Septicaemia - Foal

Introduction

Septicaemia in the foal is a serious and life-threatening condition that requires prompt diagnosis and treatment. It is caused by the presence of bacteria, or bacterial toxins in the blood. The infection can either be localised (ie to the joints or umbilicus) or generalised, with systemic signs.

Several bacteria can cause septicaemia, including grams negative organisms such as E. coli, Actinobacillus, and Klebsiella species,and gram positive organisms such as Streptococcus and Staphylococcus species. Occasionally anaerobic organisms such Clostridium species may also cause disease.

Signalment

Disease is caused following haematogenous spread of infection via the placenta, umbilicus, lungs or GI tract. Foals may be affected as early as the first 12 hours after birth.

Predisposing factors include:

• Failure of passive transfer - due to failure of the foal to suckle adequate quantities of colostrum, or low volume/poor quality colostrum produced by the dam.
• Dystocia
• Premature/Dysmature foal
• Over-crowding and poor hygiene
• Artificial severance and ligation of the umbilicus
• Failure to treat the umbilicus immediately after birth (with tincture of iodine)

Clinical Signs

Foals in the early stages of clinical disease may not show any specific signs, instead appearing 'off-suck' (inspecting the dams udder can give some indication of when the foal last suckled). This may be accompanied by lethargy, malaise, frequent recumbancy and pyrexia. The bacteria may localise in different organs, producing clinical signs directly related to that organ:

• Cardiac localisation produces tachycardia
• Gastrointestinal localisation produces ileus, colic and diarrhoea
• Integumentary localisation produces anasarca
• Locomotor localisation produces joint effusion and/or septic arthritis
• Neurological localisation produces seizures and depression
• Ocular localisation produces hypopyon and iritis
• Respiratory localisation produces polypnoea
• Urogenital localisation produces anuria

The disease may then advance to septic shock. Clinical signs include prolonged recumbancy, depression, dehydration, and tachycardia with cold extremities, weak thready pulses, slow capillary refill time and muddy mucous membranes; indicative of hypotension. Dependant on the organs affected, signs of individual or multiple organ dysfunction may be present.

Clinical signs can progress very rapidly therefore prompt recognition is necessary.

Diagnosis

Definitive diagnosis is by positive blood culture, however a negative blood culture does not rule out septicaemia. As the foal may deteriorate quickly and the results of the blood culture are not immediate, a provisional diagnosis of neonatal septicaemia is made using a sepsis scoring system. This combines the all the physical findings and in-house test results to provide an overall clinical picture and sepsis score that then guides treatment prior to the return of the blood culture results.

Aspects incorporated in the sepsis scoring system are; the clinical signs and history, the results of individual tests (for example ultrasound on the umbilicus and joint arthrocentesis), haematology showing a neutropaenia with toxic change, and FPT measurements - serum IgG levels of less than 4 g/litre indicate failure of passive transfer. Levels of 4g/litre and above are acceptable when coupled with good hygiene. An IgG level of 8 g/litre or more indicates successful transfer of maternal antibodies.

Treatment

If septicaemia is suspected the foal should be immediately treated with broad spectrum IV antibiotics until culture results are known. Multiple plasma transfusions may be required to raise IgG serum levels, and IV fluid therapy should be administered to treat endotoxic shock. Nutritional support is necessary, either by helping the foal suckle the dam or administration of the dams milk (or a substitute) via nasogastric tube. In addition, glucose levels should be measured frequently and dextrose added to the IV fluid therapy if necessary. The use of anti-endotoxin drugs (flunixin, anti-prostoglandin, polymyxin B) as an adjunct treatment has also been reported.

General supportive care, recumbant foal management and TLC (tender loving care) is also necessary - this may continue for several weeks after infection. Organ-specific treatments such as joint lavage with joint sepsis and oxygen therapy with pneumonia may also be needed.

If the umbilicus is a localised source of infection, it can be surgically resected to reduce the spread of infection to distant organs.

Prevention

• Ensuring adequate intake of colostrum in the first 12-24 hours of life. Levels can be checked by measuring serum IgG (>800mg/dl)
• Appropriate treatment of the umbilicus with tincture of iodine promptly after birth
• Providing a clean, warm and well ventilated environment for the neonate

Prognosis

Prognosis is dependant on the severity of clinical signs and the individual organs affected. Early recognition and aggressive treatment are key to an improved prognosis.

Septicaemia - Foal Learning Resources
Flashcards Test your knowledge using flashcard type questions	Equine Internal Medicine Q&A 13

References

Merck & Co (2009) The Merck Veterinary Manual (Ninth Edition), Merial

Captain M. Horace Hays FRCVS Veterinary Notes for Horse Owners (Revised Edition), Stanley Paul

RVC staff (2009) Urogenital system RVC Intergrated BVetMed Course, Royal Veterinary College

Mair, TS & Divers, TJ (1997) Self-Assessment Colour Review Equine Internal Medicine Manson Publishing Ltd

Stoneham, S (1997) Collection and administration of plasma to a new born foal In Practice 1997 19: 384-38