Camelid - Neurologic Dz Flashcards
What is the causative agent of parasitic myelopathy (a.k.a. ‘meningeal worm’) of camelids?
Parelaphostrongylus tenuis (nematode).
Describe the life cycle of P. tenuis.
Definitive host = white-tailed deer: adults living in subdural space and associated vessels lay eggs –> hatch in pulmonary capillaries –> L1 migrate to alveoli, coughed up and swallowed –> L1 passed in feces –> ingested by intermediate host = snails –> molt x 2 –> snails containing L3 ingested by definitive hosts or aberrant hosts e.g. camelids.
Describe the pathophysiology of P. tenuis infection in camelids.
in snails ingested by camelid –> migration to CNS parenchyma –> scattered foci of haemorrhagic necrosis and parenchymal loss –> CSx in ~40-50d.
List the neurologic deficits reported in camelids with parasitic myelopathy.
- Typical CSx: wide-based hindlimb stance, hindlimb ataxia +/- progressing to recumbency; BAR.
- Lesions vary: can see FL or lateralised deficits.
- Atypical form: brain involvement –> acute-onset brain or vestibular signs including depression, seizures,
circling, leaning, head tilt, and slow PLRs.
How do you diagnose parasitic myelopathy in a camelid anti-mortem?
- CSF: eosinophilic pleocytosis with inc protein in most cases.
- CBC: usually WNL +/- inc CK and AST.
At what time of year is parasitic myelopathy most frequently observed and in what age group of camelids?
Autumn and Winter (Oct to Mar).
Adults > young animals.
Describe the characteristic lesions of parasitic myelopathy observed on post-mortem of affected camelids.
Lesions of parasite migration: randomly distributed axonal degeneration that progresses to pannecrosis characterised by axon and axon sheath swelling, axon drop out, axonophagia, accumulation of gitter cells.
Lesions mainly in white matter.
Larvae rarely seen.
Outline the treatment of parasitic myelopathy in camelids.
- Fenbendazole 50mg/kg PO for 5 days.
- NSAIDs e.g. flunixin meglumine 1mg/kg q24-48h.
- DMSO in severe cases.
- Vitamin E and B (non-specific therapy).
- IVF if required.
- Physical therapy.
What is the prognosis for survival in cases of parasitic myelopathy of camelids?
- Good if able to stand with assistance.
- Poorer if recumbent.
- Guarded with brain lesions.
What segment of the spinal cord is most frequently affected by trauma in camelids and was is the most common source of the trauma?
- Cervical spinal cord.
- Fence-related injuries.
Describe clinical examination findings in a camelid with cervical trauma.
- ‘Lump’ or ‘kink’ in neck (fibrosis, periosteal reaction).
- Abnormal head and neck posture.
- UMN/LMN deficits in FLs, UMN deficits in HLs.
- May not see CSx after acute inflammation resolves due to wide spinal canal.
List treatment options for traumatic lesions of the cervical spinal cord in camelids?
- Supportive care: NSAIDs, confinement.
- Sx may be indicated in young, growing animals to stabilise vertebral canal –> aim to produce fusion between neighbouring vertebrae.
List possible aetiologies of otitis media in camelids.
- Ascending infection up the eustachian tubes.
- Extension of otitis interna.
- Spinous ear ticks (Texas).
- Most common bacteria isolated: Arcanobacter pyogenes, Staphylococcus app and Bacillus spp.
What abnormalities may be identified on neurologic examination of a camelid with otitis media?
Head tilt, facial nerve deficits (e.g. droopy ear, flaccid facial muscles, ptosis, inability to blink), circling, ataxia, nystagmus.
How do you diagnose otitis media in a camelid?
- CT ideal.
- Radiographs may be helpful if bony changes present.
- CSF to rule out other causes of vestibular dz e.g. listeriosis; protein inc in 50% cases.
