Endocrinology Flashcards
Causes of hypothyroidism
Primary:
without a goitre: idiopathic atrophy, treatment, agenesis or a lingual thyroid,
with a goitre: chronic thyroidisis, Drugs (lithium, amiodarone), endemic iodine deficiency, iodine-induced hypothyroidism
Secondary: pituitary lesions
Tertiary: hypothalamic lesions
Transient: thyroid hormone treatment withdrawn, subacute thyroiditis, postpartum throiditis
what is the differential diagnosis of a neck mass?
Congenital
- thyroglossal cyst
lymphadenopathy
- bacterial, viral - including HIV, granulomatous- (sarcoidosis and tuberculosis),
- malignant
vascular
- carotid artery aneurysm/carotid body tumour
- jugular vein thromboiss/haemangioma
Neurogenic
- schwannoma, neurofibroma, and malignant
what are the complications of large goitres?
dyspnoea and upper airway obstruciton dysphaiga hoarseness - recurrent laryngeal nerve paralyiss HOrner's syndrome jugular vein compression and SVC obstruction
Management of thyroid storm
●A beta blocker to control the symptoms and signs induced by increased adrenergic tone- Propranolol to achieve adequate control of heart rate: 60-80mg Q4h or propylthiouracil 200mg Q4h (PTU faver over methimazole because PTU’s effect to decrease T4 to T3 conversion)
●A thionamide to block new hormone synthesis
●An iodine solution to block the release of thyroid hormone – after first does of thionamide, administer LUgol’s solution
●An iodinated radiocontrast agent (if available) to inhibit the peripheral conversion of thyroxine (T4) to triiodothyronine (T3)
●Glucocorticoids to reduce T4-to-T3 conversion, promote vasomotor stability, and possibly treat an associated relative adrenal insufficiency – hydrocortisone 100mg Q8h
●(Bile acid sequestrants to decrease enterohepatic recycling of thyroid hormones – Cholestyramine 4g 4 times daily)
Neo-Mercazole is believed to exert its antithyroid effect by ‘blocking’ the organic binding of iodine through inhibition of the iodination of tyrosine.
what are MEN 1
multiple endocrine neoplasia type 1
hyperparathyrodism, pituitary adenomas, pancratic islet cell tumours
What are MEN 2`
Men 2a: medullary throid cancer, phaeochromocytoma and primary hyperparathyroidism
Men 2b: medullary thyroid cancer, phaechromocytoma and mucosal neuromas involving the lips and tongue.
DPP -IV inhibitor, pathophysiology, side effect
Dipeptidyl peptidase-4 (DPP4): sitaglitin, linagliptin, saxagliptin, vidaglipin, increase the levels of increting peptides (glucason - like peptide) by inhibiting their degrading enzyme. Insulin release is increased and glucagon suppressed
side effect: no weight gain, not much hypoglycaemia
they can only be used in combination with metformin or a sulfonylurea except for linagliptin which can be used with both
they are weight neural and can be used in old patients but chronic kidney disease is a relative contraindication.
GLP-1 analogues. pathophysiology and side effect
Exenatide .the glucason anaglogue is resisitant to DPP 4 degradation. injection twice a day. specially useful for overweight patients.
Acromegaly signs and treatment
constant signs:
frontal bossing, macroglossia, splayed teeth, prognathism
hands;Size
feet:size
Active disease:
hand: sweating, carpal tunnel
BP: HTN
skin: skin tags, acanthosis nigracans, greasy skin,
Face: acne
eyes: fundi, VF, ophthalplegia
investigation: IGF-1, OGTT dx if not suppressed, MRI head
treatment;Surgery, radiation therapy, gamma knife,
medical therapy: 1st carbergoline, somatostatin anaglogue, last pegvisomant (not PBS)
what are the causes of hyperthyroidism
1) increased hormone synthesis: graves disease toxic adnoma toxic multinodular goitre hashimoto's disease iodine -induced hyperthyroidism(contrast, amiodarone) TSh secreting pituitary tumour 2) gland inflmaation and release of preformed hormone infective thyroiditis radiation thyroiditis postpartum thyroiditis drug induced thyroiditis (interferon alpha, amiodarone) de Quervain's thyroiditis
What are the causes of hypothyroidism
1)primary thyroid failure: autoimmune thyroiditis idiopathic atrophy previous radioiodine treatment or thyroidectomy iodine deficiency antithyroid drugs subacute, painless and postpartum thyroiditis infiltrative conditions 2)Secondary thyroid failure hypothalamic or pituitary diseae
Differentiation of multimodular diffuse enlarged thyroid
Simple goitre Iodine difficiency Physiological goitre Grave's disease Hashoto's disease
Differentiation of solitary nodule?
Thyroid Adenoma Thyroid cysts Thyroid cancer Toxic Adenoma A single palpable nodule in a multi-modular goitre
