Top 10 Canine Neurological Conditions for NAVLE Success: Part 2
Introduction
In this continuation of our series on canine neurological conditions, we delve into five more critical disorders that veterinary professionals should master for the NAVLE. Understanding these conditions, their diagnosis, and treatment options is essential for ensuring the best outcomes for canine patients.
6. Fibrocartilaginous Embolism (FCE) / Type III Disc
Classic Case:
FCE typically presents as acute, asymmetrical, non-painful, and non-progressive paraparesis or tetraparesis, often following vigorous exercise. While it can affect any breed, it is most common in large nonchondrodystrophoid breeds, as well as miniature schnauzers and Shetland sheepdogs.
Diagnosis:
- MRI: The preferred diagnostic tool for identifying FCE.
- Myelography: May show normal results or slight swelling of the spinal cord.
Treatment:
- Bladder Management: Use an indwelling catheter or manually express if necessary.
- Ulcer Prevention: Frequent turning and well-padded bedding.
- Physical Therapy: To support recovery.
- Steroids: Use is controversial and generally avoided.
Pearls:
- FCE is characterized by the embolization of fibrocartilage into the spinal cord.
- Type III disc refers to a non-compressive nucleus pulposus extrusion.
7. Otitis Media/Interna
Classic Case:
Symptoms include a head tilt toward the lesion, horizontal nystagmus (fast phase away from the lesion), ataxia, and circling. It may also present with ipsilateral facial neuropathy or Horner syndrome but does not affect conscious proprioception.
Diagnosis:
- MRI or CT: For imaging the inner and middle ear structures.
- Otoscopy and Myringotomy: To collect fluid for cytology and culture.
Treatment:
- Myringotomy: To relieve fluid and obtain samples.
- Antibiotics: Based on culture and sensitivity results.
- Bulla Osteotomy: For surgical intervention if necessary.
Pearls:
Infection routes include otitis externa, hematogenous spread, or via the auditory tube.
8. Encephalitis
Classic Case:
Clinical signs vary depending on the affected brain region and may include seizures, circling, pacing, abnormal behavior, head pressing, ataxia, and nystagmus.
Diagnosis:
- CBC and CSF Analysis: To check for elevated protein, cytology, and infectious agents.
- Infectious Disease Testing: Includes titers or PCR for distemper, Toxoplasma, Neospora, and other pathogens.
- MRI: May be utilized to assess brain structures.
Treatment:
- Idiopathic or Noninfectious: Immunosuppression.
- Fungal Infections: Antifungals.
- Rickettsial Infections: Doxycycline.
- Bacterial Infections: Antibiotics.
- Protozoal Infections: Clindamycin or sulfonamides.
Pearls:
- Necrotizing meningoencephalitis and necrotizing leukoencephalitis can be breed-related.
- Granulomatous meningoencephalomyelitis (GME) is a common noninfectious cause.
9. Idiopathic Laryngeal Paralysis
Classic Case:
Dogs exhibit stridor, dysphonia, and coughing or retching when eating or drinking. It commonly affects older large or giant breeds such as Labradors, Chesapeake Bay retrievers, and Afghan hounds.
Diagnosis:
- Laryngoscopy: Conducted under light anesthesia.
- Rule Out: Conditions like hypothyroidism and myasthenia gravis.
Treatment:
- Exercise Restriction and Stress Avoidance: Key management strategies.
- Arytenoid Lateralization: Also known as tieback surgery.
Pearls:
Prognosis is guarded to good if treated appropriately, with complications such as aspiration pneumonia being possible.
10. Acquired Myasthenia Gravis
Classic Case:
Symptoms include episodic weakness, coughing, gagging, regurgitation, and a depressed or absent palpebral reflex upon repeated stimulation. There is no loss of conscious proprioception.
Diagnosis:
- Acetylcholine Receptor Antibody Test: The gold standard for diagnosis.
- Edrophonium Challenge Test: Conduct with atropine available for cholinergic crisis.
- Thoracic Radiographs: To check for megaesophagus or aspiration pneumonia.
Treatment:
- Supportive Care: Includes antibiotics for aspiration pneumonia and elevated feeding.
- Anticholinesterase Drugs: Such as pyridostigmine (Mestinon®).
Pearls:
Prognosis is guarded with conditions like megaesophagus and aspiration pneumonia, especially in breeds like German shepherds and golden retrievers.