- Hashimoto’s disease:
- Most common. Iodine deficiency most common cause worldwide. Can also be due to pituitary insufficiency or drug-induced (amiodarone, lithium).
- Diagnose with low free T4, elevated TSH, thyroid antibodies
- Symptoms: cold intolerance, dry skin, fatigue, weight gain, bradycardia, slow reflexes, coarse skin and hair, periorbital swelling, goiter, menstrual irregularities
- Levothyroxine is the drug of choice at 1.6 mcg/kg per day. If cardiovascular disease, 12.5-25 mcg/kg per day. Dose on empty stomach apart from other meds. Increase or decrease in 12.5-25 mcg/day increments.
- May take 4-8 weeks.
- Adverse effects: hyperthyroidism, tachyarrhythmias, angina, myocardial infarction, some risk of fracture
Liothyronine, liotrix and desiccated thyroid not recommended
- Severe and life-threatening hypothyroid
- Precipitating causes: trauma, infections, heart failure, meds (sedatives, narcotics, anesthesia, lithium, amiodarone). “Coma” is a misnomer, it usually doesn’t cause coma.
- IV thyroid: T4 100-500 mg loading dose followed by 75-100 mcg/day. Change to PO when tolerated.
- Antibiotic therapy for common causes. Some advocate broad spectrum.
- Corticosteroids: Hydrocortisone 100 mg every 8 hours