A case of congestive heart failure due to reversible dilated cardiomyopathy caused by hyperthyroidism

Thyrotoxicosis is an uncommon cause of low-output congestive heart failure. The case of a 41-year-old male who presented with severe symptomatic congestive heart failure, and was subsequently diagnosed with dilated cardiomyopathy secondary to hyperthyroidism, is presented. The cause of his hyperthyroidism was Graves disease. Despite an initial left ventricular systolic ejection fraction of 20% and evidence of global hypokinesis on echocardiography, treatment with antithyroid agents led to rapid improvement in his clinical status and normalization of his ejection fraction. The proposed mechanisms underlying the development of systolic dysfunction in thyrotoxicosis are discussed, and the literature on similar cases previously reported is reviewed.

[Thyrotoxic encephalopathy showing reversible diffusion-weighted imaging abnormalities]

A 31-year-old man was transferred to our emergency room (ER) with acute onset of high-grade fever and consciousness disturbance. His consciousness at ER was severely disturbed with restlessness. No apparent focal neurological signs were seen. MRI with diffusion-weighted images (DWI) showed high signal intensities at the corpus callosum, left cerebellar hemisphere, left deep white matter and right middle cerebellar peduncle. These lesions were low signals in apparent diffusion coefficient(ADC) map, indicating cytotoxic edema. EEG showed enhanced fast waves seen in predominantly frontal regions. CSF examination was normal except elevated initial pressure of 210 mmH2O. He was treated with high dose dexamethasone and acyclovir. His consciousness and high-grade fever with systemic inflammatory responses were dramatically improved after these treatments. Subsequent data showed hyperthyroidism with anti-thyroid stimulating hormone receptor antibodies. This case was thought to be a thyrotoxic encephalopathy with beneficial response to corticosteroid therapy. Abnormalities seen in DWI and EEG were normalized ten days later.

Failure to gain weight on long-term parenteral nutrition attributed to tri-iodothyronine thyrotoxicosis

We describe the case of a 49-y-old female patient on long-term parenteral nutrition after abdominal surgery who failed to gain weight despite nutritional provision in excess of theoretical requirements. On investigation, she was found to have a negative nitrogen balance (-5.9 g) and to have a tri-iodothyronine thyrotoxicosis but without many of the typical clinical features of hyperthyroidism. The patient also had mild hypercalcemia and hyperphosphatemia, which resolved fully after mobilization and treatment of the thyrotoxicosis. A derangement of the liver function tests was observed, which worsened progressively during parenteral nutrition but resolved promptly at its discontinuation. This case illustrates the importance of carrying out appropriate investigations including all thyroid function tests on patients who fail to gain weight on nutritional support.

Thyrotoxicosis Presenting as Hypogonadism: A Case of Central Hyperthyroidism

Herein, we present a case of central thyrotoxicosis with well-documented serial therapeutic interventions. Thyroid-stimulating hormone (TSH)-secreting pituitary tumors represent a rare cause of hyperthyroidism. It is being diagnosed more frequently with the third-generation TSH assay. Many conditions can produce normal or elevated TSH levels in combination with elevated thyroid hormone levels. The differential diagnosis includes resistance to thyroid hormone (RTH, Refetoff's syndrome), assay interference from anti-T4/T3 and heterophile antibodies, elevated or altered binding proteins, drugs affecting peripheral metabolism, and noncompliance with thyroid replacement therapy. In contrast to RTH, our patient presented had high alpha-subunit-to-TSH molar ratio, failed TSH response to thyrotropin-releasing hormone stimulation, and a large pituitary mass. Normal or high TSH in the presence of elevated T4 or T3 is a fairly common clinical scenario with many etiologic possibilities. This TSH-producing adenoma represents an unusual initial clinical presentation, as hypogonadism appeared before features of thyrotoxicosis were appreciated. This case represents the most modern therapeutic approach to the management of this rare disease. Our patient has done well on octreotide with control of thyrotoxicosis and an additional 30% shrinkage of his tumor mass.

[Hypokalemic paralysis with thyrotoxicosis]

Hypokalemic periodic paralysis as a complication of thyrotoxicosis (thyrotoxic periodic paralysis) most often occurs in east Asian men. It is characterised by recurrent episodes of flaccid paralysis, hypokalemia, and underlying hyperthyroidism. It needs to be distinguished from sporadic and familial forms of periodic hypokalemic paralysis. No disturbances in the acid-base state and no extracorporal potassium loss are present. We report on the typical case of a young Chinese man presenting with hypokalemic periodic paralysis associated with yet unknown Graves' disease. Intravenous substitution of potassium and oral propranolol were administered. Complete remission was achieved after 10 hours. After medical therapy had normalised thyroid hormone levels, no further hypokalemic paralytic attacks occurred.

Diagnosis and management of amiodarone-induced thyrotoxicosis in Europe: results of an international survey among members of the European Thyroid Association

OBJECTIVE

To determine how expert European thyroidologists assess and treat amiodarone-induced thyrotoxicosis (AIT).

DESIGN

Members of the European Thyroid Association (ETA) with clinical interests were asked to answer a questionnaire on the diagnosis and management of AIT. A total of 124 responses were received: 116 from Europe, seven from USA and one from Brazil. After excluding responses coming from the same centre, 101 responses from 24 European countries were analysed, representing approximately 65% of clinically active European ETA members.

RESULTS

The majority of respondents (68%) see 1-10 new cases of AIT/year, and AIT seems to be more frequent than amiodarone-induced hypothyroidism in Europe, where in many instances iodine intake is borderline or moderately deficient. A good collaboration with cardiologists exists in most centres, and patients receiving chronic amiodarone treatment are checked for thyroid function most commonly every 4-6 months. When AIT is suspected, a diffuse or nodular goitre is present or in the absence of apparent abnormalities of the thyroid, free thyroxine (FT4), free triiodothyronine (FT3) and TSH are assayed by almost 90% of respondents. Thyroid autoimmunity is evaluated in the initial assessment by > 80%, while evaluation of urinary iodine excretion is unhelpful for > 60%. Most commonly used additional diagnostic procedures include thyroid ultrasonography, particularly colour flow Doppler sonography, and, to a lesser extent, a thyroid uptake scan. If the thyroid gland is apparently normal, measurement of thyroidal radioactive iodine uptake is considered useful by a large proportion of respondents to establish the destructive nature of the process. Differentiation of type I and type II AIT is difficult and, possibly, not correct for 27% of respondents, who believe that mixed (or indefinite) forms are probably more frequent than previously recognized. Approximately 10-20% do not consider amiodarone withdrawal necessary in the therapeutic strategy of AIT, especially if the thyroid gland is apparently normal. Most respondents (82%) treat type I AIT with thionamides, either alone (51%) or in combination with potassium perchlorate (31%), while the preferred treatment for type II AIT is represented by glucocorticoids (46%). Some respondents, in view of diagnostic difficulties, initially treat all cases of AIT with a combination of thionamides and glucocorticoids. After restoration of euthyroidism, ablative therapy is recommended by 34% in type I and only 8% in type II AIT. If amiodarone therapy needs to be reinstituted, prophylactic thyroid ablation is recommended by 65% in type I AIT, while a wait-and-see strategy is adopted by 70% in type II AIT.

CONCLUSION

Areas of certainty and uncertainty concerning AIT are present among expert European thyroidologists, both from a diagnostic and a therapeutic standpoint. Diagnostic criteria need to be refined in order to improve therapeutic outcome.

Hyperthyroidism as a cause of persistent vomiting

A 32-year-old woman presented with persistent vomiting, epigastric pain and weight loss. A sinus tachycardia was the clue to the diagnosis of hyperthyroidism due to Graves' disease. On treatment with propylthiouracil and a beta-blocking agent, her symptoms resolved within one day, even though her free thyroxine level was still high. Hyperthyroidism is an uncommon, but previously reported cause of persistent vomiting.

Juvenile thyrotoxicosis; can we do better?

Thyrotoxicosis remains a frustrating condition for the young person, family, and health professionals involved. The associated symptoms do not always suggest thyroid disease and patients can be unwell for many months before the diagnosis is made. The antithyroid drug regimen used to treat children and adolescents with thyrotoxicosis varies from one unit to another and yet the potentially life threatening side effects and remission rates post-treatment may be related to the regimen used. Most patients with thyrotoxicosis will need many years of drug therapy if the thyroid gland is not removed surgically or destroyed by radioiodine. Even "definitive" treatment will typically necessitate thyroxine replacement for life.

Itch: a symptom of occult disease

BACKGROUND

Pruritus, (the Latin word for itch), is defined as the 'desire to scratch'. It is a distressing, subjective symptom that may interfere significantly with the quality of a patient's life.

OBJECTIVE

This article summarises the systemic causes of pruritus, describes the assessment of a patient presenting with itch without dermatological cause, and discusses the management of itch in patients with cancer.

DISCUSSION

Patients with pruritus that does not respond to conservative therapy should be evaluated for underlying systemic disease. Causes of systemic pruritus include cholestasis, thyroid disease, polycythaemia rubra vera, uraemia, Hodgkin disease, and HIV. A thorough history and a complete physical examination are central to the evaluation of pruritus. In the absence of skin lesions, diagnostic testing is directed by the clinical evaluation and may include a complete blood count, liver function tests, serum creatinine, blood urea nitrogen levels, measurement of thyroid stimulating hormone, and chest X-ray. Removal of the causative agent and appropriate investigation and treatment of the underlying disease are essential first line measures in the treatment of pruritus.

Low failure rate of fixed administered activity of 400 MBq 131I with pre-treatment with carbimazole for thyrotoxicosis: the Gateshead Protocol

BACKGROUND

Thyrotoxicosis is associated with significant morbidity, therefore adequate control of the disease is paramount. The outcome of treatment of thyrotoxicosis using radioiodine shows variable failure rates depending, amongst other things, on the administered activity of radioiodine and the use of anti-thyroid drugs. Thus, management should follow an evidence based protocol, which has a low failure rate.

METHOD

We prospectively analysed the outcome of treatment using our Gateshead protocol of a fixed administered activity of radioiodine therapy (400 MBq) given to 201 patients (including 140 with Graves' disease, 48 with toxic multinodular goitre (TMNG) and 13 with toxic nodule) followed up for a median period of 12 months (range, 6-77 months). Carbimazole was discontinued in patients rendered euthyroid 16 days prior to radioiodine. No routine anti-thyroid drugs or thyroxine were given following radioiodine unless hypothyroidism or thyrotoxicosis occurred.

RESULTS

Following the Gateshead protocol led to a failure rate of 6.5% (eight females with Graves' disease, four females with TMNG and one female with toxic nodule), 29% euthyroidism and 64% hypothyroidism. The rates of hypothyroidism for women and for men were: in Graves' disease 77% and 79%, in TMNG 29% and 75%, in toxic nodule 42% and 0%, respectively.

CONCLUSIONS

Our observations show that withholding an antithyroid drug in excess of just over 2 weeks prior to administering a fixed administered activity of radioiodine in patients with thyrotoxicosis leads to the lowest reported failure rate, irrespective of the underlying cause. One possible mechanism for this could be the avoidance of drug induced radio-resistance.

High diagnostic value of a radioiodine uptake test with and without iodine restriction in Graves' disease and silent thyroiditis

The necessity of iodine restriction before radioiodine uptake (RAIU) testing for differentiation of thyrotoxicosis is controversial. The present study was undertaken to investigate the effects of iodine restriction on the RAIU value, and the necessity of iodine restriction in differentiating between Graves' disease (GD) and silent thyroiditis (ST). We investigated 415 patients, 277 of whom were patients with GD who had undergone iodine restriction before RAIU [GD(+)], 66 were patients with GD who did not undergo iodine restriction [GD(-)], 61 were patients with ST who had undergone iodine restriction [ST(+)], and the remaining 11 were patients with ST who did not undergo iodine restriction [ST(-)]. The RAIU value of the GD(+) group, 47.6% +/-14.4% (mean +/-standard deviation [SD]), was significantly higher than that of the GD(-) group, 42.4% +/- 17.6% (p = 0.03). However, the areas under the curves from the receiver operator characteristics analyses for the comparison between groups GD(+)/ST(+), GD(+)/ST(-), GD(-)/ST(+) and GD(-)/ST(-) were 0.99967, 0.99967, 0.98436, and 0.98485, and very high, respectively. High diagnostic value of the RAIU test was confirmed, but not affected by the presence of iodine restriction in the differentiation between GD and ST, therefore, iodine restriction before the RAIU test was unnecessary.

Thyrotoxicosis after Gastric Bypass

Obesity surgery is the optimal therapy for morbid obesity. A case is presented of a young woman who developed thyrotoxicosis, believed to be part of subacute thyroiditis, some days after undergoing laparoscopic Roux-en-Y gastric bypass. This clinical entity can present difficulties in differential diagnosis from potential postoperative complications. The correct diagnosis and adequate treatment made possible a favorable recovery.

Acute Hypercapnic Respiratory Failure due to Thyrotoxic Periodic Paralysis

Acute hypercapnic respiratory failure is a potentially life-threatening complication of profound hypokalemia usually seen in patients with large total-body potassium (K+) deficits. It has rarely been reported in thyrotoxic periodic paralysis (TPP), which is due to intra-cellular shifts of K+. The authors report on a 29-year-old man who presented with sudden onset of muscle paralysis in all extremities and acute progressive respiratory insufficiency requiring artificial respiratory support. He was treated with intravenous KCl. After six hours, muscular strength had returned to normal, with plasma K+ concentration of 3.0 mmol/L. At the eighth hour, rebound hyperkalemia (6.6 mmol/L) developed with high-tented T waves, even after the KCl was discontinued. Ventilatory support was uneventfully weaned at 14 hours. Elevated free thyroxine and undetectable thyroid-stimulating hormone confirmed the diagnosis of TPP. TPP should be kept in mind as a cause of acute respiratory failure in association with acute muscle weakness to avoid delayed diagnosis and improper management.

[Amiodarone and the thyroid gland]

Amiodarone is an iodine-rich drug. Its chronic administration may lead to disturbances in thyroid hormone metabolism and/or overt gland dysfunction. It causes an increased in serum fT4, rT3, and TSH concentrations and a decreased serum level of fT3 without thyroid dysfunction. Amiodarone may induce thyrotoxicosis (AIT--Amiodarone-induced thyrotoxicosis) or hypothyroidism (AIH--Amiodarone-induced hypothyroidism) in some persons. AIT occurs more frequently in areas with low iodine intake. The excess iodine contributes to excessive thyroid hormone synthesis-type I AIT or may lead to thyroiditis and a destructive process of thyroid follicular cells, resulting in excess thyroid hormone release-type II AIT. The mixed form of AIT also occurs. Type I AIT should be treated with antithyroid drugs alone or in association with potassium perchlorate, type II AIT benefits from treatment with glucocorticoids, whereas the mixed form of AIT is most effectively treated with a combination of thionamides, potassium perchlorate, and glucocorticoids. AIT often requires thyroidectomy after restoration of euthyroidism or radioiodine therapy, provided that 24-h thyroid radioactive iodine uptake values permit. AIH prevails in areas with high dietary iodine intake. It requires a discontinuation of amiodarone therapy and thyroid hormone (levothyroxine) replacement. It can remit spontaneously. Amiodarone and L-thyroxine therapy is also possible. Baseline thyroid function tests, thyroid antibodies, and imaging examinations such as thyroid ultrasound on initial evaluation and follow-ups every 6 months must be carefully monitored before starting amiodarone therapy.

Thyrotoxic hypokalaemic paralysis in a pregnant Afro-Caribbean woman. A case report and review of the literature

This paper reports the case of a 21-year-old Afro-Caribbean pregnant woman with hyperthyroidism and hypokalaemic quadriparesis and reviews the literature on the topic. Thyrotoxic periodic paralysis is a very rare condition in the Caribbean. This case reminds West Indian physicians to consider this rare condition in any patient that presents with paralysis.

Glycemic status in hyperthyroid subjects

This was an observational case-control study carried out in the Department of Biochemistry, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka jointly with the 'Thyroid and Endocrine Clinic' of the same institution during the period of January 2002 to December 2002. Sixty-five (65) newly diagnosed hyperthyroid patients between 20-60 years of age were studied, where forty-five (45) were Graves' disease and twenty (20) were TMNG (Toxic multinodular goiter) patients. Thyrotoxicosis was diagnosed by history, clinical examination and biochemical investigations- FT4, TSH, and Radioactive iodine uptake (RAIU) test. Thirty (30) age and sex matched healthy subjects were taken as control. The mean age was 33.02+/-9.24 years in Graves' disease and 37.55+/-9.49 years in TMNG. Female predominance observed in both the diseases. Glucose intolerance was found in 72.3% of thyrotoxic patients, which is much higher than European population. Our study showed Diabetes mellitus (DM) in 11% of Graves' disease patients. The incidence of DM in Graves' disease was slightly higher in our population. Incidence of DM in TMNG in our study was much lower (5%) than that of Graves' disease (11%) but the incidence of IGT (Impaired glucose tolerance) in TMNG was more (85%) in relation to Graves' disease (54%). Percentage of RAIU was more marked in Graves' disease than TMNG. There is a significant positive correlation (p<0.05) between plasma glucose and FT4 in Graves' disease. Glucose intolerance is frequently found in Thyrotoxic patients.

[First degree atrio-ventricular block in acute thyrotoxicosis]

Thyrotoxicosis may present with a variety of cardiovascular symptoms. Sinus tachycardia is the most frequently encountered electrocardiographic abnormality and conduction disturbances are extremely uncommon. We present a case of first degree atrio-ventricular block in a patient with newly diagnosed hyperthyroidism and discuss the underlying pathophysiological mechanisms and the clinical implications from the internist's standpoint.