Page 1339 - Problem-Based Feline Medicine

66 – THE CAT WITH AN ABNORMAL THIRD EYELID 1331

NEOPLASTIC
● Squamous cell carcinoma*** (p 1134)
Proliferative pink mass growing from the third eyelid with verrucous or ulcerated surface.
● Other neoplastic disease of the third eyelid (adenoma, adenocarcinoma, mast cell
tumor, lymphoma, hemangioma)* (p 1138)
Tumors result in generalized swelling, a localized mass lesion, or erosion on the third eyelid.
Hemangioma may form a discrete mass on the third eyelid, usually red to purple in color, which
may hemorrhage.
PHYSICAL
● Prolapsed gland of the third eyelid (p 1340)
Pink to red mass protruding from behind the leading edge of the third eyelid (rare).
● Everted nictitans cartilage (p 1331)
Folded edge of third eyelid margin, without fleshy mass suggestive of gland prolapse (rare).
● Third eyelid prominence related to ocular pain* (p @)
Occurs secondary to enophthalmos (globe retraction) due to the pain.
INFECTIOUS
● Infectious disease involving the conjunctiva of third eyelid (feline herpesvirus-
1**, Chlamydophila felis** Mycoplasma*) (p 1337)
Signs include acute onset of hyperemia and chemosis of conjunctival surfaces and serous or
mucopurulent ocular discharge, often together with concurrent upper respiratory tract signs.
Chlamydial and mycoplasmal conjunctivitis may involve one or both eyes initially, and her-
pesvirus causes bilateral involvement.
● Tetanus (p 1339)
Bilateral third eyelid prominence in association with contraction of facial muscles, and increased
tone in muscles of mastication (“lockjaw”). Rare in cats.
IMMUNE
● Eosinophilic keratoconjunctivitis** (p 1335)
Pink to whitish plaque-like thickening of the third eyelid, sometimes associated with similar
lesions on the cornea.
IDIOPATHIC

● Third eyelid dysautonomia (“Haws”)*** (p 1338)
Acute onset of bilateral third eyelid prominence, which is non-painful, and resolves over days to
weeks without treatment.
● Feline dysautonomia (p 1338)
Third eyelid prominence, in association with any of a range of other systemic signs, e.g. keratocon-
junctivitis sicca, dilated non-responsive pupils, anisocoria, dry nose and/or mouth, bradycardia, consti-
pation megaesophagus and urinary or fecal incontinence. Onset of signs is over 48 h, and is associated
with depression and anorexia.

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