Transcript Document

CASE A
HISTORICAL FINDINGS AND PRESENTING SIGNS
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4 year-old Warmblood gelding used for pleasure riding (455 kg)
No history of previous illness
Regular deworming and vaccination program. Teeth checked once every a year
by a local equine dentist
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Vaccinated against influenza and EHV-4 12 days prior to presentation and
developed a fever (40.6 ˚C), mild colic and anorexia two days later
• The horse was treated with NSAIDs by the referring veterinarian and the colic
resolved; however the horse remained inappetent, intermittently pyrexic and
began to develop oedema in all four legs
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CLINICAL FINDINGS (on day of presentation)
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On presentation, the horse was depressed and in moderate body
condition (CS 5/9)
HR 52 bpm, RR 18 bpm, T 39.6 ˚C
On cardiac auscultation, heart rhythm was normal and no murmurs
could be heard
On respiratory auscultation, normal tracheobronchial sounds were
heard over the large airways and there was no evidence of wheezes or
crackles
On abdominal auscultation, gut sounds were decreased in all four
quadrants
Pitting oedema was evident in all four legs, the muzzle and the ventral
aspect of the thorax
Digital pulses were palpable but not bounding. The feet were cool on
palpation and the horse was able to walk comfortably
No abnormalities were identified on transrectal palpation
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CLINICAL FINDINGS (on day of presentation)
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The mucous membranes were pale pink with petechial and ecchymotic
haemorrhages evident on the gingiva, nasal mucosa and third eyelid
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CLINICAL FINDINGS (on day of presentation)
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It was also noted that the horse was bleeding excessively from the
jugular venipuncture site
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When you enter the examination room, you will be asked to
1. Identify and interpret the clinical problems using information obtained
from the history and physical examination
2. Formulate a list of differential diagnoses using your problem list and be
able to justify your choices
3. Comment on how you would further differentiate between the main
differential diagnoses
From this stage onwards, further information (clinical and
laboratory data) will be provided either on your request or
automatically. You will be asked to comment on this data.
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PERITONEAL FLUID ANALYSIS
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PERITONEAL FLUID ANALYSIS
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RESULTS OF OTHER ANCILLIARY
DIAGNOSTICS
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PERITONEAL FLUID CULTURE: pure growth of Streptococcus equi
sub species Zooepidemicus
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SKIN BIOPSY: no evidence of leukocytoclastic vasculitis
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PLATELET COUNT: thrombocytopenia (31.1 x 109/l)
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COAGULATION PROFILE: PT; PTT; and activated clotting time
normal. Plasma AT III concentration normal. No FDPs
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ANTIPLATELET ANTIBODY TEST: normal
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SEROLOGY: Coggins negative for EIA
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PCR: negative for Anaplasma phagocytophilum and EVA
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LABORATORY DATA (on day of presentation)
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CASE PROGRESSION (on day 2)
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The horse was treated with intravenous ringer’s acetate; flunixin
meglumine (1.1 mg/kg IV SID); penicillin (22000 iu/kg QID IV) and
gentamicin (6.6.mg/kg IV SID)
Administration of platelet rich plasma was considered at this point but it
was decided to wait for 24 hours and see if the horse had responded to
the initial treatments, as the horse was not in immediate danger of fatal
haemorrhage.
On day 2, the horse was very depressed and remained inappetant
HR 52 bpm, RR 24 bpm, Temp 39.4 deg C
A repeat CBC was obtained
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LABORATORY DATA (on day 2)
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BONE MARROW ASPIRATE
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Bone marrow aspirates from the sternum were haemodilute and did not
contain spicules, megakaryocytes, polychromasia or appreciable iron
reserves. The differential cell count was composed of 42% lymphoid
cells, 5% differentiated myeloid cells, 24% erythroid cells
(predominantly rubricytes and metarubricytes) and 29% blast cells with
occasional plasma cells.
The low cellularity of the specimen meant that an accurate M:E ratio
could not be calculated
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DIAGNOSIS
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T or B cell markers (CD3, CD79a) were not detected on
immunohistochemical analysis of the surface of the blast cells, ruling
out lymphoid leukaemia
There was no positive result to lysozyme (muramidase) which identifies
monocytes and neutrophils, ruling out granulocytic leukaemia or
monocytic leukaemia.
The tumour cells were therefore most likely undifferentiated round cells
(probably precursor cells from the monocytic or myelocyte lines)
The clinicopathological diagnosis was MALIGNANT
MYELOMONOCYTIC LEUKAEMIA (initially aleukaemic)
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