ORBITAL DISCHARGE
ORBITAL DISCHARGE: Excerpt from Differential Diagnosis in Primary Care
A clear or purulent discharge from the eye is usually due to allergy or infection, but a few notable exceptions exist. In addition to using anatomy to formulate the list of diagnostic possibilities, it is well to apply the mnemonic MINT to the various anatomic components.
ORBITAL DISCHARGE
Beginning with the eyelids, one should recall the following:
- M—Malformations like a chalazion, ectropion, and entropion
- I—Inflammatory conditions like blepharitis, a hordeolum (stye), and allergic or infectious conjunctivitis
- N—Neoplasms such as squamous cell carcinoma and angioma
- T—Traumatic conditions, especially foreign bodies
The nasolacrimal duct may become inflamed and obstructed (dacryocystitis). The bulbar conjuctiva may be involved by malformations like a pterygium or a pingueculae and cause a clear discharge. Inflammatory and traumatic conditions here are similar to those of the palpebral conjunctiva. It is well to mention toxic causes of a nonbloody discharge, such as irritation from tobacco smoke, cold, and irritating gases; chronic alcoholism, arsenic poisoning, and iodism may cause a clear discharge.
Separating the eyeball into its various components, one recalls the cornea and immediately one should think of a foreign body of the cornea or of a laceration, a keratitis, and malformations like keratoconus. Next the iris suggests iritis as a cause of discharge, but by using the mnemonic one will not forget albinism as a cause of excessive tearing. In addition, the iris angle should remind one of acute glaucoma, which often presents with lacrimation as well as with pain. The lens should suggest refractive errors as a major cause of a clear discharge and predisposition to infection of the lids. Finally, the sclera is the site of episcleritis and scleritis, which are frequently associated with a nonbloody discharge.
Turning to the lacrimal gland one should remember mumps of this gland and other infections. The vascular supply to the eye should suggest the tearful discharge of histamine cephalalgia and obstruction of the venous drainage by a cavernous sinus thrombosis. Paralysis of the muscles of the eye, especially the facial nerve, creates a discharge by excessive exposure to dust and air.
Approach to the Diagnosis
Anatomy has served us well in developing a differential, although the cause of a discharge from the eye is often easy to establish. Foreign bodies, trauma, toxins, and conjunctivitis are the conditions most commonly responsible. This is why in the approach to the diagnosis one will first examine the eye carefully under magnification and use fluorescein to rule out a foreign body or laceration. Then, a careful history of exposure to toxins (e.g., industrial) is in order. Finally, if the discharge is unilateral, a smear and culture of specific bacteria are valuable before treatment. If it is bilateral, allergy should be considered, as well as refractive errors. Tonometry should be performed. Referral to. an ophthalmologist may be appropriate at any one of these stages (when in doubt, refer it out).
Other Useful Tests
- CBC and differential
- Sedimentation rate
- Urinalysis
- Smear and culture of discharge
- VDRL test
- Tuberculin test
- ANA test (uveitis)
- Smear for eosinophils (allergic conjunctivitis)
- Tonometry (glaucoma)
- Refraction
- Thyroid function test (Graves disease)
- Visual fields
- X-ray of skull
- X-ray of sinuses (acute sinusitis)
- Sonogram
- CT scan (orbital tumor)
- Biopsy
- Exploratory surgery
- Mumps skin test
- Histamine test (histamine cephalalgia)
Book Source Details
- Book Title: Differential Diagnosis in Primary Care
- Author(s): R. Douglas Collins
- Year of Publication: 2007
- Copyright Details: Differential Diagnosis in Primary Care, Copyright © 2007 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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