The CT scan triggered thyrotoxicosis in her!

Clinical scenario :

         A 52-year-old lady with known past history of goiter displayed to the ER with a quickly developing goiter and shortness of breath of 5 days length .

The shortness of breath was positional, basically when lying down without any history of chest pain, lower limb edema, or fever. The neck swelling had begun 18 years ago and was continuously and gradually expanding in estimate .She detailed a long- standing history of wheezing, weakness, and daytime fatigue. She denied any history of palpitation, sweating, weight loss/gain or loose bowels. Else, her past medical/surgical history was non-significant. She denied any sensitivity to medicines.

Examination :

 She was conscious oriented and had stable vitals .Her physical examination revealed a non-tender enlarged goiter with negative Pemberton’s sign and no visible dilated vein, facial edema, or proptosis. Her systemic examination was normal

Course in the hospital:

           Keeping in view her obstructive symptoms she was planned for surgical removal of this large goiter.  Her hemoglobin levels were normal .She had normal  tests on Kidney and Liver functions . The thyroid ultrasound showed a multinodular goiter with retro-sternal extension with 2 right thyroid nodules, the largest measuring 6x4x3 cm and 1 left thyroid nodule measuring 5×4×4 cm. 

The thyroid functions T3 of 6.44 (normal 3.1–6.8), negative thyroid perox- idase and thyroglobulin antibody. 

           Levothyroxine 25 mcg was discontinued which she had been using intermittently  (Table.1) and was started on oral Tab Dexamethasone 8mg 8hrly  . Her shortness of breath improved with the dexamethasone but there were no changes in her snoring or fatigue. 

             On hospital day 5, she underwent a CT scan of the neck with contrast, which showed both thyroid lobes were enlarged, with the right lobe measuring 10×6.5×5 cm and left lobe measuring 12.5×7.5×6.5 cm. The gland reached the sub- mandibular region, with left lobe compression and shifting the oropharynx and the trachea to the right side with both lobes displaced. 

             After CT Scan her thyroid function tests showed features of Hyperthyroidism  induced by contrast. This phenomenon of  thyrotoxicosis precipitated by Iodine in the contrast  is called Jod-Basedow phenomenon 

She  had refractory hyperthyroidism despite being on a high dose of carbimazole for 3 weeks, propranolol and high-dose dexamethasone. 

She was then started on oral Tab Cholestyramine 4g twice daily and dexamethasone was tapered. She was carefully monitored  and on hospital day 43, she underwent total thyroidectomy .The final histopathology report revealed a multi-nodular goiter with no malignancy.

On hospital day 50, she was discharged home in stable condition with resolution of the shortness of breath and improvement of the snoring without any hoarseness of the voice post-operatively.