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

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.