Definition and classification of conjunctivitis. Differential diagnosis of red eye.
Definition
Inflammation of the bulbar and or palpebral conjunctiva (the transparent lubricating mucous membrane that covers both the surface of the eye and lining of the undersurface of the eyelid)
Acute conjunctivitis: duration < 4 weeks
Chronic conjunctivitis: > 4 weeks.
Overview
It makes the eye appear pink or reddish. There may also be pain, burning, scratchiness, or itchiness. The affected eye may have increased tears or be "stuck shut" in the morning. Swelling of the white part of the eye may also occur. Conjunctivitis can affect one or both eyes. The most common infectious causes are viral followed by bacterial. Diagnosis is often based on signs and symptoms. Occasionally a sample of the discharge is sent for culture.
Etiology:
- infectious: bacteria, viruses, fungi, parasites
- irritation: physical or chemical stimuli, UV light, trauma
- allergic diseases
- secondary inflmmation: Sicca syndrom, spreaded inflammation (sinusitis), incorrect corrected refraction error
Differential diagnosis
There are more serious conditions that can present with a red eye, e.g. keratitis, angluce-closure glaucoma or iritis. Signs of such conditions include decreased vision, significantly increased sensitivity to light, inablitily to keep eye open, pupil that does not respond to light or a severe headache with nausea. Fluctuating blurring is common, due to tearing and mucoid discharge. Mild photphobia is common, However, if any of these symptoms are prominent, it is important to consider other diseases such as glaucoma, uveitis, keratitis and even meningitis or carotico varnous fstula
DD red eye
- corneal abrasion
- subconjunctival hemorrhae
- pinguecula
- blepharitis
- dacryocystitis
- keratoconjunctivitis sicca
- keratitis
- herpes simplex
- herpes zoster
- episcleritis – an inflammatory condition that produces a similar appearance to conjunctivitis but without discharge or tearing
- uveitis
- acute angle closure glaucuoma