Carcinoid syndrome


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Carcinoid syndrome


Adrenal gland disorders

Congenital adrenal hyperplasia

Primary adrenal insufficiency

Waterhouse-Friderichsen syndrome


Adrenal cortical carcinoma

Cushing syndrome

Conn syndrome

Thyroid gland disorders

Thyroglossal duct cyst


Graves disease

Thyroid eye disease (NORD)

Toxic multinodular goiter

Thyroid storm


Euthyroid sick syndrome

Hashimoto thyroiditis

Subacute granulomatous thyroiditis

Riedel thyroiditis

Postpartum thyroiditis

Thyroid cancer

Parathyroid gland disorders





Pancreatic disorders

Diabetes mellitus

Diabetic retinopathy

Diabetic nephropathy

Pituitary gland disorders


Pituitary adenoma






Growth hormone deficiency

Pituitary apoplexy

Sheehan syndrome


Constitutional growth delay

Diabetes insipidus

Syndrome of inappropriate antidiuretic hormone secretion (SIADH)

Gonadal dysfunction

Precocious puberty

Delayed puberty

Premature ovarian failure

Polycystic ovary syndrome

Androgen insensitivity syndrome

Kallmann syndrome

5-alpha-reductase deficiency

Polyglandular syndromes

Autoimmune polyglandular syndrome type 1 (NORD)

Endocrine tumors

Multiple endocrine neoplasia

Pancreatic neuroendocrine neoplasms

Zollinger-Ellison syndrome

Carcinoid syndrome



Opsoclonus myoclonus syndrome (NORD)

Endocrine system pathology review

Adrenal insufficiency: Pathology review

Adrenal masses: Pathology review

Hyperthyroidism: Pathology review

Hypothyroidism: Pathology review

Thyroid nodules and thyroid cancer: Pathology review

Parathyroid disorders and calcium imbalance: Pathology review

Diabetes mellitus: Pathology review

Cushing syndrome and Cushing disease: Pathology review

Pituitary tumors: Pathology review

Hypopituitarism: Pathology review

Diabetes insipidus and SIADH: Pathology review

Multiple endocrine neoplasia: Pathology review

Neuroendocrine tumors of the gastrointestinal system: Pathology review


Carcinoid syndrome


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High Yield Notes

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Carcinoid syndrome

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External References

First Aid








Carcinoid syndrome p. 356, 592

bronchial carcinoid tumors p. 707

somatostatin for p. 362

treatment p. 725

Cutaneous flushing

carcinoid syndrome p. 357

5-hydroxyindoleacetic acid (5-HIAA)

in carcinoid syndrome p. 357

Heart failure p. 318

carcinoid syndrome p. 592

Octreotide p. 380, 409

carcinoid syndrome p. 359

for carcinoid syndrome p. 725

Pulmonic stenosis

carcinoid syndrome p. 359

Right heart failure

carcinoid syndrome p. 592


in carcinoid syndrome p. 356

Tricuspid regurgitation

carcinoid syndrome as cause p. 359



Alaina Mueller

Sam Gillespie, BSc

Carcinoid syndrome refers to a constellation of symptoms like diarrhea, shortness of breath and flushing, which arise when a specific type of tumor called a neuroendocrine tumor begins secreting hormones.

Neuroendocrine tumors were also called “carcinoid tumors” in the past, because of their association with carcinoid syndrome.

Neuroendocrine cells are found in tissues throughout the body, particularly in the epithelial layer of gastrointestinal organs and the lungs. They receive signals from nerve cells and, in response, they release hormones into the blood.

Neuroendocrine cells release a variety of hormones including amines, like serotonin and histamine; polypeptides, like bradykinin, a vasodilator; and prostaglandins which are also powerful vasodilators. The production of these hormones can also be regulated by other hormones.

For example, somatostatin is a hormone that’s made by cells in the hypothalamus as well as the gastrointestinal tract, and it travels through the blood and binds to receptors on the surface of neuroendocrine cells.

Binding of somatostatin inhibits the release of a number of hormones from neuroendocrine cells, including serotonin.

Now, when serotonin does get released from neuroendocrine cells, it enters the liver through the portal vein.

In the liver, some of the serotonin is metabolized to 5-hydroxyindoleacetic acid which is eliminated from the body through the urine.

The remaining serotonin is not metabolized, and this portion remains in the systemic circulation where it has various effects.

In the gastrointestinal tract, serotonin increases motility and peristalsis; in the vasculature, platelets take up the serotonin and later use it to constrict blood vessels, particularly after injury; and in the connective tissue of the heart, it stimulates fibroblasts which make lots of collagen.


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  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
  4. "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
  5. "Harrison's Endocrinology, 4E" McGraw-Hill Education / Medical (2016)
  6. "Carcinoid heart disease: presentation, diagnosis, and management" Heart (2004)

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