Completing the loop: follow up and outcome of patients receiving radioactive iodine for thyrotoxicosis - the impact of a telephone clinic and adjunctive lithium
C Mehta, E Murphy, S Stanley & K Meeran
Significant delays in follow up and institution of thyroxine replacement for patients developing post-radioiodine (RAI) hypothyroidism were revealed by a three year retrospective audit. To reduce the incidence of undiagnosed early hypothyroidism and lengthy waits between outpatient visits, a telephone clinic was introduced in August 2000. Thyroid function tests are checked at 3, 6, 9 and 12 weeks post-treatment. Results are checked weekly by a Specialist Registrar. Patients who become hypothyroid post-treatment (fT4 <14pmol/L) are telephoned and started on thyroxine 100 micrograms daily. Following initial success lithium carbonate (800 mg nocte) was introduced as a standard adjunct to RAI. Aim: To establish whether the telephone clinic had improved follow up and treatment outcome after RAI, and to determine if lithium increases RAI effectiveness. Method: All patients (N=251) who had received RAI were identified and a comparison made of clinical and biochemical parameters between those patients who had received RAI treatment prior to the telephone clinic and subsequently. Results: The telephone clinic significantly reduced the time between RAI and first TFTs from 49 (SD 49, range 1-326) to an average of 28 days (SD 16, range 11-104, 42.2% reduction), and between hypothyroidism emerging and institution of thyroxine from 29 (SD 138, range 0-779) to an average of 11 days (SD 14, range 0-83,63.5% reduction). With the addition of lithium these delays have fallen further still to just 8 and 5 days, respectively and mean weight gain (3.5 vs. 2.5 kg, p=<0.01) following RAI and peak TSH (28.9 vs. 11.6 mU/L, P=<0.05) were significantly reduced. Lithium significantly increased the cure rate from 78% to 100% in our patients, as well as the time to cure, with a similar dose of RAI (550 MBq). In conclusion the telephone clinic allows close and standardised monitoring of patients after RAI and lithium carbonate is a safe adjunct, dramatically increasing effectiveness of RAI, and may result in 100% cure.