P126 – 2738: Non-thyroidal illness associated with aseptic meningitis in a child

Background Non-thyroidal illness syndrome (NITS) or sick euthyroid syndrome is a maladaptive state of abnormal thyroid hormone function in critically ill patients. Previous studies have demonstrated the presence of this condition in children with severe sepsis eg meningococcal septicaemia and after cardiac surgery. We report the first case of non-thyroidal illness syndrome in a child with aseptic meningitis. Case presentation A previously well 11 year old child presented with fever and cough. He was started on oral antibiotics for presumed chest infection. A week later he developed headache, vomiting and increased daytime somnolence; features consistent with encephalopathy. He had mild neck stiffness and fluctuating GCS of 9–10. He was notably bradycardic, (heart rate 38bpm, sinus rhythm) with poor urine output. Lumbar puncture showed 30 polymorphs, no organisms on Gram-Stain or culture. His viral PCR was negative. A brain MRI with contrast was normal. Further investigations revealed a low TSH (0.32 mU/L), low fT3 (2 pmol/L). Fasting cortisol level was normal. NMDA and VGKC antibodies were negative. He was diagnosed with a non-thyroidal illness syndrome with aseptic meningitis and managed conservatively. He was given IV antibiotics, fluid and calorie intake was optimised. Neurological status was closely monitored. His encephalopathy gradually improved as did the urine output, bradycardia and thyroid function. Discussion In severe sepsis, previously normal thyroid function may become suppressed. Studies comparing thyroid function in children suffering from bacterial and viral meningitis, have shown a more significant decrease in the levels of thyroid hormones (especially TSH and fT3) at the beginning of bacterial meningitis. Previous literature shows that early initiation of oral/enteral nutrition in these patients, improves thyroid hormone status without the need for replacement therapy. Paediatricians and paediatric neurologists need to be aware of this rare condition. Empirical treatment with corticosteroids or thyroid replacement therapy is not required.