Hyperparathyroidism is an endocrinopathy based on excessive production of parathyroid hormone by the parathyroid glands. Hyperparathyroidism leads to an increase in the level of calcium in the blood and pathological changes occurring primarily in bone tissue and kidneys. The incidence of hyperparathyroidism among women is 2-3 times more common than in men. Hyperparathyroidism is more susceptible to women from 25 to 50 years old. Hyperparathyroidism can have a subclinical course, bone, visceropathic, mixed form, as well as an acute course in the form of a hypercalcemic crisis. Diagnostics includes determination of Ca, P and parathyroid hormone in the blood, X-ray examination and densitometry.
Classification and causes
Hyperparathyroidism can be primary, secondary and tertiary. The clinical forms of primary hyperparathyroidism can be diverse.
Primary hyperparathyroidism
Primary hyperparathyroidism is divided into three types:
I. Subclinical primary hyperparathyroidism.
- biochemical stage;
- asymptomatic stage (“mute” form).
II. Clinical primary hyperparathyroidism. Depending on the nature of the most pronounced symptoms , there are:
- bone form (parathyroid osteodystrophy, or Recklinghausen’s disease). It is manifested by deformity of the limbs, leading to subsequent disability. Fractures appear “by themselves”, without injury, heal for a long time and difficult, a decrease in bone density leads to the development of osteoporosis.
- visceropathic form:
- renal – with the predominance of severe urolithiasis, with frequent attacks of renal colic, the development of renal failure;
- gastrointestinal form – with manifestations of gastric and duodenal ulcers, cholecystitis, pancreatitis;
- mixed form.
III. Acute primary hyperparathyroidism (or hypercalcemia).
Primary hyperparathyroidism develops in the presence of:
- one or more adenomas (benign tumor-like formations) in the parathyroid glands;
- diffuse hyperplasia (enlargement of the size of the gland);
- hormone–active cancerous tumor (rarely, in 1-1.5% of cases).
In 10% of patients, hyperparathyroidism is combined with various hormonal tumors (pituitary tumors, thyroid cancer, pheochromocytoma). Primary hyperparathyroidism also includes hereditary hyperparathyroidism, which is accompanied by other hereditary endocrinopathies.
Secondary hyperparathyroidism
Secondary hyperparathyroidism serves as a compensatory reaction to a long-term low Ca level in the blood. In this case, the increased synthesis of parathyroid hormone is associated with a violation of calcium-phosphorus metabolism in chronic renal failure, vitamin D deficiency, malabsorption syndrome (impaired absorption of Ca in the small intestine). Tertiary hyperparathyroidism develops in the case of untreated long-term secondary hyperparthyroidism and is associated with the development of autonomously functioning parathyroid adenoma.
Pseudohyperparathyroidism (or ectopic hyperparathyroidism) occurs with malignant tumors of various localization (breast cancer, bronchogenic cancer) capable of producing a parathyroid substance, with multiple endocrine adenomatoses of type I and II.
Hyperparathyroidism is manifested by an excess of parathyroid hormone, which promotes the excretion of calcium and phosphorus from the bone tissue. Bones become fragile, soften, can bend, and the risk of fractures increases. Hypercalcemia (excessive Ca levels in the blood) leads to the development of muscle weakness, the release of excess Ca in the urine. Urination increases, constant thirst appears, kidney stone disease (nephrolithiasis) develops, the deposition of calcium salts in the parenchyma of the kidneys (nephrocalcinosis). Arterial hypertension in hyperparathyroidism is caused by the effect of excess Ca on the tone of blood vessels.
Hyperparathyroidism symptoms
Hyperparathyroidism may be asymptomatic and be diagnosed accidentally during examination. With hyperparathyroidism, the patient simultaneously develops symptoms of damage to various organs and systems – stomach ulcer, osteoporosis, urolithiasis, cholelithiasis, etc.
Early manifestations of hyperparathyroidism include rapid fatigue during exercise, muscle weakness, headache, difficulty walking (especially when climbing, overcoming long distances), a waddling gait is characteristic. Most patients report memory impairment, emotional instability, anxiety, depression. The elderly may have severe mental disorders. With prolonged hyperparathyroidism, the skin becomes an earthy gray color.
At a late stage of bone hyperparathyroidism, softening, curvature, pathological fractures (with normal movements, in bed) of bones occur, scattered pains occur in the bones of the arms and legs, spine. As a result of osteoporosis of the jaws, healthy teeth are loosened and fall out. Due to the deformation of the skeleton, the patient may become shorter. Pathological fractures are not painful, but they heal very slowly, often with deformities of the limbs and the formation of false joints. Periarticular calcifications are found on the arms and legs. A large adenoma can be palpated on the neck in the area of the parathyroid glands.
Visceropathic hyperparathyroidism is characterized by nonspecific symptoms and gradual onset. With the development of hyperparathyroidism, nausea, stomach pains, vomiting, flatulence occur, appetite is disturbed, weight decreases sharply. Patients have peptic ulcers with bleeding of various localization, prone to frequent exacerbations, relapses, as well as signs of damage to the gallbladder and pancreas. Polyuria develops, urine density decreases, and an unquenchable thirst appears. In the later stages, nephrocalcinosis is detected, symptoms of renal insufficiency develop, progressing with time, uremia.
Hypercalciuria and hypercalcemia, the development of calcification and vascular sclerosis, leads to impaired nutrition of tissues and organs. A high concentration of Ca in the blood contributes to the defeat of the heart vessels and an increase in blood pressure, the occurrence of angina attacks. With calcification of the conjunctiva and cornea of the eyes, red eye syndrome is observed.
Complications
Hypercalcemic crisis refers to severe complications of hyperparathyroidism that threaten the patient’s life. Risk factors are prolonged bed rest, uncontrolled intake of Ca and vitamin D preparations, thiazide diuretics (reduce the excretion of Ca in the urine). The crisis occurs suddenly with acute hypercalcemia (Ca in the blood is 3.5 – 5 mmol / l, with a norm of 2.15 – 2.50 mmol / l) and is manifested by a sharp exacerbation of all clinical symptoms. This condition is characterized by: high (up to 39-40 ° C) body temperature, acute epigastric pain, vomiting, drowsiness, impaired consciousness, comatose state. Weakness increases sharply, dehydration of the body occurs, a particularly severe complication is the development of myopathy (muscle atrophy) of the intercostal muscles and diaphragm, proximal parts of the trunk. Pulmonary edema, thrombosis, bleeding, perforation of peptic ulcers may also occur.
Diagnostics
Primary hyperparathyroidism does not have specific manifestations, so it is quite difficult to make a diagnosis based on the clinical picture. It is necessary to consult an endocrinologist, examine the patient and interpret the results obtained:
Urine acquires an alkaline reaction, the excretion of calcium in the urine (hypercalciuria) and an increase in the content of P in it (hyperphosphaturia) is determined. The relative density drops to 1000, there is often protein in the urine (proteinuria). Granular and hyaline cylinders are found in the sediment.
- blood test (calcium, phosphorus, parathyroid hormone)
The concentration of total and ionized Ca in blood plasma increases, the P content is below normal, the activity of alkaline phosphatase is increased. More indicative in hyperparathyroidism is the determination of the concentration of parathyroid hormone in the blood (5-8 ng / ml and higher at a norm of 0.15—1 ng / ml).
- ultrasound examination
Ultrasound of the thyroid gland is informative only when parathyroid adenomas are located in typical places – in the thyroid gland.
- X-ray examination, CT and MRI
Radiography allows you to detect osteoporosis, cystic bone changes, pathological fractures. Densitometry is performed to assess bone density. With the help of an X-ray examination with a contrast agent, peptic ulcers in the gastrointestinal tract that occur with hyperparathyroidism are diagnosed. CT of the kidneys and urinary tract reveals stones. X-ray tomography of the chest space with esophageal contrast with barium suspension makes it possible to identify parathyroid adenoma and its location. Magnetic resonance imaging is more informative than CT and ultrasound, visualizes any localization of the parathyroid glands.
- scintigraphy of the parathyroid glands
Allows you to identify the localization of usually and abnormally located glands. In the case of secondary hyperparathyroidism, the defining disease is diagnosed.
Hyperparathyroidism treatment
Complex treatment of hyperparathyroidism combines surgical surgery and conservative therapy with medications. The main method of treating primary hyperparathyroidism is surgery, which consists in removing parathyroid adenoma or hyperplastic parathyroid glands. To date, surgical endocrinology has minimally invasive methods of surgical interventions performed in hyperparathyroidism, including with the use of endoscopic equipment.
If a patient has been diagnosed with a hypercalcemic crisis, an operation for emergency indications is necessary. Prior to surgery, it is mandatory to prescribe conservative treatment aimed at reducing Ca in the blood: copious drinking, intravenous isotonic NaCl solution, in the absence of renal insufficiency – furosemide with KCl and 5% glucose, cattle thyroid extract (under control of Ca levels in the blood), biphosphonates (pamidronic acid and sodium ethidronate), glucocorticoids.
After surgery for malignant tumors of the parathyroid glands, radiation therapy is performed, and an antitumor antibiotic, plicamycin, is also used. After surgical treatment, the amount of Ca in the blood decreases in most patients, so they are prescribed vitamin D preparations (in more severe cases, intravenous Ca salts).
Prognosis and prevention
The prognosis of hyperparathyroidism is favorable only in the case of early diagnosis and timely surgical treatment. Restoration of the patient’s normal working capacity after surgical treatment of bone hyperparathyroidism depends on the degree of bone tissue damage. With a mild course of the disease, performance is restored after surgical treatment for about 3 to 4 months, in severe cases – during the first 2 years. In advanced cases, bone deformities that limit the ability to work may remain.
In the renal form of hyperparathyroidism, the prognosis for recovery is less favorable and depends on the severity of kidney damage at the preoperative stage. Without surgical intervention, patients usually become disabled and die from progressive cachexia and chronic renal failure. With the development of a hypercalcemic crisis, the prognosis is determined by the timeliness and adequacy of the treatment, the mortality rate for this complication of hyperparathyroidism is 32%.
In the presence of chronic renal insufficiency, drug prevention of secondary hyperparathyroidism is important.