Introduction: Haemophagocyte lymphohistiocytosis (HLH) is a hematological disorder, autosomal recessive and in which there is benign proliferation of histiocytes with intense phagocytic activity of hematopoietic cells. The clinical features include fever, pancytopenia, coagulation disorders, liver dysfunction, the presence of histiocytes and haemophagocytes in the bone marrow, lymph nodes, spleen and liver. The nervous system is always involved and sooner or later patients develop a nervous system disorder with variable symptoms which may include irritability, disorders of consciousness, convulsions, ataxia, nystagmus or signs of intracranial hypertension.
Clinical case: Onset of the disease showing purely neurological features is rare. We therefore describe the case of an 8 month old baby with HLH with a purely neurological condition involving irritability, horizontal rapid eye movements and vertical saccadic movements of both eyes and focal convulsive seizures. Initial complementary examinations were normal, except for study of the CSF with a lowered protein level and cells (monocytes). Finding hepatosplenomegaly and pallor, together with the laboratory investigations, made it advisable to do a bone marrow punch biopsy to detect haemophagocytes which would be diagnostic of HLH. In spite of chemotherapy there was rapid neurological deterioration, with alterations of the white matter and hydrocephaly which required insertion of a ventriculo-peritoneal shunt. The patient died when he was 10 months old.
Conclusions: The cases of HLH in which cerebromeningeal disorders alone precede systemic symptoms are extremely rare. Hence the interest in reporting this case, so that it may be borne in mind in other cases of acute neurological onset. In this case initially there was encephalitis alone, but this was rapidly followed by systemic complications.