Page 817 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

792 CHAPTER 4

VetBooks.ir Differential diagnosis edge of the orad intestine telescoping into the outer
distad segment, the intussuscipiens.
Many other causes of colic and abdominal distension
The relative frequency of intussusception varies
should be considered, including intestinal accident,
meconium impaction, intestinal atresia, severe enter- geographically and anatomically. It is more common
itis with impending diarrhoea and uroperitoneum. in younger horses (<3 years), and may be more com-
mon in Standardbreds, Thoroughbreds and ponies.
Diagnosis The most common locations include jejunoileal,
Progressive abdominal distension and lack of defaeca- ileocaecal, caecocaecal and caecocolic sites; however,
tion in a white foal of an Overo–Overo mating within other sites such as the ascending and descending
the first 48 hours of life is highly suggestive. Abdominal colon have also been reported.
radiographs or ultrasound only demonstrate intestinal
distension. Confirmation of the diagnosis is made at Aetiology/pathophysiology
necropsy via demonstration of a lack of myenteric gan- The aetiology of intussusception has been hypothesised
glia in the small colon, or by demonstration that the as a physical consequence of motility waves in a certain
foal is homozygous for the gene mutation. structure meeting a structure of different mechanical
and functional properties. This may occur at sites of
Management anatomical differences, such as at the jejunoileal junc-
No treatment options are available. Breeding stock tion or at the ileocaecal valve. The intestine may also
should be tested for the genetic mutation. A hetero- become predisposed to intussusception by alteration of
zygote should not be bred to another heterozygote. the mechanical function or by the presence of intestinal
parasites. The tapeworm Anoplocephala perfoliata is most
Prognosis often associated with intussusception, but larval cya-
This is a fatal condition and foals should be euthanased. thostomes have also been implicated. Other potential
risk factors include motility-modifying drugs, enteritis
INTUSSUSCEPTION and surgical modification to the intestine.
The consequence of the formation of an intus-
Definition/overview susception is that the effective intestinal lumen is
Intussusception is a condition where the intestine reduced and the blood supply to the intussusceptum
telescopes into itself (Figs. 4.118, 4.119). The intus- may be compromised. Damage to this blood supply
susception consists of an intussusceptum, the leading can cause oedema and necrosis of the intussusceptum.

4.118 4.119

Fig. 4.118 Jejunojejunal intussusception. The Fig. 4.119 Note the haemorrhagic strangulation
intussusceptum (left side of the picture) is clearly lesion on the intussusceptum (left side of the picture).
observed to invaginate into the lumen of the
intussuscipiens (right side of the picture).