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Myxedema Coma

Myxedema coma (MC) is defined as an extreme, uncommon and life-threatening manifestation of hypothyroidism characterized by a marked and general decompensation.


Presentation

Myxedema coma is preceded by a long history of hypothyroidism-related symptoms, such as generalized fatigue, cold intolerance, constipation, and dry skin, which slowly progress into more pronounced clinical manifestations such as lethargy, delirium, and coma. This progression is usually accelerated by the triggers mentioned above, like heart failure, trauma, or infection. Since these symptoms are non-specific, hypothyroidism can frequently go undiagnosed and clinically missed.

Comatose state does not necessarily occur in every myxedema coma episode, but certainly it characterizes the worst cases. The usual signs instead, which can be typically observed in all cases, include weight gain, the already mentioned fatigue, constipation, and cold intolerance. These are usually coupled with coarsened hair, deepened voice and dry, pale, and cool skin. They are commonly followed by an hypothermic state characterized by core body temperatures less than 35.5 C°. Furthermore, the hypotensive state is usually associated with bradycardia and hypoventilation, that in turn might cause sleep apnea

In any case, the signs involve almost all the organic systems. As previously said, the skin appears cool, pale, and dry, usually associated with brittle nails ecchymoses, purpura, and sallowness due to carotenemia. It is also possible to observe signs of periorbital and non-pitting edema on hands and feet, as well as enlarged tonsils, facial swelling, and thinning of hair [5]. Slowed respiration rate, congestion, and hypoventilation may be present. The thyroid may appear enlarged or with scars indicating the presence of previous thyroidectomy. Soft sounds, coupled with diminished apical impulse, bradycardia and pericardial effusion, can be detected in the heart, and in the abdomen and bladder there are clear signs of distension with the bowel sounds appearing diminished or absent.

The neuromuscular system is also largely affected, presenting the classical signs of confusion, stupor, slow speech, obtundation, and reflexes with a slow relaxation phase, usually followed by more pronounced signs such as seizures and coma. Apathy, low mood, and a general cognitive decline can also frequently observed and are often mixed up with the symptoms of dementia and depression.

It is important to notice that many patients might have been treated with diuretics for edematous states before showing the signs of myxedema coma. This condition might mask the development and delay the final diagnosis [11], causing a marked increase in the mortality of this disorder [12].

Hypothermia
  • A 6-year-old Chinese girl presented with coma and hypothermia preceded by pneumonia.[ncbi.nlm.nih.gov]
  • A 74-year-old man with myxedema and hypothermia had increased activities in plasma of creatine kinase (CK; EC 2.7.3.2), aspartate aminotransferase (AST; EC 2.6.1.1), and lactate dehydrogenase (LD; EC 1.1.1.27) and increased proportions of CK-MB (up to[ncbi.nlm.nih.gov]
  • Aside from altered mental status, heart block was present in addition to hypothermia and hypercarbia. Diffuse cerebral cortical and corpus callosum atrophy were seen on MRI.[ncbi.nlm.nih.gov]
  • It typically presents in older women in the winter months and is associated with signs of hypothyroidism, hypothermia, hyponatremia, hypercarbia, and hypoxemia. Treatment must be initiated promptly in an intensive care unit setting.[ncbi.nlm.nih.gov]
  • Symptoms included somnolence, hypothermia, and prolonged QTc with torsades de pointes resistant to magnesium therapy requiring defibrillation and overdrive pacing.[ncbi.nlm.nih.gov]
Noncompliance
  • Though MC is rare, occurring mainly with noncompliance in primary hypothyroidism, it may occur at the diagnosis of secondary hypothyroidism.[ncbi.nlm.nih.gov]
  • Conclusion: Though MC is rare, occurring mainly with noncompliance in primary hypothyroidism, it may occur at the diagnosis of secondary hypothyroidism.[karger.com]
Movement Disorder
  • Although chorea is a rare manifestation of hyperthyroidism, this is the first report of a patient with acquired, reversible choreiform movement disorder while still being severely hypothyroid and treated with levothyroxine.[ncbi.nlm.nih.gov]
Hypoventilation
  • Low blood sugar, low blood pressure, hyponatremia, hypercapnia, hypoxia, slowed heart rate, and hypoventilation may also occur.[en.wikipedia.org]
  • She presented to the hospital with alteration of the mental status, generalized edema, hypothermia, hypoventilation, and hypotension. Initially her brain stem reflexes were absent.[ncbi.nlm.nih.gov]
  • Based on features like hypothermia, hypoventilation, and cardiovascular instability occurring in the setting of central hypothyroidism, it should be suspected and managed urgently in order to avert the associated high mortality resulting from treatment[ncbi.nlm.nih.gov]
  • […] respiratory muscle weakness, mechanical obstruction by a large tongue, and obesity-hypoventilation syndrome.[emedicine.medscape.com]
Bradypnea
  • Signs And Symptoms Hypothermia Hypoventilation Decreased mental function Fatigue Activity intolerance Hyporeflexia Cardiac or respiratory failure Physical Examination Vital Signs BP: hypotension or hypertension HR: bradycardia RR: bradypnea Temperature[nursingcrib.com]
  • The urinalysis may show signs of a urinary tract infection; ABGs may show acidosis, hypoxemia, and hypercapnia secondary to bradypnea. The ECG may reveal conduction abnormalities and bradycardia.[journals.lww.com]
Rales
  • During the second week, the condition of their lungs deteriorated and prolonged respiratory failure ensued with fever, rales, excessive bronchial secretion, homogeneous densities in the chest radiograms and persistent hypoxemia even though mechanical[ncbi.nlm.nih.gov]
Pharyngeal Edema
  • Some patients will require endotracheal intubation in the emergency department (ED), and physicians should be aware that unanticipated posterior pharyngeal edema in myxedema coma could severely complicate airway management.[ncbi.nlm.nih.gov]
Decreased Bowel Sounds
  • bowel sounds Endocrine Thyroid maybe nonpalpable, enlarged, or nodular Acute Care Patient Management NURSING DIAGNOSIS: Decreased cardiac output related to bradycardia and decreased stroke volume.[nursingcrib.com]
  • His abdomen was slightly distended with decreased bowel sound and his extremities were cold.[jmedicalcasereports.biomedcentral.com]
Angioedema
  • We describe a case of an unidentified woman who presented to the ED with myxedema coma requiring urgent endotracheal intubation and was found to have extensive posterior pharyngeal angioedema inconsistent with her relatively benign external examination[ncbi.nlm.nih.gov]
  • Severe angioedema in myxedema coma: a difficult airway in a rare endocrine emergency. Am J Emerg Med. 2009;27(8):1021. Google Scholar 7. Batniji RK, Butehorn 3rd HF, Cevera JJ, Gavin JP, Seymour PE, Parnes SM.[link.springer.com]
Purpura
  • As previously said, the skin appears cool, pale, and dry, usually associated with brittle nails ecchymoses, purpura, and sallowness due to carotenemia.[symptoma.com]
Severe Osteoporosis
  • This was not only a rare case of MC with TSH deficiency and Hashimoto's thyroiditis; the patient also developed severe osteoporosis and possessed transient elevated levels of serum carcinoembryonic antigen (CEA).[ncbi.nlm.nih.gov]
Stroke
  • A person may have lab values identical to a "normal" hypothyroid state, but a stressful event (such as an infection, myocardial infarction or stroke) precipitates the myxedema coma state, usually in the elderly.[en.wikipedia.org]
  • These triggering factors include infections, especially those affecting lungs and kidneys, heart failure, stroke, trauma, some types of surgery, and drug therapies.[symptoma.com]
  • Precipitating factors may include (but are limited to) infection, trauma, surgery, heart failure, stroke, or central nervous system depressants. Hypothyroidism depresses metabolic rate, thus seriously affecting all body system.[nursingcrib.com]
  • Cardiovascular Cardiac contractility is impaired, leading to reduced stroke volume, low cardiac output, bradycardia and sometimes hypotension. [6] Reduced stroke volume in severe cases may also be due to pericardial effusions caused by the accumulation[emedicine.medscape.com]
Altered Mental Status
  • Myxedema coma (MC), a medical emergency defined as severe hypothyroidism leading to altered mental status, is more common in older women with hypothyroidism.[ncbi.nlm.nih.gov]
  • Myxedema coma (MC) is extremely rare but lethal in pediatric patients with hypothyroidism leading to altered mental status and hypothermia. But there is no clinical guideline for such cases.[ncbi.nlm.nih.gov]
  • The three essential elements for the diagnosis of myxedema coma include altered mental status, defective thermoregulation and a precipitating event or illness; all of these were present in our patient.[ncbi.nlm.nih.gov]
  • Primary symptoms of myxedema coma are altered mental status and low body temperature. Low blood sugar, low blood pressure, hyponatremia, hypercapnia, hypoxia, slowed heart rate, and hypoventilation may also occur.[en.wikipedia.org]
  • LT4 load is safe and effective at reversing symptoms, particularly [altered mental status], within a short period of time ( For more information: Wu KC. Oral #221.[healio.com]
Stupor
  • Symptoms include hypoglycemia, hyponatremia, hypothermia, hypoventilation, progressive weakness, stupor, shock, and death.[boardprep.net]
  • The typical progression is lethargy evolving into stupor and, eventually, into coma with respiratory failure and hypothermia. It mainly affects elderly women, often occurring in winter and is relatively rare.[ncbi.nlm.nih.gov]
  • […] and coma with mcc 081 Nontraumatic stupor and coma without mcc 793 Full term neonate with major problems Convert E03.5 to ICD-9-CM Code History 2016 (effective 10/1/2015) : New code (first year of non-draft ICD-10-CM) 2017 (effective 10/1/2016) : No[icd10data.com]
Cerebellar Ataxia
  • Cerebellar ataxia, intention tremor, nystagmus, and difficulty with coordinated movements may occur. Twenty-five percent of those who develop myxedema coma initially present with grand mal seizure.[emjournal.net]
  • ProlactinNeuromuscular• Aches and pains• Muscle stiffness• Carpel tunnel syndrome• Deafness, Hoarseness• Cerebellar ataxia• Delayed DTR, Myotonia• Depression, PsychosisGastro-intestinal• Constipation, Ileus, AscitesDermatological• Dry flaky skin and hair[slideshare.net]
Chorea

Workup

The diagnosis of myxedema coma is largely based on laboratory studies. In particular, levels of T3 and T4 should be low or even undetectable, while the level of TSH should usually be elevated due to a primary thyroid disorder. Complete blood count should detect the presence of infection, while Pan-culture is used to rule out sepsis. Equally important are also tests to measure the levels of electrolytes, creatinine and glucose, to reveal low serum osmolarity, decreased renal perfusion, and adrenal insufficiency.

Imagining studies could be useful in the diagnosis, especially chest radiography which is strongly recommended to detect cardiomegaly, congestive heart failure, and pericardial and pleural effusion. Electrocardiography might also be useful, especially to detect signs of sinus bradycardia.

Enlarged Sella
  • In addition, he demonstrated an inability to release TSH after intravenous administration of TRH and was found to have an enlarged sella turcica. A partial defect in peripheral conversion of T4 to T3 is postulated.[ncbi.nlm.nih.gov]
Triphasic Waves
  • Triphasic waves occur in metabolic and nonmetabolic encephalopathies. We report an elderly patient in whom triphasic waves were associated with myxedema coma and disappeared after thyroid replacement therapy was initiated.[ncbi.nlm.nih.gov]
Hypercapnia
  • Low blood sugar, low blood pressure, hyponatremia, hypercapnia, hypoxia, slowed heart rate, and hypoventilation may also occur.[en.wikipedia.org]
  • […] muscle weakness Mechanical obstruction by a large tongue Sleep apnea Degree of hypoventilation and hypercapnia is not usually clinically important Hyponatremia Found in approx ½ of pts with myxedema coma May contribute to the decrease in mental status[lilywhite.us]
  • […] was worsening and she was transferred to a Universitary Hospital, where myxedema coma was suspected (history of untreated autoimmune hypothyroidism, apparently normal temperature – 36 C despite the infection, bradycardia, hypotension, hypoventilation, hypercapnia[endocrine-abstracts.org]
  • – Sx of hypothyroidism ( weight gain, cold intolerance, constipation, hair loss …) – Hypothermia (often profound-even down to 27 Celsius) – AMS (coma not common- more likely to see lethargy and confusion) -Respiratory sx ( hypoventilation - hypoxia/hypercapnia[dailyem.wordpress.com]
Abnormal Thyroid Function Test
  • Frequency of abnormal thyroid function tests in Kuwaiti Arabs with autoimmune diseases. Med Princ Pract (2008) 17(1):61–5. doi:10.1159/000109592 PubMed Abstract CrossRef Full Text Google Scholar 304. Luongo C, Trivisano L, Alfano F, Salvatore D.[doi.org]
Torsades De Pointes
  • Symptoms included somnolence, hypothermia, and prolonged QTc with torsades de pointes resistant to magnesium therapy requiring defibrillation and overdrive pacing.[ncbi.nlm.nih.gov]
  • Severe primary hypothyroidism manifesting with torsades de pointes. Am J Med Sci. 2006;331:154–6. CrossRef PubMed Google Scholar 10. Fukunaga K. Refractory gastrointestinal bleeding treated with thyroid hormone replacement.[link.springer.com]
  • Severe primary hypothyroidism manifesting with torsades de pointes. American Journal of the Medical Sciences . 2006; 331 (3):154–156. [ PubMed ] [ Google Scholar ] 21. Roberts CG, Ladenson PW. Hypothyroidism.[ncbi.nlm.nih.gov]

Treatment

Patients affected by myxedema coma should receive intensive care to carefully monitor the progress of the disorder. They might show signs of hypercapnia or hypoxia that have to be treated with mechanical ventilation. The cardiovascular status too should be carefully checked trough ECG, paying attention to exclude myocardial infarction, monitor blood pressure and avoid pressor agents and inotropes which cause arrhythmias.

Thyroid should immediately treated with intravenous thyroid replacement, even though a harsh controversy exists over what combination of thyroid hormones has to be taken into consideration, T4 alone, T4 combined with T3, or T3 alone. In general, clinicians tends to treat adults with T4 alone, with an initial dose of intravenous T4 of 100-500 micrograms, subsequently followed by a dose of 75-100 micrograms until patients are able to take oral replacements. In younger patients, instead, clinicians tend to administer T4 combined with T3, especially when the cardiovascular risk is low.

Since many patients affected by myxedema coma might develop infections, a treatment based on brad-spectrum antibiotics is strongly recommended. Furthermore, they might also develop adrenal insufficiency secondary to hypopituitarism, which should be treated with a dose of 100 mg of hydrocortisone taken every 8 hours.

Prognosis

The prognosis largely depends on the general conditions of the patients and the presence of other possible pathological disorders. However, the mortality rate appears to be quite high, even when patients have received proper treatment. The prognosis improves when myxedema coma has been diagnosed very early and the patients have undergone presumptive thyroid hormone replacement as well as hydrocortisone-based therapy with related supportive care [1].

Etiology

Myxedema coma usually appears in subjects who are already affected by a long-lasting and untreated form of hypothyroidism, which is the baseline condition out of which the disorder can manifests itself. In this situation myxedema coma is triggered by a series of other factors which start the crisis. These triggering factors can include infections, especially those affecting lungs and kidneys, heart failure, stroke, trauma, some types of surgery, and drug therapies. The crisis can also be started by the failure of the patient to take the prescribed thyroid medications.

Epidemiology

Myxedema coma is around four times more common in women than men, a characteristic that underlines the high incidence and prevalence of hypothyroidisms in the female population, especially those aged over 50. In any case, the disorder almost exclusively occurs in patients older than 60 years of age, especially in those communities characterized by high levels of iodine deficiency, such as some population living in isolated and mountain regions of Asia, Africa and South America. Being much more frequent in winter months [1] [7], the conditions has also a seasonal variation that might be connected with the two classical hypothyroidism signs of age-related loss of temperature sense and decreased heat production.

As previously mentioned, myxedema coma is particularly common in those with long-lasting hypothyroidism, frequently undiagnosed or not properly treated because of a lack of efficient monitoring or poor compliance of the patients to follow the correct therapy. Mortality remains very high, between 25% to 50%, even when patients receive appropriate medical intervention [8].

There is no data suggesting the existence of a race-related epidemiological difference. However, the frequency increases with age [9], even though this tendency is not sufficient to rule out the occurrence of episodes in young adults. Other factors fostering the occurrence of episodes include hypoglycemia, infection, trauma, hemorrhage or a change in the medication prescribed.

Sex distribution
Age distribution

Pathophysiology

Myxedema coma is a form of decompensated hypothyroidism which develops after the occurrence of an additional stress, where the body is no longer capable of adapting and fails to maintain homeostasis [10]. For example, peripheral vasoconstriction occurs in concomitance with reduced metabolic rate and oxygen consumption, to maintain core body temperature. If this fails to occur the body temperature can no longer be preserved. This condition ends up affecting all organs of the body, including heart, lungs, kidneys, gastrointestinal tract and even brain. Obviously, the crisis occurs much more frequently in elderly, who are weaker than younger subjects and much more prone to systemic organic failures.

Prevention

Subjects with a history of hyperthyroidism are at high risk of developing myxedema coma, and are advised to have the TSH levels checked each year. They should also be aware that they might experience other episodes of myxedema coma in the future and therefore should understand how to recognize the signs of this disorder, even by receiving an appropriate training. Patients are also recommended to constantly comply with the therapy and the administration of the drugs prescribed and have the thyroid function frequently monitored.

Summary

The term myxedema also refers to two different dermatological conditions caused hypothyroid and hyperthyroid states. Myxedema coma (MC), instead, refers to the state of decompensated hypothyroidism, seen as an endocrine emergency affecting the entire body [1] [2] [3] [4]. Very rare and potentially fatal [5], this disorder not necessarily involves the occurrence of a comatose state or shows the classical skin changes of myxedema. This is the reason why many experts prefer to refer to the condition as myxedema crisis.

Myxedema coma frequently turns out to be difficult to diagnose and treat successfully, a problem that underlies the high mortality of 50% associated with it [6]. In fact, patients might have the laboratory values of a normal hypothyroid state, but might develop myxedema coma after experiencing a stressful event such as infection, myocardial infarction or stroke. Mainly affecting the elderly with long-lasting and untreated hypothyroidism, the primary signs include altered mental status, low body temperature, low blood sugar and low blood pressure.

Patient Information

Myxedema coma (MC) is an extreme, uncommon and life-threatening manifestation of hypothyroidism characterized by a marked and general decompensation. The term myxedema also refers to different dermatological conditions which might appear with disorders of the thyroid gland. Very rare and potentially fatal [5], myxedema coma not necessarily involves the occurrence of a comatose state or shows the classical skin changes of myxedema. This is the reason why many experts prefer to call it as myxedema crisis.
The condition frequently appears in subjects who are already affected by a long-lasting and untreated form of hypothyroidism. In this situation myxedema coma may be triggered by a series of other factors which start the “crisis”. These triggering factors include infections, especially those affecting lungs and kidneys, heart failure, stroke, trauma, some types of surgery, and drug therapies. The crisis can also be started by the failure to take the prescribed thyroid medications.

Comatose state does not necessarily occurs in every myxedema coma episode, but certainly it characterizes the worst cases. The usual signs instead, which can be typically observed in all cases include weight gain, fatigue, constipation, cold intolerance, coarsened hair, deepened voice and dry, pale and cool skin, facial swelling, low body temperature (less than 35.5 C°), slow heart rate, slow pulse and confusion.

Myxedema coma is around four times more common in women than men, especially in those aged over 50. The prognosis largely depends on the general health and the presence of other possible pathological disorders. However, the mortality rate appears to be quite high, even with proper treatment.

Subjects with a history of hyperthyroidism are at high risk of developing myxedema coma, and are advised to have the TSH levels checked each year. They should also be aware that they might experience other episodes of myxedema coma in the future and therefore should understand how to recognize the signs of this disorder, even by receiving an appropriate training. Patients are also recommended to constantly comply with the therapy and the administration of the drugs prescribed and have the thyroid function frequently monitored.

References

Article

  1. Wall CR. Myxedema coma: diagnosis and treatment. Am Fam Physician. Dec 1 2000;62(11):2485-90.
  2. Fliers E, Wiersinga WM. Myxedema coma. Rev Endocr Metab Disord. May 2003;4(2):137-41. 
  3. Kwaku MP, Burman KD. Myxedema coma. J Intensive Care Med. Jul-Aug 2007;22(4):224-31. 
  4. Klubo-Gwiezdzinska J, Wartofsky L. Thyroid emergencies. Med Clin North Am. Mar 2012;96(2):385-403. 
  5. Sheu CC, Cheng MH, Tsai JR, et al; Myxedema coma: a well-known but unfamiliar medical emergency. Thyroid. 2007 Apr;17(4):371-2. 
  6. Kearney T, Dang C; Diabetic and endocrine emergencies. Postgrad Med J. 2007 Feb;83(976):79-86. 
  7. Wartofsky L; Myxedema coma. Endocrinol Metab Clin North Am. 2006 Dec;35(4):687-98, vii-viii. 
  8. Mathew V, Misgar RA, Ghosh S, Mukhopadhyay P, Roychowdhury P, Pandit K, et al. Myxedema coma: a new look into an old crisis. J Thyroid Res. 2011;2011:493462. 
  9. Rehman SU, Cope DW, Senseney AD, et al. Thyroid disorders in elderly patients. South Med J. May 2005;98(5):543-9. 
  10. Nicoloff JT, LoPresti JS. Myxedema coma. A form of decompensated hypothyroidism. Endocrinol Metab Clin North Am. Jun 1993;22(2):279-90. 
  11. Dutta P, Bhansali A, Masoodi SR, et al. Predictors of outcome in myxoedema coma: a study from a tertiary care centre. Crit Care. 2008;12(1):R1. 
  12. Rimar D, Kruzel-Davila E, Dori G, et al. Hyperammonemic coma--barking up the wrong tree. J Gen Intern Med. Apr 2007;22(4):549-52. 

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Last updated: 2019-07-11 22:12