Myxedema coma
Myxedema coma | |
---|---|
Specialty | Endocrinology |
Symptoms | deterioration of the patient's mental status[1] |
Causes | infections (especially pneumonia and urosepsis), certain medications, failure to reinstate thyroid replacement therapy[1] |
Treatment | admission to the intensive care unit, correct hypovolemia and electrolyte abnormalities, mechanical ventilation if needed, thyroid hormone replacement[1] |
Myxedema coma is an extreme or
According to newer theories, myxedema coma could result from allostatic overload in a situation where the effects of hypothyroidism are amplified by nonthyroidal illness syndrome.[6]
Causes
Myxedema coma represents an extreme or decompensated form of hypothyroidism. Most cases occur in patients who have been previously diagnosed with hypothyroidism, yet in some cases, hypothyroidism may not have been previously identified. [1][2][3]
Common precipitating factors of myxedema coma include:
- Hypothermia, especially during winter months
- Metabolic disruption including hypercalcemia
- Respiratory compromise including hypoxemia and hypercapnia
- Infections including urosepsis
- Congestive heart failure
- Cerebrovascular accidents
- Gastrointestinal bleeding
- fractures
- Medications including narcotics, amiodarone, and lithium
- Withdrawal of thyroid supplements, especially in relation to a hospitalization
Other precipitating factors include:
- Other medications including rifampin, anti-TNF therapy
- Burns
- Influenza
- Surgery
- Consumption of raw bok choy
- Diabetic ketoacidosis after total thyroidectomy
Pathophysiology
The
The most common cause of hypothyroidism worldwide is too little dietary iodine. Hashimoto's thyroiditis is the most common cause of hypothyroidism in countries with sufficient dietary iodine. With the cessation of the production of thyroid hormone, the thyroid gland contains enough reserve T3 and T4 to last 2 to 3 months.[3]
The thyroid hormones T3 and T4 influence the production by virtually all cells in the body of hundreds of new intracellular proteins and enzymes. This influence includes the expression of the
Diagnosis
Clinical features of myxedema coma:[1][2][3]
- Cardiovascular
- Bradycardia
- Bundle branch blocks
- Complete heart block and arrhythmias
- Cardiomegaly
- Elevated diastolic blood pressure—early
- Hypotension—late
- Low cardiac output
- Non-specific ECG findings
- Pericardial effusion
- Polymorphic ventricular tachycardia (torsades de pointes)
- Prolonged QT interval
- Respiratory
- Hypoxia
- Hypercapnia
- Hyperventilation
- Myxedema of the larynx
- Pleural effusion
- Gastrointestinal
- Abdominal distention
- Abdominal pain
- Anasarca
- Anorexia and nausea
- Decreased motility
- Fecal impaction and constipation
- Gastrointestinal atony or ileus
- Myxedema or toxic megacolon—late
- Neurogenic oropharyngeal dysphagia
- ileus
- Neurological
- Altered mentation
- Coma
- Confusion and obtundation
- Delayed tendon reflexes
- Depression
- Poor cognitive function
- Psychosis
- Seizures
- Renal and urinary function
- Bladder dystonia and distension
- Fluid retention
- Appearance and dermatological
- Alopecia
- Coarse, sparse hair
- Dry, cool, doughy skin
- Myxedematous face
- Generalized swelling
- Goiter
- Macroglossia
- Non-pitting edema
- Ptosis
- Periorbital edema
- Surgical scar from prior thyroidectomy
- Hypothermia
Laboratory features in myxedema coma:[1][2][3]
- Anemia
- Elevated creatine kinase (CPK)
- Elevated creatinine
- Elevated transaminases
- Hypercapnia
- Hypercholesterolemia (elevated LDL)
- Hyperlipidemia
- Hypoglycemia
- Hyponatremia
- Hypoxia
- Leukopenia
- Respiratory acidosis
Epidemiology
Hypothyroidism is four times more common in women than men. The incidence of myxedema coma has been reported to be 0.22 per 1000000 per year but the data is limited and especially lacking in countries outside the western world and countries along the equator. Myxedema coma is most common in people 60 years old and older and is most common in the winter months when hypothermia is more common.[1][2][3]
See also
References
- ^ PMID 11130234.
- ^ PMID 21941682.
- ^ PMID 31424777.
- ISBN 978-1-60327-176-9.
- OCLC 1075522289.)
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: CS1 maint: multiple names: authors list (link - PMID 28775711.