Only your veterinarian can help you understand the reason for blood in the bowel movements of your cat. In general though, there are a number of causes underlying this problem. Your veterinarian will first take a history that includes additional details such as: Is there blood in every movement? How much? For how long has blood been noted in the box? Fresh blood? Dark clots? Is there diarrhea or constipation? Is the cat currently on a deworming schedule? Goes outside? Hunts? Fed bones? Your comments will be a valuable component of the diagnostic evaluation.
The level of testing required varies tremendously between patients, and once the history has been taken, based on that additional input and the results of a physical examination, your veterinarian will advise you re: what tests are recommended.
Though animals can get polyps or benign tumors of the lower bowel, true hemorrhoids are not typically found in companion animal species.
Potential causes may include:
- Allergy (food)
- Infection
- Trauma
- Inflammation (e.g. Inflammatory bowel disease or IBD)
- Parasites
- Cancer of colon or rectum area
- Foreign material in colon or rectum (such as bone fragments)
- Disease of the anal sacs (infection or sacculitis, abscess)
- Constipation / megacolon (stool buildup causes lower bowel damage)
- Pseudocoprostasis (where stool and matted hair block the exit of the bowels or the anus and tissues may bleed secondary to infection and pressure on tissues, termed pressure necrosis)
- Urinary tract bleeding may sometimes be confused with bowel bleeding if they end up deposited together in the litter box. Both problems may cause some straining and bleeding.
Blood in the stools is abnormal, and if it continues, a professional evaluation is warranted. Though some causes are easily dealt with, others may be progressive.