Ophthalmology - Red eye Flashcards
What are the features of bacterial conjunctivitis?
Acute purulent bacterial conjunctivitis is extremely common. There is diffuse conjunctival infection and the discharge is often profuse enough to cause lashes to stick together. When the discharge is washed out of the eyes, the vision is usually normal. Treatment is with topic antibiotics - chloramphenicol or fusidic acid eye drops - and regular lid toilet. Most cases should show improvement within 5 to 7 days of commencing treatment.
Staphs are the most common cause and resistance to ciprofloxacin and gentamicin is spreading.
What should recurrent conjunctivitis alert you to?
It should prompt examination for an underlying cause (such as nasolacrimal duct obstruction) or consider other diagnoses. In prolonged conjunctivitis, especially in young adults or those with sexual disease, consider chlamydial infection.
How does infective adenoviral keratoconjunctivitis present?
This is where viral conjuncitivitis causes corneal inflammation (keratitis). It presents with unilateral or bilateral red eyes, with marked watery discharge. The patient may have an upper respiratory tract infection and preauricular lymphadenopathy is often present. If the patient is photophobic one must suspect corneal involvement (keratoconjunctivitis) which is characterised by mutliple subepithelial opacities, seen as white dots on the cornea. Visual acuity can be reduced if the cornea is involved.
Adenovirus is the most common cause of viral conjunctivitis and small lymphoid aggregates appear as follicles on the conjunctiva. It is HIGHLY contagious and symptoms can last for up to 6 weeks.
How should a subtarsal foreign body be managed?
Patients with a subtarsal foreign body can often localise a gritty sensation to the area beneath the upper lid. Foreign bodies will not be detected unless the upper id is everted. Prior to everting the upper lid, it is helpful to instill a drop of local anaesthetic into the eye. The patient is then asked to look down and relax the upper lid levator muscle, the lashes of the upper lid are grasped and gentle downward traction applied to the lid. A cotton wool tip can be used to gently remove the foreign body. Upper lid eversion should NOT be attempted if a penetrating eye injury is suspected.
How do patients with a corneal foreign body present?
Patients with a corneal foreign body (CFB) have an intensely painful gritty sensation in the affected eye with marked photophobia and lacrimation. Symptoms may develop several hours after injury. The history of the injury is important, CFBs are common in manual workers.
How should a corneal foreign body be examined?
After instillation of one drop of local anaesthetic, the symptoms are usually temporarily alleviated and examination with a pen torch and magnification will reveal the CFB. The possibility of a pentrating eye injury and intraocular foreign body should be considered in all patients who have exposed to high velocity projectile, for example, when hammering. These patients should have an X ray of the orbits. Referral is usually necessary for CFB and rust ring removal.
How should penetrating eye injuries be managed?
Penetrating eye injuries can result from a wide variety of circumstances and a detailed history is often essential. Any ocular trauma involving glass should raise suspicion. Penetrating injuries are often associated with prolapse of intraocular contents, for example the iris. It is possible to repair these severely damaged eyes and restore good vision. It is therefore essential to prevent any further damage to the eye when the patient is first seen. Care should be taken to avoid applying any pressure to the lids or globe and a rigid shield should be placed over the eye. Anti-emetic therapy should be given if the patient is vomiting, and urgent ophthalmology referral is needed.
What is a corneal abrasion?
This is an epithelial breach and usually occurs without keratitis (e.g. trauma), when prophylactic antibiotic ointment may be used. Ulceration with keratitis is more serious and should be treated as an emergency. Loss of corneal epithalial causes pain, photophobia and sometimes reduced vision. Uninfective corneal ulcers may result from scratches from sharp objects, trauma, chemical injury or previous corneal disease.
How can corneal abrasions be diagnosed?
Fluorscein drops and a (blue) bright light (shone tangentially across the globe) aids the diagnosis. Corneal lesions stain green (drops are orange and become more yellow on contact with the eye).
How should chemical eye injury be managed?
This is an absolute emergency. Unless copious irrigation of the eyes occurs then the patient may suffer irreversible loss of vision. Alkaline agents are the most destructive. Whatever the chemical agent, irrigation with a large volume of water or normal saline should be commenced and continued for at least 10 minutes. This irrigation should take priority and be performed before attempting to contact an ophthalmologist. Irrigation should continue until the pH of the fluid irrigated from the eye is consistently neutral. It is especially important to remove large pieces of particulate matter, for example lime, which can be hidden in the fornices (lid eversion is necessary). Urgent transfer to an ophthalmic unit is the necessary.
What is hyphaema?
Traumatic hyphaemia usually results from blunt trauma to the globe or orbit, for example from a tennis ball injury. The possibility that there could be co-existing occult globe perforation should be considered. Traumatic hyphaema is often associated with elevated intraocular pressure and retinal trauma. Patients need urgent (same day) referral and should be advised regarding strict rest for a period of about 7 days and should avoid significant activity. The principal serious complication to avoid in the first week after traumatic hyphaema is secondary re bleed.
Hyphaema should not be confused with subconjunctival haemorrhage. In hyphaema the blood fills the anterior chamber which occludes the pupil.
What patients suffer subconjunctival haemorrhage?
This harmless but alarming pool of blood behind the conjunctiva is from a small bleed. It often occurs in frail old ladies who may be on warfarin. Their BP should be checked and you can make them laugh by asking “have you been white-water rafting recently?” (leptospira in sewage). If a patient has recurrent subconjunctival haemorrhages, one should consider the possibility of an orbital vascular anomaly.
What is a dendritic ulcer? How are they diagnosed?
Corneal ulcers may be bacterial, herpetic, fungal, protozoal or from vasculitis. Dendritic ulcers are caused by herpes simplex keratitis. Herpetic infections of the cornea are common and recurrent episodes of inflammation can lead to severe corneal scarring. The patient may have a PMH of herpetic disease elsewhere, for example “cold sores” on the lips or eyelids. Corneal lesions are characteristically dendritic (branching) and stain with fluorescein and rose bengal. Reduced corneal sensitivity is often present. It is important to initiate prompt topical antiviral therapy.
What can happen if a patient with dendritic ulcers is given topic steroids?
If topical steroid medications are given to a patient who has a Herpes simplex dendritic ulcer of the cornea the results can be devastating! Uncontrolled viral replication can rapidly lead to the formation of a large “amoeboid” geographical ulcer of the cornea with PERMANENT visual loss. Topical steroid treatment should never be prescribed without a definite diagnosis in cases of red eye. It is easy to miss the diagnosis of many corneal lesions unless fluorescein drops are instilled into the conjunctival sac. Always remove contact lenses before doing this. Fluorescein stains the lesions green.
How should corneal ulcers be managed?
First remember a few causes:
1) Bacterial - e.g. pseudomonas may progress rapidly
2) Herpetic - e.g. simplex, zoster
3) Fungal - e.g. candida, aspergillus
4) Protozoal
5) Vasculitis - e.g. RA
Don’t try treating ulcerative keratitis on your own. Scarring and visual loss may occur. Except for a simple abrasion (which normally occurs without keratitis and is treated with topical chloramphenicol +/- cytoplegia) get help TODAY for urgent diagnostic smear/ gram stain and scrape. Liase with micro.
In the early stages of ophthalmic shingles, use aciclovir.
What is marginal keratitis?
Patients with marginal keratitis present with a painful, gritty, photophobic red eye. Small, white sterile inflammatory infiltrates are visible in the peripheral cornea. Patients often have co-existing lid margin disease (e.g. blepharitis). It is often difficult to differentiate marginal keratitis from an infective corneal ulcer, and immediate ophthalmic opinion is necessary.
How do patients with contact lens related keratitis present?
There are many causes of inflammatory corneal disease associated with contact lens wear. The most serious problem is contact lens-related infection. Patients often present with a painful, photophobic red eye and are unable to wear their contact lenes. A discrete corneal abscess may be visible. Many organisms can cause corneal infection include Acanthamoebal species present in domestic tap water. Immediate ophthalmic referral is essential, because certain organisms such as pseudomonas or pneumococcus can cause irreversible damage to the eye within 24 hours.
What is the characteristic feature of allergic conjunctivitis?
Severe itching and the present of chronic string, mucoid discharge are prominant features. When the upper lids are everted the tarsal conjunctiva is often red and oedematous with numerous giant papillae. Allergen avoidance, for example, house dust mite is an important part of therapy.
How is allergic conjunctivitis managed?
Agents that stabilise mast cells(e.g. sodium cromoglicate) and reduce itching are the main forms of treatment and may need to be used on a long term basis. It may be necessary to use topic steroid drops to control allergic eye disease, but these should ONLY be used under very close ophthalmic supervision. Chronic use of steroids may result in cataract and glaucoma.
Antihistamine drops - e.g. emedastine or olopatadine can be tried.
What is Pterygium?
Pterygia are caused by light (actinic) damage and are common in people who have spent long periods in hot climates. They appear as fleshy, vascular growths extending from the conjunctiva onto the cornea, and occur most commonly in the medial conjunctival area. They are often asymptomatic and need no treatment. They may, however, be associated with marked ocular surface discomfort and may grow towards the visual axis. Surgical excision is the treatment of choice for progressive pterygia, but there is a significant recurrence rate after surgery.
