Introduction: Haemophagocytic lymphohistiocytosis (HLH) and acute necrotizing encephalopathy of childhood (ANEC) are life-threatening conditions with severe consequences and high mortality. Prompt recognition and treatment is essential. While systemic HLH is well known, central nervous system HLH is not. The association of these diseases has been rarely observed. We report 3 such cases.

Methods: The 3 cases were evaluated with a detailed history, examination, and investigations.

Results: Case-1: 6-year-old girl presented with fever, seizures, and altered sensorium. MRI (Magnetic Resonance Imaging) brain-focal nodular hyperintensities in cerebellum, T2/FLAIR (Fluid-Attenuated Inversion Recovery) hyperintensities in external capsule, cortex, pons, and bulky thalami. She had hypo-fibrinogenaemia, hyper-ferritinaemia, and haemophagocytes and histiocytes in bone-marrow aspirate. (Fig-1)

Case-2: 8-year-old girl had fever, seizures, and altered sensorium for 3 days. MRI on day-2 of illness was normal apart from contrast enhancement in dorsal pons. MRI on day-3: T2/FLAIR hyperintensities in hippocampi, external capsule, dorsal pons, and thalami with donut sign on diffusion-weighted imaging. Ferritin was 40466 ng/mL. (Fig-2)

Case-3: 6-year-old girl had fever, seizures, and altered sensorium. MRI- T2/FLAIR hyperintensities in cerebellum, brainstem, and thalami, with donut sign. She had hyperferritinaemia, hypertriglyceridaemia, hypofibrinogenaemia, and bicytopenia. (Fig-3)

ANE-MRI scoring was 2 for case-1, and 3 for cases 2 and 3.

Conclusion: Co-occurrence or overlap of ANEC and CNS HLH can occur. Awareness of this entity is important for diagnosis, early referral, and institution of immunomodulatory therapy. Early Tocilizumab within 48 hours gives a good outcome. MRI plays a key role in diagnosis. Both conditions share a common patho-mechanism.

Thanuja Basavanagowda
Jawaharlal Nehru Medical College
India

Mahesh Kamate
Jawaharlal Nehru Medical College
India

Ashwin Sardesai
Jawaharalal Nehru Medical College
India