Endocrinology Flashcards
What medications are known to interfere with thyroxine absorption?
cholestyramine and sevelamer, iron sulphate, and proton pump inhibitors
What’s MEN1?
- Parathyroid hyperplasia, pancreatic endocrine tumours (gastrinoma, insulinoma, VIP-oma), pituitary adenomas (prolactinoma, acromegaly)
- Autosomal dominant, high penetrance
- Germline and somatic mutation at chromosome 11q13.
- Many different mutations described - makes screening challenging
What’s MEN2a?
Medullary thyroid cancer (MTC), phaeochromocytoma and parathyroid tumours.
MEN 2 conditions are autosomal dominant due to mutations at 10q11 causing formation of the ret oncogene.
Biochemical screen with annual calcium, calcitonin and urinary metaphrines, and MRI adrenals every three years are needed
What’s MEN2b?
MTC, phaeochromocytoma, mucosal ganglioneuromatosis, marfanoid habitus
Mucosal ganglioneuromatosis is characterised by nodules on the tongue
MEN 2 conditions are autosomal dominant due to mutations at 10q11 causing formation of the ret oncogene.
Biochemical screen with annual calcium, calcitonin and urinary metaphrines, and MRI adrenals every three years are needed
What is sick euthyroid syndrome?
Sick euthyroid syndrome, or non-thyroidal illness, refers to alterations in thyroid function and thyroxine function during significant illness.
Thyroid-stimulating hormone (TSH) decreases during the acute phase of the illness and increases during recovery.
Free tri-iodothyronine (fT3) is low due to reduced peripheral conversion of thyroxine (T4) to T3 by deiodinase enzymes. Similar issues can occur in chronic nutritional deficiency, poorly controlled diabetes mellitus and drug treatment with hydrocortisone or beta blockers.
Reverse T3 (rT3) is made instead of normal T3.
T4 is often normal or slightly low.
Thyroid binding proteins.
What autoimmune conditions is vitiligo associated with?
Autoimmune thyroiditis
Pernicious anaemia
Alopecia areata, and
Diabetes mellitus.
List congenital and acquired causes of primary hypogonadism
Congenital abnormalities:
Klinefelter syndrome (and other chromosomal abnormalities)
Mutation in the FSH and LH receptor genes
Cryptorchidism
Varicocele
Disorders of androgen synthesis, and
Myotonic dystrophy.
Acquired diseases:
Infections (especially mumps) Radiation Alkylating agents Ketoconazole Glucocorticoids Environmental toxins Trauma Testicular torsion Autoimmune damage Chronic systemic illnesses Hepatic cirrhosis Chronic renal failure AIDS, and Idiopathic.
What is th Jod-Basedow effect?
The Jod-Basedow effect is hyperthyroidism following administration of iodine or iodide, either as a dietary supplement or as iodinated contrast for medical imaging.
With a Jod-Basedow effect one would expect increased uptake on the radio-iodine uptake scan
What is the Wollf-Chaikoff effect?
The Wollf-Chaikoff effect is a presumed reduction in thyroid hormone levels caused by ingestion of a large amount of iodine
What are features of glucagonoma?
Diabetes mellitus Hypoaminoacidaemia Cheilosis Normochromic normocytic anaemia Venous thrombosis Neuropsychiatric features. Necrolytic Migratory Erythema
What are the features of malignant exophtalmos?
Proptosis, chemosis, palpebral oedema and periorbital swelling
What is Diabetic cheiroarthropathy?
Diabetic cheiroarthropathy is a condition of limited joint mobility that occurs in subjects with diabetes
Cheiroarthropathy is characterised by thickening of the skin resulting in contracture of the fingers. Cheiroarthropathy causes such limited motion of the fingers that the affected individual is unable to extend the fingers to flatten the hand fully. Typically both hands are affected by cheiroarthropathy.
Cheiroarthropathy has been reported in over half of patients with insulin-dependent diabetes and approximately three quarters of those with non-insulin-dependent diabetes.
List biochemical features of Addison’s disease
Low aldosterone secretion (leading to salt wasting) High plasma renin High adrenocorticotrophic hormone (ACTH) High lipotropin Elevated plasma vasopressin, and Angiotensin II.
