LAUSR

© BMJ Publishing Group Limited 2022. No commercial reuse. See rights and permissions. Published by BMJ. DESCRIPTION A previously healthy teenage boy presented to an outside emergency department for oral bleeding and worsening headache. Examination revealed diffuse petechia and periorbital ecchymosis, which began 3 days before admission. Neurological examination at presentation was normal. CT of the head revealed a right temporal haemorrhagic mass with a 3 cm midline shift (figure 1A). Subsequent MRI demonstrated a large right temporal parenchymal haemorrhage (figure 1B–F) with surrounding oedema and without evidence of an underlying vascular malformation on magnetic resonance angiography (figure 1G). Complete blood count demonstrated leucocytosis with a white cell count of 596x10/L with 97% other cells. This was accompanied by anaemia (haemoglobin level, 76 g/L; mean corpuscular volume, 90 fL) and thrombocytopenia (platelet count, 8 x10/L). The patient’s uric acid and lactate dehydrogenase levels were elevated to 10.9 mg/dL and >10 750 U/L, respectively. Ddimer of 5.98 μg/mL and international normalised ratio of 1.57 revealed a coagulopathy. His presentation was consistent with leucostasis, most often seen in patients with acute myelogenous leukaemia. However, flow cytometry confirmed a diagnosis of Tcell acute lymphoblastic leukaemia (TALL) and following successful leucapheresis, he began induction chemotherapy. One year postdiagnosis, the patient remains on therapy without disease progression and a normal neurological examination. Acute lymphoblastic leukaemia (ALL) is the most common malignancy in the paediatric population, and TALL accounts for 12%–15% of newly diagnosed cases. While TALL is a heterogeneous disease with diverse clinical and molecular features, hyperleucocytosis and central nervous system (CNS) involvement are common components of its clinical profile. 3 The first manifestation of ALL is usually nonspecific, and there have been only a few reports of intracerebral haemorrhage (ICH) as an initial presentation of acute leukaemia in adolescents. To our knowledge, three out of six of those reports involved fatal ICH. Haemorrhage is the second most common cause of mortality in acute leukaemia, and associated risk factors of fatal ICH include leucocytosis, thrombocytopenia and prolonged prothrombin time. 11 The location and type of ICH may also influence prognostic prediction and overall outcomes, which neuroimaging can reveal. Hyperleucocytosis and thrombocytopenia, as demonstrated by our case, are significant risk factors for haemorrhagic diathesis that coincides with ICH. Leucostasis induced by hyperleucocytosis can lead to the obstruction of small cerebral veins and microchannels. Further vascular wall damage may occur from proliferation and local invasion of leukaemic cells. 15 Products from increased nucleoprotein catabolism, indicated by marked uric acid levels in patients with acute leukaemia, may act as vasodilators and perpetuate CNS bleeding. Additional risk factors of ICH development with acute leukaemia include the presence of a blast crisis, disseminated intravascular coagulation, platelet dysfunction, coagulation factor deficiency, increased fibrinolysis, anticoagulant therapy, hypoxia and sepsis. 16