New-Onset Seizures and Acute Renal Failure: An Atypical and Severe Sarcoidosis Presentation

Sarcoidosis is a multisystem granulomatous disease with highly variable clinical expression.Although pulmonary involvement predominates, extrapulmonary presentations may be severe and diagnostically challenging, particularly in the absence of typical thoracic findings.This case report describes a male in his early 30s, with mild cognitive impairment, admitted with generalized tonic-clonic seizures and encephalopathy.Clinical, laboratory, imaging, and histopathological findings were retrospectively analyzed.The patient presented with a three-month history of progressive constitutional symptoms, including weight loss, insomnia, xerosis, and lower limb edema.On admission, he developed recurrent seizures requiring sedation and mechanical ventilation.Investigation revealed severe metabolic acidosis, acute kidney injury, and pancytopenia.Neuroimaging showed nonspecific white matter changes, and electroencephalogram demonstrated epileptiform activity.Thoracoabdominal computed tomography identified splenomegaly, lymphadenopathy, and hepatic and renal lesions, without typical pulmonary involvement.Cerebrospinal fluid analysis was non-inflammatory.Further workup showed lymphocytic alveolitis with an elevated CD4/CD8 ratio and increased serum angiotensin-converting enzyme levels.Renal biopsy demonstrated granulomatous interstitial nephritis, establishing the diagnosis of systemic sarcoidosis with multiorgan involvement.High-dose corticosteroid therapy resulted in rapid clinical improvement, with recovery of renal function and resolution of encephalopathy.Temporary renal replacement therapy was required.Seizures were effectively controlled with levetiracetam.This case illustrates a rare and severe presentation of sarcoidosis, in which life-threatening neurological and renal involvement occurred in the absence of classic pulmonary features.It emphasizes the need for early recognition of atypical multisystem presentations and the pivotal role of histological confirmation.Prompt immunosuppressive therapy can be life-saving and lead to significant clinical recovery.