Clinical findings and treatment
On admission, a clinical assessment of the horse found that despite
having poor body condition ( BCS 4/9), the TPR values were within
normal limits, the mucous membranes were normal, and the submandibular
lymph nodes were not enlarged. Hematological and biochemical parameters
were also found to be completely normal. However the horse was extremely
pruritic and presented with generalised “moth-eaten” alopecia, with
scabs containing blood (Fig. 2) over some of the alopecic areas. The
lesions were however superficial (Fig. 3 and 4). Additionally there was
no skin efflorescence observable to indicate the pruritus was caused by
a common skin disease. Skin smears and scrapings were performed and were
positive for Pantoea agglomerans , Staphylococcus
epidermidis , and aerobic spore-forming species. These pathogens were
discounted as being the primary source of the pathology and interpreted
as being a consequence of secondary infection. Additionally there was no
evidence of ectoparasites or fungal infection present. After skin
scraping samples were obtained, the horse was repeatedly bathed once
a day with Vetericyn Foam Care medicated shampoo, combined with
ketoconazole (Innovacyn Inc, California), but to no effect. The
parasitologist who was asked to examine the horse strongly suspected
hypersensitivity to the bite of Culicoides spp . 30 ml of Ancesol
(Chlorphenamine maleate, 10 mg/ml, Richter Pharma AG, Austria) was
administered IV for three days in a row, but also to no effect. Due to
the tail rubbing and the suddenly slightly increased eosinophils
(0.84x10ˆ9/l; RI 0.00-0.80x10ˆ9/l), a coprological examination was
performed, which was highly positive for Strongylus spp . The
horse was dewormed with a 5-day course of fenbendazole per os (Panacur;
Intervet International BV, The Netherlands) and on the sixth day
moxidectin with praziquantel (Equest pramox, Zoetis, Czech Republic) was
applied PO for 600 kg of BW. For psychogenic pruritus, amitriptyline
(Amitriptyline-Slovakofarma tbl flm 50x25 mg, Zentiva, as; The
Netherlands) was administered twice a day at a dose of 1-2 mg/kg which
had a mild calming effect lasting for a few hours after application, but
the pruritus was still present. To reduce the pathological effects of
stress and the medication administered, antiulcer therapy, 4 mg/kg of
omeprazole (Peptizole, Norbrook, Ireland) PO SID was introduced. After
the first week of the above-mentioned therapy, the pruritus was still
intense and did not respond to the therapy. Due to suspicion of atopic
dermatitis, prednisolone was administered for 10 days per os, initially
at a dose of 0.1 mg/kg once a day, increasing to to 1.5 mg/kg twice a
day, without effect. Topical therapy with mometasone-furoate (Elocom
ung; Organon, The Netherlands) was applied only once to the lesions,
however also without effect. Due to a secondary skin infection, the
patient was bathed with a 4% chlorhexyderm shampoo (Clorexyderm,
Industria Chimica Fine sri, Italy), which improved the pruritus only for
a few hours, but subsequently worsened to the extent that the horse bit
himself intensively and started to bleed from the self inflicted wounds
around the coronary bands and groin (Fig 6 and 8). The distal limbs were
subsequently bandaged to prevent further occurance. Sulfadiazine
ointment (Ialugen, IBSA Group, Switzerland) was applied to the wounds
for skin softening and laser was applied to promote healing. At this
point there were also changes in the haematological examination; with an
increase in WBC (14.36x10ˆ9/l; RI4.9-11.10x10ˆ9/l) and NEU
(12.65x10ˆ9/l; RI 2.50-6.90 x10ˆ9/l).The secondary skin infection
worsened and the body temperature increased in one evening to 39.6°C,
however the pulse rate remained normal. Skin smears and scrapings were
performed again and were positive for Bacillus spp .,Dermatophilus congolensis and Staphylococcus aureus.Mycological examination was positive for the species Alternaria
spp . and Candida albicans . These findings were considered again
to be secondary infection due to skin trauma, but at this time
trimethoprim-sulfate (Norodine 45g; Norbrook, Ireland) PO BID for 7 days
was started and the WBC and NEU returned to normal values. Serological
tests were negative for Culicoides saliva hypersensitivity.
Because paraneoplastic pruritus was suspected, an ultrasonographic
examination of the thorax and abdominal cavity was performed, but did
not yield any pathological findings. Rectal examination was negative for
a mass. Generally the horse continued to have an appetite, but on
occasion was not interested in food especially during episodes of
nervousness due to pruritus. On dental examination a few lesions around
the incisors were observed as well as sharp edges on the premolars and
molars, which were likely the cause of the erosions on the buccal
mucosa. The lesions near the incisors were small and it is impossible to
deduce if they could have been a clinical sign or if they arose as
a consequence of self-mutilation and rubbing of the nose against the
walls. After two weeks of hospitalization, the horse started to loose
body condition to 3/9 BCS. During the third week, the hematological
profile showed a decrease in lymphocytes (0.91x10ˆ9/l; RI 1.50-5.10
x10ˆ9/l) and monocytes (0.15x10ˆ9/l; RI 0.20-0.60x10ˆ9/l) and at the
same time a slight swelling in the preputial area was noticed. At the
end of the third week of hospitalization, the horse began to clinically
deteriorate over the course of one evening. The horse became nervous,
started kicking at the abdomen, and became aggressively pruritic. On
clinical exam it was observed that the pulse rate had increased to 60
beats per minute, while the body temperature remained normal.
Additionally the right submandibular lymph node become slightly
oedematous, and the jugular veins were prominent. Hematological
examination showed an increased hematocrit/ PCV (48) despite the intake
of 30 liters of fluids per os and also a further decrease in lymphocytes
(0.77 x10ˆ9/l; RI 1.50-5.10 x10ˆ9/l) and monocytes (0.10x10ˆ9/l; RI
0.20-0.60x10ˆ9/l). Biochemical blood analysis values remained normal.
Blood lactate, haptoglobin, and SAA also stayed within normal values.
Rectal examination showed mild dehydration of the large colon, otherwise
there were no pathological findings. Ultrasonographic examination of the
abdominal cavity revealed an increase in free fluid and a change on the
ultrasonographic pattern of the spleen around the gastrosplenic vein
(Fig. 11). Ultrasonographic examination of the thoracic cavity showed
massive pleural effusion and secondary compressive atelectasis of the
lungs (Fig. 12). It was deduced that the increased heart rate was as a
consequence of compensation for this condition. An ultrasonographic
examination of the mediastinal nodes was attempted, but no mass was
identified ultrasonographically. Thoracocentesis was performed
bilaterally, due to a non-fenestrated mediastinum, from which 12 liters
of serosanguinous fluid was drained from the thorax. The pulse rate did
not however drop after drainage of the chest chavity or after analgesia
was provided with flunixin 1.1 mg/kg IV (Flunixin, Norbrook, Ireland).
The drained fluid was sent to the laboratory for analysis (Table 1). A
cytological examination was concurrently performed as a tumour within
the thoracic cavity was highly suspected. The sample contained large
numbers of small lymphocytes with round nuclei and reduced cytoplasm.
The findings of numerous poorly differentiated anaplastic cells with
marked macrokaryolysis and numerous nuclei confirmed the presence of a
lymphoblastic process. On the second day after thoracentesis, the
patient developed a fever of 38.9 °C (the second time during
hospitalization). The pulse rate increased to 74 beats per minute and
anorexia was evident for the first time. A repeated ultrasonographic
examination of the thorax confirmed a massive pleural effusion, and due
to the poor prognosis, the horse was humanely euthanized and subjected
to a post-mortem examination.