As seen in Table 1, the clinical features of excess or deficient thyroid hormone are almost a mirror image of one another and reflect known actions of T3 in various target tissues. Depending on the cause of the condition, both hyper- and hypothyroid individuals often present with an enlarged thyroid gland, known as goiter, due to overstimulation of the TSH receptor.

Table1. Some Clinical Features of Disturbed Thyroid Hormone Status

In instances of thyroid hormone excess, the subject has an accelerated BMR and an elevated cardiac output associated with high body temperature, warm skin, and sweating that is inappropriate for the ambient temperature. Because muscle mass constitutes 50% of body weight, and because muscle tissue has a high rate of oxygen consumption, the increased muscular metabolic activity makes a substantial contribution to the higher BMR. Although hyperthyroid individuals often increase their food intake, there is usually a concomitant weight loss related to the greater gastrointestinal activity and associated diarrhea. Such an individual is often hyper active, with rapid movements and exaggerated reflexes, and frequently exhibits short attention span. Muscle myopathy occurs and is attributable to both abnormal protein catabolism with negative nitrogen balance and abnormal neuromuscular transmission.

In a hypothyroid subject, both BMR and cardiac output are reduced. Accordingly, the body temperature is lowered and the skin is cool and dry, since sweating is reduced in relation to the ambient temperature. The appetite of a hypothyroid individual is poor and there is reduced gastrointestinal activity. Although the skeletal muscles can be somewhat enlarged, there is no obvious myopathy. The principal external clinical features of hypothyroidism include a myxedemic appearance, described as an accumulation under the skin of mucoproteins and fluids resulting in a puffiness as a consequence of alterations in electrolyte and water balances. In addition to the features mentioned in Table1, a deficit of thyroid hormone during development and child hood results in impaired skeletal growth. The effects of T3 on the nervous system continue through adulthood so that the hypothyroid individual often shows signs of lethargy, and poor memory. In severe cases of long standing, a precipitating event, such as cold exposure, can result in myxedema coma.

اخر الاخبار

اخبار العتبة العباسية المقدسة

بالتعاون مع جامعة ستانفورد.. جامعة الكفيل تعتمد منهجًا متطورًا لطب الطوارئ

سماحة السيد الصافي يستقبل وفد شركة (سيتي فارما) الباكستانية المختصة في الأدوية

شعبة فاطمة بنت أسد تعلن أسماء الفائزات في مسابقة ميثاق العدالة

المجمع العلمي يطلق البرنامج التطويري الربيعي لطلبة الحفظ بنسخته الخامسة في كربلاء

المزيد

الآخبار الصحية

اللحظات الأخيرة قبل الموت.. هذا هو تسلسل "فقدان الحواس"

وخز الأطراف وضعف الذاكرة.. علامات على نقص فيتامين هام

عادة صباحية بسيطة.. تأثيرها قد يحسن ضغط الدم

عادات يومية تدمر قلبك بصمت.. خبراء يطلقون التحذير

المزيد

الآخبار التكنلوجية

الذكاء الاصطناعي يفك لغز آثار أقدام الديناصورات

القمر أولا.."سبيس إكس" تؤجل خططها الخاصة بالرحلات إلى المريخ

الذكور أم الإناث؟ دراسة "تنسف الشائع" بشأن التوحد

خبير يكشف عن اقتراب العلماء من فك شفرات "لغات الحيوانات" !

المزيد

مواضيع ذات صلة

Hyperthyroidism: Etiology and Treatment

Clinical Associations of Aplastic Anemia

Typical and Atypical Presentations of Aplastic Anemia

Pathophysiologic Pathways Leading to Aplastic anemia

Epidemiology of Aplastic anemia

Pneumonia

Bronchitis

Pathogenesis of the respiratory tract: Microorganism Factors

Pathogenesis of the respiratory tract: Host Factors

Clinical Manifestations of Bloodstream Infections

Definition of Sepsis

Types of Bloodstream Infections