Endocrine Dysfunction Flashcards
Thyroid Hormone Pathway
Brainstem/Paraventricular nucleus releases TRH; which acts on anterior pituitary; which releases TSH; which acts on the thyroid gland; which releases T4 and T3; which impact all cells of the body.
Thyroid hormone is transported in the blood via
proteins secreted by the liver
T3 is a nuclear transcription factor
drives transcription and translation in other cells of the body.
Hyperthyroidism (Thyrotoxicosis). Too much thyroid hormone. Symptoms:
Abdominal pain, vomiting, weight loss despite increase in appetite
Hyperthyroidism associated with:
Pernicious anemia affecting stomach, celiac, IBD
Upper GI tract symptoms of hyperthyroidism:
- Dysphagia 2/2 goiter compression, neurohormonal regulation, skeletal myopathy affecting pharynx and upper esophagus.
-Atrophic gastritis (autoimmune, graves, pernicious anemia), achlorhydria, hypergastrinemia, recurrence of H pylori.
Hyperthyroidism and motility issues
- Esophageal contractility increases velocity of esophageal contractions.
- Gastric emptying can be increased or decreased.
- Accelerated transit can cause diarrhea, steatorrhea.
Hyperthyroidism and lower GI tract symptoms
Lactose intolerance.
Hypothyroidism (Hashimoto’s thyroiditis). Too little thyroid hormone symptoms:
anorexia, nausea, vomiting, abdominal pain, constipation.
weight gain due to myxedema,
anemia: menorrhagia, pernicious anemia/achlorhydria
ascites due to myxedema (high protein content).
- GI bleeding
- GI disease (celiac) can affect absorption of oral thyroid hormone replacement
Hypothyroidism is associated with
IBD, Pernicious anemia/B12 malabsorption, DM, Celiac, T21,
Hypothyroidism motility problems
-Esophageal motor and LES/goiter: dysphagia and dyspepsia.
- GER (Esophageal/LES)
- Delayed gastric emptying: phytobezoars.
- Ileus: SBBO: pain, bloating, flatulence.
- Megacolon, constipation, colonic pseudo-obstruction.
Hyperparathyroidism (Hypercalcemia due to elevated PTH). DDX:
- Sporadic adenoma.
- MEN types I-4.
- Other: post renal transplant, chronic hyperphosphatemia, bone malignancy.
Hyperparathyroidism symptoms
- Gastroparesis: N/V, abdominal pain.
- PUD (gastric hypersecretion). Ca drives gastric acid.
- Decreased colonic transit (constipation)
- Pancreatitis (acute and chronic): abdominal pain and steatorrhea.
Hypoparathyroidism (Hypocalcemia). Congenital causes
-Congenital (suspect in infants with tremor, jitteriness, emesis, feeding issues). DiGeorge (microdeletion in chromosome 22q11.2).
- Other genes: PTH1R
Hypoparathyroidism Acquired
AIRE (autoimmune polyendocrinopathy syndrome type I), IPEX, post -surgical, radiation destruction.
Hypoparathyroidism Infiltrative
Wilson’s, Hemochromatosis, Neoplasm, Sarcoidosis
Other causes of hypoparathyroidism include
Hypomagnesemia/hypermagnesemia
Hypoparathyroidism (low calcium) impacts on GI tract
-low Ca causes decreased cholecystokinin (liver: steatorrhea, poor GB contractility; pancreas: decreased enzyme secretion).
Hypoparathyroidism associations
Celiac
Steatorrhea
Vitamin D deficiency
Cushing’s disease (Chronic glucocorticoid excess) symptoms
Cushingoid facies, buffalo hump, failure of longitudinal growth, hirsutism, muscle weakness, acne, striae, hypertension. DM
Considerations if Cushing’s disease is central in origin
elevated serum ACTH and cortisol level can cause gastric ulceration (particularly if associated with NSAID use)
Cushing’s syndrome and increased serum growth hormone levels associated with
colorectal polyps and cancer.
Addison’s disease (adrenal insufficiency) symptoms.
Acute: low BP, shock, weakness, apathy, confusion, anorexia, nausea, vomiting, dehydration, abdominal pain, hyperthermia, hypoglycemia.
chronic: weakness, fatigue, anorexia, hypotension and hyperpigmentation.
Symptoms can be cyclical and mistaken for CVS
Addison’s disease and enterocyte dysfunction
diarrhea, malabsorption, FTT
Addison’s disease associated with
pernicious anemia (atrophic gastritis and achlorhydria), celiac disease.
MEN genotypes
MEN type 1: MEN1
MEN type 2a: RET
MEN type 2b: RET
MEN1
Gene: MEN1.
Autosomal dominant, rarely denovo.
constellation of tumors (often bilateral and multiple), parathyroid, pituitary, pancreas, duodenum.
presents as hyperparathyroidism and anterior pituitary tumors (can release prolactin, GH, ACTH).
carcinoids (neuroendocrine tumors of GI tract). Gastrinoma (ZE syndrome), Insulinoma, Somatostainoma
MEN 1 Does NOT have
Medullary thyroid carcinoma or Pheochromocytoma.
MEN 2A
Gene: RET, autosomal dominant.
Paraganglionomas.
BIlatreal medullary thyroid carcinoma and bilateral (70%) pheochromocytoma.
Primary hyperparathyroidism.
MEN 2B
Gene: RET: Denovo. more aggressive.
Mucosal neuronal phenotype. Lots of ganglionomas of lips, tongue,
-100% medullary thyroid carcinoma, 50% pheochromocytoma
MEN 2A and 2B do not have
Pancreatic neuroendocrine tumors
