What is Primary Hyperparathyroidism?
Primary hyperparathyroidism is a disease of the parathyroid glands, manifested by excessive production of parathyroid hormone with the development of hypercalcemia syndrome.
Causes of Primary Hyperparathyroidism
In 85% of cases, the cause of primary hyperparathyroidism is solitary parathyroid adenoma (parathyroid), much less often multiple adenomas (5%), even less often (<5%) – parathyroid cancer. Hyperplasia of all parathyroid glands occurs in approximately 15% of patients.
Pathogenesis during Primary Hyperparathyroidism
Hyperproduction of parathyroid hormone leads to excessive excretion of phosphate through the kidneys. A decrease in the plasma level of the latter stimulates the synthesis of l, 25- (OH) 2-D3, which promotes the absorption of excess Ca2 + in the intestine. An excess of parathyroid hormone leads to an acceleration of metabolism in bone tissue, acceleration of bone resorption and bone formation, but the formation of a new bone lags behind its resorption, which leads to generalized osteoporosis and osteodystrophy, leaching of calcium from bone depots and hypercalcemia, as well as hypercalciuria, which contributes to damage to the epithelium of the kidneys and the formation of kidney stones. Nephrocalcinosis, in turn, leads to a decrease in kidney function. In the occurrence of ulcerative lesions of the stomach and duodenum, an important role is played by hypercalcemia with vascular calcification. Hypercalcemia, along with an increase in blood pressure, creates the prerequisites for the formation of left ventricular hypertrophy, whose function is also impaired by valve, coronary and myocardial calcifications, typical for hyperparathyroidism.
Symptoms of Primary Hyperparathyroidism
In most patients, primary hyperparathyroidism is asymptomatic and the diagnosis is established by examination for hypercalcemia.
- Renal symptoms include polyuria, polydipsia, nephrolithiasis (25%), often complicated by pyelonephritis; rarely – nephrocalcinosis with the development of renal failure.
- Gastrointestinal symptoms: anorexia, nausea, flatulence, weight loss. In 10% of cases, stomach ulcers and / or duodenal ulcers develop, in 10% – pancreatitis, less commonly pancreaticalculosis. 2 times more often than in the population, gallstone disease occurs.
- Cardiovascular symptomatology: arterial hypertension and its complications.
- Bone changes: osteoporosis, chondrocalcinosis; in severe primary hyperparathyroidism: subperiosteal resorption, acroosteolysis of the terminal phalanges of the hands and feet, skeleton deformation, pathological bone fractures, cysts, giant cell tumors and epulids (cystic formations).
- Central nervous system: depression, drowsiness, confusion, agitation, pruritus.
- Hypercalcemic crisis is a rare severe complication of primary hyperparathyroidism. Drowsiness, stupor, coma, psychosis, followed by increasing anorexia, vomiting, epigastric pain, are characteristic; sharp weakness, dehydration, anuria, coma develop rapidly; a serious complication is myopathy involving the proximal trunk, intercostal muscles and diaphragm; fever up to 38-39 ° C is typical. Crisis develops with a plasma calcium level of more than 4 mmol / L and is provoked by prolonged bed rest, thiazide diuretics, calcium and vitamin D.
Diagnosis of Primary Hyperparathyroidism
- Hypercalcemia, as a rule, is detected in individuals without any symptoms in a routine biochemical blood test. In addition, hypophosphatemia, hypercalciuria and hyperphosphaturia, an increase in plasma alkaline phosphatase and urinary excretion of hydroxyproline and cAMP are characteristic.
- Increased parathyroid hormone.
- Ultrasound, CT, MRI (neck and mediastinum).
- Diagnosis of complications of primary hyperparathyroidism: osteoporosis, nephrocalcinosis, etc.
Primary Hyperparathyroidism Treatment
Approaches to treatment are determined by the severity of primary hyperparathyroidism, the age and physical condition of the patient, since the only radical treatment option is surgery.
Surgical treatment: with solitary parathyroid – its removal with subsequent therapy of hypoparathyroidism.
Indications for surgical treatment of primary hyperparathyroidism.
- Severe hypercalcemia (> 3 mmol / L)
- Episodes of severe hypercalcemia in the past
- Impaired renal function
- Kidney stones (with or without symptoms)
- Severe hypercalciuria (> 10 mmol / day)
- Severe concomitant pathology
- The complexity of dynamic observation
- Young age (<50 years)
- Patient desire
Dynamic observation is carried out when a mild primary hyperparathyroidism is detected in the elderly. It is permissible in situations of absence of absolute indications for surgical treatment. Dynamic observation involves determining the level of calcium, kidney function, blood pressure every 6-12 months, bone densitometry and ultrasound of the kidneys every 2-3 years.