MYXEDEMA; A STUDY OF 400 CASES

Myxedema Psychosis: Systematic Review and Pooled Analysis

BACKGROUND AND OBJECTIVE

The term myxedema psychosis (MP) was introduced to describe the occurrence of psychotic symptoms in patients with untreated hypothyroidism, but the optimal assessment and treatment of this condition are unclear. We aimed to synthesize data from the literature to characterize the clinical presentation and management of MP.

METHODS

We performed a systematic review according to the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines in PubMed (Medline), Embase, Google Scholar, and Cochrane databases, including observational studies, case series, and case reports published from 1/1/1980 to 31/12/2019 in the English language. Descriptive statistics along with univariate and multivariate analysis were used for data synthesis.

RESULTS

Out of 1583 articles screened, 71 case reports met our inclusion criteria providing data on 75 MP cases. The median age at diagnosis was 42 years [32-56]. About 53% had no prior hypothyroidism diagnosis. Delusions occurred in 91%, with a predominance of persecutory ideas (84%), while hallucinations occurred in 78%. Physical symptoms and signs of hypothyroidism were absent in 37% and 26%, respectively. If symptoms occurred, nonspecific fatigue was seen most frequently (63%). The median thyroid-stimulating hormone value was 93 mIU/L [60-139]. Thyroid peroxidase antibodies were found positive in 75% (23/33) of reported cases. Creatinine kinase was reported abnormal in seven cases. Cranial imaging (CT or MRI) and electroencephalogram were normal in 89%, 75%, and 73% of the cases reported. The majority of patients were treated orally with thyroxine in combination with short-term antipsychotics. More than 90% of them showed complete recovery. Univariate analysis revealed a trend towards a shorter duration of psychosis with IV thyroid hormone therapy (p= 0.0502), but the effect was not consistent in a multivariate analysis.

CONCLUSION

While we identified a substantial lack of published research on MP, our pooled analysis of case observations suggests that the condition presents a broad spectrum of psychiatric and physical symptoms lending support to the value of screening for thyroid dysfunction in patients with first-ever psychosis.

PROSPERO REGISTRATION NUMBER

CRD42020160310.

The interplay between thyroid and liver: implications for clinical practice

A complex relationship exists between thyroid and liver in health and disease. Liver plays an essential physiological role in thyroid hormone activation and inactivation, transport, and metabolism. Conversely, thyroid hormones affect activities of hepatocytes and hepatic metabolism. Serum liver enzyme abnormalities observed in hypothyroidism may be related to impaired lipid metabolism, hepatic steatosis or hypothyroidism-induced myopathy. Severe hypothyroidism may have biochemical and clinical features, such as hyperammonemia and ascites, mimicking those of liver failure. Liver function tests are frequently abnormal also in hyperthyroidism, due to oxidative stress, cholestasis, or enhanced osteoblastic activity. Antithyroid drug-associated hepatotoxicity is a rare event, likely related mainly to an idiosyncratic mechanism, ranging from a mild hepatocellular damage to liver failure. Propylthiouracil-induced liver damage is usually more severe than that caused by methimazole. On the other hand, thyroid abnormalities can be found in liver diseases, such as chronic hepatitis C, liver cirrhosis, hepatocellular carcinoma, and cholangiocarcinoma. In particular, autoimmune thyroid diseases are frequently found in patients with hepatitis C virus infection. These patients, especially if thyroid autoimmunity preexists, are at risk of hypothyroidism or, less frequently, thyrotoxicosis, during and after treatment with interpheron-alpha alone or in combination with ribavirin, commonly used before the introduction of new antiviral drugs. The present review summarizes both liver abnormalities related to thyroid disorders and their treatment, and thyroid abnormalities related to liver diseases and their treatment.

Myxedema Coma: a Review

Myxedema coma, represents the extreme degree of severity of hypothyroidism, whose mortality can reach very high percentages, therefore, it is a true medical emergency. In general, its development is associated with the presence of a triggering factor in a controlled hypothyroid patient and manifests with multisystem alteration. Currently, tools have been developed for clinical diagnosis that use the profile and clinical models, and have good sensitivity-specificity. They allow an early diagnosis which favored the early start of treatment and therefore improves the prognosis. The patient with myxedema coma needs an integral approach, with intensive treatment and close monitoring of hemodynamic parameters. However, the basis of treatment remains hormone replacement, which should be initiated with a combination of levothyroxine and triiodothyronine.

Thyroid disease and the nervous system

Thyroid disorders are common in the general population and in hospitalized patients. Thyroid disease may present first with neurological complications or else may occur concurrently in patients suffering other neurological disorders, particularly those with an autoimmune etiology. For this reason neurologists will commonly encounter patients with thyroid disease. This chapter provides an overview of the neurological complications and associations of disorders of the thyroid gland. Particular emphasis is placed on conditions such as thyrotoxic periodic paralysis and myxedema coma in which the underlying thyroid disorder may be occult leading to a first, often emergency, presentation to a neurologist. Information about clinical features, diagnosis, pathogenesis, therapy, and prognosis is provided. Emphasis is placed on those aspects most likely to be relevant to the practicing neurologist and the interested reader is directed to references to good, recent review articles for further information.

Myxedema ascites with high CA-125: Case and a review of literature

Ascites appearing in a previously healthy female patient is usually ascribed to a variety of causes, among which, is a cancerous process, especially if it comes with a raised CA-125 level. Although the CA-125 antigen is present on more than 80% of malignant epithelial ovarian tissue of non-mucinous type, it is also found on both healthy and malignant cells of mesothelial and non-mesothelial origin. Myxedema ascites which is caused by hypothyroidism is a rare entity, but on the other hand is easy to treat. It is one of the differential diagnoses when the ascites is refractory to treatment and no other obvious cause can be identified. If the diagnosis is delayed, patients will frequently receive unnecessary procedures, while treatment has very good response rates and ascites resolve with serum CA-125 normalization after adequate hormonal treatment.

A literature review on the adverse effects of hypothyroidism on kidney function

Thyroid produce two important hormone of thyroxine or tetraidothyronine (T4) and triidothyronine (T3), which are involved in whole aspect of metabolism. T4 and T3 play vital role in all biochemical function, growth and development in human body. The basic metabolic pathways in kidney and every organ in human controlled by these hormones. T4 and T3 are involved in kidney function in health and diseases condition therefore the pathophysiology of kidney can be directly influenced and regulated by thyroid hormones. Kidney growth, haemodynamic, blood circulation, tubular, electrolyte balance and glomerular filtration rate (GFR) are among such crucial process. Hypothyroidism which accompanied with reduced thyroid hormone production adversely affect the renal functions, development and eventually leading to reduced weight, kidney vascular disorders, electrolyte, tubular transport imbalances, lower filtration rate and other adverse consequences of hypothyroidism. On other hand kidney diseases can also disrupt the thyroid function metabolism resulting in the subsequent hypothyroidism. It is an interesting subject in how thyroid and kidney in health and diseases closely interacted. For the ideal clinical follow up of either of thyroid and renal diseases the two organs should be simultaneously examined for a proper patient management. Close correlation of thyroid and kidney clinical teams are essential to check the cross reactions and adverse interactions which might be produced between these two vital organs to avoid misdiagnosis either of thyroid or kidney abnormalities.

The thyroid and the gut

Thyroid disease is common, and its effects on the gastrointestinal system are protean, affecting most hollow organs. Hashimoto disease, the most common cause of hypothyroidism, may be associated with an esophageal motility disorder presenting as dysphagia or heartburn. Dyspepsia, nausea, or vomiting may be due to delayed gastric emptying. Abdominal discomfort, flatulence, and bloating occur in those with bacterial overgrowth and improve with antibiotics. Reduced acid production may be due to autoimmune gastritis or low gastrin levels. Constipation may result from diminished motility, leading to an ileus, megacolon, or rarely pseudoobstruction. Ascites in myxedema is characterized by a high protein concentration. Graves' disease accounts for 60% to 80% of thyrotoxicosis. Hyperthyroidism is accompanied by normal gastric emptying with low acid production, partly due to an autoimmune gastritis with hypergastrinemia. Transit time from mouth to cecum is accelerated, resulting in diarrhea. Steatorrhea is due to hyperphagia and stimulation of the adrenergic system. Diarrhea in medullary carcinoma of the thyroid (MCT) may be due to elevated calcitonin, prostaglandins, or 5-hydroxyindoleacetic acid. Ileal or colonic function may be abnormal. The esophagus may be compressed by benign processes, but more often by malignancies. MRI and CT scans are the best diagnostic modalities. The gastrointestinal manifestations of thyroid disease are generally due to reduced motility in hypothyroidism, increased motility in hyperthyroidism, autoimmune gastritis, or esophageal compression by a thyroid process. Symptoms usually resolve with treatment of the thyroid disease.

Thyroid hormone induced brown adipose tissue and amelioration of diabetes in a patient with extreme insulin resistance

CONTEXT

Brown adipose tissue (BAT) found by positron emission/computed tomography (PET-CT) using flouro-deoxyglucose (FDG) is inducible by cold exposure in men. Factors leading to increased BAT are of great interest for its potential role in the treatment of diabetes and obesity.

OBJECTIVE

We tested whether thyroid hormone (TH) levels are related to the volume and activity of BAT in a patient with a mutation in the insulin receptor gene. DESIGN/SETTING/INTERVENTION: Our work was based on the case report of a patient in an observational study at the National Institutes of Health.

PATIENT

The patient discontinued insulin and oral antidiabetics after thyroidectomy and suppressive-dose levothyroxine therapy for thyroid cancer. PET-CT uptake in BAT was confirmed by histology and molecular analysis.

OUTCOMES

PET-CT studies were performed, and we measured hemoglobin A1c and resting energy expenditure before and after levothyroxine discontinuation for thyroid cancer testing. Molecular studies of BAT and white adipose samples are presented.

RESULT

Supraclavicular and periumbilical sc adipose tissue demonstrated molecular features of BAT including uncoupling protein-1, type 2 deiodinase, and PR domain containing 16 by quantitative PCR. Activity of type 2 deiodinase activity was increased. The discontinuation of levothyroxine resulted in decreased FDG uptake and diminished volume of BAT depots accompanied by worsening of diabetic control.

CONCLUSIONS

This case demonstrates the TH effect on BAT activity and volume in this patient and an association between BAT activity and glucose levels in this patient. Because the contribution of TH on skeletal muscle energy expenditure and fuel metabolism was not assessed, an association between BAT activity and glucose homeostasis can only be suggested.

Respiratory failure with myxedema ascites in a patient with idiopathic myxedema

Here we report the case of a 50-year-old woman presenting with weight gain, whole-body edema, and massive ascites. Blood examination revealed primary hypothyroidism with TSH-blocking antibody, and the echocardiogram showed diffuse hypokinesis of the left ventricle with pericardial effusion. Although she received thyroid hormone replacement therapy immediately, her ascites increased and she developed type II respiratory failure requiring transient noninvasive positive pressure ventilation (NIPPV). She recovered following the temporary drainage of the ascites, administration of diuretics, and continuous thyroid hormone replacement. The amount of ascites decreased during therapy, along with an increase in thyroid hormone levels. Finally, the ascites disappeared completely, followed by the normalization of the cardiac wall motion. Herein we report this rare case in detail, and also discuss the mechanism by which primary hypothyroidism induced such severe conditions in our patient.

Effect of levo-thyroxine treatment on weight and body mass index in children with acquired hypothyroidism

OBJECTIVE

To determine whether normalization of thyroid-stimulating hormone (TSH) in children with acquired hypothyroidism is associated with a decrease in weight or body mass index (BMI).

STUDY DESIGN

We retrospectively identified 68 subjects with acquired hypothyroidism who were seen at least once in our center in follow-up between 1995 and 2006.

RESULTS

Treatment with levo-thyroxine decreased the mean TSH level from 147 microU/mL initially to 5.0 microU/mL at the second visit 4.4 months later. This was not associated with a significant change in weight or BMI. Of the 68 subjects, 31% lost weight by the second visit (mean 2.3 kg). The mean initial TSH level of this group was 349 microU/mL. Thirty of the 68 children had at least 2 years of follow-up, and 19/68 had at least 4 years of follow-up. Over those intervals, weight and BMI percentiles and z scores did not change significantly from baseline values.

CONCLUSIONS

Most children treated for acquired hypothyroidism exhibited little short-term or long-term change in weight or BMI despite near-normalization of TSH. Those children who lost weight tended to have severe hypothyroidism and to have only a small weight loss. Consequently, practitioners should not expect significant decreases in weight after treatment in most children with hypothyroidism.

Severe ascites with hypothyroidism and elevated CA125 concentration: a case report

Ascites caused by hypothyroidism is rare and the pathogenesis is unclear. Several reports have presented cases of progressive ascites with hypothyroidism and elevated tumor markers. We report a 31-year-old female case with massive ascites and elevated serum CA 125 concentrations. The patient had no typical feature of hypothyroidism except an accumulation of ascitic fluid which showed elevated total protein concentration and a high serum-ascites albumin gradient (SAAG). There was no finding of malignancy. Following thyroid hormone replacement, the ascites was completely resolved accompanied by reduced concentrations of serum CA125. In general, primary hypothyroidism with ascites presents with coexisting massive pericardial or pleural effusion. The massive ascites and increased serum CA125 concentrations may have led us to make the incorrect diagnosis of ovarian malignancy. The evaluation of thyroid function is useful to determine the pathology of high-protein ascites or elevated tumor markers, and ascites may be treatable by thyroid replacement therapy.

Age modifies the pituitary TSH response to thyroid failure

OBJECTIVE

To investigate the association between serum TSH, total T4 and various patient characteristics when hypothyroidism is diagnosed in a population, and to study how age, sex and serum T4 levels influenced pituitary TSH response.

DESIGN

A computer-based register linked to laboratory databases prospectively identified all patients with new, biochemically overt hypothyroidism (n = 685) in an open cohort in Denmark. The diagnosis was verified in each patient, and disease was classified into nosological type. Serum TSH and total T4 were recorded at the time of diagnosis in untreated patients with spontaneous autoimmune hypothyroidism (n = 578).

MAIN OUTCOME

In untreated primary, spontaneous autoimmune hypothyroidism, we observed a four fold difference in average serum TSH levels between the youngest (0-20 years: TSH = 100 mU/l) and the oldest (80+ years: TSH = 24.4 mU/l) group of patients. No age dependent variation was observed in serum total T4. Log TSH showed an inverse linear correlation with age. An inverse linear correlation was present between log TSH and total T4 in both young and old patients, but for all total T4 values we observed lower median serum TSH values in elderly patients.

CONCLUSIONS

For the same degree of thyroid failure, the serum TSH is lower among the elderly. This is most likely caused by a decrease in the hypothalamic/pituitary response to low serum T4. A certain increase in serum TSH may indicate more severe hypothyroidism in an old than in a young patient, and longer time may be needed after thyroid hormone withdrawal before elderly patients with thyroid cancer reach sufficiently high TSH values to allow for an effective radio-iodine treatment.

Madarosis

Madarosis may be a presenting feature of a number of vision and life-threatening conditions, including herpes zoster, leprosy, HIV/AIDS, trachoma, malignant eyelid tumors, discoid lupus, scleroderma, and hypothyroidism. It may occur via two broad pathogenic pathways: scarring and non-scarring, which indicates the potential for lash re-growth. Madarosis may occur as an isolated finding or together with loss of other body and scalp hair. The etiology of madarosis can be further divided into dermatological, infection, endocrine, neoplastic, drug-related, congenital, and trauma. This report includes salient points in the clinical history and examination of patients with madarosis, with an emphasis on excluding or diagnosing visual or life threatening disorders associated with madarosis.

Myxedema ascites: case report and literature review

Myxedema ascites caused by hypothyroidism is rare, so its diagnosis is often delayed and patients frequently receive unnecessary procedures such as liver biopsies and exploratory laparotomies. We report a 71-yr-old man with clinical ascites that was the first manifestation of hypothyroidism, and which resolved completely in response to thyroid hormone replacement therapy. To our knowledge, this is the first report of myxedema ascites in Korea. A review of the literature revealed 51 well-documented cases of myxedema ascites. Analyses of ascites from patients in this condition usually show high protein (>2.5 g/dL) and low white blood cell counts, with a high proportion of lymphocytes. A consistent feature is the good response to thyroid hormone replacement therapy, which has always led to resolution of the ascites. Myxedema ascites is thus rare but easy to treat; it should be borne in mind, especially if the ascites fluid has a high protein content.

[Hypothyroid dilated cardiomyopathy]

Most patients with dilated cardiomyopathy have a poor prognosis due to progressive and irreversible myocardial dysfunction. Rarely, is a metabolic etiology responsive to specific therapy identified. Although many studies have confirmed that thyroid hormone deficiency is associated with a reversible decrease in myocardial contractility, it has remained controversial whether hypothyroidism alone can cause a dilated cardiomyopathy and clinical heart failure. In this study, we report the case of a patient with severe hypothyroidism and a dilated cardiomyopathy complicated by heart failure, which has receded after recovery to euthyroidism with L-thyroxin therapy. This case suggests that hypothyroidism should be evoked systematically when a dilated cardiomyopathy is diagnosed.

Thyroid hormone and blood pressure regulation

Thyroid hormone has well-recognized effects on the cardiovascular system and blood pressure regulation. Blood pressure is altered across the entire spectrum of thyroid disease. The effects of hyperthyroidism include increased cardiac output, contractility, tachycardia, widened pulse pressure, decreased systemic vascular resistance, and increased basal metabolic rate. The manifestations of hypothyroidism are in marked contrast to those of hyperthyroidism and include decreased cardiac output, narrow pulse pressure, increased systemic vascular resistance, and decreased metabolic rate. Although thyroid hormone affects almost all tissues of the body and mediates changes in homeostasis, adaptations of the cardiovascular system can result in changes in blood pressure to accommodate the new demands on the system. In this paper, we review the direct and indirect thyroid hormone-mediated effects on blood pressure.

Thyroid hormone and cardiovascular disease

Thyroid hormone directly affects the heart and peripheral vascular system. The hormone can increase myocardial inotropy and heart rate and dilate peripheral arteries to increase cardiac output. An excessive deficiency of thyroid hormone can cause cardiovascular disease and aggravate many preexisting conditions. In severe systemic illness and after major surgical procedures changes in thyroid function can occur, leading to the "euthyroid sick syndrome." Patients will have normal or decreased levels of T4, decreased free and total T3, and usually normal levels of thyroid stimulating hormone. This syndrome may be an adaptive response to systemic illness that usually will revert to normal without hormone supplementation as the illness subsides. Recently, however, many investigators have explored the benefits of thyroid hormone supplementation in those diseases associated with euthyroid sick syndrome. Thyroid hormone's effects on the cardiovascular system make it an attractive therapy for those patients with impaired hemodynamics and low T3. Thyroid hormone has also been considered a treatment for patients with congestive heart failure, for patients undergoing cardiopulmonary bypass and heart transplantation, and for patients with hyperlipidemia. At present there is no evidence suggesting a favorable treatment outcome using thyroid hormone supplementation for any systemic condition except in those patients with documented hypothyroidism.

A longitudinal study of central and peripheral nerve conduction in hypothyroid rats

In order to detect the dysfunction of central and peripheral nervous systems among rats with varied duration of hypothyroidism and to elucidate the pattern of recovery after thyroxine replacement, a series of BAEP and PNCS (Peripheral Nerve Conduction Study) were conducted and compared with age-matched controls. BAEP and PNCS were performed in three groups of hypothyroid animals 1, 3 and 5 months after thyroidectomy, respectively. Following initial electrophysiological assessment, thyroxine replacement was administered to each group of hypothyroid rats, and BAEP and PNCS were performed at two month intervals, up to two successive normal studies, or six months after the initiation of therapy, whichever came first. For BAEP, prolonged I-V interpeak latency was the most consistent abnormal finding in all groups of hypothyroid rats, and longer hypothyroid states correlated well with more severe central conduction disorder. Nevertheless, these abnormalities usually returned to normal after thyroxine replacement if the duration of hypothyroidism was less than 5 months. Regarding PNCS, all groups of thyroidectomized rats showed normal conduction before and after thyroxine therapy. The present study indicates that, in rats: (1) the peripheral nervous system seems to be more resistant to hypothyroidism than the central nervous system, or (2) the pathogenesis of central and peripheral nerve dysfunction in hypothyroid rats may occur through different mechanisms.

Mutations in the c-erbA beta 1 gene: do they underlie euthyroid fibromyalgia?

Fibromyalgia, a chronic condition of widespread pain, stiffness, and fatigue, has proven unresponsive to drugs, the use of which is based on the 'serotonin-deficiency hypothesis'. An alternative hypothesis-failed transcription regulation by thyroid hormone-can explain the serotonin deficiency and other objective findings and symptoms of euthyroid fibromyalgia. Virtually every feature of fibromyalgia corresponds to signs or symptoms associated with failed transcription regulation by thyroid hormone. In hypothyroid fibromyalgia, failed transcription regulation would result from thyroid-hormone deficiency. In euthyroid fibromyalgia, failed transcription regulation may result from low-affinity thyroid hormone receptors coded by a mutated c-erbA beta 1 gene, yielding partial peripheral resistance to thyroid hormone. The hypothesis of this paper is that, in euthyroid fibromyalgia, a mutant c-erbA beta 1 gene (or alternately, the c-erbA alpha 1 gene) results in low-affinity thyroid-hormone receptors that prevent normal thyroid hormone regulation of transcription. As in hypothyroidism, this would cause a shift toward alpha-adrenergic dominance and increases in both cyclic adenosine 3'-5'-phosphate phosphodiesterase and inhibitory Gi proteins. The result would be tissue-specific hypothyroid-like symptoms despite normal circulating thyroid-hormone levels.

Clinical presentation of spontaneous primary hypothyroidism in adults

In a retrospective study of 309 cases of hypothyroidism seen at King Fahd Hospital of the University (KFHU), Al-Khobar, 124 (90 Saudis and 34 non-Saudis) adult patients with spontaneous primary hypothyroidism satisfied the inclusion criteria for detailed analysis. Their male:female ratios for Saudis and non-Saudis were 1:4.6 and 1:3.9 respectively. The majority were diagnosed in their third and fourth decades. The prevalence of previously undiagnosed spontaneous and biochemically overt primary hypothyroidism in Saudis was 5.2/1000 females and 0.94/1000 males. FT4I was normal in 43 (35%) and low in 81 (65%). FT4I correlated with cold intolerance, constipation, dry skin, hoarseness, delayed reflex relaxation, and coarse and cold skin. In rank order, presenting symptoms in those with low FT4I were tiredness (56%), cold intolerance (38%), constipation, weight gain, menstrual disturbance - especially amenorrhea - (36% each), dry skin (35%), hoarseness (31%); signs were coarse skin (53%), delayed reflex relaxation (32%), cold skin and goiter (24% each). The above clinical findings may help physicians in the early detection of primary hypothyroidism. Population-based studies are necessary to provide more data on this disease in this country.

Pituitary hyperplasia mimicking pituitary tumor

Reactive enlargement of the pituitary gland in primary end organ failure may be indistinguishable from primary pituitary lesions in clinical presentation and on magnetic resonance imaging. The diagnosis of pituitary hyperplasia secondary to end organ failure must be based on endocrinologic investigations. Recognition of this condition and distinguishing it from primary pituitary tumors is important and may eliminate unnecessary surgery.

Etiopathogenesis of canine hypothyroidism

Hypothyroidism in dogs usually results from a progressive destruction of the thyroid, associated with either lymphocytic thyroiditis or idiopathic atrophy. Both syndromes seem to occur with approximately equal frequency. Lymphocytic thyroiditis, which resembles Hashimoto's thyroiditis in humans, is probably an autoimmune disease, and patients often show thyroid autoantibody titers in circulation. By contrast, the pathogenesis of idiopathic atrophy is unclear, and the thyroid seems simply replaced by adipose and connective tissue.

Hepatic conversion of amino nitrogen to urea nitrogen in hypothyroid patients and upon L-thyroxine therapy

Conflicting studies have been reported regarding the influence of thyroid hormones on hepatic nitrogen metabolism and liver metabolic activity. We studied urea N synthesis rate (UNSR), functional hepatic N clearance (FHNC), galactose elimination capacity, and antipyrine clearance in six hypothyroid female patients before and after achievement of a stable euthyroid status. In both conditions, UNSR measured at intervals in response to constant alanine infusion was linearly related to the average alpha-amino N concentrations. In the hypothyroid state, peak UNSR was decreased by 31% in comparison with values measured in euthyroidism, which were in the normal range. FHNC (ie, the slope of the linear relation between UNSR and blood alpha-amino N concentration) is a measure of the kinetics of the process of hepatic amino N to urea N conversion; it was 19.8 +/- 4.0 L.h-1 in hypothyroid patients and increased to normal values after L-thyroxine replacement (30.4 +/- 3.3 L.h-1, P < .01; normal values > 25 L.h-1). Hepatic microsomal and cytosolic activities (antipyrine clearance and galactose elimination) were normal in hypothyroid patients and did not change significantly after therapy. Our data show a specific defect in hepatic handling of amino acids in hypothyroid patients, leading to reduced alpha-amino N to urea N conversion, in the absence of any detectable impairment in different hepatic metabolic activities.

Cardiac function in thyroid disease: clinical features and management considerations

Thyroid disease is often manifested by cardiac abnormalities. The site of the cardiac actions of thyroid hormone, whether from a direct, nuclear effect or an extranuclear effect, remains to be established. Nuclear effects are delayed 1/2 to 1 hour after administration of thyroid hormone, require ongoing protein synthesis, and are thought to result from the binding of thyroid hormone to two separate isoforms of the nuclear thyroid hormone receptor. This binding, which is specific to thyroid hormone response elements, stimulates transcription and results in translation of specific enzymes or contractile proteins. Extranuclear effects may influence plasma membrane transport of calcium, sugar, and amino acids in addition to directly influencing mitochondria and are very rapid, occurring within minutes. It is possible that there exists an interaction between the adrenergic system and the thyroid hormone system, which may also contribute to the cardiac actions of thyroid hormone. This review highlights the clinical manifestations of thyroid disease and the mechanisms of thyroid hormone involved in the cardiac abnormalities.

An unusual case of myxedema megacolon with features of ischemic and pseudomembranous colitis

Myxedema megacolon is rare; usually, it manifests with abdominal distention, flatulence, and constipation. Herein we describe a 72-year-old man who had intermittent diarrhea, bloating, and abdominal pain for more than a year. Cultures of stool specimens for Clostridium difficile enterotoxin were variably positive and negative. Colonoscopic biopsy specimens were thought to be consistent with chronic ischemia. Thyroid function tests showed severe hypothyroidism; the patient's symptoms resolved with thyroid hormone replacement. We hypothesize that gross dilatation of the colon, attributed to myxedema, was followed by intestinal ischemia and complicated by recurrent episodes of pseudomembranous colitis. A review of the relevant literature is provided. This unusual manifestation of myxedema should be considered in the differential diagnosis when a patient has diarrhea, bloating, and abdominal pain.

Alopecia of myxedema: clinical response to levothyroxine sodium

Noncicatricial alopecia resulting from myxedema developed in a 58-year-old woman. We report the response of her alopecia to treatment with levothyroxine sodium and review the literature on the subject.

Long-term weight changes in treated hyperthyroid and hypothyroid patients

To compare the effect of three treatments for thyrotoxicosis on subsequent body weight, a retrospective survey of 65 patients was performed. The effect of thyroxine replacement on body weight in 25 patients with primary hypothyroidism was also examined. In one year after starting therapy 21 patients treated with carbimazole gained a mean of 5.4kg (95% confidence interval 3.6 to 7.2kg); 20 patients after thyroidectomy gained a mean of 6.3kg (95% c.i. 3.4 to 9.2kg); and 24 patients given radioiodine gained a mean of 7.4kg (95% c.i. 5.2 to 9.6kg), p less than 0.001 in all three groups. The weight gain in the three groups was not significantly different. 54-67% of the weight gain occurred in the first three months. The patients treated for hypothyroidism had lost an insignificant amount of weight 12 months after starting therapy--mean change was -0.6kg (95% c.i. -2.2 to +1.1kg) p greater than 0.1. This data suggests that all patients treated for thyrotoxicosis will gain body weight irrespective of the treatment used, but patients treated for primary hypothyroidism will not lose an appreciable amount of weight. Therefore dietary advice should be given, where appropriate, at the onset of any treatment of thyroid dysfunction.

Catecholamine-thyroid hormone interactions and the cardiovascular manifestations of hyperthyroidism

The spectrum of classic symptoms of hyperthyroidism suggests that in addition to the effects of increased thyroid hormone, affecting various organ systems, there is also a hyperadrenergic state. Despite this clinical impression, direct measures of serum levels of catecholamines and their urinary metabolites demonstrate values that are equal to or less than normal. In contrast, the hypothyroid patient who clinically manifests signs of decreased adrenergic stimulation can be expected to have increased levels of epinephrine, norepinephrine, and its metabolites. This review discusses possible mechanisms to explain this seeming paradox. Treatment of hyperthyroidism includes the rapid reversal of many of the adrenergic symptoms with use of beta-blocking drugs. Return to a clinically and chemically euthyroid state, however, requires antithyroid therapy accomplished over a longer period of time. A knowledge of the interaction of the cardiovascular and extracardiovascular manifestations of hyperthyroidism and the role of the adrenergic nervous system is important in the rational management of these patients.

Hypothyroidism and polyneuropathy

The prevalence and characteristics of polyneuropathy were assessed using standard clinical and electrophysiological criteria in 39 consecutive outpatients with primary hypothyroidism, 15 of whom were previously untreated. Subjective complaints, mainly paraesthesiae, were recorded from 25 cases (64%) and objective findings supporting a clinical diagnosis of polyneuropathy were present in 13 (33%). Using standard electrophysiological criteria, a definite diagnosis of polyneuropathy was made in 28 cases (72%). The commonest sites of abnormal nerve conduction were the sensory nerves, especially the sural nerve. Polyneuropathy was generally mild. None of the clinical and biochemical indicators of hypothyroidism were significantly correlated with the electrophysiological signs of peripheral nerve impairment or the diagnosis of polyneuropathy.

Endocrine-skin interactions. Cutaneous manifestations of pituitary disease, thyroid disease, calcium disorders, and diabetes

Endocrinologic disorders occasionally manifest themselves by their associated or induced cutaneous abnormalities. In some instances the initial and most prominent complaints of the patient are related to alterations in the skin, and thus the dermatologist will at times be the first physician consulted. In this article we describe the cutaneous lesions that occur in patients with acromegaly, hypopituitarism, hypothyroidism, hyperthyroidism, diabetes mellitus, glucagonomas, hypercalcemia, hypoparathyroidism, and fibrous dysplasia. In addition, we also discuss the role of the skin in vitamin D metabolism. Whenever possible and where known, we have attempted to point out the pathophysiologic mechanisms that account for the cutaneous changes.

Endoneural vessel involvement in hypothyroidism

Light-microscope findings and pathological ultrastructural changes in sural nerve biopsies from two patients affected by hypothyroidism, one with overt signs of peripheral neuropathy, the other asymptomatic, were studied. In both patients the endoneural vessels showed clear pathological changes similar to those of other metabolic neuropathies, but more marked in the symptomatic patient. It is proposed that the changes observed in the nerve fibers in hypothyroid neuropathy are secondary to changes in the endothelial cells and in the vessel wall.

Spinal epidural lipomatosis: report of a case secondary to hypothyroidism and review of literature

Epidural lipomatosis usually occurs as a complication of steroid therapy. This report includes the first description of a case secondary to hypothyroidism. Adults in all age groups can be affected and present with progressive signs and symptoms of spinal cord or cauda equina compression. The dorsal aspect of the thoracic spine is most commonly involved, usually in its total extent. Spine radiographs are normal and myelography poorly delineates the nature and extent of abnormality. While computed tomography can provide information about the nature of the spinal mass, magnetic resonance imaging is the investigation of choice. Extensive decompressive laminectomy is useful but the results are variable. Correction of underlying endocrine abnormality can reverse the process. The need for early diagnosis of this disorder is therefore emphasized.

Pseudohypothyroidism. Differentiation from true hypothyroidism

Pseudohypothyroidism is a prevalent "non-disease" that represents an erroneous diagnosis of hypothyroidism. The error in diagnosis can be readily recognized, and unnecessary therapy with thyroid hormones--which are ineffective and potentially can induce harmful side effects--can be terminated. By recognizing that hypothyroidism is not the cause of the patient's complaints, the physician can pursue further investigation to elucidate the true cause.

The cutaneous mucinoses

The cutaneous mucinoses are a group of connective tissue disorders characterized by the deposition of mucin, either focally or diffusely, in the interstices of the dermis. The diseases may be a primary (metabolic) or secondary (catabolic) process. Systemic abnormalities are seen with most of these disorders. This review discusses the primary mucinoses in which the predominant dermal mucin is hyaluronic acid. Current therapy and proposed mechanisms for the mucinoses are considered.

Pituitary enlargement mimicking pituitary tumor

Primary hypothyroidism can result in reactive enlargement of the pituitary gland which is indistinguishable from primary pituitary lesions on computerized tomography (CT) scans. The presenting symptoms may be due to pituitary gland enlargement, as in two of the three cases reported here. Therefore, the diagnosis of pituitary hypertrophy or hyperplasia secondary to hypothyroidism must be based on the endocrinological work-up. Following treatment of primary hypothyroidism, the diminution in size of the pituitary gland can be demonstrated with CT.

Clinical importance of reversibility in primary goitrous hypothyroidism

Twenty seven hypothyroid patients with a serum concentration of thyroid stimulating hormone (TSH) of over 40 mU/1 were followed up for three to 20 weeks without replacement therapy. The serum thyroid hormone concentrations increased with a dramatic decrease in serum TSH values in 14 patients (reversible group) but there was no significant change in the other 13 (irreversible group). Fourteen out of 19 patients with goitre but none of the eight patients without goitre belonged to the reversible group. All of the 11 patients with a high uptake of iodide by the thyroid, three of the six with a normal uptake, and none of the 10 with a low uptake belonged to the reversible group. These observations indicate that patients with goitrous hypothyroidism with a preserved thyroid uptake of iodide are likely to become euthyroid spontaneously without replacement therapy.

Myxedema megacolon after external neck irradiation

Myxedema megacolon is a rare manifestation of hypothyroidism. It may respond to appropriate treatment but is sometimes irreversible, resulting in fatal complications. Two possible mechanisms to explain the colonic atony include (1) myxomatous infiltration of the submucosa with separation of the muscular fibers from the ganglia of Auerbach's plexus, and (2) severe autonomic neuropathy affecting the extrinsic nerves to the colon and the myenteric plexus. Histology from our case supports the first proposed mechanism. Urecholine challenge and manometric measure response may help predict reversibility of colonic atony. Treatment should be individualized and should include factors such as age, duration of symptoms, and other medical illness. Low-dose oral or intravenous triiodothyronine is effective. Hypothyroidism following external radiation of the neck for lymphoma is not uncommon, and the risk increases following one or more lymphangiograms. Such patients should be followed up with regular TSH estimations for at least three years.

Echocardiographic characterization of the reversible cardiomyopathy of hypothyroidism

Nineteen patients with untreated hypothyroidism were evaluated by M-mode echocardiography. Asymmetric septal hypertrophy (ASH), defined as a ratio of interventricular septal thickness to left ventricular posterior wall thickness (IVS/LVPW) equal to or greater than 1.3, was identified in 17 cases. Additional abnormalities recognized by echocardiography included reduced amplitude of systolic septal excursion (SSex) [13 patients], reduced per cent of systolic septal thickening (%SST)[19 patients], reduced left ventricular outflow tract dimension (LVOT)[five patients] and systolic anterior motion of the mitral valve (SAM)[five patients]. These findings are similar to some of the echocardiographic features of idiopathic hypertrophic subaortic stenosis (IHSS). In 10 patients who returned to euthyroid state with L-thyroxine therapy, these abnormalities resolved. We conclude that long-standing hypothyroidism leads to a reversible cardiomyopathy, manifested by asymmetric septal hypertrophy with or without other echocardiographic features of a hypertrophic obstructive cardiomyopathy. This previously unrecognized features of hypothyroidism has important diagnostic and therapeutic implications.

Myxedema megacolon

The radiological findings on barium enema examination of 239 patients with thyroid deficiency (192 hypothyroid and 47 myxedematous) were reviewed. A new radiologic finding of transverse ridging superimposed on megacolon is described in myxedema and an explanation for this finding is postulated. The colonic findings associated with thyroid deficiency are presented.