63 year old gentleman, admitted in Nov 2018. Feeling generally unwell, decreased appetite, lethargy and poor mobility. Known lung cancer (diagnosed January 2018) On Immunotherapy last received in October 2018CT scan (September 2018) after 4 cycles of Pembrolizumabexcellent response to treatment. Routine blood tests were normal apart from a raised CRP at 551 and white cell count. A random cortisol level was done and found to be low at 135. Blood, urine, sputum and stool cultures were all negative. He was commenced on intravenous antibiotics for sepsis but had no clinical improvement after 48 h. Discussed with oncology team who advised a CT scan of head, thorax, abdomen, pelvis. This was done and revealed no evidence of disease progression. Advice was then given to commence patient on Prednisolone 1 mg/kg. There was a clinical and physical improvement in the patient with a couple of days. Patient was discharged home with oncology and endocrine follow up with advice on tapering steroid dose.
Discussion: Potential for immunomodulation to result in an increased incidence of autoimmune disease against endocrine organs. Agents are directed against immune check point molecules such as CTLA-4 or PD-1 and these modulate T cell response to malignancy- enhancing activity and proliferation leading to immune related adverse events. Pembrolizumab is anti-PD-1. Caused by a type II hypersensitivity reaction resulting in hypophysitis. Screen for other causes of pituitary dysfunction and hormone profile assessment. ACTH/cortisol measurements low. Secondary hypothyroidism low TSH & FT4. Secondary hypogonadism. Growth hormone axis is spared. With emerging immunotherapy use, awareness of drug related adverse effects is important. Pituitary hormone profile should be appropriately monitored throughout immunotherapy and treatment instituted soon. Physicians should be aware and patients should be educated to notify symptoms promptly. A joint pathway of surveillance with oncologists is currently in process.