Pheochromocytoma

　　The prevalence of pheochromocytoma in patients with hypertension is 0.05% to 0.2%, with an incidence peak between 20 to 50 years old. Pheochromocytoma located in the adrenal glands accounts for 80% to 90%, and most are unilateral; adrenal extramedullary tumors are mainly located in the peritoneal cavity and adjacent to the abdominal aorta. Most are benign, and malignant ones account for 10%. Like most tumors, the etiology of sporadic pheochromocytoma is still unclear. Familial pheochromocytoma is related to genetics.

　　Pay attention to the occurrence of complications, such as heart failure, arrhythmias, hypertensive encephalopathy, pulmonary infection, and other abnormal changes. In case of pheochromocytoma crisis, blood should be immediately drawn to measure blood urea nitrogen, creatinine, blood glucose, etc., and avoid palpating the tumor area.

　　It can be complicated with the following complications:

　　1. Cardiovascular complications: phenylephrine cardiomyopathy, arrhythmias, and shock.

　　2. Cerebrovascular complications: stroke, transient ischemic attack (TIA), hypertensive encephalopathy, and mental disorders.

　　3. Other conditions such as diabetes, ischemic colitis, cholelithiasis, etc.

　　The disease is most common in young and middle-aged patients aged 20 to 40, with almost equal male to female ratio. Its main symptoms are hypertension and changes in basal metabolism: hypertension can be paroxysmal, persistent, or paroxysmal exacerbation of persistent hypertension. Persistent hypertension patients often have dizziness, headache, chest tightness, chest pain, palpitations, blurred vision, nervousness, anxiety, and aversion to heat. Paroxysmal patients experience sudden severe headache, palpitations, chest tightness, pale complexion, profuse sweating, rapid breathing, and a feeling of impending death. At this time, blood pressure can reach 40.OkPa (200-300 mmHg), and may resolve spontaneously after about half an hour. After recovery, it is as normal as ever. In the future, it may recur after encountering certain stimuli. The frequency of recurrence gradually increases, the interval shortens, and the condition becomes more severe. The triggering stimulus may not be very strong, and it may occur during brushing teeth or waking up from a dream with sweating and a feeling of impending death. There are also cases of massive tumors and high blood pressure without any symptoms, or without tumors and without episodes, who die during surgery for other diseases. Therefore, patients with such symptoms should be examined and treated early.

　　The general tests and examinations for pheochromocytoma include the following:

　　Laboratory examination:

　　1. Blood and urine catecholamines and their metabolites measurement.

　　2. Pharmacological tests: divided into stimulation and inhibition tests.

　　Other auxiliary examinations:

　　1. Adrenal CT scan is the first choice. When performing CT examination, due to changes in position or injection of intravenous contrast agent, a hypertensive attack may be triggered. Alpha-adrenergic receptor blocking agents should be used first to control hypertension, and phenylephrine should be prepared at any time during the scanning process for emergency use.

　　2. Magnetic resonance imaging (MRI) can show the anatomical relationship and structural characteristics of the tumor with surrounding tissues, and has high diagnostic value.

　　3. Ultrasound is convenient, easy, and inexpensive, but its sensitivity is not as good as CT and MRI, and it is not easy to detect smaller tumors. It can be used as a means of initial screening and localization.

　　4. 131I-MIBG scintigraphy has high diagnostic value for the localization of adrenal extraneous, multiple, or malignant metastatic pheochromocytoma lesions, and it has both qualitative and locational significance. However, it is poor for imaging of hypofunctional tumors and is affected by various drugs such as reserpine, cocaine, tricyclic antidepressants, and others, leading to false negatives. Therefore, it should be discontinued one week before the examination, and a compound iodine solution should be taken before the examination to protect the thyroid.

　　In recent years, 11-carbon hydroxy ephedrine, octreotide imaging, or PET have been used for the diagnosis of this disease.

　　5. In cases where clinical and biochemical tests support the disease but the aforementioned non-invasive imaging tests have not localized the tumor, adrenal venous catheterization for blood plasma CA measurement can be considered. There is a possibility of triggering a hypertensive crisis during the operation, and phenylephrine should be prepared for emergency use.

　　Pay attention to dietary balance:Dietary balance is the foundation for maintaining the body's immune function. Common foods are the best sources of nutrients for the body. For patients with malnutrition and other clinical conditions, individualized nutritional treatment should be carried out.

　　Diversify food and rationalize the matching:To ensure the intake of balanced and comprehensive nutrition, it is necessary to have a diverse diet every day, that is, to match the five major categories of food in accordance with the ratio shown in the Chinese Resident Balanced Diet Pyramid.

　　Eat small, frequent meals, and choose light, easily digestible foods:For patients after radiotherapy, chemotherapy, and surgery, due to weakened digestive function, increasing the number of meals can help reduce the burden on the digestive tract and increase food intake at the same time. It is not advisable to avoid certain foods: the avoidance of certain foods should be determined according to the condition, nature of the disease, and individual characteristics of different patients, and excessive avoidance is not recommended. Generally, foods that patients need to limit or avoid include: high-temperature fried, smoked, roasted, spicy,刺激性, greasy, and hard foods. It is recommended to choose foods with anti-cancer effects: vegetables and fruits (such as asparagus, carrots, spinach, tomatoes, broccoli, tubers, kiwi, citrus), soybeans and their products, edible mushrooms, nuts, seaweed, Job's tears, milk, eggs, and so on.

　　Western medicine indicates that the surgical resection of pheochromocytoma is the most effective treatment method, but surgery has certain risks. The compression of the tumor during anesthesia and surgery is prone to cause fluctuations in blood pressure. The tumor has abundant blood supply and is close to large blood vessels, which is easy to cause a large amount of bleeding. Therefore, it is extremely important to handle the preoperative, intraoperative, and postoperative stages correctly.

　　Patients with pheochromocytoma, due to the secretion of catecholamines, the blood vessels are in a state of contraction for a long time, although the blood pressure is high, the blood volume is often insufficient. Therefore, sufficient drug preparation should be given before surgery to achieve the purpose of dilating blood vessels, lowering blood pressure, and expanding blood volume. Currently, α-adrenergic receptor blockers phenybenzamine (phenybenzamine) are widely used, with a dose of 10-20mg, taken 2-3 times a day, for 2-6 weeks. Propranolol, a β-adrenergic receptor blocker, 10mg, taken 2-3 times a day, can be taken for about a week before surgery to prevent tachycardia and arrhythmia during surgery.

　　The selection of anesthesia methods and anesthetic drugs should meet the following conditions: ① It should not have a significant inhibitory effect on cardiac pump function, ② It should not increase sympathetic excitability, ③ It should be conducive to blood pressure control during surgery, ④ It should be beneficial to restore blood volume and maintain blood pressure after tumor resection. At present, general anesthesia is still widely advocated. The incision can be determined according to the accuracy of diagnosis and localization as well as the size of the tumor, and most abdominal exploration incisions are more secure.

　　The preoperative placement of floating catheters (Swan-Ganz catheter) for monitoring pulmonary artery wedge pressure can accurately and reliably monitor the patient's cardiac pumping status and effectively maintain blood volume, providing favorable conditions for the smooth completion of the operation.