Introduction: Hypothyroid patients with failure to take/absorb oral levothyroxine might require intravenous levothyroxine. IV levothyroxine is neither licensed nor available in UK. It has to be imported (with special request), and is unexpectedly costly. IV liothyronine has shorter duration of action, need 23 injections/day, and exhibits sudden surges increasing risk of angina/arrhythmia. Moreover, IV liothyronine is much more expensive than IV levothyroxine.
Case report: 50 year old lady presented to endocrine OPD with sub-optimal TFTs. She is hypothyroid since 2008 (previously well controlled). She has been suffering from intractable vomiting and abdominal pain since 2012. Diagnosed to have gastroparesis (2013) and slow colonic transit with obstructive defecation (2014). Though initially responded well to gastric pacemaker (2014), it was removed due to persistent pain, with resultant deterioration of vomiting after any oral intake. Developed metoclopramide induced hyperprolactinemia/galactorrhoea (2014), which subsided on withdrawal. Diagnosed to have myenteric ganglionitis with malabsorption and was put on long term total parenteral nutrition (2014), after a failed feeding jejunostomy trial. On 11 March 2019, TSH was 13 mU/l (0.24.5) and FT4 was 10.4 pmol/l (1123). She was on 400 mcg of levothyroxine (20 ml solution spread out during the day in 2 ml sips), colecalciferol 20 000 units (alternate days), and vitamin B12 (injection). In view of sub-optimal TFTs, intravenous levothyroxine was started as 100 mcg once weekly in 100 ml 0.9% sodium chloride over 30 min (day unit, cardiac monitoring with TFT prior to each dosing). IV levothyroxine was increased in 100 mcg increments to 200 mcg twice weekly. Oral levothyroxine suspension weaned off in few weeks. IV liothyronine was not considered due to reasons described (introduction). On 8 April 2019, TSH was 4.5 mU/l and FT4 12 pmol/l. Found to have osteoporosis which was treated with annual intravenous zolendronic acid injections.
Conclusion: This case highlights the various hurdles involved in the treatment of hypothyroid patients with malabsorption.