Case Summary: by Emma Hooijberg

Signalment and history• Border Collie, neutered male, 2 years old• generally healthy, used for agility, lives with 2

other dogs• history of mild intermittent tonsillitis,

improves after amoxicillin treatment• developed small hernia and abscess post-

castration, resolved

Signalment and history

• presented with history of intermittent decreased habitus and inappetance of 1 week duration. vomited once

• dog seen by referring vet, found to have fever (40.3C), treated with meloxicam and amoxicillin

• presented to outpatients clinic of university hospital as no improvement

Clinical examination

• body temp 39.3C, small mass in area of stomach/ cranial abdomen

• adominal ultrasound – non-obstructive gastric foreign body – 2 rubber toys removed via gastroscopy 2 days ago.

• dog treated with intravenous fluids and further amoxicillin

• fever continued for the first 4 days, last 2 days resolved without anti-inflammatory therapy, habitus and appetite good

Laboratory findings

• five blood samples taken over the last 6 days since presentation:• WBC ranging from 0.7-1.4 x109/L, initial downward

trend, today improved from 0.7 x109/L to 1.2 x109/L. (RI 6.0-15.0)

• neutrophil count: 0.073-0.24 x109/L, slight improvement last 2 days

• in blood smear: occasional segmented and band neuts, reactive lymphocytes, reactive monocytes

• thrombocyte count reduced (around 80 x109/L)

• mild normocytic normochromic anemia (Hct around 30%), no reticulocytes measured. Mild polychromasie, anisocytosis, schistocytosis and poikilocytosis on blood smear

• bone marrow ( 2 days ago): hypercellular• hyperplasia of megakaryocytes with increase in immature forms• M:E ratio 4:1

• myeloblasts 13%, promyel/myelocytes 40%, metam/band/segm 47% - ie left shifted

• rubriblasts 7%, pro/rubricytes 38%, metarubr 54%

• plasma cells 2% of ANC, although in some areas make up around 5-10% of the cells – ie focally increased

• macrophages, lymphocytes around 2% of ANC• morphology of all cells normal

• In summary: severe peripheral leukopenia, bone marrow myeloid hyperplasia with left shift

Differential diagnoses • acute and transient bone marrow injury

• Parvo? - Ag test negative, awaiting results of PCR• idiosyncratic drug reaction? – meloxicam? rubber toys? other (none in

history despite repeated enquiries)• Border Collie related diseases

• Cobalamin deficiency – neutropenia not usually so severe, no dysplastic erythroid changes – awaiting serum cobalamin measurement

• Trapped Neutrophil Syndrome – usually experience problems when young, most euthanased < 1year. Unfortunately no previous blood samples. Considering genetic testing

• Cyclic hematopoiesis – not a grey Collie, too old• Immune-mediated neutropenia (but all leukocytes plus

thrombocytes low)

• our questions!• in the case of a bone marrow injury with apparent

recovery based on the BM cytology, how long should it take for these myeloid cells to enter the blood and for the leukopenia to resolve? 2 days ago the bone marrow looked ready to explode with nice healthy helpful-looking neutrophils….are we too impatient?

• any other ideas, additions or comments on our DD list?• since the dog is clinically doing well, the clinicians are in

a patient mood, but there are whispers of prednisolone treatment if all tests come back negative

Answers received

• Leukocytes should normalized by 3-4 days• AB-Testing difficult – however try steroids• Give parenteral Cobalamin for a couple of days

– WBC should turn to normal within a couple of days.

• Try flow-cytrometric detection of PLT autoantibodies;

Further Test results + Clinical course

• Cobalamin concentration WRI• Gen-Test for Leukocyte-Trapping: negative• Ab against Neutrophils: negative

• Waxing and waning course of TWBC and neutrophils; dog only on antibiotics – no steroids!

• Splenic mass was detected on US• FNA: inconclusive, haematoma slight inflammatory

infiltration

• Splenectomy on 22nd of May because the mass seemed to grow

• Spontaneous increase of TWBC and Neutrophils on d1 post OP but then a new decline, but not as low as at the beginning

• See Graphs• Histopathology of splenic mass:• High grade splenic hyperaemia• Hematoma in organisation• No evidence of immune mediated disease

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Our Questions

• Could it be cyclic leukopoesis?• Has the course of MPXI any meaning?