Hypothyroidism clinical presentation

Thyroid dysregulation has also been reported in depressed patients. Up to 25% of depressed patients are reported to have abnormal thyroid function. These include a blunting of response of thyrotropin to thyrotropin-releasing hormone, and elevations in circulating thyroxine during depressed states. Clinical hypothyroidism often presents with depressive symptoms, which resolve with thyroid hormone supplementation. Thyroid hormones are also commonly used in... 

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. 

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. 

Signs and symptoms usually associated with thyroid hypofunction in middle age and in the elderly are summarized in Table 106.2. Clinical presentation of hypothyroidism... 

LT4 is indicated for patients with overt hypothyroidism.22 However, the need for treatment is controversial in patients with mild or subclinical disease (TSH less than 10 milli-units/L). There are no large clinical trials that show an outcome benefit with treating these patients, and the therapeutic decision must be individualized.1,23 Many patients with subclinical hypothyroidism do, in fact, have subtle symptoms that improve with LT4 replacement. If the patient s serum cholesterol is elevated,24 or if serum anti-TPOAbs are present, many clinicians recommend LT4 therapy. 

BW, a 50-year-old woman with a history of osteoarthritis and hypothyroidism, presents to the clinic complaining of hot flashes, vaginal dryness, and insomnia. She states that she experiences approximately two hot flashes per day and is awakened from sleep at least three to four times a week in a "pool of sweat" requiring her to change her clothes and bed linens. Her symptoms began about 3 months ago, and over that time, they have worsened to the point where they have become very bothersome. On questioning, she states her last menstrual period was 1 year ago. 

This point of view overlooks the fact that every well and normal individual is potentially an ill individual, and the roots of disease may be present in his make-up years before there is any overt disease. A dozen young men used as normal controls may each have metabolic peculiarities that point toward a different metabolic derangement gout, multiple sclerosis, diabetes, anemia, atherosclerosis, hypertension, nephrosis, hypothyroidism, rheumatoid arthritis, rheumatic heart disease, liver cirrhosis, and myasthenia gravis, for example, and yet at the time of their use as controls these young men may show no symptoms of the disease which is to appear later in life. It seems far from safe to assume that because an individual on clinical examination seems well, all of his blood values, for example, are normal and meaningless so far as disease susceptibilities are concerned. 

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. 

Long-term side effects of lithium treatment include weight gain. The treatment is associated with development of hypothyroidism in about 10-15% of cases. There is an association with kidney disease. Birch has expressed the general view that Li may interact with magnesium-dependent processes, and theoretical chemistry supports this view. Despite the widespread clinical significance of Li, there is presently no consensus on its mode of action. One postulate for the mechanism is termed hyperpolarization . Li affects the conductivity in cell transport channels. Other explanations include modulation of neurotransmitter concentrations and inhibition of Na+/K+/Mg2+/ Ca2+ ATPases. 

The clinical, biochemical, and thyroid imaging characteristics of thyrotoxicosis resulting from interferon alfa treatment have been retrospectively analysed from data on 10 of 321 patients with chronic hepatitis (75 with chronic hepatitis B and 246 with chronic hepatitis C) who developed biochemical thyrotoxicosis (161). Seven patients had symptomatic disorders, but none had ocular symptoms or a palpable goiter. Six had features of Graves disease that required interferon alfa withdrawal in four and prolonged treatment with antithyroid drugs in all six. Three presented with transient thyrotoxicosis that subsequently progressed to hypothyroidism and required interferon withdrawal in one and thyroxine treatment in aU three. 

As discussed elsewhere in more detail (Morreale de Escobar et ai, 2004), it is inaccurate to assume, which has been very frequently done, that inhabitants of areas of ID are chnically hypothyroid individuals. The present experimental model supports the epidemiological findings that inhabitants of areas of ID are not clinically hypothyroid individuals, as their normal circulating T3 ensures euthyroidism of most tissues by extrathyroid adaptive mechanisms known to be operative in man when iodine availability decreases. But, as shown experimentally here, this does not avoid selective hypothyroidism of tissues, such as the brain, that depend mostly on T4 for their intracellular T3 supply. This selective hypothyroidism is aheady present in conditions of mildly decreased iodine availability, and may already negatively affect mental functions (Delange, 2001 Vitti et al., 2003 Vermiglio et ai, 2004). Indeed, inhabitants of areas of ID are often described as dull. Whole populations appear to wake up when their ID — and the consequent hypothyroxinemia — are corrected (Dunn, 1992). 

A more modern study examined thyroid function patients attending a university geriatrics primary care clinic. In a retrospective chart analysis of 370 patients, 23.5% presented with a history of known hypothyroidism or thyroid surgery. 

In elderly patients, especially those with multisystemic diseases, hypothyroidism may become severe and fife threatening. Myxedema coma represents the most extreme form of severe hypothyroidism. This medical emergency may occur when severe hypothyroidism is complicated by trauma, infection, myocardial infarction, cold exposure, or administration of hypnotics or opiates, medications that suppress central nervous system function, particularly ventilatory drive. It typically presents in older women in winter. The main clinical features are hypothermia and a variable degree of altered consciousness (Iglesias et ai, 1999). Serum T4, TSH and cortisol should be measured to confirm the diagnosis and evaluate adrenal reserve. When there is a reasonably high level of suspicion, treatment should not be delayed to await laboratory results. 

In this chapter, after presenting an outline of both hypertensive and hypothyroid states, we will review the cardiovascular and (neuro)endocrine relationships between the two disorders, beginning with a discussion of basic cellular mechanisms and concluding with a discussion of pathophysiological and clinically related aspects. 

Clinical Features Several symptoms and signs of hypothyroidism may be mistaken with those presented by a euthyroid pregnant woman (asthenia, weight increase, drowsiness, constipation, etc.), although others may make the diagnosis doubtful (bradycardia, sensitivity to cold, dry skin) (Abalovich et al., 2006). In contrast, 70-80% of women with OH, and almost all SGH carriers, may remain asymptomatic. Thus, particular attention... 

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