Hyperthyroidism clinical presentation

In a retrospective review of 497 patients taking propylthiouracil for hyperthyroidism, clinically overt hepatitis developed in six patients at 12-49 days after starting the drug (50). Jaundice and itching were present in five, fever in two, rash in two, and arthralgia in one. Serum bilirubin, alanine transaminase, and alkaline phosphatase were increased in five, four, and six patients respectively. The type of hepatic injury was cholestatic in three, hepatocellular in one, and mixed in two. There were no differences in age, sex, drug dose, or serum thyroid hormone concentrations at time of diagnosis in those with hepatic injury compared with those without. Liver function normalized in all patients at 16-145 days after withdrawal of propylthiouracil. In addition to these cases of overt liver injury, 14% of the cohort had mild asymptomatic liver enzyme rises at a mean of 75 days after the start of treatment. 

A goitre is an enlarged thyroid gland (Fig. 4). This may be as.stKiated with hypofunction. hyperfunclion or, indeed, normal concentrations of thyroid hormones in blood. With such a clinical presentation, the bitK hemistry laboratory can confirm if a patient is hypothyroid, hyperthyroid or euthyroid. 

There is no discrete target tissue for thyroid hormones virtually every cell in the body is affected by thyroid hormones in some way. These hormones are intimately involved in the maintenance of normal function in virtually every cell type, including cellular responsiveness to other hormones, to the availability of metabolic substrates, to growth factors, and so on. Thyroid dysfunction can produce dramatic changes in the metabolism of proteins, carbohydrates, and lipids at the cellular level that can have repercussions for the operation of the cardiovascular, gastrointestinal, musculoskeletal, reproductive, and nervous systems. Some of the clinical manifestations of thyroid dysfunction are presented next in the discussions of hypothyroid and hyperthyroid states. 

Choanal atresia has been described in an infant whose mother presented in early pregnancy with Graves hyperthyroidism and who took carbimazole in doses up to 60 mg/day in the first trimester (102). She was also clinically and biochemically severely hyperthyroid at this time. 

There are numerous thyroid gland function tests, each designed to determine the etiology of thyroid dysfunction. In general, though, when hypothyroidism is present, circulating T3 and T4 levels are down and TSH is up. The opposite is true of hyperthyroidism. In addition, free (non-protein-bound) T4 and TBG may be determined to clarify inconclusive results. In hyperthyroidism, free T4 is increased but total T4 may be normal. It is the free serum T4 that has been correlated with clinical symptoms rather than total T4. 

Clinically, the practitioner may observe conjimctival chemosis and erythema, abnormal eyelid position (lid retraction), lid lag, and proptosis. Conjunctival injection is most marked over the involved rectus muscles. Nervousness, palpitations, weight loss, hyperhidrosis, and heat intolerance are systemic symptoms occurring in more than 80% of hyperthyroid patients. Other signs, such as tremor, hyperreflexia, tachycardia, skin changes, stare, and eyelid lag, are observed in more than 60%. Additionally, goiter is present in more than 95% of Graves disease patients. In most cases, however, the laboratory confirmation of thyrotoxicosis is helpful to corroborate the diagnosis. 

Thyroid dysfunction is common in the elderly. Diagnosis may be overlooked since many of the clinical manifestations of thyroid disease may be misinterpreted as just the normal ageing process (Fig. 2). Unusual presentations arc common e.g. elderly patients with hyperthyroidism are more likely than younger patients to present with the cardiac-related effects of increased thyroid hormone. 

Mutations of the TSH receptor result in clinical thyroid dysfunction. Germline mutations can present as autosomal dominant toxic thyroid hyperplasia (gain-of-frmction mutations) or as gestational hyperthyroidism due to receptor hypersensitivity to hCG. Somatic mutations that result in constitutive activation of the receptor are associated with hyperfrmctioning thyroid adenomas. 

The most severe form (f hyperthyroidism is thyroid storm, a rare but life-threatening disease that usually is precipitated by an intercurrent medical problem. Precipitating factors include infections, stress, trauma, thyroidal or nonthyroidal surgery, diabetic ketoacidosis, labor, heart disease, and rarely, radioactive iodine ablation. Clinical features are similar to those of thyrotoxicosis, but are more severe. Cardinal features include fever and tachycardia out of proportion to the fever. Nausea, vomiting, diarrhea, agitation, and confusion are frequent presentations. The abnormalities in TFTs are not necessarily worse than those in uncomplicated thyrotoxicosis and thyroid storm is a clinical diagnosis. 

In this section, an attempt will be made to rationalize the use of thyroid function tests in various clinical areas, particularly in those where interpretation can sometimes be diflScult. It is superfluous here to discuss in any detail the use of thyroid tests in certain clear-cut areas, such as in confirming the diagnosis in a newly presenting case of Graves disease or of idiopadiic myxedema. What is indicated is a standard regime of either an FTI or ETR (or similar test) or even both. If these measurements are in the overlap region between hypothyroid and normal subjects, a TSH assay is needed. If the routine tests are in the overlap between values for hyperthyroid patients and normal subjects, then a serum Ts concentration is indicated. 

Creatine is present in muscle, brain, and blood and, although not present in large amounts in normal urine from adults, it is abundantly present in the urine of adults who have recently ingested creatine supplements. Ingestion of a creatine supplement has been shown to increase the level of phosphocreatine, and this has become extremely popular in recent years with many athletes who want to increase muscular power and to enhance their performance. Because of this, analysis for creatine has become more important in the clinical setting. Additionally, elevated serum concentrations of creatine can be observed in some cases of muscle catabolism such as primary myopathy, myositis, and muskelatrophie, as well as in the case of hyperthyroidism. 

CLINICAL SIGNIFICANCE - There are no young cretinoids and more subtle effects of iodine defficiency in children were not studied. However, hyperthyroid patients from the most affected areas presented with a high prevalence of nodular lodbasedow, as compared to Graves disease. Also, the ratio of follicular to papillary carcinomas was different in affected and non affected regions. As these data were obtained from an hospital based registry only ratios could be calculated but not absolute incidences or prevalences. 

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