Fylkesnes_2000_Tidsskr.Nor.Laegeforen_120_905

BACKGROUND: The clinical presentation of hypothyroidism varies considerably and may be dominated by cognitive deficits and psychological symptoms. Hence, when diagnosing dementia it is important to rule out hypothyroidism. Hypothyroidism has also been considered a classic reversible dementia; however, the aetiological association between dementia and hypothyroidism is by no means indisputable. MATERIAL AND
METHODS: A review of available literature concerning hypothyroidism, cognitive functioning and dementia.
RESULTS: The importance of thyroxin for the development of the brain and for intellectual development is well known. Early reports suggested that thyroxin improved or reversed dementia in patients with hypothyroidism. Later studies have shown contradictory results; however, several prospective intervention and follow-up studies of overt and subclinical hypothyroidism do not provide for support the belief that there is an aetiological association between dementia and hypothyroidism. INTERPRETATION: The lack of association between dementia and hypothyroidism has consequences for the treatment, and for information to patients and relatives of patients with concomitant dementia symptoms and hypothyroidism. The introduction of acetylcholinesterase inhibitors in the treatment of patients with Alzheimer's disease has brought new interest to this matter. When hypothyroidism is detected in a patient with suspected dementia, thyroxin should be tried first of all. If there is no obvious improvement of symptoms and there still is evidence of dementia, one should consider whether the patient is suitable for a trial with an acetylcholine inhibitor.