Overview of Constipation in Dogs
Constipation is infrequent, incomplete, or difficult defecation with passage of hard or dry feces. Constipation is sometimes used interchangeably with obstipation, which is intractable constipation where defecation becomes impossible. It may cause great distress and pain.
Causes of Canine Constipation
Mechanical obstruction (physical blockage)
Metabolic and Endocrine diseases
What to Watch For
Straining to defecate and passing a small amount of feces or none at all
Hard, dry feces
Small amount of liquid feces produced after prolonged straining
Lack of appetite
Diagnosis of Constipation in Dogs
The diagnosis is usually made by a supportive history and physical examination findings. However, there are many tests that may also help. The following is a list of the most common tests that your veterinarian may recommend:
Baseline blood tests to include a complete blood count (CBC), biochemical profile, and urinalysis
Abdominal radiographs (X-rays)
Treatment of Constipation in Dogs
There are several things your veterinarian might recommend to treat your dog with constipation symptomatically, prior to instituting a full diagnostic work up.
If an underlying cause has been identified, remove it if possible.
Discontinue any medications that may cause constipation. Your veterinarian will advise.
Alter the diet to include bulking agents such as methylcellulose, bran, or pumpkin.
Promote frequent exercise.
If a dog is severely impacted and/or dehydrated, it may be necessary to hospitalize for fluids, enemas, and possible manual removal of feces, which often necessitates general anesthesia.
Your veterinarian may recommend some treatments at home. These may include:
The use of lubricants, suppositories or laxatives
Warm, soapy water enemas. Do not use over-the-counter enemas unless directed by your veterinarian. Some may be toxic to your dog.
Abdominal palpation. Owners of chronically constipated dogs may be taught to palpate their dog’s colon abdominally to detect constipation before it progresses to obstipation.
In-depth Information on Constipation in Dogs
There are many causes of constipation. Although it is not unusual for a normal dog to have a bout or two of constipation over the course of their lives, it is not normal or acceptable for them to have recurring problems, hence, establishing an underlying cause should be attempted in these cases.
Dietary related factors are the most common cause for constipation in veterinary medicine. Foreign material, especially hair, bones, sticks, and sand can form hard masses that the dog has difficulty eliminating. In some cases, this material is retained, causing an inability to defecate and eventual obstipation. In addition, diets low in fiber may predispose to constipation.
Certain environmental factors may contribute to constipation. Limited exercise, limited access to water, and failure to provide the appropriate time and place for defecation may cause fecal retention and constipation.
Certain drugs, including antacids, Kaopectate, iron supplements, antihistamines, barium, and diuretics may cause constipation.
Painful defecation associated with anorectal disease (anal sacculitis or abscess, perianal fistula, stricture, rectal foreign body or tumor, or rectal prolapse) or trauma (fractured pelvis, limb, or back, laceration, bite wound).
Mechanical obstruction (something physically blocking the path of stool elimination) can be caused by extraluminal (from outside the colon wall) or intraluminal (from inside the colon wall) causes. Extraluminal disorders causing constipation include narrowed pelvic canal from a previous fracture, prostatic enlargement secondary to multiple prostatic disorders, sublumbar lymphadenopathy (enlarged lymph nodes above the colon), and rectal tumors. Intraluminal disorders include colonic or rectal tumors or polyps, rectal foreign bodies, strictures, diverticulum (outpouching of the colonic wall), perianal hernias, and rectal prolapse.
Neurologic disorders including paralysis, spinal cord disease, disc disease, rabies, lead toxicosis, dysautonomia (a hereditary condition), and idiopathic megacolon can all cause constipation.
Metabolic and endocrine disorders can cause constipation as they may impair normal transit through the colon. These include hyperparathyroidism (a disorder causing elevated calcium levels), hypothyroidism, and hypokalemia (decreased potassium), and renal (kidney) disease.
Constipation is relatively common in dogs. However, it must be differentiated from obstipation and megacolon. Obstipation is intractable (resistant to control) constipation, and megacolon is a condition of extreme dilation of the colon. Obstipated dogs or those with megacolon are always constipated; however, constipated animals are not always obstipated or have megacolon.
Constipation can occur in association with any disorder that impairs the passage of fecal material through the colon, slowing its transit time. This delay in transit allows the removal of additional salt and water from the feces, producing harder and drier stools.
Systemic signs of constipation vary. Feces can be retained for days before any deleterious effects are observed. Some animals may display mild signs, such as a slightly prolonged posture while defecating, and then produce a dry, firm stool. Others will have frequent or painful attempts to defecate with little or no fecal passage. Severely constipated patients often exhibit depression, weakness, lack of appetite, and vomiting. These animals are quite ill and may require hospitalization. It is important to establish a definitive diagnosis and cause, especially in the dog with recurrent constipation.
Obtaining a complete medical history (including diet, eating habits, environment) and performing a thorough physical examination including a thorough digital rectal examination are necessary in order to create an appropriate diagnostic plan for the constipated patient.
A complete blood count (CBC) will evaluate for the presence of systemic infection or inflammation sometimes associated with abscesses, fistulae, or prostatic disorders.
A biochemical profile evaluates kidney, liver, electrolytes (specifically, potassium and calcium), total protein, and blood sugar status. All of these parameters are important to establish in the chronically constipated patient, and to rule out the possibility of concurrent diseases.
A urinalysis helps evaluate the kidneys and hydration status of the patient.
Abdominal radiographs (X-rays) may reveal colonic or rectal foreign bodies or tumors, prostatic enlargement, old pelvic fractures, hip dysplasia, and will reveal the degree of constipation.
Multiple fecal examinations are important to rule out gastrointestinal parasites, specifically whipworms, which can cause pain and straining associated with constipation.
Your veterinarian may recommend additional tests to insure optimal medical care. These are selected on a case-by-case basis.
A thyroid profile may be recommended in the chronically constipated dog, as hypothyroidism can be associated with constipation.
A parathyroid level may be recommended in the hypercalcemic (elevated calcium) constipated patient, as hyperparathyroidism has been associated with constipation.
An abdominal ultrasound evaluates the abdominal organs and helps assess for the presence of tumors. It is a very sensitive test in evaluating the prostate. The procedure is relatively safe, although it may require a mild sedative. It is often recommended that a specialist perform the procedure.
Colonoscopy (lower GI endoscopy) may be of benefit in the patient with constipation. It is a rather noninvasive way to evaluate the colon, and identify the presence of a tumor, stricture, or other lesion. Your veterinarian may also want to sample tissue for the presence of inflammation or cancer.
Since it is necessary to “clean out” your dog to allow for proper visualization of the colon, oral solutions are administered the evening and morning before the procedure, in addition to several enemas. Hospitalization is brief, and healing is generally quick and uneventful. It does, however, necessitate general anesthesia, and therefore is associated with minor risks. It is often necessary to refer the patient to a specialist, and is only performed when other diagnostics are either inconclusive or the patient is not responding well to therapy.
One or more of the diagnostic tests described above may be recommended for your dog by your veterinarian. In the meantime, treatment of the symptoms might be needed, especially if the problem is severe.
The following nonspecific (symptomatic) treatments may be applicable to some dogs with constipation. These treatments may reduce severity of symptoms or provide relief for your dog. However, nonspecific therapy is not a substitute for definitive treatment of the underlying disease responsible for your dog’s condition. Medical and dietary therapy may be lifelong and often frustrating.
If an underlying cause has been identified, treat it or remove it if possible.
Discontinue any medications that may cause constipation.
Alter the diet to be altered to include bulking agents such as methylcellulose, bran, or pumpkin.
Stool softeners such as docusate sodium (DSS, Colace) may be used as instructed by your veterinarian.
Promote frequent exercise, as this helps promote regular bowel movements.
If a dog is severely impacted and/or dehydrated, it may be necessary to hospitalize him for fluids, enemas, and possible manual removal of feces, which often necessitates general anesthesia.
In a small percentage of patients where constipation continually progresses to obstipation, a colectomy (surgical removal of the colon) may be necessary if medical management is not of benefit.
Follow-up Care for Dogs with Constipation
Optimal treatment for your dog requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your dog does not improve rapidly. It is important to note that chronic or recurrent constipation can lead to obstipation and acquired megacolon, at which point prognosis is guarded for normal function.
It is important to monitor the frequency of defecation and the consistency of feces. Administer all prescribed medication as directed. Alert your veterinarian if you are experiencing problems treating your dog. Overuse of laxatives and enemas can cause diarrhea.
Discontinue/avoid any medication or substance that may be causing or exacerbating (worsening) constipation.