Definition
Von Hippel–Lindau disease (VHL) is an autosomal dominant disorder characterized by pheochromocytoma (frequently bilateral), paraganglioma (rarely), retinal angiomas, cerebellar hemangioblastoma, epididymal cystadenoma, renal and pancreatic cysts, and renal cell carcinoma.
Pheochromocytoma is reported to occur in about 10 to 20% of patients with VHL. Nearly 100% of patients with VHL have an identifiable gene mutation (VHL tumor suppressor gene).
Certain missense mutations appear to be associated with a “pheochromocytoma only” presentation of VHL
Sunday, 28 August 2011
PHEOCHROMOCYTOMA IN PREGNANCY
Pheochromocytoma in pregnancy can cause the death of both the fetus and the mother.
The approach to the biochemical diagnosis is the same as for the nonpregnant patient. MRI is the preferred imaging modality, and 123I-MIBG is contraindicated.
The treatment of hypertensive crises is the same as for nonpregnant patients except that use of nitroprusside should be avoided.
Although the most appropriate management is debated, adrenal pheochromocytomas should be removed promptly if diagnosis is made during the first two trimesters of pregnancy. The preoperative preparation is the same as for a nonpregnant patient. If the pregnancy is in the third trimester, one operation is recommended for a cesarean delivery and removal of the adrenal pheochromocytoma at the same time. Spontaneous labor and delivery should be avoided. The management of catecholamine-secreting paragangliomas in pregnancy may require modification of these guidelines, depending on tumor location.
The approach to the biochemical diagnosis is the same as for the nonpregnant patient. MRI is the preferred imaging modality, and 123I-MIBG is contraindicated.
The treatment of hypertensive crises is the same as for nonpregnant patients except that use of nitroprusside should be avoided.
Although the most appropriate management is debated, adrenal pheochromocytomas should be removed promptly if diagnosis is made during the first two trimesters of pregnancy. The preoperative preparation is the same as for a nonpregnant patient. If the pregnancy is in the third trimester, one operation is recommended for a cesarean delivery and removal of the adrenal pheochromocytoma at the same time. Spontaneous labor and delivery should be avoided. The management of catecholamine-secreting paragangliomas in pregnancy may require modification of these guidelines, depending on tumor location.
Pheochromocytoma
Definition
Pheochromocytomas are autonomously functioning, catecholamine-secreting, chromaffin-cell neoplasms.
Etiology
About 90% are benign solitary nodules found within the adrenal medulla itself. However, because they can arise any
where neural crest tissue has migrated during the course of embryonic development, approximately 10% are located intra-abdominally in close proximity to the celiac or mesenteric sympathetic ganglia. Adrenal medullary pheochromocytomas are almost always (90%) unilateral. Bilateral lesions usually occur as familial neoplasms, as in type IIa (Sipple's syndrome) or type IIb multiple endocrine neoplasia syndrome (Table 69.5). The multiple endocrine neoplasia syndromes are transmitted as autosomal dominant diseases with incomplete penetrance and variable expression.
Sign And Symptoms
SPELL RELATED
Anxiety and fear of impending death
Diaphoresis
Dyspnea
Epigastric and chest pain
Headache
Hypertension
Nausea and vomiting
Pallor
Palpitation (forceful heartbeat)
Tremor
CHRONIC
Anxiety and fear of impending death
Cold hands and feet
Congestive heart failure—dilated or hypertrophic cardiomyopathy
Constipation
Diaphoresis
Dyspnea
Ectopic hormone secretion–dependent symptoms (e.g., CRH/ACTH, GHRH, PTH-RP, VIP)
Epigastric and chest pain
Fatigue
Fever
General increase in sweating
Grade II to IV retinopathy
Headache
Hyperglycemia
Hypertension
Nausea and vomiting
Orthostatic hypotension
Painless hematuria (associated with urinary bladder paraganglioma)
Pallor
Palpitation (forceful heartbeat)
Tremor
Weight loss
Diagnosis
The most commonly used screening test is a 24-hour urine measurement of catecholamines (norepinephrine and epinephrine) or their metabolites (metanephrine and vanillylmandelic acid).
Note:
(levodopa, tricyclic antidepressants, and decongestants) influence the test results, all medications should be withheld for a minimum of 1 to 2 days
Plasma norepinephrine, another useful screening test in pheochromocytomas, typically exceeds 2,000 pg/mL
Treatment
Surgical Therapy
Pheochromocytoma is almost always cured by surgical excision of the tumor
Medical Therapy
Combined α- and β-adrenergic blockade is one approach to control blood pressure and to prevent intraoperative hypertensive crises. α-Adrenergic blockade should be started 7 to 10 days preoperatively to normalize blood pressure and to expand the contracted blood volume.
Cushing's Syndrome
Definition
Cushing's syndrome is a condition caused by excess amounts of cortisol adenoma or cancer resulting from hypersecretion of the adrenal cortex which may result from a hypersecreting adrenal tumor, ectopic ACTH, or prolonged exposure to high therapeutic doses of glucocorticoids or prolonged exposure to high therapeutic doses of glucocorticoids.
Etiology
exogenous
the most common cause of Cushing's syndrome is iatrogenic or exogenous glucocorticoid use.
Endogenous
cases may be either
ACTH dependent (e.g., ACTH-secreting pituitary adenoma or ectopic ACTH-secreting neoplasm)
or
ACTH independent (e.g., adrenal adenoma, adrenal carcinoma)
Sign or Symptom
Decreased libido in men and women
Obesity or weight gain
Plethora
Round face
Menstrual changes
Hirsutism
Hypertension
Ecchymoses
Lethargy, depression
Striae
Weakness
Electrocardiographic changes or atherosclerosis
Dorsal fat pad
Edema
Abnormal glucose tolerance
Osteopenia or fracture
Headache
Backache
Recurrent infections
Abdominal pain
Acne
Female balding
Diagnosis
Urine free cortisol excretion during 24 hours is a good screening test
Dexamethasone Suppression Tests
It involves giving dexamethasone, 1 mg, orally between 2300 and midnight and measurement of plasma cortisol concentration between 0800 and 0900 the following morning.
Treatment
Surgical Therapy
The optimal treatment of Cushing's syndrome is surgical resection of the lesion that is producing excessive ACTH or cortisol
Radiation Therapy
Medical Therapy
Combination of Surgical and Medical Therapy is to be used
Medical therapy alone is rarely appropriate for Cushing's disease because it requires close monitoring and adjustment of dose and has low long-term efficacy.
Patients with ectopic ACTH secretion can be cured if the tumor can be removed and is not metastatic. Otherwise, adrenalectomy or medical therapy is chosen. Adrenalectomy is appropriate when the patient cannot tolerate the cost, medical toxicity, or adverse psychological effects of long-term medical therapy and monitoring or if the patient requires rapid correction of hypercortisolism. Adrenalectomy is appropriate when maximal daily doses of ketoconazole (1600 mg), aminoglutethimide (2 g), and metyrapone (2 g) given in combination do not render the patient eucortisolemic.
Cushing's syndrome is a condition caused by excess amounts of cortisol adenoma or cancer resulting from hypersecretion of the adrenal cortex which may result from a hypersecreting adrenal tumor, ectopic ACTH, or prolonged exposure to high therapeutic doses of glucocorticoids or prolonged exposure to high therapeutic doses of glucocorticoids.
Etiology
exogenous
the most common cause of Cushing's syndrome is iatrogenic or exogenous glucocorticoid use.
Endogenous
cases may be either
ACTH dependent (e.g., ACTH-secreting pituitary adenoma or ectopic ACTH-secreting neoplasm)
or
ACTH independent (e.g., adrenal adenoma, adrenal carcinoma)
Sign or Symptom
Decreased libido in men and women
Obesity or weight gain
Plethora
Round face
Menstrual changes
Hirsutism
Hypertension
Ecchymoses
Lethargy, depression
Striae
Weakness
Electrocardiographic changes or atherosclerosis
Dorsal fat pad
Edema
Abnormal glucose tolerance
Osteopenia or fracture
Headache
Backache
Recurrent infections
Abdominal pain
Acne
Female balding
Diagnosis
Urine free cortisol excretion during 24 hours is a good screening test
Dexamethasone Suppression Tests
It involves giving dexamethasone, 1 mg, orally between 2300 and midnight and measurement of plasma cortisol concentration between 0800 and 0900 the following morning.
Treatment
Surgical Therapy
The optimal treatment of Cushing's syndrome is surgical resection of the lesion that is producing excessive ACTH or cortisol
Radiation Therapy
Medical Therapy
Combination of Surgical and Medical Therapy is to be used
Medical therapy alone is rarely appropriate for Cushing's disease because it requires close monitoring and adjustment of dose and has low long-term efficacy.
Patients with ectopic ACTH secretion can be cured if the tumor can be removed and is not metastatic. Otherwise, adrenalectomy or medical therapy is chosen. Adrenalectomy is appropriate when the patient cannot tolerate the cost, medical toxicity, or adverse psychological effects of long-term medical therapy and monitoring or if the patient requires rapid correction of hypercortisolism. Adrenalectomy is appropriate when maximal daily doses of ketoconazole (1600 mg), aminoglutethimide (2 g), and metyrapone (2 g) given in combination do not render the patient eucortisolemic.
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