Abstract
Hypothyroidism is a common disease, affecting up to 5% of the population. Neurological symptoms are frequent in hypothyroidism, involving both the central and peripheral nervous systems.
In some cases, hypothyroidism is a direct cause of a manifestation or deterioration of neurological symptoms; at other times, it is an association on the basis of a common pathogenic (autoimmune) background; however, there are also cases when a causal link is controversial, being burdened with methodological selection bias of published studies. In manifest hypothyroidism, replacement therapy with levothyroxine leads, in most cases, to partial or total regression of neurological symptomatology.
In subclinical hypothyroidism or euthyroid autoimmune thyroiditis wherein the associations with neurological symptoms are weaker and often controversial, the results of interventional studies with levothyroxine mostly failed to show a favourable effect of treatment.