J Am Board Fam Pract: first published as 10.3122/jabfm.8.5.376 on 1 September 1995. Downloaded from Myxedema Coma In The Elderly (vnthia G. Olsen, M[) Background: Myxedema coma in the elderly, although uncommon, is frequently overlooked and has a high mortality rate. Signs and symptoms are many and are often insidious. Nearly every organ system is involved. Prompt recognition and treatment are mandatory for a successful outcome. Methods: A case study is presented. Using the key words "myxedema" with the word "aged," MEDLINE files were searched from 1989 to present. Articles dating before 1989 were accessed from the reference lists of the more recent articles. Results and Conclusions: This review describes the signs and symptoms of myxedema coma in the elderly. Epidemiology and histopathology of the disorder are discussed. Prompt recognition and emergency medical treatment are essential for a successful outcome. Prevention requires screening of elderly patients at risk for hypothyroidism and assuring thyroid hormone replacement therapy. (J Am Board Fam Pract 1995; 8:376-83.) Myxedema coma, the extreme expression of sodium depletion. A history of thyroidectomy for hypothyroidism, is a medical emergency re­ goiter in the remote past was discovered, and the quiring a high degree of clinical suspicion. The patient had not received thyroid hormone re­ term myxedema was proposed by Ord in 1878 placement therapy. A family history was notable to describe the peculiar nonpitting swelling in that her son had a thyroid goiter. of skin in the hypothyroid adult and has been During the physical examination the woman used interchangeably with hypothyroidism in was obtunded and unable to communicate with the medical literature. 1 Although the actual inci­ the examiner. She weighed 72.7 kg, her tempera­ dence is unknown, myxedema coma is uncom­ ture was 36.3° C, her pulse was ret,Tular at 80 beats mon; only 200 cases were reported between 1953 per minute, respirations were 24/min, and her and 1986.2 The mortality rate in these patients is blood pressure was 178/94 mmHg. On appear­ 50 percent or greater even with immediate thy­ ance her face was swollen, especially about the roid hormone replacement therapy and support­ eyes. Her mucous membranes were dry and the ive measures. Early recognition and intervention tongue was thickened. Neck masses were not can be lifesaving. found. Her skin was cool and doughy in consis­ tency, and there was marked pitting edema of the http://www.jabfm.org/ Illustrative Case lower extremities up to the knees. Lung examina­ A 90-year-old woman who had been residing in a tion demonstrated bilateral pulmonary edema nursing home for several years was brought in for with pleural effusions. The heart had a regular cOllSultation. The nursing staff and family re­ rate and rhythm with a grade IIM systolic ejec­ ported gradually increasing lethargy, depression, tion murmur. Neurologically the patient was and diminished mental alertness. semicomatose. Deep tendon reflexes were dimin­ on 24 September 2021 by guest. Protected copyright. She had a history of cerebrovascular accidents, ished with a slowed response. Rectal examination which precipitated her nursing home admission. found a fecal impaction. The medical chart reflected persistent chronic La bora tory studies discl osed the following hyponatremia unresponsive to fluid restriction. values: sodium 127 mEq/L, potassium 3.9 mEqlL, The patient had increasing pulmonary and pe­ chloride 93 mEqlL, and carbon dioxide 25 mEqlL. ripheral edema as a result of congestive heart fail­ Blood urea nitrogen (BUN) and serum creati­ ure. '[reatment with diuretics had worsened her nine were 17 mg/dL and 0.6 mg/dL, respectively. Serum osmolality was 250 mOsm/kg. Her fast­ ing blood glucose was 128 mg/dL. The serum Submittl'd, ITviSl'd, ~ May 1')');. total protein was 5.8 g/dL, and serum albumin From thl' Department of Family rvkdicillc, V\rright State Uni­ was 3.l g/dL. A complete blood count showed a versity School of Medicine, Dayton, Ohio. Address rl'print re­ mild microcytic, normochromic anemia. A urin­ quests to Cynthia G Olsen, MD, Department of Family Ml'di­ cinc, School of ,Vlcdicine, \Vright St'ltc University, (,27 Edwin alysis was positive for pyuria and bacteriuria. C. .'vloses Boulcvard, Dayton, 011 .:tHOll. Thyroid function studies showed a depressed 37(' JABFP Sept.-Oct.1995 Vol. R No.5 J Am Board Fam Pract: first published as 10.3122/jabfm.8.5.376 on 1 September 1995. Downloaded from thyroxine level of3.0 ,...g/dL and an elevated thy­ Table 1. Precipitating Causes of Myxedema Coma. roid stimulating hormone (TSH) of 53 ,...U/mL. Cause Type An adrenocorticotropic hormone (ACTH) level was normal at 34 pg/mL. A blood gas determina­ Infections Pneumonia tion on 2 L of nasal cannula oxygen revealed aci­ Urinary tract infection dosis with a pH of 7.24, p02 of 118 mmHg, Influenza pC02 of 145 mmHg, and a bicarbonate of 50.4 Drugs mEq/L. A chest radiograph showed marked car­ Sedating Narcotics diomegaly with bilateral pleural effusions. A Phenothiazines two-dimension echo cardiogram showed mild Tranquilizers and barbiturates aortic stenosis and a dilated left ventricle with Other central nervous preserved function. system depressants The patient was hospitalized for myxedema General anesthesia coma caused by untreated hypothyroidism with Cardiac drugs f3- Blockers concurrent metabolic derangement, possible Amiodarone heart failure, and urinary tract infection. She re­ Stressors Surgery ceived intravenous hydrocortisone 75 mg every 6 hours. An initial bolus of 400 mg of synthetic Hospitalization thyroxine was followed by 200 mg on day 2 and Burns 100 mg daily thereafter. She received treatment Trauma of her heart failure with diuretics, supplemental Exposure to cold oxygen and potassium, and digoxin. On day 5 she was switched to oral medications of pred­ to the water-binding capacity of the acid gly­ nisone 10 mg, levothyroxine 125 mg, digoxin 25 cosaminoglycans within the papillary and reticu­ mg, and indapamide 2.5 mg. A follow-up chest lar layers.7 Other changes of the skin that contrib­ radiograph showed resolution of the pulmonary ute to edema in myxedema are increased capillary congestion. permeability, lymphatic obstruction, and perivas­ The patient returned to the nursing home on culitis. Acid glycosaminoglycans are also found in supplemental oxygen. During the next few the tissues of the tongue, myocardium, striated months the patient had an improved level of muscle, and intestines.8 Thyroid hormone re­ alertness and was able to recognize family mem­ placement treatment reduces hyaluronic acid http://www.jabfm.org/ bers. Her cardiac failure improved, and her meta­ concentrations in the skin, whereas the three bolic problems stabilized. other glycosaminoglycans remain unchanged.9 Muscle biopsy in severe myxedema reveals type II Epidemiology muscle fiber loss and atrophy, an increased num­ Myxedema coma occurs almost exclusively during ber of mitochondria, and an accumulation of gly­ or after the 6th decade with 80 percent of the cogen and lipids on the membranes. This effect is on 24 September 2021 by guest. Protected copyright. cases occurring in women.3,4 More than 90 percent also somewhat reversible with treatment. 10 of cases have been reported to have occurred dur­ ing winter months and are frequently associated Clinical Presentations with intercurrent illness or stressors (Table 1). Because the patient is in a coma, the initial diag­ Pneumonia or other infections and sedating drugs nosis is suggested by a history of clinical signs and are common precipitants.4-6 About 50 percent of symptoms of hypothyroidism and a history of myxedema coma patients have lapsed into coma thyroid surgery, high-dose external radiation of after admission to the hospital, probably as the re­ the neck, or discontinuation of thyroid hormone sult of stress caused by diagnostic and therapeutic replacement therapy (Table 2). interventions encountered during hospitalization. In addition to knowing the symptoms preced­ ing the onset of coma, physical findings will also Histopathology aid the physician in making the diagnosis. The The clinical manifestations of myxedema are in- patient typically has periorbital swelling, ptosis, duration and thickening of the skin, attributable and a thickened tongue. Nonpitting edema of the Myxedema Coma 377 J Am Board Fam Pract: first published as 10.3122/jabfm.8.5.376 on 1 September 1995. Downloaded from Table 2. (;linical Signs and Symptoms of Myxedema atony. This serious condition can lead to visceral (;oma. perforation. The resulting colonic ileus can he in­ distinguishahle from mechanical ohstrllction. H (\rea Si~n or Sy1l1pt' 1111 Barium enem,) shows localized transverse thick­ Constitlltion,d, g·eneral Lethargy ening of the colonic haustration. l ) Myxedema \Veight gain or loss megacolon appearing as pseudomembranolls \\'eakness Sleep disturhance colitis and intestinal ischemia is rare. II) Ilypotonia of the esophagus, stomach, duodenum, gallblad­ I lead and neck llearing imp,]innent Obstructive sleep apnea der, and small intestine can also occur. M,]Croglossia The lowered metabolic state in myxedema Periorbital swellin~ coma patients results in bradycardia, slowed res­ Lid ptosis piratory rate, hypothermia, and hypotension. 17 I)erm,](ologic I Llir 10" Coarse, dry skin Shivering is diminished or absent. Hypothermia, I'retihiallllyxedellla common in the aging population, can also he Edema found with hypoglycemia and occasionally septi­ ( ;,]strointestinal Fecal impaction cemia. IH A core temperature of less than 35 .5°C Megacolon occurs in about HO percent of comatose patients. llrologic Bladder atony In fact, a normal temperature in a myxedema Urinary rdention coma patient should be considered relative hyper­ Musculo'ikelctal Muscle hypertrophy thermia. Underlying infection in these patients is Neurologic and psychiatrie Psychosis common and might be the precipitating factor Restlessness Delirium leading to coma. Reduced immune defenses often Dementia obscure the signs of infection. PsychoJl]otor retardation In the severe, chronic hypothyroid patient, the heart can be dilated and the myocardium atonic.