Typhlitis
Basic Information 
Clinical Presentation
Physical Exam Findings
• Variable signs of abdominal pain, usually mild to moderate.
• Variable tachycardia and tachypnea.
• Mucous membranes are often injected and hyperemic with a “toxic line.”
• Capillary refill time may range from brisk (<1 sec) in the early stages to prolonged (2–4 sec) as dehydration progresses.
• Hypermotile, “fluidy” gastrointestinal borborygmi in the right abdominal quadrants
• Severe diarrhea is typically not observed unless concurrent colitis is present, although the feces may be soft in horses with primary typhlitis.
• Rectal examination: The ventral cecal band is often taut, and the cecum may be pulled cranially and ventrally. Occasionally, fluid contents are palpable within the cecum, although this is not consistently observed.
Etiology and Pathophysiology
• Salmonella, Clostridium difficile and Clostridium perfringens, and larval cyathastominosis are the most likely causes of typhlitis, either on its own or in conjunction with colitis.
• Idiopathic typhlitis, in which a specific cause cannot be determined, is also fairly common.
• The cecal mucosal barrier is damaged via the same mechanisms as the colonic mucosal barrier in acute colitis (see “Colitis/Diarrhea, Acute, in Adult Horses” in this section), resulting in loss of fluid and electrolytes into the cecal lumen and systemic exposure to bacterial toxins.
