Retrospective assessment of ophthalmic disease development in domestic dogs and cats when hospitalised with tick paralysis caused by Ixodes holocyclus

B D Reynolds; E Perry; H G Nagel; C J Whittaker; K A Caruso; M J Annear; W M Irving; P M McCarthy; A Dion; Jm-S Yi; E Hall; J S Smith

doi:10.1111/avj.13325

Retrospective assessment of ophthalmic disease development in domestic dogs and cats when hospitalised with tick paralysis caused by Ixodes holocyclus

Aust Vet J. 2024 Feb 18. doi: 10.1111/avj.13325. Online ahead of print.

Authors

B D Reynolds¹, E Perry², H G Nagel³, C J Whittaker¹, K A Caruso¹, M J Annear¹, W M Irving¹, P M McCarthy¹, A Dion², Jm-S Yi², E Hall⁴, J S Smith¹

Affiliations

¹ Eye Clinic for Animals, Sydney, New South Wales, 2064, Australia.
² Northside Emergency Veterinary Service, Sydney, New South Wales, 2084, Australia.
³ Terrey Hills Animal Hospital, Sydney, New South Wales, 2084, Australia.
⁴ University of Sydney, Sydney, New South Wales, 2006, Australia.

PMID: 38369322
DOI: 10.1111/avj.13325

Abstract

Objective: To investigate the incidence and predisposing factors leading to the development of corneal ulcers and the loss of a palpebral reflex in hospitalised canine and feline patients with tick paralysis (TP).

Animals studied: A total of 102 dogs and 100 cats retrospectively were assessed from previously hospitalised patients.

Methods: A retrospective cohort study was performed on 102 different canine and 100 different feline patients who were hospitalised for TP from October 2020-January 2022. Patient data were collected, and logistic regression was conducted to determine factors affecting the palpebral reflex and the development of corneal ulcers.

Results: Corneal ulcers occurred in 23/102 (22.5%) dogs during hospitalisation and were strongly associated with an incomplete palpebral reflex ipsilaterally during hospitalisation (P < 0.001), hospitalisation ≥3 days (P = 0.004), mechanical ventilation ≥3 days (P = 0.015) or a tick location cranial to C1 (P = 0.003). An incomplete palpebral reflex during hospitalisation was observed in 29/102 (28.4%) dogs and was significantly associated with decreasing patient weight (P = 0.018), increasing days hospitalised (P = 0.001), having a tick found cranial to C1 (P = 0.004), highest recorded GP grade (P = 0.01), highest recorded RP grade (P = 0.005), use of amoxycillin-clavulanic acid during hospitalisation (P = 0.002) and use of piperacillin/tazobactam during hospitalisation (P = 0.003). There was a significant association between the loss of a complete palpebral reflex and mortality during hospitalisation in dogs (OR = 4.5, P = 0.029). Corneal ulcers occurred in 10/100 (10.0%) cats during hospitalisation, and was significantly more likely to occur to an eye if an incomplete palpebral reflex was observed ipsilaterally during hospitalisation (OR = 20.1, P < 0.0001) and with increasing patient age (P = 0.019). The absence of a complete palpebral reflex during hospitalisation was observed in 18/10 (18.0%) cats and was significantly associated with increasing days hospitalised (P = 0.034). There was no significant association between the loss of a complete palpebral reflex and mortality during hospitalisation in cats.

Conclusions: The frequency of corneal ulcers and loss of palpebral reflexes were significant in dogs and cats hospitalised by TP, with many factors contributing to the risk of these developing.

Keywords: emergency medicine; feline medicine; ophthalmology; small animal medicine; small animal practice; tick.