THYROID DISORDERS
Thyroid dysfunction is common in adults with Down’s syndrome, with a steady decline in thyroid function increasing with age. Both hypo- and hyper-thyroidism can occur in adults with Down’s syndrome, although hypothyroid ism is much more common and often caused through an autoimmune process whereby the immunological defense system targets its own body tissues and organs.
Hypothyroidism is caused by a deficiency of thyroxine – a naturally occurring hormone, secreted by the thyroid gland. It is more commonly known as an ‘underactive’ thyroid. It occurs because the thyroxin gland stops making sufficient thyroxine. Typical symptoms include putting on weight, increasing tiredness and lethargy, constipation and generalized aches and pains (British Thyroid Foundation 2005a). Table 1 outlines further clinical features.
The clinical picture of an adult with Down’s syndrome suffering from hypothyroidism can be similar to those of both depression and dementia, and careful assessment is required to aid the correct diagnosis and follow-on treatment. This similarity of presenting symptoms is known as differential diagnosis, and therefore careful investigation and diagnosis are needed. Indeed,
Table 1 Clinical features of hypothyroidism
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• Hearing difficulties
• Facial puffiness
• Husky voice
• Weight gain
• Intolerance of cold
• Hair loss
• Dry skin
• Slow pulse rate
• Constipation
• Lethargy
• Apathy, mental dullness
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Table 2 Clinical features of hyperthyroidism
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• Anxiety
• Irritability
• Palpitations
• Weight loss
• Heat intolerance
• Increased sweating
• Fine tremor
• Menstrual disturbance
• Increased pulse rate
• Warm, sweaty skin
• Diarrhea
• Retracted eyelids – making the eyes look out-standing
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Dennis (2000), representing the Down’s Syndrome Association, advises that because of this differential diagnosis, regular blood tests should be carried out on adults with Down’s syndrome to assess their thyroid function. It also recommends that carers be alert to the possibility of the thyroid gland slowing down and report these concerns to their GP or learning disability team.
Hyperthyroidism is more usually known as ‘overactive thyroid’. The thyroid gland makes too much thyroxine, resulting in some of the following symptoms: noticeable weight loss coupled with an increase in appetite, inability to sleep, restlessness and irritability, palpitations and sweating (British Thyroid Foundation 2005b). Table 2 outlines further clinical features.
