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Trauma and common infections of the eye
HEAD AND NECK
Lid lacerations Lid lacerations that do not involve the lid margin are repaired using non-absorbable 5/0 to 7/0 sutures with subcutaneous absorbable sutures in deeper wounds. Lacerations involving the lid margin must be sutured with perfect alignment to prevent notching, which can cause abnormalities of the tear film and entropion. A 6/0 silk suture is passed through the grey line at both margins of the lid laceration with the ends left long. Absorbable 6/0 interrupted sutures are used for the tarsal plate and orbicularis muscle. The skin is closed with 6/0 non-absorbable sutures using the uppermost suture to tie down the long end of the grey line suture, which may otherwise cause a corneal abrasion. All sutures are removed in seven days. Medial lid lacerations (especially of the lower lid) involving the lacrimal canaliculi should be repaired within 24 hours with lacrimal intubation using silicone tubing in order to avoid a watery eye postoperatively.
Trauma and common infections of the eye Annie Joseph
Trauma The general surgeon usually encounters eye injuries as part of a larger traumatic episode (e.g. road traffic accidents): life-threatening injuries take precedence over ocular trauma, so one must assess the eye quickly and decide on immediate management. A haematoma (black eye) suggests an associated eye injury and the integrity of the globe (eyeball) must be assessed. Lid retractors must be used to examine the eye (without exerting pressure on the globe) if there is extensive oedema of the lid. Patients with multiple injuries often undergo CT scans as soon as they are stable; if an eye injury is suspected, a request for scans of the globe, orbit and optic nerves is very helpful.
Blunt trauma Blunt trauma may result in a closed contusion injury or a full- or partial-thickness rupture (where the globe gives way at its weakest point, which may not be at the site of impact). Any of the features discussed below may be observed after blunt trauma to the eye. Corneal abrasions cause blurring of vision if they are in the visual axis. A corneal abrasion is identified as an area on the surface of the cornea that stains green when a drop of fluorescein is instilled (visualized using the blue light setting of the direct ophthalmoscope). A corneal abrasion may be encountered on the first day after surgery if the eyes were not adequately protected during general anaesthesia. Treatment involves use of antibiotic ointment with topical cycloplegia using 1% cyclopentolate, (if necessary). Uncomplicated small corneal abrasions heal within 24 hours whilst larger abrasions may take longer to heal completely.
Fractures around the orbit Bilateral ring haematomas around the eyes suggest a basal skull fracture. A periocular haematoma associated with subconjunctival haemorrhage without a visible posterior limit suggests a fracture of the orbital roof. Orbital blow-out fractures are typically caused by a sudden increase in orbital pressure by a projectile (e.g. tennis ball, fist) that is larger that the diameter of the orbital rim. This fracture involves the floor of the orbit and occasionally the medial orbital wall. Initial ecchymosis, oedema and subcutaneous emphysema associated with a blow-out fracture may mask the enophthalmos, which becomes apparent after a few days. Diplopia due to limitation of ocular movements may resolve if it is caused by soft tissue swelling or persist if the cause is entrapment of soft tissue or muscle in the fracture. Infraorbital anaesthesia is due to involvement of the nerve in the infraorbital canal. Associated blunt injury to the globe must be excluded by slit-lamp and fundus examination of the eye. CT scans (coronal views) classically show the ‘teardrop sign’ and help to evaluate the extent of injury. Patients with orbital blow-out fractures should not blow their nose and should initially be treated conservatively with broad-spectrum antibiotics (e.g. co-amoxiclav) because there is an increased risk of infection (especially if the fracture involves the maxillary sinus). Subsequent surgery is aimed at preventing permanent vertical diplopia and/or significant enophthalmos. Fractures involving more than one-half of the orbital floor with entrapment of orbital contents and persistent diplopia in the primary position must be repaired within two weeks to prevent permanent changes due to scarring.
Haemorrhage into the anterior chamber (hyphaema): small hyphaemas can be identified only by slit-lamp examination and usually absorb spontaneously. Larger hyphaemas appear as a fluid level in the anterior chamber (between the cornea and iris). The height of the hyphaema should be measured as a proportion of the anterior chamber that is filled with blood. The level of the blood may vary according to posture and should be measured after the patient has been upright for a few hours. The source of the bleeding is the iris or ciliary body and there is a risk of secondary haemorrhage (which can occur up to ten days after the original injury). Treatmentt includes complete rest at home or in hospital, depending on the amount of hyphaema. There should be regular measurement and treatment of any secondary increase in intraocular pressure. Topical coticosteroids are used in the absence of a corneal abrasion to treat associated traumatic uveitis. The pupil may be small in post-traumatic uveitis or large in traumatic mydriasis where the iris sphincter is damaged. In both cases, the pupillary reaction to light and accommodation is sluggish or absent. Iris: disinsertion of the iris from its root (iridodialysis) results in a D-shaped pupil, and may be asymptomatic or associated with uniocular diplopia.
Annie Joseph is a Specialist Registrar in Ophthalmology at Queen’s Medical Centre, Nottingham, UK.
SURGERY 22:8
191
© 2004 The Medicine Publishing Company Ltd
HEAD AND NECK
The lens may subluxate, dislocate or become cataractous following blunt trauma; all of which require surgical correction if associated with significant visual impairment or secondary glaucoma. Posterior segment: posterior vitreous detachment may occur and may be associated with vitreous haemorrhage. Retinal oedema secondary to blunt trauma is called commotio retinae; the involved retina has a greyish-white appearance. If the macula is involved by commotio retinae, a cherry-red spot may be seen at the fovea. Most cases of commotio retinae resolve without sequelae; a few patients develop progressive degeneration and retinal hole formation. Choroidal ruptures are seen as white crescent-shaped streaks, concentric with the optic disc and sometimes involving the fovea. Retinal breaks following trauma may be in the form of retinal dialyses where the retina and vitreous base are avulsed, equatorial retinal tears or macular holes. Any of these may lead to retinal detachment, the symptoms of which include flashing lights, floaters (visual perception of cobweb- or tadpole-like opacities that move with eye movements) and a grey shadow in the visual field. Any opacity in the ocular media (e.g. cataracts, vitreous haemorrhage, large retinal detachments) results in the absence of a good red reflex on ophthalmoscopy. Rupture of the globe is usually anterior and easily recognized, but may be posterior without much visible injury to the eye. Asymmetry in the depth of the anterior chamber and low intraocular pressure raises the possibility of a posterior rupture. Patients who have had previous cataract surgery invariably rupture their globe at the junction of the cornea and sclera; this is a common injury following a fall in an elderly patient. Optic neuropathy and optic nerve avulsion are rare, but will cause blindness.
1 Slit-lamp photograph of a metallic foreign body on the corneal surface with a rust ring around it.
pentolate (cycloplegic) may be instilled for pain relief at the end of the procedure. Injuries caused by chemicals Severe injuries caused by chemicals are potentially sight-threatening and are an emergency. The eye must be irrigated copiously with 0.9% saline for 15–30 minutes until the pH is neutral. Any adherent particles of the chemical (acid or alkali) are removed under direct visualization at the slit-lamp, using topical anaesthesia and a sterile 26 G needle or forceps. The upper lid should be double-inverted and examined for retained particulate matter which, if unnoticed, can cause a slow, persistent burn. Further management depends on the extent of the injury. A uniformly red eye is a reassuring sign; large white non-perfused areas at the limbus and sclera indicate severe limbal ischaemia and severe burn. Alkalis penetrate deeper into tissues and cause worse burns than acids (which coagulate surface proteins and thus form a protective barrier). Severe chemical burns carry a poor prognosis and require additional intensive therapy with topical citrate, ascorbate and early surgery to preserve the integrity of the eye. Mild burns respond readily to a short course of topical corticosteroid (in the absence of corneal abrasion), antibiotic and cycloplegic.
Penetrating trauma Penetrating injuries are usually caused by assault, domestic accidents or sport. If there is a strong suspicion of a penetrating eye injury, no further clinical examination of the eye should be undertaken because the injury may be worsened if pressure is applied. A pad and plastic shield should be applied to the eye and an ophthalmologist involved for repair of the eye. Broad-spectrum systemic antibiotics (co-amoxiclav, ciprofloxacillin) are started to minimize the risk of infection (the consequences of which may be worse than the original injury). A radiograph of the orbits is necessary if an intraocular foreign body is suspected. Foreign bodies Patients complaining of a foreign body sensation do not necessarily have a foreign body in the eye; inturning lashes and corneal epithelial erosions (often secondary to dry eyes) may be the cause. Foreign bodies in the conjunctiva and cornea (Figure 1) are common and are removed at the slit-lamp using a sterile 26-gauge (G) needle after instillation of topical anaesthetic (proxymetacaine or benoxinate). If a patient presents with a foreign body sensation, but one is not obvious, the examination is not complete until the upper lid is everted and a subtarsal foreign body has been sought. A subtarsal foreign body causes linear corneal abrasions that is identified with the instillation of a drop of fluorescein and viewing the cornea with a blue light. Following removal of a foreign body on the ocular surface, treatment with topical chloramphenicol should be continued for a few days till the epithelial defect heals. One percent cyclo-
SURGERY 22:8
Infections Lids Inflammation of the lid margins (blepharitis) may be associated with seborrhoeic dermatitis or dysfunction of a Meibomian gland. It is characterized by hypaeremic lid margins and crusting at the base of the lashes and can lead to chronic conjunctivitis and secondary corneal and tear film abnormalities. Treatmentt consists of lid hygiene to remove crusts using a weak solution of baby shampoo, a short course of antibiotic ointment to the lids and tear substitutes. A hordeolum externum (stye) is an acute infection (caused by staphylococci) of an eyelash with obstruction of the associated glands. Treatment is with hot compresses and topical chloramphenicol; epilation of the eyelash may hasten discharge of the abscess.
192
© 2004 The Medicine Publishing Company Ltd
HEAD AND NECK
A hordeolum internum is an acute infection (caused by staphylococci) of the Meibomian gland and is treated as for a stye in the acute phase. Residual chronic inflammation of the Meibomian gland causes formation of a nodule in the lid (chalazion) which may require incision and curettage under local anaesthesia. Herpes zoster ophthalmicus is one of the common causes of painful unilateral maculopapular rash that progresses to form pustules and crusting lesions on the lid and forehead. Diagnosis is clinical and treatment consists of systemic antiviral agents (acyclovir, famciclovir) for one week. Ocular complications of herpes zoster ophthalmicus include corneal dendritic ulcers, uveitis and glaucoma. These can occur at any time during the course of the disease and may result in blindness; therefore a red eye associated with herpes zoster ophthalmicus must be referred to an ophthalmologist. 2 Slit-lamp photograph of advanced exposure keratitis showing impending perforation of the cornea (the darker circle on the inferior aspect of the cornea is a desmetocoele).
Conjunctiva Conjunctivitis is one of the most common causes of a red eye and is broadly classified into viral, bacterial, chlamydial and allergic.
Herpes simplex viral infections result in reduced corneal sensation and a dendritic ulcer which has a classic linear staining pattern with fluorescein. Treatment is topical acyclovir five times a day.
Viral conjunctivitis presents as a watery, sore red eye which may be unilateral or bilateral, and which is often associated with tender preauricular lymphadenopathy. The usual cause is the highly contagious adenovirus, which can also cause pharyngitis and fever (pharyngoconjunctival fever). Treatmentt is supportive because the condition usually resolves spontaneously. Patients must be advised how to reduce the spread of infection. Antiviral agents (e.g. acyclovir) are ineffective. Topical corticosteroids may be indicated if blurred vision develops due to adenoviral keratitis.
Bacterial and fungal keratitis are recognized by white or yellow infiltrates on the cornea; frequent topical antibiotics or antifungal treatment is instituted after the infiltrates have been scraped for laboratory tests. Keratitis is commonly encountered in the ICU; patients who are comatose or paralysed and ventilated often suffer exposure keratitis (Figure 2) with secondary bacterial infection. The liberal use of artificial tear drops and ointment in comatose patients and covering exposed eyes with jelloperm will prevent exposure. If exposure keratitis develops despite these prophylactic measures, management should involve an ophthalmologist.
Simple bacterial conjunctivitis presents as an acute red eye with a sticky discharge and soreness. Treatment involves topical broad-spectrum antibiotic (chloramphenicol, fusidic acid) drops q.d.s and an antibiotic ointment at night to prevent the lids from sticking together in the morning.
Endophthalmitis Endophthalmitis is an infection of the contents of the eye and may be endogenous (secondary to infection elsewhere in the body) or exogenous (postoperative or secondary to trauma). Patients present with pain and a decrease in visual acuity and must be referred to the ophthalmologist urgently for vitreous biopsy and intravitreal instillation of antibiotics because it can rapidly cause irreversible blindness.
Gonococcal conjunctivitis is virulent and can invade the intact corneal epithelium. It presents with a red eye with profuse purulent discharge. The diagnosis is confirmed by cultures from the conjunctiva, but treatment (systemic cephalosporins and topical gentamicin) is instituted on clinical suspicion in order to prevent corneal ulceration which can rapidly perforate and lead to endophthalmitis.
Red eye Conjunctivitis and corneal ulcers make up some of the infectious causes for a red eye, but differential diagnosis includes acute glaucoma and uveitis, and patients should be referred to an ophthalmologist. Patients with acute glaucoma often are systemically unwell (nausea, vomiting, severe pain) which may simulate the features of an acute abdomen. Vision is usually blurred and the pupil is mid-dilated, vertically oval and does not react to light or accommodation. The patient with uveitis complains of ocular discomfort and blurred vision; signs include a red eye with predominantly circumciliary injection (around the corneoscleral junction) with a small, irregular pupil.
Adult chlamydial conjunctivitis presents with unilateral or bilateral mucopurulent discharge, follicles and, in chronic cases, superior corneal inflammation (pannus). Diagnosis and treatment are clinical, but laboratory confirmation must be sought if presentation is atypical or a sexually transmitted disease is suspected. Patients with a laboratory diagnosis of gonococcal or chlamydial conjunctivitis must be referred to the genitourinary clinic. Treatment is topical tetracycline q.d.s. for six weeks together with systemic doxycycline or erythromycin. Cornea Inflammation of the cornea (keratitis) is potentially sight-threatening and should be managed with an ophthalmologist. Corneal infections may be viral, bacterial or fungal.
SURGERY 22:8
193
© 2004 The Medicine Publishing Company Ltd
Lid lacerations Lid lacerations that do not involve the lid margin are repaired using non-absorbable 5/0 to 7/0 sutures with subcutaneous absorbable sutures in deeper wounds. Lacerations involving the lid margin must be sutured with perfect alignment to prevent notching, which can cause abnormalities of the tear film and entropion. A 6/0 silk suture is passed through the grey line at both margins of the lid laceration with the ends left long. Absorbable 6/0 interrupted sutures are used for the tarsal plate and orbicularis muscle. The skin is closed with 6/0 non-absorbable sutures using the uppermost suture to tie down the long end of the grey line suture, which may otherwise cause a corneal abrasion. All sutures are removed in seven days. Medial lid lacerations (especially of the lower lid) involving the lacrimal canaliculi should be repaired within 24 hours with lacrimal intubation using silicone tubing in order to avoid a watery eye postoperatively.
Trauma and common infections of the eye Annie Joseph
Trauma The general surgeon usually encounters eye injuries as part of a larger traumatic episode (e.g. road traffic accidents): life-threatening injuries take precedence over ocular trauma, so one must assess the eye quickly and decide on immediate management. A haematoma (black eye) suggests an associated eye injury and the integrity of the globe (eyeball) must be assessed. Lid retractors must be used to examine the eye (without exerting pressure on the globe) if there is extensive oedema of the lid. Patients with multiple injuries often undergo CT scans as soon as they are stable; if an eye injury is suspected, a request for scans of the globe, orbit and optic nerves is very helpful.
Blunt trauma Blunt trauma may result in a closed contusion injury or a full- or partial-thickness rupture (where the globe gives way at its weakest point, which may not be at the site of impact). Any of the features discussed below may be observed after blunt trauma to the eye. Corneal abrasions cause blurring of vision if they are in the visual axis. A corneal abrasion is identified as an area on the surface of the cornea that stains green when a drop of fluorescein is instilled (visualized using the blue light setting of the direct ophthalmoscope). A corneal abrasion may be encountered on the first day after surgery if the eyes were not adequately protected during general anaesthesia. Treatment involves use of antibiotic ointment with topical cycloplegia using 1% cyclopentolate, (if necessary). Uncomplicated small corneal abrasions heal within 24 hours whilst larger abrasions may take longer to heal completely.
Fractures around the orbit Bilateral ring haematomas around the eyes suggest a basal skull fracture. A periocular haematoma associated with subconjunctival haemorrhage without a visible posterior limit suggests a fracture of the orbital roof. Orbital blow-out fractures are typically caused by a sudden increase in orbital pressure by a projectile (e.g. tennis ball, fist) that is larger that the diameter of the orbital rim. This fracture involves the floor of the orbit and occasionally the medial orbital wall. Initial ecchymosis, oedema and subcutaneous emphysema associated with a blow-out fracture may mask the enophthalmos, which becomes apparent after a few days. Diplopia due to limitation of ocular movements may resolve if it is caused by soft tissue swelling or persist if the cause is entrapment of soft tissue or muscle in the fracture. Infraorbital anaesthesia is due to involvement of the nerve in the infraorbital canal. Associated blunt injury to the globe must be excluded by slit-lamp and fundus examination of the eye. CT scans (coronal views) classically show the ‘teardrop sign’ and help to evaluate the extent of injury. Patients with orbital blow-out fractures should not blow their nose and should initially be treated conservatively with broad-spectrum antibiotics (e.g. co-amoxiclav) because there is an increased risk of infection (especially if the fracture involves the maxillary sinus). Subsequent surgery is aimed at preventing permanent vertical diplopia and/or significant enophthalmos. Fractures involving more than one-half of the orbital floor with entrapment of orbital contents and persistent diplopia in the primary position must be repaired within two weeks to prevent permanent changes due to scarring.
Haemorrhage into the anterior chamber (hyphaema): small hyphaemas can be identified only by slit-lamp examination and usually absorb spontaneously. Larger hyphaemas appear as a fluid level in the anterior chamber (between the cornea and iris). The height of the hyphaema should be measured as a proportion of the anterior chamber that is filled with blood. The level of the blood may vary according to posture and should be measured after the patient has been upright for a few hours. The source of the bleeding is the iris or ciliary body and there is a risk of secondary haemorrhage (which can occur up to ten days after the original injury). Treatmentt includes complete rest at home or in hospital, depending on the amount of hyphaema. There should be regular measurement and treatment of any secondary increase in intraocular pressure. Topical coticosteroids are used in the absence of a corneal abrasion to treat associated traumatic uveitis. The pupil may be small in post-traumatic uveitis or large in traumatic mydriasis where the iris sphincter is damaged. In both cases, the pupillary reaction to light and accommodation is sluggish or absent. Iris: disinsertion of the iris from its root (iridodialysis) results in a D-shaped pupil, and may be asymptomatic or associated with uniocular diplopia.
Annie Joseph is a Specialist Registrar in Ophthalmology at Queen’s Medical Centre, Nottingham, UK.
SURGERY 22:8
191
© 2004 The Medicine Publishing Company Ltd
HEAD AND NECK
The lens may subluxate, dislocate or become cataractous following blunt trauma; all of which require surgical correction if associated with significant visual impairment or secondary glaucoma. Posterior segment: posterior vitreous detachment may occur and may be associated with vitreous haemorrhage. Retinal oedema secondary to blunt trauma is called commotio retinae; the involved retina has a greyish-white appearance. If the macula is involved by commotio retinae, a cherry-red spot may be seen at the fovea. Most cases of commotio retinae resolve without sequelae; a few patients develop progressive degeneration and retinal hole formation. Choroidal ruptures are seen as white crescent-shaped streaks, concentric with the optic disc and sometimes involving the fovea. Retinal breaks following trauma may be in the form of retinal dialyses where the retina and vitreous base are avulsed, equatorial retinal tears or macular holes. Any of these may lead to retinal detachment, the symptoms of which include flashing lights, floaters (visual perception of cobweb- or tadpole-like opacities that move with eye movements) and a grey shadow in the visual field. Any opacity in the ocular media (e.g. cataracts, vitreous haemorrhage, large retinal detachments) results in the absence of a good red reflex on ophthalmoscopy. Rupture of the globe is usually anterior and easily recognized, but may be posterior without much visible injury to the eye. Asymmetry in the depth of the anterior chamber and low intraocular pressure raises the possibility of a posterior rupture. Patients who have had previous cataract surgery invariably rupture their globe at the junction of the cornea and sclera; this is a common injury following a fall in an elderly patient. Optic neuropathy and optic nerve avulsion are rare, but will cause blindness.
1 Slit-lamp photograph of a metallic foreign body on the corneal surface with a rust ring around it.
pentolate (cycloplegic) may be instilled for pain relief at the end of the procedure. Injuries caused by chemicals Severe injuries caused by chemicals are potentially sight-threatening and are an emergency. The eye must be irrigated copiously with 0.9% saline for 15–30 minutes until the pH is neutral. Any adherent particles of the chemical (acid or alkali) are removed under direct visualization at the slit-lamp, using topical anaesthesia and a sterile 26 G needle or forceps. The upper lid should be double-inverted and examined for retained particulate matter which, if unnoticed, can cause a slow, persistent burn. Further management depends on the extent of the injury. A uniformly red eye is a reassuring sign; large white non-perfused areas at the limbus and sclera indicate severe limbal ischaemia and severe burn. Alkalis penetrate deeper into tissues and cause worse burns than acids (which coagulate surface proteins and thus form a protective barrier). Severe chemical burns carry a poor prognosis and require additional intensive therapy with topical citrate, ascorbate and early surgery to preserve the integrity of the eye. Mild burns respond readily to a short course of topical corticosteroid (in the absence of corneal abrasion), antibiotic and cycloplegic.
Penetrating trauma Penetrating injuries are usually caused by assault, domestic accidents or sport. If there is a strong suspicion of a penetrating eye injury, no further clinical examination of the eye should be undertaken because the injury may be worsened if pressure is applied. A pad and plastic shield should be applied to the eye and an ophthalmologist involved for repair of the eye. Broad-spectrum systemic antibiotics (co-amoxiclav, ciprofloxacillin) are started to minimize the risk of infection (the consequences of which may be worse than the original injury). A radiograph of the orbits is necessary if an intraocular foreign body is suspected. Foreign bodies Patients complaining of a foreign body sensation do not necessarily have a foreign body in the eye; inturning lashes and corneal epithelial erosions (often secondary to dry eyes) may be the cause. Foreign bodies in the conjunctiva and cornea (Figure 1) are common and are removed at the slit-lamp using a sterile 26-gauge (G) needle after instillation of topical anaesthetic (proxymetacaine or benoxinate). If a patient presents with a foreign body sensation, but one is not obvious, the examination is not complete until the upper lid is everted and a subtarsal foreign body has been sought. A subtarsal foreign body causes linear corneal abrasions that is identified with the instillation of a drop of fluorescein and viewing the cornea with a blue light. Following removal of a foreign body on the ocular surface, treatment with topical chloramphenicol should be continued for a few days till the epithelial defect heals. One percent cyclo-
SURGERY 22:8
Infections Lids Inflammation of the lid margins (blepharitis) may be associated with seborrhoeic dermatitis or dysfunction of a Meibomian gland. It is characterized by hypaeremic lid margins and crusting at the base of the lashes and can lead to chronic conjunctivitis and secondary corneal and tear film abnormalities. Treatmentt consists of lid hygiene to remove crusts using a weak solution of baby shampoo, a short course of antibiotic ointment to the lids and tear substitutes. A hordeolum externum (stye) is an acute infection (caused by staphylococci) of an eyelash with obstruction of the associated glands. Treatment is with hot compresses and topical chloramphenicol; epilation of the eyelash may hasten discharge of the abscess.
192
© 2004 The Medicine Publishing Company Ltd
HEAD AND NECK
A hordeolum internum is an acute infection (caused by staphylococci) of the Meibomian gland and is treated as for a stye in the acute phase. Residual chronic inflammation of the Meibomian gland causes formation of a nodule in the lid (chalazion) which may require incision and curettage under local anaesthesia. Herpes zoster ophthalmicus is one of the common causes of painful unilateral maculopapular rash that progresses to form pustules and crusting lesions on the lid and forehead. Diagnosis is clinical and treatment consists of systemic antiviral agents (acyclovir, famciclovir) for one week. Ocular complications of herpes zoster ophthalmicus include corneal dendritic ulcers, uveitis and glaucoma. These can occur at any time during the course of the disease and may result in blindness; therefore a red eye associated with herpes zoster ophthalmicus must be referred to an ophthalmologist. 2 Slit-lamp photograph of advanced exposure keratitis showing impending perforation of the cornea (the darker circle on the inferior aspect of the cornea is a desmetocoele).
Conjunctiva Conjunctivitis is one of the most common causes of a red eye and is broadly classified into viral, bacterial, chlamydial and allergic.
Herpes simplex viral infections result in reduced corneal sensation and a dendritic ulcer which has a classic linear staining pattern with fluorescein. Treatment is topical acyclovir five times a day.
Viral conjunctivitis presents as a watery, sore red eye which may be unilateral or bilateral, and which is often associated with tender preauricular lymphadenopathy. The usual cause is the highly contagious adenovirus, which can also cause pharyngitis and fever (pharyngoconjunctival fever). Treatmentt is supportive because the condition usually resolves spontaneously. Patients must be advised how to reduce the spread of infection. Antiviral agents (e.g. acyclovir) are ineffective. Topical corticosteroids may be indicated if blurred vision develops due to adenoviral keratitis.
Bacterial and fungal keratitis are recognized by white or yellow infiltrates on the cornea; frequent topical antibiotics or antifungal treatment is instituted after the infiltrates have been scraped for laboratory tests. Keratitis is commonly encountered in the ICU; patients who are comatose or paralysed and ventilated often suffer exposure keratitis (Figure 2) with secondary bacterial infection. The liberal use of artificial tear drops and ointment in comatose patients and covering exposed eyes with jelloperm will prevent exposure. If exposure keratitis develops despite these prophylactic measures, management should involve an ophthalmologist.
Simple bacterial conjunctivitis presents as an acute red eye with a sticky discharge and soreness. Treatment involves topical broad-spectrum antibiotic (chloramphenicol, fusidic acid) drops q.d.s and an antibiotic ointment at night to prevent the lids from sticking together in the morning.
Endophthalmitis Endophthalmitis is an infection of the contents of the eye and may be endogenous (secondary to infection elsewhere in the body) or exogenous (postoperative or secondary to trauma). Patients present with pain and a decrease in visual acuity and must be referred to the ophthalmologist urgently for vitreous biopsy and intravitreal instillation of antibiotics because it can rapidly cause irreversible blindness.
Gonococcal conjunctivitis is virulent and can invade the intact corneal epithelium. It presents with a red eye with profuse purulent discharge. The diagnosis is confirmed by cultures from the conjunctiva, but treatment (systemic cephalosporins and topical gentamicin) is instituted on clinical suspicion in order to prevent corneal ulceration which can rapidly perforate and lead to endophthalmitis.
Red eye Conjunctivitis and corneal ulcers make up some of the infectious causes for a red eye, but differential diagnosis includes acute glaucoma and uveitis, and patients should be referred to an ophthalmologist. Patients with acute glaucoma often are systemically unwell (nausea, vomiting, severe pain) which may simulate the features of an acute abdomen. Vision is usually blurred and the pupil is mid-dilated, vertically oval and does not react to light or accommodation. The patient with uveitis complains of ocular discomfort and blurred vision; signs include a red eye with predominantly circumciliary injection (around the corneoscleral junction) with a small, irregular pupil.
Adult chlamydial conjunctivitis presents with unilateral or bilateral mucopurulent discharge, follicles and, in chronic cases, superior corneal inflammation (pannus). Diagnosis and treatment are clinical, but laboratory confirmation must be sought if presentation is atypical or a sexually transmitted disease is suspected. Patients with a laboratory diagnosis of gonococcal or chlamydial conjunctivitis must be referred to the genitourinary clinic. Treatment is topical tetracycline q.d.s. for six weeks together with systemic doxycycline or erythromycin. Cornea Inflammation of the cornea (keratitis) is potentially sight-threatening and should be managed with an ophthalmologist. Corneal infections may be viral, bacterial or fungal.
SURGERY 22:8
193
© 2004 The Medicine Publishing Company Ltd