Key points are not available for this paper at this time.
Abstract Disclosure: L. Escano Volquez: None. P. Desai: None. Pembrolizumab is an immune check-point inhibitor that blocks the PD1 receptor and is currently used in the treatment of a vast variety of malignancies. Despite adrenal insufficiency (AI) already being documented as a rare but potential side effect, its diagnosis is usually delayed due to vague presentation, increasing the risk of deleterious outcomes. We present a case of secondary AI while on pembrolizumab in which diagnosis was delayed due to unspecific clinical picture.This is a 66-year-old male who presented to the hospital with decreased appetite, nausea and generalized weakness. Patient was seen a month prior with similar symptoms which were thought to be secondary to poor oral intake in the setting of underlying malignancy. Medical history remarkable for squamous cell carcinoma of the skin with recent lung metastasis for which he was started on pembrolizumab a year ago. On arrival to the emergency department, patient was hypertensive with BP 144/68 mmHg, HR 88, and RR 15. Orthostatic vitals were positive. Physical examination otherwise unremarkable. Laboratory tests revealed mild hypernatremia of 147, potassium of 4.7, chloride 108, HCO3 18, anion gap 21, BUN 33, elevated creatinine 1.62 and elevated beta-hydroxybutyrate 5.4. EKG revealed sinus rhythm. Patient was admitted for further evaluation of orthostasis and starvation ketosis. Initial management included IV fluids and Midodrine. However, patient continued to have episodes of orthostatic hypotension. Lack of improvement of symptoms led to further workup which revealed low AM cortisol of 1.0 and a low ACTH level 3.0 pg/ml, concerning for secondary adrenal insufficiency. Patient was administered Solu-Medrol 40 mg IV before being transitioned to a daily hydrocortisone regimen with subsequent improvement of symptoms. Pembrolizumab induced AI is a very rare event. It is estimated that the incidence approaches 1% and symptoms can develop at any time throughout treatment. Despite its low incidence, it can be life-threatening if not diagnosed and treated promptly. However, given its very heterogeneous and vague clinical presentation, a prompt diagnosis can be difficult. The clinical course of our patient and subsequent resolution of symptoms after appropriate treatment was started, supports the diagnosis of pembrolizumab induced adrenal insufficiency after a year of initiating treatment. This patient had prior hospitalizations and office visits with symptoms that are usually already present in individuals with underlying malignancy, which resulted in underestimation of his symptoms. This case highlights the importance of always considering AI as a potential adverse effect of immune check-point inhibitors. This will ensure a prompt diagnosis and treatment of an endocrine disorder that could otherwise lead to deleterious outcomes if left untreated. Presentation: 6/1/2024
Volquez et al. (Tue,) studied this question.