Common Disorders in Pet Rabbits

Common Disorders in Pet Rabbits

Lop-Eared Rabbits and Ear Disorders

• Lop-eared rabbits are prone to otitis (ear infections) due to their uniquely structured ear canals.

• The ear canal bends abnormally, making it susceptible to infections.

Administration of Ear Medication

• The ear canal has a separate pocket that ends internally.

• Recommended method for applying ear medications:

  • Use a syringe to insert medication directly into the back part of the pinna (external ear).

Respiratory Facts in Rabbits

• Rabbits are obligate nasal breathers.

• During distress, rabbits may exhibit panting or shallow respirations, which are considered normal under stress.

• Nasal infections can obstruct airflow in rabbits.

• Open-mouth breathing indicates a severe condition, often preceding death in rabbits.

• Rabbits experiencing dyspnea (difficulty breathing) are under significant stress, and over-handling could further exacerbate their condition.

The Sneezing Rabbit

• Common respiratory concern: “snuffles” (upper respiratory tract infection).

• Conditions involved include rhinitis, sinusitis, and dacryocystitis (inflammation of the tear duct).

• Caused primarily by Pasteurella multocida and other pathogens.

• Affects rabbits across various age groups and may be difficult to completely treat.

Severe Respiratory Conditions

• Severe upper respiratory infections lead to significant difficulty in breathing for affected rabbits.

• Early intervention is critical to manage these infections.

Observational Health Checks

• When assessing respiratory health, ensure nares (nostrils) are clear.

• Physical examination should also include checking the paws for signs of stress or condition.

Managing Chronic Upper Respiratory Infections (URI)

• Environmental adjustments are fundamental: use low dust bedding to minimize irritation.

• Diagnostic procedures may include:

  • Deep nasal cultures to identify pathogens.

  • Nasal flush to clear blockages.

• Long-term treatments may involve:

  • Antibiotics to combat infection.

  • Anti-histamines and anti-inflammatories to manage symptoms.

• Addressing eye issues by:

  • Flushing the nasolacrimal ducts if obstructed.

• CT scans of the skull are ideal for assessing conditions like deviated septums, rhinoliths, and erosion of turbinates.

Nasolacrimal Tear Duct Anatomy

• Rabbits possess a single nasolacrimal duct (NLD) puncta located medially.

• The duct is tortuous and runs along the upper maxillary tooth roots, connecting the eye to the nose.

• Elongated tooth roots can press against this duct, leading to:

  • Chronic epiphora (tear overflow).

  • Possible complications such as dacryocystitis and URI resulting in pus/inflammation.

• Regular flush of the duct is recommended to prevent chronic conditions.

Diagnosing Duct Issues

• Contrast studies can be used to assess the NLD for proper function.

• Tall tooth roots have the potential to permanently block the duct and cause epiphora.

Chronic Epiphora and Associated Rash

• Generally, chronic epiphora can lead to mild rashes; however, severe skin issues may arise.

Tear Flow and Collection Techniques

• Tears may flow out through the nose or accumulate in a sterile syringe for culturing to identify underlying infections (pus vs. tears).

Lower Respiratory Tract Disease

• Indications of thoracic diseases include:

  • Abdominal breathing noted as abnormal against typical panting.

  • Potential causes include pneumonia, thymoma (common in older rabbits), heart failure, and metastatic cancer (particularly in older females).

• Observing abdominal movements helps differentiate abnormal respiratory efforts.

Diagnosing Bronchopneumonia

• Typically, bronchopneumonia is bacterial; diagnosed via radiographic assessments showing small airway fields.

• Prognosis is often guarded, underlining the importance of timely diagnostic imaging.

Thymoma in Rabbits

• Rabbits maintain a persistent thymus throughout their lives.

• Older rabbits (> 4 years) may develop thymomas in the mediastinum, leading to notable bulging eyes due to impaired venous return.

Skin Diseases Related to Thymoma

• Sebaceous adenitis often occurs alongside thymoma and necessitates radiographic evaluation for diagnosis.

Heart Disease in Rabbits

• Commonly presents with signs of heart failure, including cardiomegaly and effusion.

Metastatic Uterine Adenocarcinoma

• Particularly prevalent in older female rabbits (> 4 years), with the lungs often being a site for metastatic disease.

Managing Dyspneic Rabbits

• Initial steps include weighing the rabbit for proper medication calculations.

• Minimize handling to reduce stress and provide oxygen support.

• Consider anxiolytic and analgesic med administration:

  • Midazolam: 0.5 mg/kg IM.

  • Buprenorphine: 0.06 mg/kg IM.

• Use only injectables during stabilization, then proceed with diagnostics and treatment:

  • Conduct radiographs, and bloodwork to gain deeper insights into the condition.

  • Administer supportive interventions such as fluids and antibiotics post evaluation.

The Vestibular Rabbit

• Common issue presenting as head tilts, which may indicate:

  • Mild to severe torticollis and rolling.

  • Potential causes include otitis media/interna (bacterial) and Encephalitozoon cuniculi infestation.

Encephalitozoon cuniculi Overview

• Encephalitozoon cuniculi is an obligate intracellular microsporidia (fungal) parasite.

• Rabbits are natural hosts but other species may also transmit.

• Infection is typically acquired at birth and primarily reproduces in the kidneys, having strong affinity for neural tissues (e.g., eye, brain).

• Symptoms may include:

  • Head tilts, seizures, ataxia, and uveitis.

• Infections can lay dormant and subsequently reactivate, forming inflammatory responses that might complicate kidney health.

Phacoclastic Uveitis vs. Cataract

• A ruptured lens capsule might contain EC (Encephalitozoon) spores, potentially leading to cataracts and glaucoma.

Diagnosing E. cuniculi

• Diagnosis may rely on clinical signs, particularly prevalent in dwarf breeds.

• Recommended diagnostic tests include:

  • Blood testing (e.g., Univ of Miami panel) for IgG, IgM, and C-reactive protein levels.

  • Kidney or brain biopsy may be performed during necropsy.

  • Rule out otitis interna through dedicated skull radiographs or CT scans.

Therapeutic Approaches for E. cuniculi

• Benzimidazoles: e.g., fenbendazole and albendazole (may induce bone marrow suppression).

• Anti-inflammatories such as NSAIDs.

• Use of corticosteroids to modulate immune responses is contentious.

• Combination antibiotic therapy may be indicated in cases of otitis media (e.g., marbofloxacin plus metronidazole or injectable penicillin).

• Supportive care is crucial, including fluids, nutritional feeding, analgesics, and ensuring a safe environment (e.g., padded cells in case of rolling).

Dental Considerations

• Rabbits have open-rooted teeth which grow continuously requiring regular attrition from chewing.

• Mal-alignment can create dental problems, leading to insufficient chewing and causing crowns to grow and form spurs.

• Sedation for repeat treatment is a common practice to address severe cases.

Urogenital Problems

• Common urogenital concerns include:

  • Uterine adeno carcinoma.

  • Spirochetosis (rabbit syphilis).

  • Uroliths (bladder stones) and calciuria (bladder sludge).

  • Occasional benign testicular tumors in older males.

Uterine Adenocarcinoma

• Identified as the most prevalent cancer in rabbits, with an occurrence near 80% in certain breeds over the age of 3 years.

• Most intact does are likely to develop uterine disease.

• Ovariohysterectomy is recommended for prevention.

Metastatic Uterine Adenocarcinoma

• Some rabbits may present with signs of metastatic disease impacting lungs, bones, or soft tissue.

Understanding Uterine Disease Causes

• Continuous hormonal release from the ovaries leads to changes in the uterine lining:

  • Initiates as endometrial hyperplasia, may progress to adenocarcinoma.

  • Slow rate of metastasis observed (approx. 7-9 months).

  • Early diagnosis and spaying may be curative.

Causes of Hematuria

• Common reasons include:

  • Porphyrins (rust-colored pigment) mistaken for blood.

  • Cystitis where blood presence is unlikely.

  • Urolithiasis leading to stones in the urinary tract.

  • Uterine adenocarcinoma.

  • Benign endometrial disease.

• Important diagnostic question: Is the rabbit a female? Is she spayed?

Other Urinary Problems

• Conditions related to urinary health include:

  • Bacterial cystitis (uncommon, bleeding rare).

  • Crystal cystitis resulting in sludge-like urine.

  • Urolithiasis arising from stone formations.

Calciuria vs. Urolithias

• All stones consist of calcium carbonate and are easily identifiable on radiographs.

• Calciuria issues can resolve with medical therapy, while stones generally require surgical intervention as they cannot be dissolved through diet.

Rabbit Syphilis: Treponema cuniculi

• Known as “vent disease”, also categorized as Treponematosis or Spirochetosis and is not zoonotic in nature.

Diagnosis and Treatment of Syphilis

• Commonly diagnosed through clinical signs, notably scabs on the nose and vent areas.

• PCR testing is used for confirmation.

• Treatment involves administering Penicillin, particularly with a regimen of two SQ doses of Combi-PenⓇ administered four days apart (Combi-Pen combines procaine and benzathine pen G).

Integumentary Disease: Parasites

• Ear Mites, specifically Psoroptes cuniculi, are common in rabbits and typically treated with ivermectin SQ or selamectin applied topically.

Fur Mites: Cheyletiella parasitavorax

• Commonly referred to as “Walking Dandruff”, prominently affecting older rabbits.

• Diagnosis may be confirmed via a Scotch-tape test on a slide.

• Treatment aligns with that for ear mites using ivermectin or selamectin.

External Parasite Control Alternatives

• Selamectin (Revolution®): Requires weekly application.

• Imidocloprid (Advantage®): Recommended every three weeks; more effective.

• Imidocloprid plus moxidectin (Advantage Plus®): Effective for ear mites, fur mites, fleas; also suitable for ferrets.

Safety Concerns with Fipronil (Frontline®)

• Inquiry regarding the safety profile of Fipronil for use in rabbits remains important as not all treatments are compatible.

Rabbit Viral Hemorrhagic Disease (RHD)

• A serious, highly contagious, and fatal disease primarily caused by Calicivirus.

• All lagomorphs are susceptible, and recent cases have emerged in the USA affecting wild rabbit populations.

• Symptoms include:

  • Acute fever (> 104 F) and bleeding.

  • Sudden death can occur, alongside liver failure.

• Vaccination options include Medgene killed virus vaccine, administered as two doses spaced three weeks apart.

Questions?

• Open Q&A session to address any additional concerns or inquiries regarding the health management of pet rabbits.