From Dr E. R. Blay, MRPharmS
SIR,-In Dr MacFarlane's article (PJ, August 12, p240) the reference to delayed relaxation of reflexes in hypothyroidism reminds me that before the advent of tests for T4, T3 and TSH the relaxation time of the plantar reflex was measured with an electronic device which used a light sensor as a means of confirming the clinical diagnosis of over- or under-activity of the thyroid gland. The test was carried out with the patient kneeling on a chair so that the sole of the foot could be scanned by a light sensor, the output from the electronic device was fed into an electrocardiogram machine to record the result. Modern electronic design could easily give a direct reading in milliseconds.
In these cost-conscious days, it would be worthwhile determining how closely the correlation is between the electronic and blood test results. Furthermore, I see a role for the pharmacist equipped with such a device in monitoring thyroid medication. It is not necessary to take a shoe off, let alone uncover a vein.
E. R. Blay
Fareham, Hampshire