vitamin C deficiency
Introduction
Introduction to vitamin C deficiency Long-term lack of vitamin C (ascorbic acid, ascorbic acid) caused by the total disease, is currently rare, but in the northern pastoral areas lacking vegetables, fruits, or urban, townships, artificial feeding, neglected complementary food supplements, especially in rural remote areas, still due to Improper feeding causes the disease. Since Pauling published the relationship between cold and vitamin C in 1970, the problems related to the function of vitamin C in the body and the high-dose clinical application have attracted the attention of many scholars. basic knowledge The proportion of illness: 0.06% Susceptible people: no special people Mode of infection: non-infectious Complications: Osteoporosis Malnutrition Otitis Media Pneumonia
Cause
Vitamin C deficiency
(1) Causes of the disease
Insufficient intake (40%):
If the pregnant mother has proper nutrition, the child has a suitable vitamin C reserve at birth. The plasma vitamin C content of cord blood is 2 to 4 times higher than that of the mother plasma. Therefore, the infants under 3 months have less incidence, but if the pregnant mother's diet lacks vitamin C, Newborns can also suffer from scurvy. Normal human milk contains about 40-70 mg/L (4-7 mg/dl) of vitamin C, which can meet the needs of ordinary babies. The content of vitamin C in human milk is proportional to the amount of vitamin C in the lactating mother. For example, if the lactating mother's diet lacks vitamin C, the baby may suffer from scurvy. The fresh animal milk contains less vitamin C than human milk. The content of milk is generally only 1/4 of that of human milk. After storage, disinfection and dilution, etc. After that, there are very few deposits. Therefore, infants fed with milk, goat milk or unfortified milk powder, milk cake, batter, etc., if they do not supplement vitamin C, fruits or vegetables on time, are prone to scurvy, and older children are bad. Blood disease is caused by the lack of fresh vegetables and fruits in the diet.
The amount of Vc required is increased (30%):
When the metabolic rate increases, the vitamin C requirement increases. When the growth is active, the vitamin C content in the body tissue decreases sharply. The premature infants grow faster and faster. The vitamin C requirement is relatively larger than that of normal infants, and should be supplemented more. Hot sexually transmitted diseases, acute and chronic infectious diseases such as diarrhea, dysentery, pneumonia, tuberculosis, etc., the amount of vitamin C needs to increase, such as long-term illness, and did not increase the intake of vitamin C, easy to be complicated by the severity of bad blood disease.
Other factors (20%):
Such as long-term intake of a large amount of vitamin C, its catabolism and renal excretion increased to reduce plasma vitamin C concentration, such as sudden withdrawal of large amounts of vitamin C, can occur scurvy, long-term application of large amounts of vitamin C during pregnancy, even after birth Ingestion of regular amounts of vitamin C may still cause scurvy.
Vitamin C is essential for the formation of normal collagen in the human body. Vitamin C cannot be synthesized in the human body and needs to be taken from the diet. Vitamin C is widely found in fruits and vegetables. The fruits are tannins, grapes, and berries. Rich in content, vegetables are green leafy vegetables, sprouted vegetables or beans, tubers, potato content, human adrenal gland and eye crystals contain a high amount of vitamin C, vitamin C is very soluble in water, there is a strong Reducibility, easily damaged in the following situations: 1 alkaline environment; 2 trace copper; 3 vegetables are smashed, cut, squeezed, and released ascorbate oxidase after tearing; 4 heating boiling time is too long; 5 system The prepared dishes are placed too long.
The structure of vitamin C is similar to monosaccharide. It is generally considered to be an important cofactor for prolylhydroxylase and Lysylhydroxylase, which are essential for collagen biosynthesis, and can enhance various hydroxylases and oxidation. The activity of the enzyme, due to its reversibility of oxidation-reduction ability, is active in microsomal electron transport, plays an important role in preventing collagen depolymerization and maintaining matrix integrity, and can convert folic acid into Tetrahydrofolate, which promotes the maturation of red blood cells; reduces ferric iron to divalent iron, which facilitates intestinal absorption of iron and synthesis of hemoglobin and formation of ferritin in the liver, and promotes certain adrenal and pituitary hormones. Synthesis of immunoglobulins and neurotransmitters.
Some aromatic amino acid metabolism requires vitamin C to participate, so tyrosineuria may occur in scurvy; in the neonatal period, especially in low-weight children, transient tyrosine is too high; premature infants are fed with high-protein emulsion A large amount of tyrosine and phenylalanine are often excreted in the urine, and these conditions can be corrected by vitamin C.
Vitamin C deficiency can lead to collagen fiber formation disorders, decreased intercellular binding, stagnant dentin and bone-like tissue formation, capillary hemorrhage, delayed wound healing, folic acid and iron metabolism disorders leading to anemia and a series of lesions.
(two) pathogenesis
Vitamin C is closely related to collagen synthesis. When vitamin C is deficient, it is caused by collagen synthesis disorder, which leads to wounds, ulcers are not easy to heal, bones, teeth, etc. are easy to break and fall off; capillary fragility increases, causing skin, mucous membrane, muscle bleeding Wait for vitamin C deficiency symptoms.
Because vitamin C is closely related to collagen synthesis, the pathological changes of vitamin C deficiency caused by vitamin C deficiency are mainly in the connective tissue between cells, especially in collagen, such as growing bone, tooth and Blood vessels, etc., the lesions in the bone are mainly slow growth, the cartilage matrix can not be normal calcification, bleeding can be seen in the bone of the cartilage, the backbone joint, the trabecular bone fracture of the cartilage matrix, sometimes dislocation, separation or osteophyte embedding, subperiosteal hemorrhage Adults are rare, but they are common in infants with vitamin C deficiency. Capillary hemorrhage due to loose adhesion of periosteum can cause large periosteum to be released. This subperiosteal hemorrhage is most common at the lower end of the femur, the upper end of the humerus, and both ends of the tibia. At the junction of the middle ribs and the costal cartilage, the capillaries of the skin become brittle, resulting in bruises, ecchymoses and hematoma. The bleeding of the gums can cause swelling of the gums, fragile tissue or even gangrene, and loose teeth can occur due to alveolar bone absorption; children's Abnormal tooth development, minimal matrix formation, and sponge-like dentin.
The main lesion is due to the lack of collagen causing bleeding and bone changes. When vitamin C is deficient, the main components of collagen, hydroxyproline and chondroitin sulfate, reduce the formation of collagen fibers. The following lesions may occur: 1 due to the formation of connective tissue, the lack of binding between capillary endothelial cells, resulting in capillary fragility and increased wall permeability, can be in the skin, mucosa, subperiosteal, joint cavity and intramuscular bleeding, 2 bones Lesions: mostly at the rib cartilage junction and long bone end, especially in the vicinity of the wrist, knee and ankle joint, due to the formation of the matrix, osteoblasts can no longer form bone-like tissue between normal cells, cartilage ossification However, the calcination in the cartilage matrix continues, characterized by temporary accumulation of calcareous calcium in the metaphysis, formation of a temporary calcification zone dense and thickening, inhibition of osteogenesis, formation of bone tissue, formation of trabecular bone becomes brittle Easy to fold, the metaphyseal bone is fragile, often leading to fracture and osteophyte separation, the original cortical bone and cancellous bone Internal bone atrophy, generalized bone atrophy, loosening of the epicardium, subperiosteal hemorrhage due to bleeding tendency, 3 tooth lesions: hyperemia and edema of the gums, degeneration of the dentate cell layer, loose teeth due to collagen deficiency, lesions of the gums The beginning is the growth of gingival papilla hyperplasia and granulation tissue, and then gradually necrosis. This lesion is common in children who have teething. In severe cases, there may be skeletal muscle degeneration, cardiac hypertrophy, myelosuppression and adrenal atrophy.
Prevention
Vitamin C deficiency prevention
High levels of vitamin C in breast milk are one of the reasons for emphasizing human breastfeeding. The diet of pregnant women and lactating mothers should include vitamin C-rich foods such as fresh vegetables and fruits, or vitamin C tablets dissolved in water and sugar, and their vitamin C needs. The amount is about 80-100mg or more per day, which can ensure that the fetus and the baby get enough ascorbic acid. Zhufu (1936) has done experiments, as long as the daily intake of cabbage and white radish is 0.5kg each, which is contained in breast milk. The concentration of vitamin C can be as high as 60 mg/L (6 mg/dl).
2 to 4 weeks after birth, the newborn should be supplemented with a diet containing more vitamin C and can be digested by the newborn, such as fresh orange juice, tomato juice, cabbage soup, radish juice, etc., starting from April to May. Mud, artificially fed babies should be supplemented with appropriate amount of vitamin C every day. The normal daily supply of vitamin C is 30mg for children, 30 to 35mg for young children, 40 to 60mg for older children, and 100mg for premature infants. According to the recommendation of 1988, vitamin C is consumed more when it is sick, and should be given a larger dose.
According to the above treatment, the mild pain and local pain are usually relieved within 1 to 2 days, the appetite is improved, the lower limbs can be active after about 4 to 5 days, the symptoms disappear after 7 to 10 days, the body weight is gradually increased, and the local tenderness is about 3 weeks. Complete elimination, while capillary fragility also returned to normal, megaloblastic anemia after retinal red blood cells treated with vitamin C and folic acid increased significantly, skeletal lesions and subperiosteal hemorrhage caused by the recovery of hematoma takes a long time, heavy for several months Disappear, even if the bone lesions are very heavy, it is easy to recover, and no deformity will occur. However, if left untreated, scurvy children may suffer from malnutrition, bleeding or infection and death.
1. Choose foods rich in vitamin C: the main source of human vitamin C is fresh vegetables and fruits; only a small amount of liver and kidney in animal foods, so there should be enough fresh vegetables in the diet, especially green leafy vegetables. If you can eat some fruits regularly, it will help prevent the deficiency of vitamin C.
2. Improve cooking methods and reduce vitamin C loss: Vitamin C is very soluble in water; sensitive to oxygen, especially iron, copper ions are more susceptible to oxidation damage, unstable to alkali, but quite acidic Stable, therefore, when cooking vegetables, first wash and cut, cut and fry, try to shorten the exposure time in the air, stir-fry without copper.
In higher plants, at least five enzyme systems are known to catalyze the oxidative destruction of vitamin C. They are vitamin C oxidase, peroxidase, polyphenol oxidase, cytochrome oxidase and laccase. Except for peroxidase, they are all copper-containing metalloenzymes. These oxidase systems are abundant in vegetables, especially cucumbers and cabbages. Therefore, vitamin C often has varying degrees of damage during vegetable storage and transportation, but these enzymes It is more heat-tolerant than vitamin C. Therefore, during the cooking process of vegetables, it is emphasized that the fire is fast-fried. When the soup is made, the soup is opened, in order to quickly destroy these enzymes to reduce the loss of vitamin C.
On the other hand, the polyphenolic compounds contained in plants have protective effects against the oxidative destruction of vitamin C. For example, rutin, quercetin and related flavonoids have such a role, they can not only make vitamin C in food. Stable, and can play a role in stabilizing vitamin C in the intestines, especially in the intestines of patients without stomach acid or low stomach acid.
3. Use wild vegetables, wild fruits and vitamin preparations: Many wild vegetables, wild fruits are rich in vitamin C, such as medlar, purslane, malan head, medlar, wild leek, mustard, etc., vitamin C content can be higher than ordinary vegetables Several times to 10 times; the pear C, pomegranate, sour willow, jujube, kiwi and sakura in the wild fruit can be 50 to 100 times higher than the average citrus, which is a good source of vitamin C. Vitamins can be used in large quantities in the country, and can be used appropriately.
Complication
Vitamin C deficiency complications Complications Osteoporosis Malnutrition Otitis Media Pneumonia
Osteoporosis, vitamin deficiency, collagen synthesis disorders, resulting in poor bone and organic matter leading to osteoporosis, often shows a prominent feature in children, that is, the long bone end is rod-shaped deformity, joint movement pain, children often The knee joint is maintained in the flexion position, and the rib and the costal cartilage junction are prominently beaded, and the angle is slightly sharper than the vitamin D deficiency disease (sickness); the inside of the convex can be sag and depression, the disease can be associated with rickets, nutrition When the dysfunction occurs at the same time, when the rickets are complicated, the different manifestations of the two diseases appear on the X-ray film, so that the confusion is unclear, the resistance of the children with scurvy is reduced, and the infections such as otitis media, rickets, pneumonia, etc. are often complicated.
Symptom
Vitamin C deficiency symptoms common symptoms skin chapped skin dry and red vitamin C deficiency bacteria infection hematuria weak inflammation calcification gum bleeding bleeding limb weakness
Typical scurvy has obvious symptoms and is easy to diagnose. It is difficult to diagnose recessive and early scurvy due to lack of specific symptoms. It should be combined with feeding history and other examinations for comprehensive analysis.
1. Feeding history and clinical symptoms: artificial feeding infants do not add complementary foods containing vitamin C, or the lack of fresh vegetables or fruits in the lactating mother diet, or the habits of the lactating mothers only eat pickles, etc., the age of scurvy (3 to 18 months) ), combined with some of the aforementioned non-specific symptoms and feeding history, can provide clues for the diagnosis of early scurvy, such as the disease has developed to a certain stage or advanced stage, according to limb swelling, frog-shaped legs, gums and submucosal bleeding, etc. Symptom diagnosis.
There is a process in the occurrence and development of vitamin C deficiency. First, the vitamin C reserve in the tissue is reduced. Further development is biochemical deficiency and dysfunction. Further development is anatomical changes and even death (Table 1). The clinical manifestations are as follows.
1. Prodromal symptoms: Before the onset of the disease, there are many weight loss, limb weakness, weakness, muscle and joint pain symptoms, and the clinical manifestations of vitamin C deficiency in adults and infants are somewhat different. In addition to the above symptoms, adult patients have gums in the early stage. Swelling, inflammation or inflammation, infants are uneasy, limbs are painful, the costal cartilage joints are enlarged, and the long bones of the extremities are swollen (especially the lower end of the femur, but not extending to the joint) and bleeding tendency. Bleeding, especially large skin bleeding, more common in adults than in infants; but bleeding around the baby's epiphysis is not easy to see in adults, congestion around the hair follicles, more common in adults, but not in infants, as for subperiosteal hemorrhage, skin hemorrhage and gums Bleeding, etc. can occur in both adults and infants. The incidence of infants is mostly from June to 1 year old, and can occur at other times. Adults often suffer from long-term lack of vitamin C in the diet.
2. Bleeding: Patients with vitamin C deficiency may have systemic punctate hemorrhage, which is initially confined to the around the hair follicle and the gums. Further development may include subcutaneous tissue, muscle, joint, tendon sheath and other hemorrhage, even hematoma or ecchymosis. Spotted in the lower extremities, the knee is the most, the internal organs, mucous membranes also have bleeding, such as nosebleeds, hematuria, blood in the stool and menorrhagia; occasionally there are occasional pericardium, chest, abdominal cavity, retroperitoneal and intracranial hemorrhage, common lower extremity swelling in children Pain, the affected limb often maintains a certain position, that is, the two legs are abducted, the calf is bent inside, and it is pseudo-sick, which is mainly caused by subperiosteal hemorrhage.
Hemorrhage around the hair follicle is one of the most special and earliest clinical signs of vitamin C deficiency. It usually occurs in highly keratinized hair follicles, especially the extension and abdomen of the arms and thighs. Common hair becomes brittle, curled and trapped inside the hair follicle. After the bleeding around the hair follicle, there may be swelling and hypertrophy of the hair follicle, that is, inflammation around the hair follicle.
Patients may have anemia. The cause of anemia is mainly due to skin and deep tissue bleeding. It may also be due to insufficient intake of folic acid in the diet. Many foods are rich in vitamin C and rich in folic acid. simultaneously exist.
3. Gingivitis: gingival bleeding can be seen, loose, especially at the tip of the gums. It can be bleeding with a little pressure, and there are ulcers and secondary infections. The severe ulcers progress very rapidly. In the short term, the teeth are due to gums and cogging. Necrosis and shedding, chronic gingival atrophy, gingival dew, and finally loosening and falling off the teeth.
Gingival bleeding is the main disease of vitamin C deficiency. In infants, small blood bags often occur on the gums, and it is easy to cover the deciduous teeth. This blood bag can be broken if it is slightly stressed, and sometimes it can cause a lot of bleeding. But life-threatening, adult vitamin C deficiency is often accompanied by chronic gum damage, that is, gingivitis, gingivitis and bacterial infection, but only when vitamin C deficiency, gingival tissue resistance is reduced.
Examine
Vitamin C deficiency check
1, X-ray inspection
2, laboratory inspection
1 After the fasting, the plasma vitamin C concentration>6mg/L (0.6mg/dl) can rule out scurvy, but the lower concentration can not confirm the existence of scurvy, the clinical diagnosis is often combined with the concentration of plasma vitamin C. Parallel, the specimen must be measured within 48 hours after collection. The vitamin C in the human body is mainly reduced, about 80% of the plasma is reduced, 20% is oxidized, and plasma vitamin C can reflect the intake of dietary vitamin C. According to the study, plasma vitamin C content is linearly related to vitamin C intake, but some reports indicate that when plasma vitamin C is reduced to 0.1-0.3 mg, clinical symptoms will not occur. Therefore, plasma vitamin C can only reflect vitamin C. Ingestion, but does not reflect the storage of vitamin C in the body.
According to China's research, the fasting plasma vitamin C content evaluation standard (2,4-dinitrophenylhydrazine colorimetric method) can be divided into four levels: <0.4mg is insufficient, 0.4-0.8mg is sufficient, >0.8mg is sufficient, 1.4 mg is saturated.
2 The white blood cell-platelet layer (blood yellow layer) of the blood treated by oxalic acid is precipitated and the ascorbic acid concentration is determined, which is a method for confirming the deficiency of vitamin C. The normal concentration is 280-300 mg/L (28~ 30mg/dl), when its content drops to zero, although there is no clinical symptoms, it also indicates recessive scurvy.
3 Another better method is the tolerance test, using ascorbic acid 20mg / kg in physiological saline to make a 4% solution, intravenous injection, such as 4 hours after the urine sample vitamin C amount> 15mg / L (1.5mg / dl), Can scurvy.
4 When vitamin C is deficient, the vitamin C content in the urine is reduced in 24 hours (normal value is 20-40 mg). Although a large amount of vitamin C is added, the content of vitamin C in the urine cannot be normalized, because all tissues in the body need to be supplemented. The amount can be excreted by the urine until the whole body has reached saturation. After the blood content increases, the excess vitamin C is excreted in the urine. The vitamin C content in the urine changes due to dietary intake and storage in the body, and can also be used as a vitamin C nutritional status. Evaluation indicators.
5 In addition, non-specific amino acid urinary tract is seen in scurvy, but the blood amino acid value is still normal. The tyrosine load test shows that the metabolites excreted by scurvy infants are similar to those of immature babies. The capillary fragility test is hidden. Sexual scurvy may be negative, dominant scurvy is tested positive, serum calcium, phosphorus normal, alkaline phosphatase activity decreased, the value decreased, contrary to active rickets, late anemia, generally small cells Sexually, when cell metabolism is impaired, large cell anemia can occur.
Capillary fragility test:
1. Compression method: This is the simplest method. Use two thumbs and index finger to firmly clamp on the subject's skin for 1 minute, then carefully observe the subject's subcutaneous bleeding point and calculate the bleeding point. number.
2. Positive pressure method (volume blood pressure method): according to the general amount of blood pressure, the mercury column is raised to 6.7 kPa (50 mmHg) or the median value of systolic pressure and diastolic blood pressure, maintaining this pressure for about 15 min, then with a diameter of 60 mm The rubber band was printed on the elbow of the subject, and the number of bleeding points in the circle was recorded. The bleeding point in the circle was <5 normal; >8 was abnormal.
Diagnosis
Diagnosis and identification of vitamin C deficiency
Diagnosis can be based on medical history, clinical symptoms, and laboratory tests.
Differential diagnosis
Discrimination should be carefully performed to avoid delays in effective treatment due to missed diagnosis, or unnecessary surgery due to misdiagnosis as local inflammation.
1, limb swelling and pain should be associated with septic arthritis, osteomyelitis, cellulitis and deep abscess, these diseases are more common in unilateral limbs, and local redness and burning, systemic symptoms, high fever, poisoning and Increased white blood cells are significantly different from scurvy. Rheumatoid arthritis is rare in infants younger than 2 to 3 years old, and is migratory. Other specific symptoms and signs of rheumatic fever can be identified.
Subperiosteal hemorrhage of scurvy sometimes needs to be differentiated from tumors, but other symptoms of scurvy are easy to identify with tumors. If necessary, X-ray examination and treatment tests can be used to confirm the diagnosis.
The general symptoms and skeletal tenderness of infantile cortical hyperosteosis are sometimes similar to scurvy, but the lesions are more common in the flat stomach, such as the jaw, scapula, calcaneal bone, clavicle, etc., the face is often involved, and sometimes the limbs are involved. Increased erythrocyte sedimentation rate and increased serum alkaline phosphatase are helpful for identification. The age of onset is more than 6 months after birth, and the scurvy is more than 6 months. The course of cortical hyperplasia is very irregular and short. For several weeks, the elders are several months, sometimes recurrent, and generally healed. X-ray examination shows bone hyperplasia and thickening of the cortex. After several months, it has nothing in common with scurvy.
The age of onset is different from scurvy, and it has characteristic hair, skin, redness, itching and severe pain, high blood pressure, sweating and shame. In severe cases, the fingers and toes become black and even fall off, which is easy to distinguish from scurvy. (See the Poisoning Section on Mercury Poisoning).
2, limb false sputum must be associated with poliomyelitis, rickets, trauma, congenital syphilis, etc.: 1 polio manifestations of flaccid paralysis, no swelling and pain, and other peripheral symptoms, and scurvy is very different; 2 rickets There are special signs and X-ray findings; 3 trauma cases should have a history of injury, and bilateral symmetrical injuries are rare, X-ray examination is very significant; 4 congenital syphilis occurs in infants less than 4 months, mother suffering Significant or invisible syphilis, children with specific signs of congenital syphilis, serological tests and X-ray long bone photography can be identified.
3, bleeding symptoms should be identified with other bleeding disorders: 1 thrombocytopenic purpura, allergic purpura, hemophilia, etc. can be identified according to platelets, bleeding and clotting time and other coagulation tests and family history; 2 leukemia bleeding, at the same time Blood and bone marrow have their characteristic changes; 3 septic epidemic cerebrospinal meningitis has neurological signs and cerebrospinal fluid changes, and it is easy to find pathogenic bacteria from the skin purpura and cerebrospinal fluid, easy to identify; 4 orbital hemorrhage and eyeball protrusion It should be differentiated from neuroblastoma and chronic yellow tumor. The latter two have no other scurvy characteristics. 5 When the gum is bleeding, when it is differentiated from gingivitis, the latter is rare in infants, and its gums are mostly flushed and not accompanied. Other symptoms of scurvy.
4, early follicular keratosis: even after the formation of keratosis, must be differentiated from the skin changes in vitamin A deficiency, but vitamin A deficiency of follicular keratosis often accompanied by vitamin C deficiency around the hair follicles, the stasis is Severe vitamin C deficiency has characteristic clinical manifestations. The vitamin C deficiency disease has a large siltation point, and it is more purple than other purpura such as thrombocytopenic purpura. It is similar to the blood stasis caused by the tourniquet, which is common in the forearm extension. In the hair growth area, with the development of vitamin C deficiency, ecchymosis may occur in the area of compression or trauma, and thereafter, there may be a large amount of bleeding in the skin, muscles, and joints.
5, gingivitis: vitamin C deficiency is the main reason, other, such as tartar stimulation, pregnancy and menstrual period can also be seen bleeding gum; uremia, diabetes and other diseases can also have gingivitis and gum bleeding; vitamin B1 deficiency disease (petal disease) , , , , , , , , , , , , , , , , , , , , Phosphorus poisoning can also cause swelling and bleeding of the gums. It can be seen that local, systemic, nutritional, non-nutritional factors can cause gingivitis, bleeding of the gums, and should be identified during diagnosis.
Vitamin D deficiency disease beading is bilaterally symmetrical, with no inner depression.
