Hypothyroidism: Difference between revisions
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==Differential Diagnosis== | ==Differential Diagnosis== | ||
*Addison's disease. | |||
*Chronic fatigue syndrome. | |||
*Constipation. | |||
*Depression. | |||
*Sick Euthyroidism | |||
*Hypopituitarism. | |||
*Hypothermia. | |||
Iodine Deficiency. | |||
==Evaluation== | ==Evaluation== | ||
Revision as of 21:14, 23 November 2016
Background
- 3-10x more common in females
- Peak incidence age >60
Types
- Primary: failure of thyroid
- elevated TSH, low FT4
- Secondary: failure of pituitary
- low TSH, low FT4
- Tertiary: failure of hypothalamus
Etiology
- Primary (thyroid gland)
- Autoimmune (Hashimoto)
- Thyroiditis (subacute, silent, postpartum)
- Often preceded by hyperthyroid phase
- Iodine deficiency
- After ablation (surgical, radioiodine)
- After external radiation
- Infiltrative disease (lymphoma, sarcoid, amyloid, TB)
- Congenital
- Meds
- Amiodarone, Li, iodine, interferon, interleukin
- Idiopathic
- Secondary (Hypothalamus-pituitary axis)
- Panhypopituitarism
- Pituitary adenoma
- Infiltrative causes (e.g., hemochromatosis, sarcoidosis)
- Tumors impinging on the hypothalamus
- History of brain irradiation
- Infection (e.g., tuberculosis)
Clinical Features
- Constitutional
- Cold intolerance
- Wt gain
- Weakness
- Lethargy
- Hypothermia
- Hoarse voice
- Hair loss
- Constipation
- Dysfunctional uterine bleeding
- Neuropsychiatric
- Delayed relaxation of DTRs
- Paresthesias
- Cardiopulmonary
- Bradycardia
- Hypoventilation
- Pericardial/pleural effusions
- Dermatologic
- Hair loss
- Non-pitting edema (periorbital, extremities)
- Facial swelling
Differential Diagnosis
- Addison's disease.
- Chronic fatigue syndrome.
- Constipation.
- Depression.
- Sick Euthyroidism
- Hypopituitarism.
- Hypothermia.
Iodine Deficiency.
Evaluation
Work-up
- TSH
- Total and Free T4
- Total and Free T3
- Thyroid Binding Globulin (TBG)
- Auto-antibodies (anti-TPO, anti-microsomal, anti-Tg)
- Thyroid ultrasound
- ECG - bradycardia, low voltage
Management
- Depends on etiology
- Consider starting levothyroxine daily but doses too high may lead to thyroid storm
Disposition
- Most hypothyroidism is treated as an outpatient followed in ambulatory clinic
- Admit and treat severe hypothyroidism or myxedema coma