Page 1416 - Cote clinical veterinary advisor dogs and cats 4th

Orbital Diseases 717

• Variable systemic signs, depending on DIAGNOSIS • Orbital abscess/cellulitis:
underlying cause Diagnostic Overview ○ Abscess is suspected if the oral mucosa
VetBooks.ir behind the last upper molar with orbital The diagnosis is suspected based on the time and conjunctiva and eyelids are inflamed. Diseases and Disorders
caudal to last upper molar is abnormal
• Inflamed oral mucosa or draining fistula
In such cases, medical stabilization (e.g.,
abscess
frame of clinical signs, signalment, and clinical
Etiology and Pathophysiology appearance of the affected eye. Orbital imaging rehydration) is warranted if necessary,
followed by surgical drainage by blunt
may be necessary for a definitive diagnosis if
Exophthalmos caused by space-occupying the globe is normal. dissection under general anesthesia
orbital lesion caudal to the eye: with small hemostats. Samples should
• Congenital Differential Diagnosis be obtained for aerobic and anaerobic
○ Orbital varix, arterial to venous shunts Exophthalmos: culture and susceptibility (C&S). Often,
(rare) • Buphthalmos oral lesion is not visible, and in those cases,
○ Orbital cysts and dermoids (rare) • Episcleritis/scleritis empirical treatment with broad-spectrum
• Acquired Enophthalmos: oral antibiotics is advised.
○ Ocular proptosis: usually unilateral, • Microphthalmia ○ Systemic nonsteroidal antiinflammatory
peracute, trauma associated • Phthisis bulbi drugs (NSAIDs) for 7 days; may require
○ Orbital abscess/cellulitis: usually unilat- • Ruptured globe longer depending on resolution of pain
eral, peracute to acute, painful resistance and inflammation.
to ocular retropulsion and mouth Initial Database ■ Dogs: carprofen 2.2 mg/kg PO q 12h,
manipulation • Complete ophthalmic exam (p. 1137) meloxicam 0.1 mg/kg PO q 24h, or
○ Orbital hemorrhage: secondary to coagu- • Complete neurologic exam, especially cranial deracoxib 1-2 mg/kg PO q 24h
lopathy or head trauma nerves (p. 1136) ■ Cats: tolfenamic acid 4 mg/kg SQ, IM,
○ Orbital neoplasia: usually unilateral, • Oral exam if orbital abscess suspected (e.g., or PO q 24h for 3-5 days, robenacoxib
progressive, typically not painful, primary buccal pain and/or purulent drainage) 1 mg/kg q 24h PO for 3 days, or
or secondary, predominantly malignant • Nasal airflow if nasal neoplasm with second- meloxicam 0.3mg/kg once SQ
○ Feline restrictive orbital myofibroblastic ary orbital invasion suspected ○ Broad-spectrum oral antibiotics for
sarcoma (FROMS; previously orbital • CBC, serum biochemistry profile, urinalysis, 14-28 days (amoxicillin-clavulanic acid
pseudotumor [cats]): rare, progressive skull radiographs, thoracic radiographs, fine- 13.5 mg/kg PO q 12h [dogs] or 62.5 mg
debilitating neoplastic orbital disease; needle aspiration of submandibular lymph PO q 12h [cats]). Amoxicillin-clavulanic
restricts mobility of the eyelids and globe; nodes if enlarged, abdominal ultrasound if acid is the first-choice antibiotic for this
may become bilateral condition orbital neoplasm suspected condition.
○ Mucocele: unilateral, progressive, arising ○ CBC may reveal evidence of inflammation ○ Hospitalization with supportive treatment
from zygomatic salivary gland (bands, toxic changes in neutrophils) with for first postoperative 24-48 hours (if
○ Myositis: bilateral, enophthalmia occurring orbital abscess necessary)
in late stages • Pharmacologic testing (topical 1% or 10% • Orbital neoplasia
Enophthalmos: caused by loss of orbital phenylephrine) for Horner’s syndrome ○ Surgical excision (exenteration, orbi-
volume or space-occupying lesion rostral to totomy, or orbitectomy) may require
the eye: Advanced or Confirmatory Testing referral to a veterinary ophthalmologist or
• Acquired • Ocular/orbital ultrasound if exophthalmos surgeon.
○ Facial fractures with associated displace- (differentiates orbital abscess, cellulitis, and ○ Adjunctive radiation therapy or chemo-
ment of orbital tissues mass) therapy, depending on type of neoplasm
○ Loss of orbital fat or muscle (e.g., weight • CT or MRI if exophthalmos (fully assess (consult veterinary oncologist)
loss, orbital fractures, cachexia) orbital mass or foreign body) • Feline restrictive orbital myofibroblastic
○ Ocular pain • Ultrasound-guided fine-needle aspiration or sarcoma: Exenteration with adjunctive radio-
○ Dehydration biopsy of orbital mass, abscess, or mucocele therapy and/or chemotherapy (referral to a
○ Horner’s syndrome under general anesthesia (referable procedure) veterinary oncologist) has been suggested as a
○ Secondary to atrophy of the masticatory • Masticatory or extraocular muscle biopsies treatment, but most patients are euthanized
muscles from myositis episode or age under general anesthesia (e.g., myositis; due to the grave prognosis.
○ Neoplasia anterior to the eye (e.g., rostral referable procedure) • Mucocele: surgical excision (typically cura-
orbit) tive); may require referral to a veterinary
○ Tetanus (rare) TREATMENT ophthalmologist or surgeon (p. 894)
Strabismus; typically caused by lesions restrict- • Myositis: prednisone 1-2 mg/kg PO q 12h,
ing extraocular muscle mobility or affecting Treatment Overview tapered gradually after response to treatment
their innervation: Although treatment of orbital abscesses and is noted (p. 637). This is long-term therapy
• Congenital myositis may not always require referral, treat- that should be tapered every 2-4 weeks
○ Unilateral or bilateral, progressive juvenile ment options for orbital neoplasms are likely to pending response to treatment. Additional
fibrosis of the medial rectus muscle seen require referral to a veterinary ophthalmologist, immunosuppressive drugs may be required
in Shar-pei dogs surgeon, and oncologist. if response to treatment is not seen within
○ Bilateral medial strabismus (esotropia) in • If possible, return the eye to its normal 1-2 weeks.
Siamese cats position.
• Acquired • Alleviate pain. Possible Complications
○ Trauma-induced extraocular muscle avul- • Preserve vision (optic neuropathy and/or • Permanent strabismus or third eyelid
sion or scarring retinal detachment may occur with space- protrusion
○ Extraocular muscle scarring from previous occupying orbital lesions). • Blindness
inflammation • Loss of the eye
○ Abnormal innervation of extraocular Acute General Treatment • Systemic complications possible (potentially
muscle(s) (e.g., cranial nerve [CN] III, Treat underlying cause: death), depending on extent of disease
IV, and/or VI lesions) • Ocular proptosis (p. 823) process

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