History
Diphtheria begins as a respiratory infection with strident coughing and fever.
Physical
Ocular manifestations of diphtheria, as those involving other organ systems, are both a result of the primary infection (keratoconjunctivitis) and the release of exotoxin (motility disorders).
In the eye, conjunctival infection may be mild, resembling a viral conjunctivitis with preauricular adenopathy, palpebral and bulbar conjunctival erythema and edema, and a moderate amount of yellowish discharge.
The more typical diphtheric infection is that of membranous conjunctivitis. Infiltration of the conjunctival surface leads to extreme edema and erythema of the eyelids with increasing stiffness of the lids. Membrane formation occurs over the palpebral and bulbar conjunctivae, and the membrane ultimately becomes necrotic and sloughs off, leaving behind severe conjunctival scarring with formation of symblepharon, entropion, trichiasis, and tear production disturbances. The conjunctiva may become necrotic, and thrombosis of perilimbal vessels can lead to corneal ulceration and scarring and to corneal perforation from corneal ischemia.
Up to 25% of patients with severe primary disease develop neurotoxicity from the effects of the exotoxin. Local paralysis of the soft palate and posterior pharyngeal wall are most common with other cranial neuropathies, leading to oculomotor and ciliary paralysis and facial and laryngeal weakness. Peripheral neuropathy may occur 10 days to 3 months postinfection, with proximal motor neuropathy initially, then moving distally, commonly involving dorsiflexors of the foot.
Oculomotor palsy and abducens palsies may be unilateral, bilateral, complete, or incomplete. Facial nerve paralysis may cause difficulties with eyelid closure. Paralysis of accommodation is common, occurring in approximately 10% of patients with diphtheria. Pupillary reactions remain normal. Usually, resolution of these cranial neuropathies occurs spontaneously within 2-6 weeks.
Causes
Diphtheria is an acute infectious disease caused by the gram-positive bacillus C diphtheriae.
Complications
With severe respiratory involvement, death can occur.
Optic neuritis has been reported as a possible rare complication of diphtheria immunization.
