Lyme and Hashimoto's.

It has been reported by “Lyme doctors” that Lyme infection is associated with endocrinopathies (disorders of the endocrine system). The most frequent is thyroid disease, generally autoimmune hypothyroidism AKA Hashimoto’s disease.  When looking at Lyme associated endocrine disorders, we need to take them one at a time.  A patient I saw today gained 70 pounds and was first diagnosed with hypothyroidism prior to Lyme. Thyroid supplementation helped him loose the weight. Thyroid disease, particularly autoimmune Hashimoto’s disease is very common. Lyme is very common. But do Lyme patients have hypothyroidism more frequently than would be expected on the basis of chance? Is there is a causal relationship? Hypothyroidism is almost entirely autoimmune. Anti-TPO and other anti-thyroid autoantibodies are invariably present. First off, we know that Hashimoto’s is a familiar disorder, e.g. mom and 2 daughters all suffer with it.  It has been well established that there is genetic predisposition, i.e. HLA DR3, DR5 mutations. 

Autoimmune disease likely is caused by several different mechanisms, one is called molecular mimicry. It has been reported that Bb shares certain amino acid sequences with thyroid proteins.  Antibodies directed against Lyme, in genetically predisposed individuals, may precipitate the productions of self-directed antibodies.  In other words, Lyme antibodies accidentally trigger anti-thyroid antibodies in some cases. 

It appears there may be a causal relationship.  I don’t think there is anything published confirming this suspicion. 

Most endocrine disorders are not autoimmune, including: hypothalamic, pituitary, adrenal disorders, sex hormones and (? POTS -- angiotensin 1 receptor).  If relationships exist, other factors are in play. 

All of my Lyme patients, who invariably complain of fatigue, have their thyroid functions checked.  Most doctors just screen with TSH.  T3 and T4 may be helpful but anti-thyroid antibodies are essential.  If these antibodies are present the patient will need thyroid supplementation sooner or later. If they have exhaustion – sooner, irrespective of the other numbers (except with hyperthyroidism or Grave’s disease).