A megacolon bunny is a rabbit that has a condition called megacolon. Megacolon is characterized by an enlarged, dilated colon that does not function properly. This condition is most commonly seen in the Netherland Dwarf breed of rabbits, but can occur in other breeds as well.
What causes megacolon in rabbits?
There are a few different potential causes of megacolon in rabbits:
- Genetics – Megacolon is believed to be linked to a recessive genetic mutation that is prevalent in some rabbit breeds like Netherland Dwarfs. Rabbits inheriting two copies of this mutant gene are predisposed to developing megacolon.
- Diet – Diets that are low in fiber or high in carbohydrates may contribute to hypomotility (slow movement) of the intestines and colon dilation. Insufficient exercise can also play a role.
- Neurological dysfunction – Damage to the nerves controlling intestinal mobility may lead to impaired motility and megacolon.
- Obstruction – Foreign material, ingested hair, parasites, or feces may cause a blockage leading to dilation of the colon.
What are the symptoms of megacolon in rabbits?
Rabbits with megacolon may exhibit the following signs and symptoms:
- Infrequent, small fecal balls
- Straining to defecate
- Lethargy
- Decreased appetite
- Bloating or distension of the abdomen
- Weight loss
- Rectal prolapse in severe cases
How is megacolon diagnosed in rabbits?
Diagnosing megacolon in rabbits involves a combination of the following:
- Medical history – Breed predisposition and clinical signs
- Physical exam – Palpating the abdomen to feel for dilation or impaction
- Radiographs – X-rays to visualize colon enlargement and rule out obstructions
- Contrast enema – Barium solution administered rectally to outline colon
- Bloodwork – To check for underlying issues like dehydration
How is megacolon treated in rabbits?
Treatment of megacolon in rabbits focuses on managing the condition through:
- Diet – Feeding a high fiber diet and plenty of hydration
- Exercise – To stimulate intestinal motility
- Laxatives/motility drugs – To promote colon contractions
- Stool softeners – To ease defecation
- Enemas – To flush the colon
- Surgery – Removing obstructing material or severely dilated sections of colon
Mild megacolon may be managed conservatively with diet and medicine. More severe cases often require surgery to remove problematic portions of colon. Even with treatment, megacolon in rabbits can be chronic and progressive.
What is the prognosis for rabbits with megacolon?
The prognosis for megacolon depends on the underlying cause and severity of the condition. In general:
- Mild cases caught early are more likely to respond to conservative treatment.
- Rabbits with an obstructive cause and relieved surgically tend to have a good prognosis.
- Idiopathic megacolon related to genetics has a poorer long-term prognosis.
- Severe dilation causing GI stasis and secondary issues can be life threatening.
With diligent home care, some rabbits with mild to moderate megacolon can live comfortably for years. But recurrences are common and the condition is progressive. Severe cases have a graver prognosis.
How is megacolon prevented in rabbits?
Preventing megacolon involves the following steps:
- Selecting breeding rabbits screened for genetic megacolon
- Feeding a high fiber diet from a young age
- Avoiding diets high in carbohydrates
- Providing ample exercise and activity
- Monitoring stool output and consistency
- Treating underlying conditions like dental disease
For breeds predisposed to megacolon, choosing breeding stock free of the megacolon gene is ideal. Early intervention also leads to better outcomes, so monitoring high-risk rabbits is important.
Key facts about megacolon in rabbits:
| Most commonly affects | Netherland Dwarf rabbits |
| Primary cause | Inherited genetic mutation |
| Key clinical signs | Infrequent, small feces; straining; bloating |
| Diagnostic methods | Radiographs, contrast enema, bloodwork |
| Treatment options | Dietary modification, medicines, surgery |
| Prognosis | Variable depending on severity; often recurrent |
Breeds prone to megacolon
Certain breeds are predisposed to developing megacolon. This is primarily linked to inherited genetic factors within these breeds:
- Netherland Dwarf
- Mini Lop
- Holland Lop
- Mini Rex
- Himalayan
- Jersey Wooly
- Dutch
- Polish
All rabbit breeds can develop megacolon. But selective breeding in the breeds above has propagated the megacolon gene. Responsible rabbit breeders should screen for this issue.
Differentials for megacolon
There are some other conditions that may be confused with megacolon or contribute to its development:
- GI stasis – Slowdown of all intestinal motility
- Cecal impaction – Blockage of the cecum pouch
- Obstruction – Foreign material or masses blocking intestines
- Dietary issues – Insufficient fiber, too many carbs
- Parasites – E. cuniculi infection damaging nerves
- Spinal injury – Impaired neural signals to the colon
A thorough diagnostic workup helps differentiate megacolon from other potential causes of similar clinical signs.
Quality of life concerns
Caring for a rabbit with chronic megacolon can be challenging. Monitoring the rabbit’s quality of life is important:
- Is the rabbit maintaining a healthy appetite and weight?
- Does the rabbit appear comfortable most of the time?
- Is pain managed with medication as needed?
- Are recurring bouts of GI stasis brief?
- Is the owner able to keep up with home care demands?
If a rabbit’s quality of life is declining despite treatment, euthanasia may be the most humane option. Discussing thresholds for quality of life with an exotics vet can help guide difficult decisions for rabbits with intractable megacolon.