Pediatric hypoparathyroidism

Introduction to pediatric hypoparathyroidism Hypoparathyroidism (hypoparathyroidism) is referred to as parathyroid hypoplasia due to parathyroid hypoplasia, insufficient hormone secretion, metabolic and synthetic disorders, or dysfunction, or structural abnormalities lacking physiological functions. Target organ receptor abnormalities are not PTH. Caused by sensitivity, clinically characterized by low blood calcium, hand, foot and high blood phosphorus. basic knowledge Sickness ratio: 0.05% Susceptible people: children Mode of infection: non-infectious Complications: Epilepsy Cataracts Malnutrition Low blood pressure

Causes of hypoparathyroidism in children

(1) Causes of the disease

According to the onset time, with or without family history and associated diseases, the low causes of parathyroidism are classified as follows:

Temporary parathyroid (30%):

(1) Early neonatal hypothyroidism.

(2) Late neonatal hypothyroidism.

(3) The mother's parathyroid or other factors cause a low side.

Parathyroid gland hypoplasia (20%):

(1) Thymus and III, IV zygomatic arch defects (DiGeorge syndrome).

(2) Chromosomal abnormalities (especially 22P chromosome).

(3) The mother was treated with 131I and was low in the side.

(4) Mother suffering from diabetes, alcoholism.

(5) Simple hypoplasia.

Familial hypothyroidism (10%):

(1) X chain lock inheritance.

(2) Autosomal dominant inheritance.

Idiopathic hypoparathyroidism (10%):

(1) Autoimmune parathyroidism.

(2) Congenital parathyroid hypoplasia.

5. Surgical removal or trauma damage the parathyroid glands.

6. Hemosiderinosis.

7. Parathyroid hormone has no effect (pseudo-parathyroid).

8. Parathyroid hormone lacks response in the target organ (CAMP lacks response to PTH in the exogenous PTH urine to pseudo-parathyroidal type I, and urinary CAMP responds to PTH to type II).

9. Increased calcitonin (medullary thyroid carcinoma).

10. Vitamin D deficiency.

11. Magnesium deficiency.

12. Inorganic phosphorus is too high.

(two) pathogenesis

Pathogenesis

(1) Early neonatal hypothyroidism: Under normal circumstances, the umbilical cord blood PTH is low at birth, and rises to the level of normal children on the 6th day after birth, and hypocalcemia occurs 12 to 72 hours after birth. For the early neonatal hypothyroidism, common causes are: premature labor, respiratory distress syndrome, intrauterine infection and intrauterine malnutrition and diabetic mothers and babies, in addition to early neonatal target organs are less sensitive to PTH, 1,25 (OH The 2-D concentration is low, the blood drops Ca, the adrenocortical hormone is high, and the comprehensive factors lead to the early hypothyroidism.

(2) Late neonatal hypothyroidism: 2 to 3 days after birth to a weekend, or later hypocalcemia, the cause may be temporary parathyroid hypoplasia, common in premature infants, infants born to high-risk mothers, During pregnancy, certain endocrine diseases such as diabetes and hyperparathyroidism affect the development of fetal parathyroid gland and blood calcium concentration. The condition is due to hypocalcemia, which stimulates the parathyroid gland to accumulate hyperplasia and secrete PTH. In the last few months, it may be More.

(3) Familial hypoparathyroidism: recessive inheritance of X-chain lock, can occur from 2 weeks to 6 months after birth, late onset from infant to young, is autosomal dominant, neither of these two types With congenital defects, only low calcium, hyperphosphatemia, low levels of PTH immunoreactivity, and no parathyroid antibodies.

(4) idiopathic hypoparathyroidism: idiopathic parathyroid hypothyroidism with the progress of the diagnosis of the disease, the disease is gradually reduced, usually in the first year of the disease are mostly congenital parathyroid gland absent, such as DiGeorge syndrome and Caused by autoimmune diseases, a small number of unknowns are idiopathic hypoparathyroidism.

(5) autoimmune parathyroid hypoplasia: often found in vivo parathyroid antibody, accompanied by other autoimmune diseases and specific organ antibodies, such as accompanied by Addison disease (Addison disease) and skin mucosal Candida infection, about 1 /3 patients are accompanied by the above situation, 70% of candidiasis occurs before the age of 5 years, before Addison disease, 90% of the incidence of parathyroidism before the age of 3, Addison disease started after 6 years old, called multiple Endocrine gland insufficiency-autoimmune-candidiasis syndrome (in addition, 10% to 25% may be accompanied by other autoimmune diseases at different times, such as alopecia areata, Hair loss, intestinal malabsorption syndrome, pernicious anemia, sexual insufficiency, chronic active hepatitis, Hashimoto's thyroiditis, etc., a small number of patients with insulin-dependent diabetes mellitus and IgA deficiency, regardless of HLA type.

2. Primary hypoparathyroidal pathophysiology When the PTH secretion is reduced to a normal amount of 1/2 for various reasons, the symptoms can be clinically present. The pathophysiology of hypoparathyroidism is mainly due to the decrease of PTH, which weakens the osteolysis effect. Ca mobilization is reduced; renal phosphorus is reduced, blood phosphorus is increased, 1,25 (OH) 2-D3 production is reduced, intestinal calcium absorption is reduced, and blood calcium is lowered.

Hypocalcemia reduces urinary calcium, often at 10-20 mg/d. Hyperphosphatemia often binds to Ca2 in bone and soft tissue, so about 1/3 of patients have increased bone density, while serum alkaline phosphatase is normal, calcium salt. It can also be deposited in other organs such as basal ganglia, blood vessel wall and subcutaneous. When hypocalcemia occurs, neuromuscular excitability is increased, and symptoms such as convulsions and throat are present.

Pediatric hypoparathyroidism prevention

1. Prevention of neonatal hypothyroidism: neonatal hypothyroidism is common in premature infants, high-risk newborns, intrauterine infections and intrauterine malnutrition; or infants born to high-risk mothers, some endocrine diseases such as diabetes during pregnancy Etc. Therefore, all kinds of health care during pregnancy and perinatal period should be done to prevent the above-mentioned conditions from appearing.

2. Prevention of hereditary diseases: Familial hypoparathyroid is X-locked recessive inheritance, and late-onset is autosomal dominant inheritance.

3. Prevention of autoimmune diseases: Infection is often a predisposing factor. Active prevention and treatment of various infectious diseases, including various vaccinations, strengthening nutrition, and strengthening physical fitness.

4. Prevention of trauma or surgical injury: surgical removal or trauma damage to the parathyroid glands can cause this disease, improve surgical procedures, improve operational techniques, and prevent damage to the parathyroid glands.

5. Balanced diet: Nutritional diseases can cause this disease, such as vitamin D deficiency, magnesium deficiency, and high levels of inorganic phosphorus. Therefore, scientific parenting knowledge should be popularized to prevent nutritional diseases.

Pediatric hypoparathyroidism complications Complications, epilepsy, cataract, malnutrition, hypotension

The most common is the attack of hand, foot and ankle, which can be systemic twitching, laryngeal, bronchospasm, hypoxia in the body, secondary epilepsy, bladder spasm can cause urinary incontinence, vasospasm causes headache, limb Raynaud's sign, extrapyramidal symptoms may occur Such as increased muscle tone, chorea or cerebellar ataxia, etc., may be related to basal ganglia calcification, often associated with Candida albicans infection, tooth calcification, enamel dysplasia, enamel shedding, cataract is more common, severe Can cause blindness, delayed mental development, low blood pressure, and even heart failure, secondary vitamin D deficiency and malnutrition.

Symptoms of hypoparathyroidism in children Common symptoms Irritability, low blood pressure, convulsions, hair spasm, irritability, convulsions, ataxia, hypocalcemia, rough skin, abdominal pain

1. Increased neuromuscular excitability: Children may have paresthesia, tendon or limb numbness, the most common hand and foot spasm, hand and foot muscles are tonic contraction, thumb adduction, both lower extremities straight and varus, may be a small attack It can also be a systemic twitch, like an epileptic seizure, easily misdiagnosed as epilepsy.

Neonatal and small infants are susceptible to irritability, muscle tremors, convulsions or seizures, when blood calcium is <1.75 to 2.0 mmol/L (7 to 8 mg/dl), and blood phosphorus is increased to >2.26 mmol/L (7 mg). /dl) can diagnose, low blood calcium can cause autonomic nerve excitement, causing smooth muscle spasm, throat, bronchospasm to cause hypoxia in the body, secondary epilepsy, intestinal cramps cause abdominal pain, bladder spasm caused by urinary incontinence, vasospasm causes headache, Limb Reynolds sign phenomenon.

In a few chronic cases, extrapyramidal symptoms such as increased muscle tone, chorea or cerebellar ataxia may occur, which may be related to calcification of the basal ganglia.

2. Changes in ectoderm tissues and organs: The disease is long, the skin is rough, desquamation, pigmentation, hair sparsely falling off, (hair, mane, eyebrows or pubic hair, etc.) can be seen alopecia areata or total baldness, fingernails atrophy and deformation, brittle thin surface lateral groove , often combined with Candida albicans infection.

Teeth erupted late, tooth calcification was incomplete, enamel was poorly developed, and enamel was detached.

3. Cataract: More common, mostly bilateral, 5 to 10 years before vision loss, there have been changes in the cortex before and after the crystal, with slit lamp examination found early and before cortical calcium deposition, severe cases can cause blindness.

4. Hypocalcemia causes other organ symptoms: Psychiatric symptoms: such as irritability, emotional instability, or delayed mental development, hand and foot spasm often cause excessive ventilation and excessive adrenal secretion, resulting in corresponding symptoms, heart palpitations, ECG QT The period is prolonged, or the T wave is low, and there may be hypotension or even heart failure.

5. Signs of latent convulsions: Sometimes blood calcium is low but there is no clinical convulsion symptoms, which can be checked by the following signs:

1Chvostek sign positive,

2Trousseau sign positive, it is worth noting that about 25% of normal people Chvostek and 50% of normal people's Trousseau sign can be positive.

Examination of hypoparathyroidism in children

1. Calcium detection: serum calcium can be as low as 1.25 ~ 1.75mmol / L (5 ~ 7mg / dl), 24h urinary calcium excretion decreased, often below 20 ~ 30mg.

2. Blood biochemical detection: serum phosphorus is often as high as 2.26 ~ 3.88mmol / L (7 ~ 12mg / dl), alkaline phosphatase is normal or reduced, 1,25 (OH) 2D3 is reduced, in the case of normal renal function, to make The above values are accurate and should be excluded due to dietary or other factors. It should be determined after three days of calcium-fixed phosphorus diet.

3. Serum radioimmunoassay measures PTH iPTH reduction, such as the detection technology is mature, PTH is increased, it is likely to be pseudo-hyperthyroidism, when iPTH is low, it should be based on clinical and serum calcium, phosphorus indicators comprehensive analysis and diagnosis.

4. Head X-ray or head CT examination: basal calcification can be found.

5. Bone X-ray examination: The bone density of the long bone is increased, and the bone density of the metacarpal bone is increased.

6. EEG: There may be diffuse slow wave or spine-slow integrated wave during seizures. There may also be a single sharp wave in the occipital region. After the blood calcium rises, it returns to normal. Wide range of slow waves can be seen. Long-term patients cause EEG. Figure irreversible lesions, should be identified with epilepsy, low blood magnesium.

7. Electrocardiogram examination: visible tachycardia, prolonged QT interval, extended ST segment, with abnormal T wave.

Diagnosis and diagnosis of hypoparathyroidism in children

In addition to clinical manifestations mainly rely on laboratory examination and diagnosis, clinical symptoms of hypocalcemia, or biochemical examination of hypocalcemia and hyperphosphatemia, should further detailed history, comprehensive physical examination, X-ray, CT , PTH in blood was measured to confirm the diagnosis.

Should be caused by other causes of hypocalcemia, such as vitamin D deficiency and its metabolic disorders caused by hypocalcemia, should also be identified with low blood magnesium, blood magnesium is lower than 1.2mmol / L (1.5mg / dl) is low Blood magnesium, hypomagnesemia may also have phlegm, hypocalcemia may also occur in patients with hypomagnesemia, and autoimmune hypothyroidism may have fatty diarrhea and hypomagnesemia.

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