Page 1037 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

1012 CHAPTER 9

VetBooks.ir Severely anaemic animals may benefit from intranasal Diagnosis
Signs or history of overt haemorrhage for an extended
oxygen therapy. Affected animals should be rested if
period of time are supportive. Characteristic find-
anaemia is present.
ings on a CBC include a non-regenerative or poorly
Prognosis regenerative microcytic, hypochromic anaemia.
The prognosis is favourable if blood loss is not life- RBCs on the smear have an increased amount of
threatening or can be stopped prior to the develop- central pallor due to insufficient haemoglobin pro-
ment of hypovolaemic shock. duction. Fragmented red cells may be observed, and
thrombocytosis may be present. Documentation
CHRONIC HAEMORRHAGE of decreased iron stores by measuring serum iron
and ferritin or examining bone marrow for iron
Definition/overview storage, is supportive. Gastroscopy should be per-
Chronic haemorrhage is bleeding that occurs slowly formed to detect gastric tumours. Care should be
over an extended period of time, often several weeks taken not to overestimate the role of gastric ulcers,
to months. The presence of bleeding may not be if present, because gastric ulcers are an uncommon
apparent until the horse begins to exhibit clinical cause of anaemia in horses. Faeces should be evalu-
signs related to worsening anaemia. Identification of ated for the presence of occult blood and parasites.
the source of bleeding may be difficult ante-mortem. Examination for cutaneous ectoparasites should also
be performed.
Aetiology/pathophysiology
Causes of chronic haemorrhage include gastric Management
squamous cell carcinoma (SCC), ulceration from Resolution of the underlying cause of bleeding is
non-steroidal anti-inflammatory drug (NSAID) integral to resolution of the anaemia. Concurrent
therapy, blood-sucking parasites and coagulopa- oral or parenteral iron supplementation may help
thies. Chronic blood loss from severe gastric ulcer- replace iron needed for erythropoiesis in the
ation is uncommon in adult horses but may be interim. Blood transfusion should be considered if
observed in foals. clinical signs of anaemia (tachycardia, tachyponea,
At first, the bone marrow responds appropriately pale mucous membranes, weakness) are present.
to the RBC deficit with erythrocytic hyperplasia.
As haemorrhage continues, iron stores necessary for Prognosis
efficient haemoglobin production become limited The prognosis is poor if the cause of bleeding is a
and the animal enters a state of iron-limiting eryth- tumour but is more favourable if parasites can be
ropoiesis with insufficient replacement of lost cells. treated successfully or NSAIDs can be discontinued.
Eventually, iron stores become depleted and a non-
regenerative iron deficiency anaemia develops. INHERITED BLEEDING DISORDERS

Clinical presentation Definition/overview
Horses may be weak and lethargic, with mucosal Inherited deficiencies of haemostasis are rare in
pallor if the anaemia is severe. Tarry faeces or hae- horses. Prekallikrein deficiency in miniature and
matochezia may be evident. Dermatological lesions Belgian horses, factor VIII deficiency (haemophilia
may exist if external parasites are the source of blood A), factor IX deficiency (haemophilia B), factor XI
loss. If a coagulopathy is present, petechial, mucosal deficiency and von Willebrand disease have been
or body cavity haemorrhage may be identified. described in horses.

Differential diagnosis Aetiology/pathophysiology
Other causes of non-regenerative anaemia, such as These diseases occur as a result of inheritance of
anaemia of inflammatory disease and primary bone a specific genetic defect that produces partial or
marrow disorders, need to be considered. absolute deficiency of the protein. Prekallikrein