B73-18 Legionnaires’ Disease With Rhabdomyolysis, Acute Renal Failure, Dysarthria, and a Splenial Lesion in an Immunocompetent Patient

Abstract Introduction Legionnaires’ disease (LD) is a severe pneumonia caused by Legionella pneumophila. It classically presents with pneumonia accompanied by systemic findings such as diarrhea and hyponatremia. However, Legionella can cause rare extrapulmonary complications, including neurologic deficits and rhabdomyolysis with acute kidney injury (AKI). These extrapulmonary manifestations are uncommon, especially in immunocompetent hosts, and can lead to multi-organ failure if not recognized early. Case Description We report the case of an immunocompetent adult who presented with high fever, dysarthria, weakness, and respiratory distress. Chest imaging showed extensive consolidation consistent with severe pneumonia. Notably, the patient had marked dysarthria on examination, accompanied by areflexia in the lower extremities. Brain MRI revealed a suspected reversible lesion in the splenium of the corpus callosum, consistent with mild encephalopathy with reversible splenial lesion (MERS). This finding is rare—only 16 cases of Legionella-associated MERS were reported in a Japanese literature review (Kageyama et al. 2022). Laboratory tests indicated rhabdomyolysis (creatine phosphokinase approximately 5,100 U/L) and anuric acute kidney injury, with creatinine peaking at 11.6 mg/dL (baseline 1.1 mg/dL prior to admission). Despite aggressive fluid resuscitation, renal function deteriorated, requiring dialysis. A Legionella urinary antigen test was positive, confirming Legionnaires’ disease. He was treated with azithromycin and ICU supportive care, including continuous renal replacement therapy. During the hospital course, his pneumonia resolved, his speech significantly improved, and his renal function recovered—allowing discontinuation of dialysis by discharge. Discussion This case highlights a rare but increasingly recognized constellation of LD complications involving the neurologic, muscular, and renal systems. Similar cases have been documented in immunocompromised hosts (e.g., El Sharu et al. 2024), demonstrating that Legionella pneumonia can present with focal neurologic deficits due to transient corpus callosum lesions, alongside severe rhabdomyolysis and acute kidney injury. A 2019 review by Soni et al. emphasized that clinicians should be cognizant of the triad of pneumonia, rhabdomyolysis, and acute renal failure, as delayed recognition and treatment significantly increase mortality. Our case underscores the importance of early identification of extrapulmonary manifestations of Legionella in otherwise healthy patients, especially when neurologic manifestations can lead to unnecessary workup and delays in appropriate treatment. Timely diagnosis and multidisciplinary supportive care involving critical care, neurology, and nephrology were crucial for our patient’s recovery. Clinicians should maintain a high index of suspicion for Legionella in any severe pneumonia with unexplained neurologic or renal involvement to ensure early appropriate therapy and improved outcomes. This abstract is funded by: None