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Haw’s syndrome
Synonym(s): eye, diarrhea, third eyelid, Haws, Haw
Podcast: Haw's syndrome
Introduction
- Cause: idiopathic but speculatively it may be associated with tapeworm infestation or virus infection.
- Signs: a syndrome of prolapse of the third eyelids (nictitating membranes) often with diarrhea as well.
- Occasionally cats can be ill but they will recover with supportive care.
- Diagnosis: usually just on signs.
- Treatment: none.
- Prognosis: good, generally completely benign and self-limiting.
Presenting signs
- Third eyelid protrusion with no other ocular disease
.
- Diarrhea.
- Depression.
- Inappetence.
Age predisposition
- Most common in young adult cats but it seems to occur at all ages.
Cost considerations
- Occasionally a cat with this syndrome can be depressed and inappetent.
- In this case an extensive diagnostic work up and intensive supportive care may be necessary.
- Most cases can be diagnosed with a minimum of tests and require no treatment.
Pathogenesis
Etiology
- Idiopathic.
- Some clinicians think that there is a connection with tapeworm infestations.
- There is some evidence that the cause is an enteric virus infection. A torovirus-like agent was implicated in one study but this was not supported in a second paper.
Predisposing factors
General
- Age (<2 years old).
- Multiple cat household.
- Contact with cats which go outside.
Pathophysiology
- The condition is idiopathic and very little research has been performed.
- It is unknown whether there is a single condition or multiple causes with different pathological processes
- It is likely that there is disease affecting the autonomic nervous system.
- The main theory for this condition is that an enteric viral infection is the cause.
- How the virus causes diarrhea or third eyelid protrusion is unknown.
- It has been assumed that the third eyelid protrusion is caused by a dysfunction of the sympathetic innervation to the third eyelid which when functioning causes the third eyelid to be in the normal retracted position.
Timecourse
- Weeks to months.
- May be recurrent.
- When multiple, cats in a household are affected there is often a couple of weeks between the onset in different individuals.
Epidemiology
- The evidence that this is caused by an infection is that there are (largely anecdotal) reports that the syndrome often affects several cats in a multiple cat household.
- Some breeding colonies see successive litters of kittens affected.
Diagnosis
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Treatment
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Prevention
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Outcomes
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Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Smith C H, Meers J, Wilks C R et al (1997) A survey for torovirus in New Zealand cats with protruding nictatating membranes. N Z Vet J 45 (2), 41-43 PubMed.
- Papasouliotis K & Gruffydd-Jones T (1996) Chronic diarrhea/protrusion of the nictitating membrane in cats and torovirus. Brits VMA in Pract 18, 5.
- Muir P, Harbour D A, Gruffydd-Jones T J et al (1990) A clinical and microbiological study of cats with protruding nictitating membrane and diarrhea - isolation of a novel virus. Vet Rec 127 (13), 324-330 PubMed.
Other sources of information
- Mitchell N & James Oliver J (2015) Feline Ophthalmology – The Manual. Natasha Mitchell and James Oliver. Grupo Asis. ISBN 978-84-16315-11-6.
- BSAVA Manual of Canine and Feline Ophthalmology (2014) 3rd edn. Edited by David Gould and Gillian McLellan. ISBN 978-1-905319-42-8.
- BSAVA Manual of Feline Practice (2013) Edited by Harvey and Tasker. ISBN 978190531939-8.