are met: 1 has 2 or more positive signs, these signs are not all in the same group of individuals, 2 has 1 or more positive When the signs and tests are abnormal.
Differential diagnosis
Should be associated with scrotal eczema and infectious keratitis, the former does not have glossitis and mouth damage, vitamin B2 treatment is not easy to achieve, the latter does not have scrotal inflammation.
