Pheochromocytoma
Summary/Definition
Pheochromocytoma is a tumor developing in the medulla of the adrenal glands, which can be divided into benign and malignant forms. Clinically, it is diagnosed as benign if the tumor is limited to one organ, and as malignant if it penetrates into surrounding tissues or gives metastases to lymph nodes, bones, lungs and other organs. Pheochromocytoma develops in the adrenal glands, and also occurs in thd area near the aorta and bladder, where sympathetic nerves pass. This condition can be accompanied by symptoms such as hypertension, tachycardia, increased sweating, headache, anxiety and insomnia caused by excessive release of catecholamines. Modern genetic studies have revealed that approximately 40% of cases of pheochromocytomas are caused by genetic mutations that may be associated with other diseases, for example, multiple endocrine adenoma type 2A, von Hippel-Lindau syndrome, neurofibromatosis type 1, familial adrenal ganglia syndrome, etc. Pheochromocytoma refers to rare diseases and occurs on average in 2-8 people per million people annually.
Symptoms
The symptoms of pheochromocytoma may vary, but the most common are headache, increased sweating, rapid heartbeat in the chest area, high blood pressure, tachycardia, anxiety and insomnia. As the tumor grows, dizziness, blurred vision, nausea, vomiting, weight loss, tinnitus, constipation, cold limbs and other symptoms may occur. Some symptoms, such as discomfort in the chest area, may resemble angina pectoris. It is important to note that despite the presence of a tumor, the course of the disease in some patients may be asymptomatic.
Diagnostics
Diagnosis of pheochromocytoma begins with a medical examination and analysis of risk factors. During physical examination, arterial hypertension, orthostatic hypotension, retinopathy, fever, pallor, tremor, Carpiore spots and neurofibromatosis may be observed. Laboratory tests may show the presence of hyperglycemia, hypercalcemia and an increase in the level of red blood cells. Risk factors for pheochromocytoma include surgery, anesthesia, body position changes, opiate sedatives, cold medications, tricyclic antidepressants to prevent catecholamine reabsorption, and cocaine. Biochemical tests allow measuring the level of catecholamine metabolites in blood and urine. Catecholamine metabolites are more often used for diagnosis, as they are continuously secreted by the tumor. The most sensitive test is the measurement of metanephrine in the blood, and the most specific is the determination of metanephrine in urine in 24 hours. An increase in the level of 2-3 times compared to the norm strongly indicates the presence of pheochromocytoma. However, it should be remembered that physical stress and certain medications can affect the results of tests. CT and MRI scans can be used to visualize the tumor. CT and MRI have similar sensitivity: CT of the abdominal cavity shows an accuracy of 85-95% in detecting adrenal tumors with a diameter of more than 1 cm, but is less effective in detecting small tumors less than 1 cm. Despite the possibility of biochemical diagnosis of pheochromocytoma, sometimes there are cases when the tumor cannot be detected by CT or MRI. In such cases, scanning with iodine-123 (123I)-metaiodbenzylguanidine (MIBG) may be required – a method based on nuclear medicine technologies. Additional diagnostic methods include genetic testing and studies for the presence of pathologies.
Treatment and course of the disease
The main goal of the treatment of pheochromocytoma is the complete removal of the tumor by surgical intervention. However, even with a little stress, the tumor can cause high levels of catecholamines and provoke seizures. Therefore, preoperative drug therapy should be prescribed in advance to normalize the patient’s condition before surgery. The plan of preoperative therapy depends on various factors, for example, the size of the tumor, its location, the presence of metastases, etc. Usually, preoperative treatment includes the use of alpha-blockers, beta-blockers, calcium channel blockers, etc. This preoperative treatment allows you to control the secretion of catecholamines, preventing the development of seizures during surgery and reducing the risk of postoperative complications. If high blood pressure occurs during surgery, hypotensive drugs are administered, and in case of arrhythmia or tachycardia, antiarrhythmic drugs are used with caution. If there are signs of shock, a saline solution is injected intravenously to maintain blood volume. Two weeks after surgery, to assess the effectiveness of tumor removal, the level of metanephrine in blood plasma is measured. If the results are within the normal range, it can be assumed that the tumor resection was successful, while complications associated with increased blood pressure are often resolved.
Complications
Among the complications that may occur, heart diseases should be noted, for example, hypertension, arrhythmia, myocarditis, myocardial infarction, dilated cardiomyopathy, pulmonary edema, hypertensive encephalopathy, stroke, neurological disorders, including cerebral hemorrhage, diabetes, anemia, osteoporosis, retinopathy, etc.
