Nursing care
Myxedema Coma nursing care: what to assess and what to do first
Written and reviewed by Dana Whitfield, RN, MSN · 5 min read · Updated September 2026
Short answer
Myxedema coma is a severe, life-threatening form of hypothyroidism marked by hypothermia, hypotension and hypoventilation, the mirror image of thyroid storm and equally fatal without prompt treatment. Nursing priorities are airway support, gradual passive rewarming, IV thyroid hormone and corticosteroid replacement, and continuous cardiac and respiratory monitoring.
Recognising it at the bedside
Myxedema coma is the profound, decompensated end of untreated or undertreated hypothyroidism, and it is the near-opposite emergency to thyroid storm. Where storm brings fever, tachycardia and agitation, myxedema coma brings hypothermia, hypotension and hypoventilation, and it is just as capable of killing the patient.
The name is misleading, since the patient is not always comatose; a depressed level of consciousness ranging from lethargy to true coma is the more accurate description. Look for a body temperature that can fall well below 95°F (35°C), a slow and weak pulse, bradycardia, and shallow, slow respirations. Skin is often dry, cool and doughy, with non-pitting oedema around the eyes and extremities, and speech, if present, is slow and slurred. This presentation most often appears in older women with a known history of hypothyroidism who have stopped their levothyroxine or become acutely ill.
Why the classic presentation misleads
Hypothyroidism is usually thought of as a slow, chronic condition, fatigue, weight gain, cold intolerance, and that framing can delay recognition of myxedema coma as the genuine emergency it is. A patient this depressed and bradycardic can look like they are simply sedated, dying of sepsis, or suffering a primary neurological event, and the diagnosis is frequently missed on first assessment.
The trigger is often something else entirely, infection, cold exposure, surgery, sedative or opioid use, or a missed dose of levothyroxine in a patient already living with unrecognised or poorly controlled hypothyroidism. Because the core problem is a profound metabolic slowdown rather than an obvious acute event, clinicians can spend precious time chasing the trigger before identifying the underlying thyroid crisis driving the whole picture.
Priority nursing actions
Airway and breathing come first. Hypoventilation with rising carbon dioxide and falling oxygen is the most immediate threat, so have intubation and mechanical ventilation equipment ready and monitor respiratory status continuously; many patients in myxedema coma require ventilatory support.
Rewarm the patient gradually and passively, warmed blankets rather than active external heat, because rapid rewarming can cause peripheral vasodilation and precipitate cardiovascular collapse in a patient whose cardiac output is already impaired. Establish IV access and administer IV levothyroxine and IV corticosteroids as ordered; steroids are given because coexisting adrenal insufficiency is common and thyroid hormone replacement alone can unmask it. Monitor blood pressure and cardiac rhythm continuously, since bradycardia and hypotension can progress to shock. Restrict free water if ordered, as these patients are prone to dilutional hyponatraemia from impaired free water clearance.
Labs and diagnostics to expect
A markedly elevated TSH with low free T4 confirms primary hypothyroidism as the underlying cause in most cases; if TSH is not elevated, consider secondary hypothyroidism from pituitary or hypothalamic failure. Serum sodium is frequently low from dilutional hyponatraemia, and this should be corrected cautiously alongside thyroid hormone replacement.
Blood glucose should be checked, since hypoglycaemia is common and compounds the depressed mental status. Arterial blood gases will often show hypercapnia and hypoxaemia consistent with hypoventilation, guiding the decision on ventilatory support. Cortisol levels are drawn before steroid replacement whenever possible to confirm coexisting adrenal insufficiency. An ECG typically shows bradycardia, low voltage and sometimes prolonged QT interval, and blood and urine cultures are usually sent given how often infection is the precipitating trigger.
Complications and their early signs
Cardiovascular collapse is the leading danger: watch for a falling blood pressure that does not respond to fluids, worsening bradycardia, or new dysrhythmia, all of which signal that cardiac output can no longer compensate. Respiratory failure can develop quickly as hypoventilation progresses, so a rising respiratory rate is not reassuring here; a falling rate or increasing somnolence is the warning sign to escalate.
Hypoglycaemia can worsen the depressed mental status further and should be checked regularly, not assumed to be thyroid-related alone. Seizures can occur from severe hyponatraemia or hypoglycaemia. Because adrenal insufficiency frequently coexists, giving thyroid hormone without corticosteroid coverage can precipitate acute adrenal crisis, so the sequencing and timing of these medications matters as much as giving them at all.
Teaching that changes outcomes
The single most important piece of teaching is medication adherence: levothyroxine must be taken every day, at the same time, indefinitely, and never stopped without medical guidance, since missed doses in an already-compromised patient are a recognised trigger for myxedema coma. Confirm the patient and family understand this is a daily, lifelong medication, not a short course.
Teach the patient and family to recognise worsening hypothyroid symptoms early, increasing fatigue, cold intolerance, constipation, slowed thinking, so they seek care before decompensation rather than after. Stress the importance of avoiding sedatives and opioids without medical supervision in known hypothyroidism, since these can precipitate or worsen respiratory depression. Advise keeping warm in cold weather and seeking prompt treatment for infections, and make sure the patient knows to inform every prescriber and treating clinician of their hypothyroidism, since this history changes how other acute illnesses are managed.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our endocrine practice questions are the closest set to what this page covers.
Common questions
How is myxedema coma different from thyroid storm?
Myxedema coma presents with hypothermia, hypotension and hypoventilation from a profound lack of thyroid hormone, while thyroid storm presents with fever, tachycardia and hyperactivity from a surge of excess hormone. They are opposite ends of thyroid dysfunction but share the fact that both are fatal without prompt treatment.
Why are corticosteroids given alongside levothyroxine in myxedema coma?
Many patients in myxedema coma have coexisting, often unrecognised, adrenal insufficiency. Giving thyroid hormone alone can increase metabolic demand and precipitate an acute adrenal crisis, so corticosteroids are given, typically before or alongside the first dose of levothyroxine.
Why is rapid rewarming avoided in myxedema coma?
Rapid active rewarming causes peripheral vasodilation, which can drop blood pressure further in a patient whose cardiac output is already depressed. Passive rewarming with blankets is used instead to raise temperature gradually and safely.
What is the most urgent nursing priority in myxedema coma?
Airway and respiratory support take priority, since hypoventilation can progress to respiratory failure quickly. Continuous respiratory monitoring and readiness for mechanical ventilation come before other interventions.
What commonly triggers myxedema coma in a patient with hypothyroidism?
Infection, cold exposure, surgery, sedative or opioid medications, and missed doses of levothyroxine are the most common triggers. It typically occurs in patients with longstanding, poorly controlled or undiagnosed hypothyroidism who then face an additional physiological stressor.