A 1-year-old sexually intact female Brazilian Shorthair cat was evaluated because of bilateral third eyelid protrusion and tremor episodes that had started 4 days earlier. According to the owner, the cat had had 1 episode of diarrhea that had resolved spontaneously. The 4 other cats that lived with the patient were healthy.
During physical and neurologic examinations, a low body condition score (3/9), dehydration (7%), moderate bilateral third eyelid protrusion, and neurologic deficits consistent with lumbosacral myelopathy were observed. According to the owner, signs of paraplegia and urinary incontinence had been present since the cat had been adopted.
Assessment
Anatomic diagnosis
The bilateral third eyelid protrusion could have been due to a lesion in the sympathetic pathway, contraction of the extraocular muscles, or a trigeminal nerve lesion. However, the absence of other neurologic signs (eg, eyelid ptosis, miosis, enophthalmos, and atrophy of the masticatory muscles) made a partial deficit in the sympathetic pathway the most likely explanation. For the paraplegia, a T3-L3 or L4-S3 myelopathy could have been considered. The absence of postural reactions and deep pain sensation in the hind limbs was suggestive of a T3-L3 or L4-S3 myelopathy; however, given the absence of spinal reflexes and muscle tone, T3-L3 myelopathy was excluded.
Likely location of a single lesion
Suspected locations of lesions were the sympathetic pathway to the eyes and L4-S3 spinal cord segments.
Etiologic diagnosis
Differential diagnoses considered for the third eyelid protrusion included enophthalmos secondary to cachexia or dehydration, microphthalmia, sedation or anesthesia, retrobulbar neoplasia, Cannabis intoxication, tetanus, rabies, a trigeminal nerve lesion, atrophy of the masticatory muscles, facial paralysis, dysautonomia, Horner syndrome, and Haws syndrome. Given the recent history of diarrhea and absence of other ophthalmic and neurologic deficits, dehydration was considered a possibility. However, a deficit in the sympathetic pathway resulting in Haws syndrome was also suspected.
Diagnostic Test Findings
The cat received IV fluid therapy with lactated Ringer solution, and blood samples were subsequently collected for clinicopathologic testing. Subcutaneous fluid therapy was then administered for 3 days while results of clinicopathologic testing were pending. After 4 days, the third eyelid protrusion and tremors persisted, suggesting that dehydration was not the underlying cause. Results of a CBC and serum biochemical profile were unremarkable, other than a high γ-glutamyltransferase (18 U/mL) activity.
The cat was administered 10% phenylephrine eye drops to establish a diagnosis of Haws syndrome (Figure 1). Ten minutes after 1 drop was administered to each eye, the third eyelid protrusion resolved, confirming the clinical suspicion. The owner was told that the cat’s vision was not impacted by the protrusion, treatment was not required, and spontaneous resolution was possible. After 35 days, the cat was rechecked and protrusion was no longer observed, although the owner reported that the third eyelids protruded in stressful situations.
Photographs of a 1-year-old Brazilian Shorthair cat that was evaluated because of bilateral third eyelid protrusion (A) and appearance 5 (B) and 10 (C) minutes after administration of 10% phenylephrine eye drops, confirming a diagnosis of Haws syndrome. The third eyelid protrusion resolved spontaneously after 35 days, although the owner reported that the third eyelids occasionally still protruded in stressful situations.
Citation: Journal of the American Veterinary Medical Association 260, 8; 10.2460/javma.20.12.0719
Photographs of a 1-year-old Brazilian Shorthair cat that was evaluated because of bilateral third eyelid protrusion (A) and appearance 5 (B) and 10 (C) minutes after administration of 10% phenylephrine eye drops, confirming a diagnosis of Haws syndrome. The third eyelid protrusion resolved spontaneously after 35 days, although the owner reported that the third eyelids occasionally still protruded in stressful situations.
Citation: Journal of the American Veterinary Medical Association 260, 8; 10.2460/javma.20.12.0719
Photographs of a 1-year-old Brazilian Shorthair cat that was evaluated because of bilateral third eyelid protrusion (A) and appearance 5 (B) and 10 (C) minutes after administration of 10% phenylephrine eye drops, confirming a diagnosis of Haws syndrome. The third eyelid protrusion resolved spontaneously after 35 days, although the owner reported that the third eyelids occasionally still protruded in stressful situations.
Citation: Journal of the American Veterinary Medical Association 260, 8; 10.2460/javma.20.12.0719
Comments
Haws syndrome is characterized by bilateral third eyelid protrusion, is more common in young cats, and is typically not accompanied by other clinical signs.1,2 However, a recent history of self-limiting diarrhea may be reported in some animals,1–3 as was the case for the cat of the present report. Published information on this syndrome is scarce, probably owing to lack of interest among researchers, given that the disease is self-limiting and has a favorable prognosis. Nevertheless, veterinary practitioners should be aware of the syndrome so they can reassure owners4,5 and avoid misdiagnosis.
The etiology of Haws syndrome is still under discussion, but the condition is thought to be idiopathic.1–3,5 Gastrointestinal tract infections accompanied by fever5 and diarrhea1–3 have been described as a suspected cause. In addition, there are reports1,6 of a Torovirus being isolated from cats with third eyelid protrusion and persistent, watery diarrhea for up to 2 weeks. However, this virus is not always identified in affected cats and the syndrome was not generated through transmission of Torovirus to other cats.5 In agreement with this, none of the other cats that lived with the affected cat described in the present report had similar signs. Another theory still without consistent scientific evidence is inflammation of the superior cervical sympathetic ganglion as the cause of Haws syndrome.2
Haws syndrome is a rare disorder and should be differentiated from other causes of third eyelid prolapse.4,7,8 Complete physical, ophthalmologic, and neurologic examinations should be performed in affected cats, although other abnormalities are not expected. The diagnosis is confirmed by observing resolution of the third eyelid protrusion after administration of sympathomimetic eye drops (eg, 1% or 2% epinephrine or 10% phenylephrine),2,4 as was the case of the cat described here.
Treatment of Haws syndrome is not necessary in most cases and is only recommended if the protruding third eyelids interfere with the cat’s vision or if the syndrome is accompanied by debilitating gastrointestinal tract disease.1,2,4 In the first situation, sympathomimetic eye drops should be administered to retract the third eyelids or mydriatic eye drops can be used to cause pupil dilation.2 In most cases, third eyelid protrusion resolves spontaneously, with a reported mean time to resolution of 47 days for individual cats.4 However, time to resolution can range from 6 months to 1 year for cats living in colonies.3 Gastrointestinal disturbances should be individually evaluated to select the best treatment, as there is no consensus on the underlying etiology.
Interestingly, in the cat described in the present report, third eyelid protrusion recurred in stressful situations, which has not been reported previously.4,5 Further investigation is required to fully understand the clinical aspects of Haws syndrome in cats.
Acknowledgments
The authors thank the Brazilian Ministry of Education for providing a scholarship for a veterinary medicine residency, which allowed the presentation of this case.
The authors declare that there were no conflicts of interest.
References
- 2. ↑
Gellat KN, Plummer CE. Neuro-ophthalmic syndromes. In: Gellat KN, Plummer CE, eds. Color Atlas of Veterinary Ophthalmology. 2nd ed. John Wiley & Sons; 2017:381–391.
- 3. ↑
Papasouliotis K, Gruffydd-Jones T. Practical approach to diarrhoea in the cat. In Pract. 1996;18(5):206–214.
- 4. ↑
Corrêa LFD, Santalucia S, de Oliveira MT, et al. Haw’s syndrome in cats. Acta Sci Vet. 2014;42(suppl 1):1–5.
- 5. ↑
Smith CH, Meers J, Wilks CR, Rice M, Jones BR. A survey for torovirus in New Zealand cats with protruding nictitating membranes. N Z Vet J. 1997;45(2):41–43. doi:10.1080/00480169.1997.35987
- 6. ↑
Muir P, Harbour DA, Gruffydd-Jones TJ, et al. A clinical and microbiological study of cats with protruding nictitating membranes and diarrhoea: isolation of a novel virus. Vet Rec. 1990;127(13):324–330. Abstract.
- 7. ↑
Hartley C. The conjunctiva and third eyelid. In: Gould D, McLellan GJ, eds. BSAVA Manual of Canine and Feline Ophthalmology. 3rd ed. British Small Animal Veterinary Association; 2014:182–199.
- 8. ↑
Garosi L, Lozrie M. Neuro-ophthalmology. In: Gould D, McLellan GJ, eds. BSAVA Manual of Canine and Feline Ophthalmology. 3rd ed. British Small Animal Veterinary Association; 2014:357–383.
