Hyperaldosteronism in children

Introduction to pediatric aldosteronism Excessive aldosterone can be primary and secondary, secondary is secondary to renin-angiotensin, which mainly describes primary aldosteronism, primary hyperaldosteronism (primary hyperaldosteronism) ) is due to increased aldosterone produced by the adrenal cortical globular zone, resulting in sodium retention, increased blood volume and inhibition of plasma renin activity, clinical symptoms of hypertension and hypokalemia, may be caused by adrenal squamous cell proliferation or tumor, Children with hyperplasia are common, often bilateral, tumors are mostly adenomas, more common on the left side. No abnormalities in the adrenal gland are called idiopathic aldosteronism (idiopathichyperaldosteronism). basic knowledge The proportion of illness: 0.002% Susceptible people: children Mode of infection: non-infectious Complications: pediatric periodic hypokalemia paralysis

Causes of aldosteronism in children

Cause:

The most common cause is adrenal adenoma or proliferative adenoma, adenoma is mostly single, most cases of pediatric cases of bilateral adrenal hyperplasia caused by increased aldosterone secretion, the cause is still unknown, known as congenital hyperaldosteronism (congenital hyperaldosteronism ).

Pathogenesis

There are several kinds of hormones that play a role in the action of adrenocortical hormones. The most powerful ones are aldosterone, 11 deoxycorticosterone (DOC), 11 deoxycortisol (compound S), corticosterone (compound B) and 18 Hydrocorticosterone, weaker effect, abnormal increase of 11-deoxycorticosterone and 11-deoxycortisol, found in congenital adrenal hyperplasia 11-hydroxylase deficiency, corticosterone and 18-hydroxycorticosterone are precursors of aldosterone substance.

The physiological role of mineralocorticoids is to promote the absorption of sodium and the excretion of sodium in the secretions of the distal nephron, sweat glands, and saliva to regulate the balance between water and electrolytes. When mineralocorticoids increase, sodium retention and hypokalemia occur. Potassium is accompanied by alkalosis, sodium, water retention caused by increased blood volume, increased cardiac output and high blood pressure, with aldosteronism as the main reason.

The action site of aldosterone is mainly distal tubules. Due to excessive secretion of aldosterone, sodium reabsorption increases, and potassium and hydrogen ion excretion increases. As a result, extracellular sodium increases, potassium decreases, hypokalemia occurs, and blood sodium increases. Increased blood volume, produce benign hypertension without avascular barrier, and feedback inhibition of renin activity, hypokalemia caused by decreased muscle tone, periodic paralysis of limbs, perceptual abnormalities and alkalosis.

Prevention of aldosteronism in children

Precautionary measures refer to birth defects, and prevention should be carried out from pre-pregnancy to prenatal:

Pre-marital medical examination plays an active role in preventing birth defects. The size of the effect depends on the examination items and contents, including general physical examination (such as blood pressure, electrocardiogram) and family history of the disease, personal medical history, serological examination (such as hepatitis B virus, Treponema pallidum, HIV), reproductive system tests (such as screening for cervical inflammation).

Systemic birth defect screening is required during antenatal care during pregnancy, including regular ultrasound, serological screening, and, if necessary, chromosomal examination.

Pregnant women should avoid harmful factors as much as possible, including away from smoke, alcohol, drugs, radiation, pesticides, noise, volatile harmful gases, toxic and harmful heavy metals.

The cause has not yet been fully elucidated, and genetic counseling should be done to do all the health care work during pregnancy. Pregnant women should strengthen nutrition, not partial eclipse, should eat more foods rich in protein and vitamins to prevent fetal growth and development.

Pediatric aldosteronism complications Complications Children with periodic hypokalemia paralysis

High blood sodium, hypokalemia, blood pressure gradually increase with the development of the disease course, long-term increase in blood pressure caused left heart hypertrophy and heart failure, there are many small arteriospasm in the fundus, occasionally a small amount of bleeding; hypokalemia with alkalosis, Hypokalemia muscle paralysis; there may be an increase in nocturia.

Symptoms of aldosteronism in children Common symptoms Low blood potassium aldosterone secretion increased nocturia increased fatigue dizziness polyuria hypertension convulsions more drink

1. Clinical manifestations Primary aldosteronism (hereinafter referred to as primary aldehyde) is a chronically developed disease. The earliest symptom in the course of the disease is hypertension. Hypertension is due to increased aldosterone secretion, blood sodium retention, high blood sodium, and low Blood potassium makes the blood vessel wall more sensitive to the pressure-boosting substance, and it also promotes the blood pressure to rise. The blood pressure gradually increases with the development of the disease course. Later, fatigue, dizziness, paresthesia, and high blood pressure are moderate, and the blood pressure is caused by long-term increase. Heart hypertrophy and heart failure, there are many small arterial spasm in the fundus, occasionally a small amount of bleeding, and hypertensive retinopathy is rare, this may be related to the inhibition of renin-angiotensin.

Hypokalemia with alkalosis due to increased potassium excretion of the renal tubules, decreased blood potassium, some patients may be diagnosed with essential hypertension after early detection of hypertension, taking diuretics to induce hypokalemia muscle paralysis; or Low blood potassium is improved with a low-salt diet, and symptoms do not appear for a long time.

For high blood pressure, hypokalemia, alkalosis, accompanied by polydipsia, nocturia, increased urinary potassium, suspected of primary aldosteronism, need further examination.

2. Clinical type

(1) Aldosterone-producing adenoma (APA): Adenomas are mostly single-shot, generally <2cm in diameter, so the general positioning test is often negative, with typical clinical and laboratory manifestations; >3cm, so the location diagnosis is mostly positive, but it can still secrete other hormones, so the clinical manifestations are more serious and complex, biochemical disorders such as hypokalemia, alkali poisoning, etc. are more obvious, prone to early metastasis.

(2) primary adrenal hyperplasia (PAH): bilateral adrenal gland diffuse hyperplasia, with typical clinical manifestations and biochemical abnormalities, its pathogenesis is now considered to be independent of ACTH.

(3) Idiopathic hyperaldosteronism: The biochemical disorder is milder than APA and PAH, and the renin and AT-II activities are not inhibited. Some people think that the occurrence of IHA may be the function and morphology of the adrenal cortex. Normal or low concentrations of AT-II are abnormal, leading to cortical hyperplasia and excessive secretion of aldosterone. Others believe that IHA may be a variant of low renin-type essential hypertension, because surgical treatment can not cure IHA, even double Total resection of the lateral adrenal gland does not eliminate its high blood pressure, but it still needs to continue to use antihypertensive drugs.

(4) Glucocorticoid-inhibitory hyperaldosteronism: an autosomal dominant hereditary disease. There is no obvious increase in the secretion of the opposite position and AT-II stimulation, and sometimes it is decreased, but the response to ACTH is significantly higher than that of normal people. Dexamethasone inhibition test and treatment can lower blood pressure, reduce aldosterone secretion, and restore normal blood potassium.

Examination of aldosteronism in children

1. Blood biochemistry: hypokalemia, most of which is lower than 3.5mmoL/L, some are intermittent hypokalemia, blood sodium is generally slightly higher than normal, above 140mmol/L, but rarely >148mmol/L, blood pH Alkaline, CO2 tension (or CO2 binding) is normal or increased, renal function, kidney function is impaired, azotemia can be found when the condition is severe, creatinine clearance rate, urea clearance rate is reduced to varying degrees, aldosterone is also Promote the excretion of magnesium, reduce the blood magnesium, the occurrence of hand and foot sputum, and may have positive signs of Chvoster and Trousseau.

2. Urine examination: Increased urine output, especially nocturia, lower specific gravity 1.010, urine specific gravity change during 1 day, urine concentration test is negative, urine volume and specific gravity are not affected by vasopressin, some patients still There may be proteinuria and/or urinary leukocytosis, and increased urinary potassium.

3. Aldosterone determination

(1) 24h urinary aldosterone: In the normal diet (sodium intake 100mmol / d), normal adult urinary aldosterone 11.08 ~ 27.7nmol / 24h (4 ~ 10g / 24h), increased the displacement of the original aldosteron 55.4 nmol / 24 h (20 g / 24h) or more.

(2) Plasma aldosterone: The plasma aldosterone content was measured by radioimmunoassay, the normal sodium content, in the supine position, the plasma aldosterone normal adult at 8:00 am (23.2 ± 1.4) pmol / L [(8.4 ± 0.5) ng / dl ] (range 8.3 ~ 44.2pmol / L) (3 ~ 16ng / dl), change position 2h, blood collection at 10:00, aldosterone concentration (37.5 ± 3.58) pmol / L [(13.6 ± 1.3) ng / dl] When the sodium intake in the food is higher than 150 mmol/d or after DOCA, the plasma aldosterone concentration is lowered, and when the sodium intake is low, the concentration is increased.

4. Plasma renin-angiotensin activity was measured below normal.

5. Electrocardiogram: hypokalemia caused changes in electrocardiogram, manifested as prolongation of QT interval, T wave widening, decreased or inverted, U wave appearance or TU wave connected to double peak, showing changes in hypertensive left ventricular hypertrophy.

6. Abdominal CT or MRI scan: can be identified as adrenal adenoma or hyperplasia, 131I-19-iodinated cholesterol adrenal scanning or photography: the lesion can be judged according to the size and concentration of the concentrated area of the radioactivity to guide the operation.

7. Kidney B-ultrasound: Understand the condition of the adrenal glands on both sides.

8.125I-cholesterol scan: Detection of aldosterone concentrations in both sides and adrenal venous blood can identify tumors and hyperplasia.

Diagnosis and diagnosis of pediatric aldosteronism

diagnosis

According to the unique clinical symptoms, it is not difficult to diagnose. The important diagnostic criteria are low blood renin and angiotensin, high aldosterone, normal cortisol in the blood or 17-KS in the urine, 17-OHCS is normal. Hypertension complicated with periodic paralysis and hand and foot convulsions, or serum potassium below 3mmol / L and urinary potassium excretion 20mmol / d or more, should be suspected of this disease.

1. Furosemide, upright position stimulation test in the morning, fasting intravenous infusion of furosemide 1mg/kg, and then maintained 2 h upright position, measuring plasma renin activity and aldosterone before and after injection of furosemide, primary aldosteronism At the time, the two values generally did not change, but sometimes the aldosterone value increased due to an increase in stress ACTH, which stimulated aldosterone secretion.

2. Limit salt test: The daily salt limit is 2g or less for 5-7 days. The plasma renin and aldosterone levels in the morning and before the salt restriction are measured. The normal human renin activity is increased and the aldosterone secretion is increased. There was no significant change in the presence of aldosteronism.

3. ACTH stimulating test (ACTH stimulating test) After 6 hours of ACTH in normal people, the plasma aldosterone content increased more than 2 times before stimulation, the primary aldosteronism increased significantly, and dexamethasone inhibited endogenous ACTH, exogenous ACTH stimulation increased aldosterone significantly, and idiopathic aldosteronism was more pronounced than primary aldosteronism.

4.DOCA stimulating test (DOCA stimulating test) After healthy people use DOCA (deoxycorticosterone acetate), sodium retention, circulating plasma volume increased, renin and aldosterone secretion were inhibited by 50% or less, but primary and special There is no change in plasma renin in aldosteronism, and there is a tendency for aldosterone to increase slightly. It is also possible to replace DOCA with 9-fluorohydrocortisone.

Differential diagnosis

The diseases that need to be differentiated from primary aldosteronism are as follows:

1. Primary hypertension occurs hypokalemia: Primary hypertension with diuretic treatment can be hypokalemia, muscle weakness when potassium has not been added, the need to stop taking diuretics and potassium after identification, primary Hyperkalemia returned to normal.

2. Renal ischemic hypertension secondary to aldosterone increase: renal ischemic hypertension is higher than the original aldehyde, high blood pressure progresses quickly, sometimes vascular murmur can be heard in the abdomen, intravenous pyelography, visible renal development of the affected side Delayed and disappeared, increased plasma renin activity, is the cause of secondary aldosterone increase, sodium loss in the body, excessive (sweating, diarrhea, renal acidosis, etc.) blood loss can occur when physiological renin - Increased secretion of aldosterone, secondary aldosteronism can also occur.

3. Malignant hypertension: High blood pressure, rapid development, due to capillary vasospasm, kidney ischemia, increased renin-angiotensin secretion and secondary aldosterone increase, hypertension often accompanied by retinopathy, retinal exudation , massive bleeding and optic disc edema, visual impairment, accompanied by renal dysfunction, azotemia, increased blood urea nitrogen, generally no alkalosis, blood sodium is not high.

4. Kidney hyperthyroidism syndrome is Liddles syndrome: there is familial, the ability of renal tubules to retain sodium is particularly strong, sodium and potassium exchange is too strong, potassium is excessively consumed, hypertension occurs, hypokalemia, high blood sodium, Alkali poisoning and urinary potassium excretion increased, aldosterone secretion did not increase but decreased, given a low-sodium diet, spironolactone (anti-Shutong) can not reduce blood sodium, dexamethasone is also ineffective, can be treated with triamterene (triamterene), Direct inhibition of the absorption of sodium in the small tubules of the small ball, and reduction of potassium excretion, while supplementing potassium chloride, can make blood pressure normal, correct hypokalemia, improve clinical symptoms.

5. Congenital adrenal hyperplasia

(1) 11-hydroxylase deficiency: 11-deoxycorticosterone and 11-deoxycortisol increase in the absence of congenital 11-hydroxylase, both of which have sodium and potassium excretion effects, can cause hypertension At the same time, there may be abnormalities in sexual characteristics.

(2) 17-hydroxylase deficiency: When 17-hydroxylase is deficient, increased synthesis of corticosterone and 11-deoxycorticosterone causes hypertension, increased blood sodium, decreased blood potassium, sexual developmental disorders, and male genitalia female.

6. Renal glomerular hyperplasia (ie Bartter syndrome): clinical manifestations of severe hypokalemia, alkalosis, blood sodium, chlorine are low, and polydipsia, polyuria, dehydration, constipation, infancy may have Vomiting, growth disorders, but normal blood pressure, increased renin-angiotensin activity in the blood, increased aldosterone concentration, increased secretion of prostaglandins, pathological findings of hyperplasia of the glomerular and adrenal spheroidal zone, The causal relationship between electrolyte imbalance and increased hormone secretion in blood is unclear. The effects of aldosterone antagonists and renin inhibitors (methyldopa) have been transient in treatment; prostaglandin inhibitors such as indomethacin (anti-inflammatory) Pain), aspirin, can make symptoms disappear, electrolyte imbalance returns to normal, it is believed that excessive prostaglandin production in the kidney is one of the causes.

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