Пациенты с пароксизмальной гипертонией,резистентной к обычным антигипертензивным препаратам (бета-блокаторам,АСЕ ингибиторам)требуют диагностического work-up в отношении возможной феохромоцитомы.
Lab Studies
* The choice of diagnostic test should be based on the clinical suspicion of a pheochromocytoma. Plasma metanephrine testing has the highest sensitivity (96%) for detecting a pheochromocytoma, but it has a lower specificity (85%) (Kudva, 2003). In comparison, a 24-hour urinary collection for catecholamines and metanephrines has a sensitivity of 87.5% and a specificity of 99.7%.
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o High-risk patients, including those who have a genetic syndrome that predisposes them to pheochromocytoma (eg, MEN 2A or 2B, VHL disease or neurofibromatosis, a prior history of a pheochromocytoma, a family history of a pheochromocytoma), should be screened with plasma metanephrine testing. In these scenarios, a higher-sensitivity test that lacks specificity is justified.
o A fractionated plasma free metanephrine level may be measured in a seated, ambulatory patient with a standard venipuncture.
o Patients at lower risk for a pheochromocytoma, including those with flushing spells, poorly controlled hypertension, or adrenal incidentalomas with an adrenocortical appearance, should be screened with a 24-hour urine collection for catecholamines and metanephrines. This test has a high specificity and acceptable sensitivity.
* Perform a 24-hour urine collection for creatinine, total catecholamines, vanillylmandelic acid, and metanephrines.
Imaging Studies
* Over 90% of pheochromocytomas are located within the adrenal glands, and 98% are within the abdomen. Extra-adrenal pheochromocytomas develop in the paraganglion chromaffin tissue of the sympathetic nervous system. They may occur anywhere from the base of the brain to the urinary bladder. Common locations for extra-adrenal pheochromocytomas include the organ of Zuckerkandl (close to origin of the inferior mesenteric artery), bladder wall, heart, mediastinum, and carotid and glomus jugulare bodies.
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* Only perform imaging studies after biochemical studies have confirmed the diagnosis of a pheochromocytoma. MRI is preferred over CT scanning. MRI has a reported sensitivity of up to 100% in detecting adrenal pheochromocytomas, does not require contrast, and does not expose the patient to ionizing radiation. MRI is also superior to CT scanning for detecting extra-adrenal pheochromocytomas. Typically, (approximately 70% of cases), pheochromocytomas appear hyperintense on T2-weighted images because of their high water content.
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* CT scanning of the abdomen has an accuracy of 85-95% for detecting adrenal masses with a spatial resolution of 1 cm or greater. CT scanning is less accurate for lesions smaller than 1 cm. Differentiating an adenoma from a pheochromocytoma is more difficult using CT scanning. While most pheochromocytomas have CT attenuation greater than 10 Hounsfield units (HU), they rarely contain sufficient intracellular fat to have an attenuation of less than 10 HU. In addition, most pheochromocytomas have enhancement loss that is similar to that of adrenal metastases and significantly less than that of adrenal adenomas. However, in patients in whom pheochromocytomas are strongly suspected, adrenal pheochromocytomas cannot be entirely excluded from the list of differential diagnoses of adrenal neoplasms with less than 10-HU attenuation value and greater than 60% washout on delayed scanning.
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* A scan with iodine I 131–labeled metaiodobenzylguanidine (MIBG) is reserved for cases in which a pheochromocytoma is confirmed biochemically but CT scanning or MRI do not show a tumor. The molecular structure of iodine I 123 MIBG resembles norepinephrine and concentrates within adrenal or extra-adrenal pheochromocytomas. This isotope has a short half-life and is expensive. It frequently is used in cases of familial pheochromocytoma syndromes, recurrent pheochromocytoma, or malignant pheochromocytoma. In the United States, only 131I-labeled MIBG is available, whereas 123I MIBG is used in Europe and Japan.
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* A somatostatin receptor analog indium In 111 pentetreotide is less sensitive than MIBG and may be used to visualize pheochromocytomas that do not concentrate MIBG.
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* Positron emission tomography (PET) scanning has been used as an imaging modality and has shown promising results. PET of 18F-fluorodeoxyglucose, which is selectively concentrated as part of the abnormal metabolism of many neoplasms, has been demonstrated to detect occult pheochromocytomas. Pheochromocytomas usually show increased uptake on PET scanning, as do adrenal metastases. The most impressive results to date have been with 6-[18F] fluorodopamine PET scanning and carbon 11 hydroxyephedrine PET scanning. Results of these studies suggest that PET scanning performed with both of these radioisotopes is extremely useful in the detection and localization of pheochromocytomas. Further study results with these agents are eagerly awaited.
Если диагноз подтвержден,то лечение-хирургическое.
При выраженном каротидном стенозе гипертензия (если есть)не будет пароксизмальной.
Вертебро-базилярная недостаточность -это аналог мифической вегето-сосудистой дистонии.
Кокаин,метамфетамин-возможно.Но пациент,обращающийся с такими жалобами к кардиологу,обычно злоупотребления такими препаратами не скрывают.Полная дифференциальная диагностика пароксизмальных гипертоний:
http://www.endotext.org/adrenal/adrenal34/ch01s03.html