Koko appears to have become fecal incontinent if she's unaware of stool passing while asleep. There are quite a few differential etiologies for fecal incontinence so I'm going to post a synopsis of this disorder for you. Please take your time reading it. It's designed for vets but you'll get a good idea of what Koko's vet needs to consider. Pay particular attention to neurogenic etiologies such as degenerative disk disease (a "slipped disk") in a 5 year old.
Inability to retain feces
Species, Age, Sex
- Young animals: inappropriate house training, congenital disorders
- Old animals: senility/cognitive dysfunction, degenerative disorders, neoplasia
Genetics and Breed Predisposition
- German shepherd: degenerative lumbosacral stenosis, perianal fistulas
- English bulldog, Manx cat: congenital spinal malformations
- Perineal surgery, radiation therapy
- Pelvic or lumbosacral trauma
- Perianal diseases
- Tail avulsion fractures
History, Chief Complaint
- Unaware of fecal elimination; unassociated with defecation behavior
- Small amounts of normal or abnormal feces dribble out, especially when intra-abdominal pressure increases suddenly (e.g. coughing).
- Urinary incontinence may be present.
- Perineal soiling
- Dogs with spinal lesions and episodic incontinence may be aware of the need to defecate but are unable to control the urge.
- Animal aware of incontinence; defecation behavior present, but is unable to control the time and place of elimination
- Abnormal feces, suggestive of rectocolonic disease (diarrhea, mucoid feces, hematochezia)
- Defecation associated with signs of rectocolonic disease (tenesmus, dyschezia)
- House soiling with normal feces and defecation
- Destructive behavior
Physical Exam Findings
- Spinal, lumbosacral pain
- Hyperesthesia of hindlimbs or perineum
- Lower motor neuron (LMN) signs: paresis/paralysis with decreased muscle tone, spinal reflexes, and anal tone; abnormal bulbocavernosus, rectal inflation, or anal reflexes; ± loss of tail tone and voluntary movement
- Upper motor neuron (UMN) signs: increased spinal reflexes, ataxia
- Intracranial disease: abnormal behavior, mentation, or cranial nerve examination
- Abnormal feces: diarrhea, constipation
- Rectal masses, mucosal changes, pain on digital rectal examination
- Signs of gastrointestinal disease (weight loss, anorexia, vomiting)
Behavior: normal physical exam
Etiology and Pathophysiology
Sphincter incontinence: diseases of the anal sphincter or adjacent structures
- Non-neurogenic: anatomic disruption of the anal sphincter preventing functional seal. Anal tone and reflexes normal.
- Neurogenic: normal sphincter anatomy
- LMN dysfunction: sphincter dysfunction due to inadequate sensory or motor nerve supply
- UMN dysfunction: incompletely understood; combination of reduced rectal sensation (disruption of afferent sensory pathways), lack of conscious control of the external anal sphincter, and exaggerated sacral defecation reflex (loss of inhibitory influences on reflex activity)
Reservoir incontinence; diseases of the colon/rectum:
- Diseases impairing colonic-rectal compliance, capacity, or causing irritation
- Normal sphincter anatomy and neural supply
- Altered fecal consistency or excessive volume: feces enter into rectum too rapidly for normal control to take place.
- Urge incontinence
- “Overflow incontinence”: liquid feces seeping around constipated fecal material
fecal incontinence is a sign, not a diagnosis. The underlying cause must be identified for optimal treatment and accurate prognostication. Neurologic exam, behavioral history, and rectal palpation are indicated in all cases.
See p. 1301 for detailed differential diagnosis.
- Sphincter incontinence
- Neurogenic sphincter incompetence
- Reservoir incontinence
- Physical examination including perineal and digital rectal examination
- Fecal analysis
- Neurologic examination (see p. 1201), especially:
- Perineal and tail sensation
- Anal sphincter and tail tone
- Minimum database (complete blood count, serum biochemistry panel, urinalysis ± culture and sensitivity): nonspecific findings
Advanced or Confirmatory Testing
- Sphincter incontinence: as dictated by working diagnosis
- Reservoir incontinence:
- Colonoscopy, proctoscopy
- Rectal-colonic mucosal biopsy: cytologic, histopathologic analysis
- Treat the primary cause.
- Supportive care
As needed, according to underlying cause:
- Intestinal motility altering agents: loperamide, diphenoxylate
- Amitriptyline has been successful in an open-label trial in humans with idiopathic fecal incontinence.
- Maintain low intrarectal pressures:
- Frequent opportunities to defecate if some control is present
- Induction of reflex defecation: warm moist washcloth on anus/perineum
- Reduce/avoid evening feedings (stimulus for nocturnal incontinence).
- Prevent fecal scalding (clip and clean perineum, intermittent tail wrap if long-haired, barrier cream).
- Change in environment to make incontinence more acceptable, “doggy diapers”
- Surgical: consider referral to a board certified surgeon.
- Anorectal reconstruction
- Silicon elastomer sling
- Fecal diversion procedures: colonostomy
- Semitendinous muscle transfer flap
May respond to a therapeutic diet trial: either low-residue or high-fiber (soluble or insoluble) diets can be tried. Success is variable and depends on the underlying etiology.
- Fecal soiling predisposes to perineal dermatitis and, in females, urinary tract infections.
- Constipation possible with motility-modifying medication
Medical management must be regarded as a therapeutic trial; response guides subsequent treatment and diagnostic testing if necessary.
Prognosis & Outcome
Guarded to poor with:
- Many neurogenic sphincter causes (degenerative neuropathies, dysautonomia, lumbosacral stenosis)
- Severe anal sphincter lesions
- Underlying cause not found
Fair to good with:
- Controlled rectocolonic disease
- Behavioral causes treated with effective behavioral modification
- There have been some encouraging results with surgical correction of even long-standing focal UMN spinal lesions.
Pearls & Considerations
- fecal incontinence caused by UMN spinal cord lesions may develop before limb deficits.
- fecal incontinence is a common reason for client-requested euthanasia.
- Response and client satisfaction are highly variable and based on client expectation and ability.
Precise and atraumatic technique when performing perineal surgery
Please respond with further questions or concerns if you wish.