Page 1064 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

H aemolymphatic system 1039

VetBooks.ir Management Aetiology/pathophysiology
Splenomegaly may be caused by obstruction of venous
The treatment plan depends on the cause and sever-
ity of the bleeding and the severity of the clinical
colon, right heart failure), acute splenitis, haemolytic
signs. Fluid therapy should be provided, particu- return (e.g. nephrosplenic entrapment of the large
larly if haemorrhagic shock is present. Intravenous anaemia, purpura haemorrhagica, infiltrative disease
administration of a balanced electrolyte solution (i.e. neoplasia), grass sickness or infarction. Cellular
should be started initially at a volume of three times infiltration, congestion and inflammation may result
the estimated blood loss. Hypertonic (5–7%) saline in an increase in splenic size.
may be useful initially, particularly when large vol-
umes of fluids are not readily available. Hypertonic Clinical presentation
saline must be followed by administration of iso- The clinical signs are highly variable, depending
tonic fluids. Synthetic colloids may inhibit platelet on the cause. They may range from inapparent to
aggregation and alter coagulation and should be signs of colic, anorexia, icterus, depression, weight
avoided. A blood transfusion should be considered loss, pyrexia, ventral oedema and tachycardia. In
with signs of shock (i.e. heart rate >80 bpm, weak- general, obstruction of venous return by left colon
ness, severe hypotension) or if the PCV is <0.2 l/l displacement will be manifested as acute colic. Acute
(20%) with acute bleeding. Alternatively, bovine- splenitis will cause fever, mild colic and potentially
source polymerised haemoglobin products (i.e. tachycardia. Signs of haemolytic anaemia have been
Oxyglobin™, 7.5–10 ml/kg i/v at up to 10 ml/kg/ discussed earlier in this chapter. Splenic neoplasia is
hour) may be used; however, this is expensive in discussed below.
an adult horse. Surgical intervention may need to
be considered with severe, uncontrolled bleeding, Differential diagnosis
but in such cases, horses are usually an anaesthetic A wide range of differential diagnoses must be con-
risk. Emergency stabilisation must be performed sidered, depending on the cause of the splenomegaly.
prior to surgery. A variety of methods of decreas-
ing intra-abdominal haemorrhage have been Diagnosis
attempted, including administration of venodila- Depending on the clinical presentation, an evalu-
tory drugs, antifibrinolytic agents (aminocaproic ation for localised or systemic infection, neoplasia,
acid), opioid antagonists (naloxone) and buffered haemolytic anaemia and colic should be performed.
formalin. There is little to no objective evidence Haematology results are highly variable, depend-
supporting these treatments and each has potential ing on the cause. Ultrasonography is used to assess
adverse effects. splenic size and architecture. Palpation p/r should
be performed to assess spleen size, location and tex-
Prognosis ture. The presence of an irregular surface or masses
If bleeding can be controlled, the prognosis is should be further evaluated.
good with trauma-associated splenic rupture.
The prognosis is poor if rupture is due to splenic Management
neoplasia. Treatment is variable depending on the incit-
ing cause, which should be addressed, if possible.
SPLENOMEGALY Successful treatment of primary splenomegaly with
splenectomy has been reported.
Definition/overview
Splenomegaly is the presence of an abnormally large Prognosis
spleen. It is a difficult condition to diagnose because The prognosis is good with nephrosplenic entrapment
of the inherent variability in spleen size in healthy of the large colon but guarded with other causes. The
animals. The clinical significance of apparent sple- prognosis with neoplasia is poor because advanced
nomegaly is often unclear. disease is usually present by the time it is diagnosed.