Anaplasmosis with associated haemophagocytic lymphohistiocytosis

Abstract

Anaplasmosis with associated haemophagocytic lymphohistiocytosisA 76-year-old man presented with fever, altered mental status, malaise and respiratory distress. His initial blood count showed a platelet count of 60 9 10 9 /l, white blood cell count of 5Á5 9 10 9 /l, neutrophil count of 0Á9 9 10 9 /l and haemoglobin concentration of 144 g/l. A computed tomography scan showed hepatomegaly without splenomegaly. Ferritin was significantly elevated at 35 531 lg/l. His clinical status rapidly worsened, and he developed respiratory failure, requiring intubation, and acute kidney injury, with an elevated creatinine of 88 lmol/l and blood urea nitrogen of 35 mg/dl (normal range 6-24 mg/dl). The clinical picture and laboratory findings suggested the possibility of haemophagocytic lymphohistiocytosis (HLH), and a broad workup was initiated, including a bone marrow biopsy, for further evaluation and to attempt to identify any inciting factors. The peripheral blood film showed multiple neutrophils with basophilic intracytoplasmic inclusions strongly suggestive of the morulae seen with Anaplasma phagocytophilum infection (top images, 9100 objective). Further, the bone marrow aspirate identified increased histiocytes and with occasional haemophagocytic cells (bottom images, 9100). Additional tests showed triglycerides of 2Á1 mmol/l, soluble interleukin 2 level of 4912 µ/ml (normal range 137-838 µ/ml) and decreased NK-cell activity, diagnostic criteria for HLH being met. Anaplasma PCR was performed and was positive, confirming the diagnosis of anaplasmosis. The patient was started on intravenous doxycycline, resulting in rapid improvement of his clinical status with subsequent extubation, and he was eventually discharged clinically well.Anaplasmosis has rarely been reported in association with HLH. Here, the inability to obtain a detailed clinical history to assess for tick exposure and the prominent HLH-related features could have masked the underlying diagnosis. This case highlights the importance of recognising the classic peripheral blood findings of anaplasmosis, this being as a potential underlying cause of HLH.

Hemophagocytic Lymphohistiocytosis (HLH) in Patients with Tick-Borne Illness: A Scoping Review of 98 Cases

“…The following were excluded from the analysis: articles published in languages other than English; case reports not providing an appropriate amount of information, or where the diagnosis was not certain; and those reporting non-human subjects. The final number of articles included was 69, which resulted in a total number of 98 patients ( Figure 1 ) [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , ...…”

Severe Fatal ARDS Due to Untreated Human Granulocytic Anaplasmosis in a 67-Year-Old Man: A Case Report

“…The pathophysiology of ARDS due to HGA is incompletely understood, but is likely due to an exaggerated inflammatory response due to infection of neutrophils [23]. Dysregulated inflammatory reaction also could explain clinical and laboratory features of HLH, and macrophage activation syndrome is reported in patients with HGA [36][37][38][39].…”