Hypothyroidism: Difference between revisions
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*3-10x more common in females | *3-10x more common in females | ||
*Peak incidence age >60 | *Peak incidence age >60 | ||
*Emergent manifestation of severe hypothyroid = [[myxedema coma]] | |||
===Etiology=== | ===Etiology=== | ||
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**Congenital | **Congenital | ||
**Meds | **Meds | ||
***[[Amiodarone]], [[lithium]], iodine, | ***[[Amiodarone]], [[lithium]], iodine, [[Interferon-α]], interleukin | ||
**Idiopathic | **Idiopathic | ||
*Secondary | *Secondary | ||
**Panhypopituitarism | **Panhypopituitarism | ||
**Pituitary adenoma | **Pituitary adenoma | ||
**Infiltrative causes (e.g., hemochromatosis, sarcoidosis) | **Infiltrative causes (e.g., [[hemochromatosis]], [[sarcoidosis]]) | ||
**Tumors impinging on the hypothalamus | **[[brain tumor|Tumors]] impinging on the hypothalamus | ||
**History of brain irradiation | **History of brain irradiation | ||
**Infection (e.g., [[tuberculosis]]) | **Infection (e.g., [[tuberculosis]]) | ||
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==Clinical Features== | ==Clinical Features== | ||
*Constitutional | *Constitutional | ||
**Cold intolerance | **Cold intolerance, [[hypothermia]] | ||
**Weight gain | **Weight gain | ||
**Weakness | **[[Weakness]] | ||
**Lethargy | **[[Lethargy]] | ||
**Hoarse voice | **Hoarse voice | ||
** | **[[Constipation]] | ||
**Dysfunctional [[vaginal Bleeding (Non-Pregnant)|uterine bleeding]] | |||
**Dysfunctional uterine bleeding | |||
*Neuropsychiatric | *Neuropsychiatric | ||
**Delayed relaxation of DTRs | **Delayed relaxation of DTRs | ||
**Paresthesias | **[[Paresthesias]] | ||
*Cardiopulmonary | *Cardiopulmonary | ||
**Bradycardia | **[[Bradycardia]] | ||
**Hypoventilation | **Hypoventilation | ||
**Pericardial/pleural effusions | **[[pericardial effusion|Pericardial]]/[[pleural effusions]] | ||
*Dermatologic | *Dermatologic | ||
**Hair loss | **Hair loss | ||
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==Differential Diagnosis== | ==Differential Diagnosis== | ||
*Addison's disease | *[[Addison's disease]] | ||
*Chronic fatigue syndrome | *Chronic fatigue syndrome | ||
*Constipation | *[[Constipation]] | ||
*Depression | *[[Depression]] | ||
*Sick Euthyroidism | *Sick Euthyroidism | ||
*Hypopituitarism | *Hypopituitarism | ||
*Hypothermia | *[[Hypothermia]] | ||
*Iodine Deficiency | *Iodine Deficiency | ||
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*Thyroid ultrasound | *Thyroid ultrasound | ||
*[[ECG]] - bradycardia, low voltage | *[[ECG]] - bradycardia, low voltage | ||
*VBG - hypercapnia from hypoventilation, possibly compensated if chronic | *[[VBG]] - hypercapnia from hypoventilation, possibly compensated if chronic | ||
===Categorization=== | ===Categorization=== | ||
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==Management== | ==Management== | ||
*Depends on etiology | *Depends on etiology | ||
**Consider starting [[levothyroxine]] daily | **Consider starting [[levothyroxine]] daily | ||
***Caution as daily doses too high may lead to [[thyroid storm]] | |||
==Disposition== | ==Disposition== | ||
*Most hypothyroidism is treated as an outpatient | *Most hypothyroidism is treated as an outpatient | ||
*Admit and treat severe hypothyroidism or [[myxedema coma]] | *Admit and treat severe hypothyroidism or [[myxedema coma]] | ||
Revision as of 16:26, 28 September 2019
Background
- 3-10x more common in females
- Peak incidence age >60
- Emergent manifestation of severe hypothyroid = myxedema coma
Etiology
- Primary
- 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, lithium, iodine, Interferon-α, interleukin
- Idiopathic
- Secondary
- 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, hypothermia
- Weight gain
- Weakness
- Lethargy
- Hoarse voice
- 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
Symptomatic bradycardia
- Cardiac
- Inferior MI (involving RCA)
- Sick sinus syndrome
- Neurocardiogenic/reflex-mediated
- Increased ICP
- Vasovagal reflex
- Hypersensitive carotid sinus syndrome
- Intra-abdominal hemorrhage (i.e. ruptured ectopic)
- Metabolic/endocrine/environmental
- Hyperkalemia
- Hypothermia (Osborn waves on ECG)
- Hypothyroidism
- Hypoglycemia (neonates)
- Toxicologic
- Infectious/Postinfectious
- Other
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
- VBG - hypercapnia from hypoventilation, possibly compensated if chronic
Categorization
| Type | Cause | TSH | FT4 |
| Primary | Failure of thyroid | Elevated | Low |
| Secondary | Failure of pituitary | Low | Low |
| Tertiary | Failure of hypothalamus |
Management
- Depends on etiology
- Consider starting levothyroxine daily
- Caution as daily doses too high may lead to thyroid storm
- Consider starting levothyroxine daily
Disposition
- Most hypothyroidism is treated as an outpatient
- Admit and treat severe hypothyroidism or myxedema coma