Feline constipation and megacolon

36 Feline constipation and megacolon



Case contributed by Nicki Reed




Initial presentation


Tenesmus, haematochezia and abdominal distension


Signalment: 8-year-old, female neutered Devon Rex cat, body weight 2.5 kg



Case history


The cat was presented for tenesmus, haematochezia and abdominal distension, accompanied by anorexia and lethargy. Since being acquired 4 years earlier she had had intermittent episodes of constipation, manifested as straining to pass hard faeces which were occasionally coated with fresh blood or mucus. The episodes had initially occurred two or three times per year, but for the past 6 months had been occurring monthly. During these episodes the cat would defecate outside the litter tray and she appeared to have abdominal bloating. Symptomatic treatment with laxatives generally improved the condition within 1 to 2 days.


Occasional episodes of small volume diarrhoea were reported (once to twice a year). At the time of presentation, she had passed no faeces for 4 days and had had a poor appetite for 2 days.


The cat was acquired from a rescue centre 4 years previously and lived indoors with one other unrelated Devon Rex cat. She was vaccinated against feline herpesvirus-1, calicivirus and feline parvovirus and de-wormed every 6 months with praziquantel and pyrantel. The cat was fed a proprietary canned cat food.


She was thought to have previously been used for breeding and was reported to have had surgery for an intussusception at 2 years of age.



Physical examination


The cat appeared slightly thin (body condition score 3/9) and had a distended abdomen (Fig 36.1). Her hydration appeared adequate and mucous membrane colour was pink with a capillary refill time of 2 seconds. Thoracic auscultation revealed a Grade I to II/VI systolic murmur, with point of maximal intensity at the left sternal border. No pulse deficits or arrhythmias were detected. Respiratory rate was mildly increased at 30 breaths per minute, attributed to stress, as no abnormal lung sounds were detected. Abdominal palpation revealed a large colon, filled with hard faeces and a moderately distended bladder.


image

Fig 36.1 Dorsal view of the cat showing distended abdomen.



Problem list and discussion of problems


The cat’s primary problem was thought to be constipation, based on the history and physical examination findings.



Differential diagnosis


Differential diagnoses for constipation include:


• Dietary causes, e.g. ingestion of bones or foreign material.

• Environmental causes, e.g. decreased exercise, litter box problems (dirty, change in type of litter or location of box; competition from other cats; inability to use the box due to arthritis or other locomotor disorders), stress

• Traumatic disorders, e.g. fractured pelvis; fractured or dislocated hip; bite wound; abscess; abdominal bruising; saccro-coccygeal luxation (tail-pull – unlikely as there was no history of trauma in this cat and the problem was chronic)

• Obstructive disorders, e.g. anal stricture; anal sac infection; rectal foreign body; rectal or colonic tumour; pelvic fracture malunion; perineal hernia; rectal diverticulum; pseudocoprostasis

• Neuromuscular disorders, e.g. spinal cord disease; congenital spinal cord anomaly (Manx cats); paraplegia/paralysis; central nervous system dysfunction; dysautonomia (Key–Gaskell syndrome); idiopathic megacolon

• Pharmacological causes, e.g. opioids; diuretics; anticholinergics; antihistamines; barium sulphate

With the chronic history and the lack of clinical signs consistent with most of the other possible differential diagnoses for constipation, the most likely cause in this cat was thought to be idiopathic megacolon, although other neurological causes and neoplasia could not be ruled out



Case work-up


A neurological examination was performed with no abnormalities detected. A rectal examination showed no evidence of herniation, anal sac disease, strictures or foreign bodies. A few small pieces of hard dry faeces were present in the rectum.



Minimum database


Routine haematology showed a moderate neutrophilia (26.2 × 109/l; reference range 2.5–12.8 × 109/l). This most likely represented a non-specific inflammatory response. Serum chemistry parameters were within the reference ranges.



Imaging


Abdominal radiography showed impaction of the transverse and descending colon with faeces (Fig 36.2). In addition, ventral spondylopathy was present at the lumbosacral junction. Two views were taken to fully evaluate narrowing of the pelvic canal.


image

Fig 36.2 Lateral abdominal radiograph showing impaction of the transverse and descending colon with faeces at initial presentation.


Further investigations that could have been beneficial include urinalysis for assessment of hydration, ultrasonography if intraluminal or extraluminal masses were suspected, colonoscopy if intraluminal disease is suspected and barium enema if a stenotic lesion was suspected. If the neurological examination had been abnormal, further evaluation with MRI may have been useful.



Diagnosis


A diagnosis of colonic impaction was made. A diagnosis of obstipation could not initially be made, as it was not known whether the condition was refractory to therapy. Initial management was commenced with manual evacuation of faeces with the cat anaesthetized and a warm water enema was given.


Oral therapy with lactulose (initial dose 0.5 ml po q 8 hours) and cisapride (1.5 mg/kg po q 12 hours) was then started and the owner advised to feed a low residue diet. The clinical signs improved initially, although the frequency of defecation remained decreased, occurring only every second day.



Follow-up


Over the following 18 months the cat required increasing doses of lactulose and cisapride and micro-enemas with sodium alkylsulphoacetate on three occasions. The cat subsequently presented after having not defecated for 4 days. She also again had a poor appetite and was lethargic. Further radiographs were obtained which showed a grossly dilated impacted colon (Fig 36.3) and as the condition was no longer responding to management a diagnosis of idiopathic megacolon was made.


image

Fig 36.3 Lateral abdominal radiograph showing a grossly dilated impacted colon at revisit.



Treatment options


The most appropriate treatment depended on the underlying cause of constipation and the severity of the problem. Potential therapy includes:


• Ensure adequate hydration and correct electrolyte imbalance if present

Related posts:

  1. Oesophageal stricture in a cat
  2. Vomiting
  3. Linear foreign body in a cat
  4. Intussusception in a cat

Stay updated, free articles. Join our Telegram channel
Tags:
Sep 22, 2016 | Posted by in SMALL ANIMAL | Comments Off on Feline constipation and megacolon

Full access? Get Clinical Tree
Get Clinical Tree app for offline access