S17C223 - Thyroid disorders: Hypothyroid and Myxedema Crisis

Question 1

Hypothyroid (HoTH): causes

Answer 1

-autoimmune
-thyroiditis
-iodine deficiency
-ablation/radiation
-infiltrative dz (lymphoma, sarcoid, TB)
-congenital
-drugs (amio, Li, iodine, alpha-interferon, interleukin)
Secondary: panhypopituiatrism, pituitary adenoma, tumor

Question 2

HoTH: symptoms

Answer 2

-constitutional: cold intolerance, wt gain, weakness, lethargy, fatigue, deep voice
Neuropsychiatric: decr DTR, dementia, psychosis, paresthesias, dpn, poor memory, confusion, ataxia
Cardiopulmonary: agina, brady, distant HS, low voltage, pericardial/pleural effusion, cardiomyopathy, hypoventilation
Dermatologic: dry skin, hair loss, non pitting edema, facial swelling, ptosis, macroglossia, periorbital edema
-dysfunctional uterine bleeding
-constipation

Question 3

Myxedema

Answer 3

• non-pitting edema that is generalized
• particularly periorobital distribution
• secondary to hyaluronic acid deposition

Question 4

Myxedema coma

Answer 4

Clinical Diagnosis:

• metabolic and multi-organ decompensation
• mental status changes or coma
• hypothermia (

Question 5

HoTH: Dx

Answer 5

high TSH plus low free T4/T3 = primary HoTH

low TSH plus low free T4/T3 = secondary HoTH (HPA error)

Question 6

Myxedema coma: Tx

Answer 6

-treat w/o waiting for labs
-supportive care: O2, fluids, inotropes, re-warm with blankets (don’t do active re-warm), steroids (For adrenal insufficiency), glucose, synthroid and treat the precipitating factor
IV T4 dose: 4mcg/kg followed by 100mcg in 24h followed by 50mcg dialy until oral doses are tolerated