Pediatric vitamin D deficiency tetany
Introduction
Introduction to vitamin D deficiency in children with hand, foot and ankle Vitamin D deficiency in children with hand and foot rickets is a common pediatric disease. Mainly due to insufficient intake of vitamin D, resulting in a decrease in the absorption of calcium ions in the body. The main symptoms are convulsions, sweating, night terrors, irritability, irritability, restless sleep, and baldness. basic knowledge The proportion of children: the incidence rate of children under 3 years old is about 0.1%-0.3% Susceptible people: children Mode of infection: non-infectious Complications: brain injury brain edema
Cause
The cause of vitamin D deficiency in children with hand and foot spasm
(1) Causes of the disease
The cause of the disease is the same as that of rickets. It is a manifestation of the first stage of rickets. The bone changes are slight, the blood calcium is low and the blood phosphorus is normal, and the alkaline phosphatase is increased.
1. Serum calcium reduction
Blood calcium ion reduction is the direct cause of this disease. If the total serum calcium level drops to 1.75~1.88mmol/L (7-7.5mg/dl), or the calcium ion drops below 1mmol/L (4mg/dl), Symptoms of convulsions can occur.
2. Factors that promote blood calcium reduction
(1) Season: The highest incidence rate in spring, the highest incidence in March-May in Beijing, because infants rarely touch direct sunlight after winter, vitamin D deficiency has reached its peak at this time, and spring begins to contact sunlight. Vitamin D suddenly increases in the body, blood phosphorus rises, and the product of calcium and phosphorus reaches 40. A large amount of calcium is deposited on the bone, and blood calcium temporarily drops to promote the onset.
(2) Age: The age of onset is more than 6 months. The baby grows fastest and needs more calcium. If the supply is insufficient in the diet, vitamin D deficiency is easy to occur. The age of onset is much earlier than that of the mother. Vitamin D is related, such as the mother's vitamin D is sufficient, the general vitamin D stored in the newborn body, enough for 3 months of application.
(3) Others: immature and artificial feeding are prone to disease.
(4) Reduced calcium absorption: long-term diarrhea or obstructive jaundice can reduce the absorption of vitamin D and calcium, resulting in lower blood calcium.
(5) The increase of blood phosphorus leads to the decrease of blood calcium: the disease often occurs after acute infection, and the release of phosphorus into the extracellular fluid may cause the serum phosphorus concentration to suddenly increase and the blood calcium to decrease.
(6) 1-alpha hydroxylase deficiency: congenital 1-alpha hydroxylase deficiency, can not produce enough 1,25-(OH)2D3 to cause hypocalcemia, and congenital resistance to 1,25-(OH)2D3 Low blood calcium.
(two) pathogenesis
When blood calcium is low, the parathyroid glands are stimulated to show secondary hyperfunction, secreting more parathyroid hormone, which increases the excretion of phosphorus in the urine, and decalcifies the bone to supplement the deficiency of blood calcium. When the glandular compensatory function is incomplete, blood calcium cannot maintain normal levels.
Normal serum calcium is divided into diffusible calcium (about 60% of total calcium) and non-dispersed calcium, the latter is part of protein binding (about 40%), and most non-dispersed calcium binds to albumin. The rest is combined with globulin. When the serum H concentration is increased, the calcium bound to the protein is reduced, and about 80% of the dispersible calcium (about 50% of the total calcium of the serum) is ionized (ie, Ca2). Its physiological function is the most important, and the rest is combined with phosphate, bicarbonate or citrate. The main factors affecting the serum calcium ion (Ca2) concentration are hydrogen ion concentration, phosphate ion concentration and protein concentration, and blood hydrogen ions. The higher the concentration, the more calcium ions, the opposite is true for alkali poisoning. The more phosphate, the less calcium ions; the higher the plasma protein, the less calcium can be dispersed, and the calcium ions are correspondingly reduced. Conversely, when the plasma protein is low, The combined calcium is also reduced, and the calcium ion is relatively high. Even if the total serum calcium level is below the level of general hand, foot and sputum, the symptoms of sputum may not occur.
Prevention
Vitamin D deficiency in children with prevention of hand, foot and sputum prevention
The best prevention is sun exposure. About 80% of the vitamin D needed by the human body is synthesized by itself. Some people have determined that after sun exposure, the skin can be synthesized in 3 hours per square centimeter of skin. In sunny outdoor, children are not dressed. Wearing a hat to prevent rickets requires a sunbathing time of 2 hours per week. Children born in spring and summer can take out the sun after the full moon. Children born in autumn and winter can also take out the outdoors for 3 months and start to stay for 10 times each time. ~15min, you can extend the time appropriately, such as opening the window indoors.
Complication
Pediatric vitamin D deficiency hand, foot and sputum complications Complications Brain injury Brain edema
1. Choking: Those with heavy throat may die of asphyxia, or inhalation of trachea such as vomit and mucus may cause obstruction of the airway.
2. Brain damage: severe convulsions can go to brain damage.
3. If early diagnosis and treatment are available, most cases can stop convulsions within 1-2 days. However, severe throat can suffocate and die due to difficulty in inhalation. Severe convulsions can lead to cerebral edema and brain damage. If you have a serious infection or diarrhea in infants, it can aggravate or delay the disease.
Symptom
Children with vitamin D deficiency, hand, foot and sputum symptoms Common symptoms Alkaline phosphatase increased throat, convulsions, eyeballs upturned and fixed local limb twitching, vitamin D deficiency, sputum, bone softening, hair loss, suffocation
Dominant symptom
(1) Convulsion: It is the most common dominant symptom in infants. It is characterized by no fever in children, and no other causes of sudden seizures. Most patients have multiple seizures, repeated repeated episodes, and the number of episodes per day. ~20 times, each time is a few seconds to half an hour or so, when the attack does not occur, the child's expression is almost normal, when the convulsions are mostly lost, the rhythm of the hand and foot twitches, the facial muscles also squat, the eyeballs turn up Incontinence of incontinence, young infants sometimes only see facial muscles twitching as the initial symptoms of the disease, sputum is more common in the left and right sides, even or biased on one side, the degree of low blood calcium is not consistent with clinical manifestations.
(2) Hand and foot sputum: The special symptoms of the disease of the hand and foot sputum, the wrist is bent, the fingers are straight, the thumb is close to the palm, the toes are straight and the ankle is slightly curved, arched, common in infants over 6 months. Young children and children.
(3) Throat: mainly seen in infants and young children before the age of 2, the throat makes breathing difficult, the inhalation is prolonged and croup occurs, which can be caused by suffocation, and when the child with severe hand, foot and ankle is intramuscularly injected, even Can induce throat.
(4) Other symptoms: There are often nervous disturbances such as sleep disturbance, easy to cry, sweating, etc. Other first-coming or concurrent diseases can cause fever.
2. Recessive symptoms
Common signs such as the following, only signs and without the above symptoms, can be called recessive hand and foot sputum.
(1) Face-to-face nerve test (Chvosteks sign): Use a fingertip or a small hammer to slam the 7th cranial nerve through the ear to make the facial muscle contract, mainly the contraction of the upper lip or eyelid. Positive results can be obtained in children, but normal newborns do not lack calcium in the first few days or even 1 month. Children who are 2 years old are occasionally seen in other neurological diseases.
(2) reflex: use a small hammer to slam the phrenic nerve on the outside of the knee (above the humeral head), and the foot contracts to the outside when positive.
(3) Artificial hand spasm (Trousseaus sign): Wrap the upper arm with a cuff of a sphygmomanometer, and pump up to pause the pulse on the temporal side. If it is positive, see the handcuff within 5 minutes.
Examine
Examination of vitamin D deficiency in children with hand, foot and ankle
1. Urine calcium qualitative examination Most of the urinary calcium qualitative examination is negative.
2. Blood biochemical examination serum total calcium <1.751.88mmol/L (77.5mg/dl), calcium ion<1mmol/L (4mg/dl); serum alkaline phosphatase increased; serum inorganic phosphorus is normal, or even More than 2.26mmol / L (7mg / dl).
3. The three routine inspections are normal.
4. Chest radiographs can exclude lung infections.
5. EEG excludes seizures caused by epilepsy and the like.
Diagnosis
Diagnosis and identification of vitamin D deficiency in children with hand, foot and ankle
diagnosis
History
Pay attention to factors such as age, season, premature birth and feeding history.
2. Clinical characteristics
(1) Athermal convulsions: convulsions are the most common in infancy, and there are several consecutive convulsions without symptoms or signs of infectious diseases. The disease is first considered.
(2) Hand, foot and ankle: Larger children are the most common with hand, foot and ankle, and are specific.
(3) Signs: There are signs of mild rickets, such as softening of the skull, large sputum and occipital hair loss.
3. Laboratory inspection
(1) urinary calcium: urinary calcium qualitative test is mostly negative.
(2) Blood biochemistry: serum calcium is reduced to 1.88 mmol/L (7.5 mg/dl) or less, serum alkaline phosphatase is increased, blood phosphorus is normal, or higher than 2.26 mmol/L (7 mg/dl).
Differential diagnosis
1. Differential diagnosis of convulsions
See the horror section. In the neonatal period, special attention should be paid to productive damage, congenital brain hypoplasia and sepsis. If it is a larger baby, special attention should be paid to various acute diseases (such as pneumonia, upper respiratory tract infection, etc.). Brain symptoms at the onset, encephalitis, meningitis with low fever (such as tuberculous meningitis, occasional lack of hyperthermia in meningococcal meningitis), infantile spasms, hypoglycemia and lead poisoning, etc. Childhood must be differentiated from epilepsy and hypoparathyroidism.
2. Differential diagnosis of laryngeal obstruction
The throat of hand, foot and ankle is mainly characterized by inspiratory croup, and the Foss is positive for diagnosis.
3. Differential diagnosis of hand, foot and ankle
(1) parathyroid insufficiency: hand and foot spasm caused by parathyroid dysfunction, such as miscutting the parathyroid gland during thyroid surgery, can cause parathyroid hormone deficiency and cause hypocalcemia; newborn just From the mother, there may be temporary hypoparathyroidism; if the newborn is fed with milk, due to the high content of phosphorus in the milk, calcium is not easily absorbed, and blood calcium is reduced to cause hand and foot spasm; in addition, congenital parathyroid glands Dysplasia, molecular abnormalities of hereditary parathyroid hormone gene, etc., all have symptoms of hand and foot sputum. All the above diseases have common blood biochemical characteristics, namely, elevated blood phosphorus, decreased blood calcium, and normal alkaline phosphatase. Treated with dihydrotachysterol or parathyroid hormone.
(2) Alkali-toxic hand, foot and ankle syndrome: hypochlorine alkalosis due to long-term vomiting or repeated gastric lavage; respiratory alkalosis due to deep breathing caused by salicylic acid poisoning; or intravenous infusion due to improper infusion A large amount of sodium bicarbonate, etc., can cause calcium ions to fall and become ill.
(3) low-magnesium hand, foot and ringworm: occasionally found in premature infants and small samples, mothers often have pregnancy poisoning, diabetes, hyperthyroidism, also seen in neonatal hemolysis with blood transfusion of citrate anticoagulation, At this time, both magnesium and calcium in the blood are reduced and the hand and foot sputum is present (the normal value of serum magnesium is 0.74 to 1.25 mmol/L), or the diarrhea may be prolonged for a long time, or the intestinal malabsorption may be affected by the lack of enzymes. Absorption, but also due to hyperaldosteronism or primary hypomagnesemia and convulsions, patients with serum magnesium decreased below normal, facial muscle twitching, hand and foot, high blood pressure, tachycardia, etc., calcium supplementation, However, symptoms can be controlled after injection or oral administration of magnesium.
(4) Nephrotic hand, foot and ankle stagnation: due to renal insufficiency, renal tubular depletion function is reduced, blood phosphorus is increased, resulting in lower blood calcium, such diseases are mostly albumin reduction or chronic acidosis, so rarely occur Symptoms, but if the serum calcium is extremely reduced, or when the pH of the serum is increased by the input of an alkaline solution, symptoms of convulsions or hand and foot spasms may occur.
(5) hyponatremia and hypernatremia: treatment of dehydration, such as improper fluid replacement, hyponatremia, sudden sleep, vomiting, convulsions and other neurological symptoms, in the process of dehydration and acidosis correction, when blood sodium rise When the blood potassium drops, hypernatremia occurs, symptoms of hand and foot spasm may occur, and neonatal asphyxia or respiratory distress syndrome may occur if a large amount of sodium bicarbonate solution is administered, and hypernatremia may occur.
(6) 6 deficiency target=_blank> Vitamin B6 deficiency and dependence: In the case of a baby, such as lack of vitamin B6 or vitamin B6 dependence, convulsions may also occur.
