How does pheochromocytoma cause diabetes?

Epinephrine-secreting pheochromocytomas may be more likely to induce glucose intolerance or frank diabetes mellitus by the preferential affinity for the β-receptor. Beta-receptors stimulate gluconeogenesis and α-2 receptors decrease insulin release.

Why does pheochromocytoma cause hyperglycemia?

Catecholamines have been shown to directly suppress insulin secretion from the pancreas and induce glycogenolysis in the liver via α-adrenergic receptor stimulation, leading to hyperglycemia (6). Catecholamine excess as a secondary cause of diabetes mellitus should be considered in patients with pheochromocytoma.

Can pheochromocytoma cause high blood sugar?

One of the classical symptoms of pheochromocytoma crisis is hyperglycemia [1] that might be caused by increased insulin resistance in peripheral tissues and impaired insulin secretion [2].

Why do patients with pheochromocytoma often experience abnormal blood sugar levels?

Hyperglycemia has been linked to aggravation of insulin resistance caused by catecholamine excess in pheochromocytoma. The inhibitory effect of catecholamines on insulin secretion is thought to be mediated by α-2 adrenergic receptors.

Can pheochromocytoma cause low blood sugar?

Pheochromocytoma, a tumor characterized by catecholamine excess, is usually associated with impaired glucose tolerance. Hypoglycemia may occur after the abrupt withdrawal of catecholamines in the postoperative period.

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Is Glucagonoma associated with diabetes?

Diabetes mellitus occurs in patients with glucagonoma because of the lack of equilibrium between insulin production and glucagon production (which occurs when high serum levels of glucagon and normal levels of insulin exist or when insulin production is reduced and a normal glucagon level is present).

Why hypercalcemia occurs in pheochromocytoma?

Sporadic pheochromocytoma may secrete calcitonin and cause hypercalcemia by non-parathyroid hormone-mediated mechanisms. The potential is clearly present for confusion with multiple endocrine neoplasia, type 2 (medullary thyroid carcinoma, pheochromocytoma, and primary hyperparathyroidism).

How does hyperglycemia occur?

What is hyperglycemia? Hyperglycemia, or high blood glucose, occurs when there is too much sugar in the blood. This happens when your body has too little insulin (the hormone that transports glucose into the blood), or if your body can’t use insulin properly. The condition is most often linked with diabetes.

What is the triad present in pheochromocytoma?

Pheochromocytoma classically presents with paroxysms of hypertension and adrenergic symptoms including classic triad of episodic headache, sweating, and tachycardia.

Why does pheochromocytoma cause sweating?

Hyperhidrosis in pheochromocytoma may be due to central activation of heat loss mechanisms resulting from the passage of plasma catecholamines across the blood-brain barrier combined with increased thermogenesis and cutaneous vasoconstriction.

Can pheochromocytoma cause weight gain?

Compared to other adrenal tumor patients with cortisol- and aldosterone- producing tumors that tend to lose weight after operation, pheochromocytoma patients on average tend to gain some weight after successful surgery.

Does pheochromocytoma cause polycythemia?

Polycythemia is rarely associated with pheochromocytoma. A patient with a 22-year history of malignant pheochromocytoma is presented in whom major complications developed as a result of long-standing polycythemia, apparently due to secretion of erythropoietin by the tumors.

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How are pheochromocytomas diagnosed?

A pheochromocytoma is a catecholamine-secreting tumor of chromaffin cells typically located in the adrenals. It causes persistent or paroxysmal hypertension. Diagnosis is by measuring catecholamine products in blood or urine. Imaging tests, especially CT or MRI, help localize tumors.

What does pheochromocytoma cause?

If you have a pheochromocytoma, the tumor releases hormones that may cause high blood pressure, headache, sweating and symptoms of a panic attack. If a pheochromocytoma isn’t treated, severe or life-threatening damage to other body systems can result.

What type of tumors cause hypoglycemia?

Insulinomas are tumors in your pancreas. They make extra insulin, more than your body can use. Insulinomas can cause hypoglycemia, or low blood sugar.

Why does pheochromocytoma cause constipation?

The mechanism by which pheochromocytoma causes constipation and pseudo-obstruction involves direct catecholamine stimulation of alpha and beta receptors in smooth muscle cells of the intestine, causing decreased motility and tonic contraction of intestinal sphincters.