histamine test

Histamine test The histamine test is an examination to determine the function of the non-sex nerve. Histamine can excite sympathetic nerves, promote the release of catecholamines stored in nerve endings, contract peripheral blood vessels, and raise blood pressure. In patients with pheochromocytoma, the sympathetic nerve endings had more catecholamine reserves than normal people, and the release of catecholamines after injection of histamine was also higher than that of normal people. Suspected pheochromocytoma was injected with exogenous histamine at the intermittent interval to trigger hypertensive seizures, to observe the degree of elevated blood pressure and the presence or absence of clinical symptoms to assist in diagnosis. Basic Information Specialist classification: neurological examination classification: neuroelectrophysiology Applicable gender: whether men and women apply fasting: not fasting Analysis results: Below normal: Normal value: no Above normal: negative: Normal people are negative in this test. Positive: Pheochromocytoma, mostly positive, the positive rate can reach 50%-80%. The content of urinary catecholamine after injection of histamine was significantly increased compared with that before injection. Tips: Maintain a normal diet and schedule. Normal value 1. After injection of histamine, the blood pressure increased by >8.0/5.3 kPa (60/40 mmHg), and the duration was >5 minutes. 2. The highest blood pressure after the injection of histamine was increased by >2.7-13.3KPa (20/10mmHg) for >5min. 3. Typical symptoms appear. Normally only one or three of them do not appear. Clinical significance Abnormal result 1. Normal person is negative in this test. 2. Pheochromocytoma, mostly positive, the positive rate can reach 50%-80%. After injecting histamine, there was a brief mild drop in blood pressure, then it rose rapidly, peaked more than 2 minutes, and clinical symptoms appeared. At this time, if benzyl oxazoline is injected, the blood pressure drops rapidly, which is more helpful for diagnosis. The content of urinary catecholamine after injection of histamine was significantly increased compared with that before injection. 3. Some patients with pheochromocytoma may be repeatedly negative for this test, which may be related to the use of antihypertensive drugs. People who need to be checked Clinically suspected pheochromocytoma, intermittent period of paroxysmal hypertension; no seizures have been observed to confirm or exclude pheochromocytoma. Positive results may be diseases: pediatric familial autonomic dysfunction syndrome, adrenal medulla hyperfunction, leprosy, paint sore precautions Forbidden before examination: Maintain a normal diet and schedule. 1. Antihypertensive drugs, sedatives, anesthetics and narcotic analgesics were stopped before the test for 2 and 3 days. 2. Paroxysmal hypertension, blood and urine catecholamines can be diagnosed in the onset of pheochromocytoma, no longer do this test. 3. This test is due to the sudden rise of blood pressure in a short period of time, which may cause the risk of cerebrovascular disease and myocardial infarction. Therefore, the test should be prepared to rescue drugs and instruments, and observe closely. 4. The cold pressure test should be done before the test for comparison. Requirements for inspection: 1. Inhalation of 5 mg of phentolamine (benzylamine) in the syringe for use. Once the blood pressure rises to a positive standard, intravenous injection is immediately performed to lower the blood pressure and prevent further elevation, causing serious adverse consequences. 2. Adverse reactions may occur during the test: headache, flushing, decreased blood pressure, and increased heart rate. This is a normal phenomenon and does not require excessive panic. Inspection process 1. Antihypertensive drugs, sedatives, anesthetics and narcotic analgesics were stopped before the test for 2 and 3 days. 2. The patient is quietly supine until the blood pressure is stable, or the blood pressure is restored to the basal level after the cold compression test, and the blood pressure after stabilization is recorded as a control. 3. Intravenous infusion of physiological saline to keep the fluid path unobstructed, and then take the histamine matrix 0.025mg-0.05mg (histamine phosphate 0.07mg-0.14mg), dissolved in 0.5ml physiological saline and quickly injected from the infusion tube. 4. After injecting histamine, measure blood pressure on the contralateral upper arm, measure once every 30s, continuously measure for 5 minutes, then change to 1 minute per minute, then measure for 10 minutes, measure 1 time, minute, or return blood pressure to the basic level. until. 5. Collect urine for 1 h before and after injection of histamine, and measure the content of catecholamine. The result is judged: 1. After injection of histamine, the blood pressure increased by >8.0/5.3 kPa (60/40 mmHg), and the duration was >5 minutes. 2. The highest blood pressure after the injection of histamine was increased by >2.7-13.3KPa (20/10mmHg) for >5min. 3. Typical symptoms appear. Those with the above 1, 3 or 2, 3 are positive for the test. Not suitable for the crowd Elderly, coronary heart disease, cerebrovascular disease, blood pressure > 22.7 / 13.3kPa (170 / 100mmHg). Adverse reactions and risks Generally no adverse reactions.