Atypical Late-onset Presentation of Secondary Hemophagocytic Lymphohistiocytosis with Central Nervous System Symptoms: A Case Report

REPORTin up to 30-73% of HLH cases and significantly contributes to morbidity and mortality.Prompt recognition and early initiation of immunosuppressive therapy are essential to prevent irreversible neurological damage. 6iven the nonspecific nature of the symptoms and the absence of classic findings in some cases, a high index of clinical suspicion is required-especially in patients presenting with fever, altered IntroductIonHemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory condition characterized by excessive immune activation involving cytotoxic T lymphocytes and natural killer (NK) cells.Clinically, it presents with persistent fever, cytopenias, hepatosplenomegaly, and laboratory evidence of immune dysregulation, including elevated ferritin and transaminases. 1 The clinical spectrum can vary significantly-from transient, mild manifestations seen in routine infections to a fulminant syndrome associated with multiorgan failure, disseminated intravascular coagulation, and metabolic derangements. 2emophagocytic lymphohistiocytosis is broadly categorized into two types: (1) primary (familial), which is linked to genetic mutations affecting cytolytic pathways, and ( 2) secondary (acquired), which arises in the setting of infections, malignancies, autoimmune conditions, or other immune dysregulatory triggers. 3While primary HLH is more frequently seen in pediatric populations, secondary HLH is more common in adults and often underrecognized due to its nonspecific and variable presentation. 4he central nervous system (CNS) is a commonly involved site in HLH, and neurological manifestations may occur either alongside or, less frequently, in isolation from systemic features.Though not part of the HLH-2004 diagnostic criteria, CNS involvement such as encephalopathy, seizures, or focal deficits can be the initial presentation, particularly in adults. 5Involvement of the CNS occurs 1,2,