Clinicopathological findings in cats with haws syndrome.

Haws syndrome is a relatively common yet poorly understood disorder in cats. Ten cats with acute haws syndrome underwent ophthalmic and physical examinations, bloodwork, faecal analysis and pharmacological testing with 1% phenylephrine. The cats were discharged with broad-spectrum deworming (with or without metronidazole) as well as topical tetrahydrozoline. Cats were 17.6 ± 9.1 (2‒36) months old. All eyes had bilateral third eyelid protrusion and ptosis but no miosis or other ocular abnormalities. Diarrhoea was noted in four of 10 cats; otherwise, the cats were systemically healthy. A newly adopted kitten with haws syndrome and diarrhoea caused the condition to develop in the other three cats (from the same multicat household) within 4‒11 days. All cats tested negative for feline immunodeficiency virus and feline leukaemia virus. Serum amyloid A levels were elevated in two of eight tested cats. Tests for the presence of Giardia were positive in four of nine tested cats. Clinical signs transiently resolved within 20 minutes of the application of topical phenylephrine or tetrahydrozoline. Haws syndrome resolved in nine of the 10 cats within 37.7 ± 23 (12‒95) days but recurred in three of the nine cats 156‒182 days later. The small sample size limits the conclusions that can be drawn. Haws syndrome occurs in generally healthy cats, with or without diarrhoea, and is characterised by a sympathetic neuropathy causing bilateral third eyelid protrusion and ptosis. Clinical signs are possibly triggered by contagious gastrointestinal pathogen(s) that presumably affect(s) the gut microbiota and influence(s) the gut‒brain axis.