Page 1364 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

The foal 1339

VetBooks.ir with joint effusion and lameness; umbilical infec- concentrations of urea and creatinine can indicate
renal dysfunction and liver enzymes are commonly
tions and patent urachus; cardiovascular collapse;
coma and death. A normal body temperature does
blood glucose and lactate, in addition to electrolyte
not rule out the presence of sepsis. mildly increased in foals with sepsis. Evaluation of
concentrations, can be very helpful in guiding ther-
Differential diagnosis apy. Hypoglycaemia is common in the early stages
Neonatal maladjustment syndrome (NMS); meta- of sepsis, frequently followed by hyperglycaemia due
bolic disturbances. to endocrine dysfunction. Hyperlactataemia is com-
mon, due to poor tissue perfusion.
Diagnosis
Diagnosis is based on history and a thorough clini- Management
cal examination combined with clinical pathology. Antibiotics
Sepsis should always be considered until proven Careful selection of the most suitable antibiotics
otherwise. If sepsis is suspected, treatment should is important. Broad-spectrum bactericidal antibi-
be instituted immediately because a delay in anti- otics with good penetration of affected tissues are
microbial administration can have a significant required. Provided renal function is not signifi-
adverse effect on outcome. A positive blood culture cantly compromised, penicillin or ampicillin and
is considered the gold standard for the diagnosis of an aminoglycoside (gentamicin or amikacin) are a
sepsis, but this technique is time consuming and commonly used first choice. Cephalosporins can
false negatives are common. To collect a sample for also be useful, especially in foals with renal dys-
blood culture, the jugular vein (or other suitable function. Dose rates appropriate for neonatal foals
peripheral vein such as the saphenous or cephalic) should be used (see Table 14.2). Antimicrobial choice
should be aseptically prepared and a sample col- can be adjusted if necessary based on results of cul-
lected and placed into blood culture medium. ture and sensitivity.
Taking more than one sample can improve the
likelihood of a positive result. Samples can also be Cardiovascular support
taken from other sources to obtain culture mate- It is important to maintain tissue perfusion and
rial, and these include joints and other synovial adequate oxygen delivery to the tissues. Monitoring
structures, tracheal washes, urine, faeces and cere- hydration, blood pressure, mental status and blood
brospinal fluid. lactate concentrations provides useful information.
Given the limitations of blood culture a sepsis Resuscitation fluid boluses (10–20 ml/kg of balanced
scoring system is often used to help increase the electrolyte solution given at a higher flow rate [i.e.
accuracy of diagnosis. This involves the collection 1 l/50 kg foal over 20 minutes]) will provide tempo-
of a number of clinical and biochemical assay results rary volume expansion. Response to therapy should
and allocating them a score in a table, which then be monitored and further boluses may be neces-
predicts the likelihood of sepsis. sary. It is important to remember that foals are more
Common laboratory findings are leucopenia and susceptible to volume overload than mature horses.
neutropenia, often with a left shift. Serum amyloid Plasma may also be useful during resuscitation.
A (SAA), an acute phase protein, typically rises dra- Plasma is particularly useful because it contributes
matically over the first 12–24 hours and can be a antibodies, metabolic nutrients and clotting factors
very useful early indicator of infection. Fibrinogen to the foal. Failure to respond to appropriate fluid
concentration rises more slowly and an increased therapy indicates the need to use ionotropes and
concentration in a foal less than 36 hours old sug- vasopressors to support blood pressure. There are
gests in-utero pathology. IgG concentration should extensive, excellent reviews of the use of haemody-
be checked to determine whether FTPI is present. namic agents and cardiovascular monitoring avail-
Biochemical evaluation can be useful to evalu- able elsewhere.
ate for evidence of organ dysfunction. Increased