Ординатура / Офтальмология / Английские материалы / Moorfields Manual of Ophthalmology_Jackson_2007

UVEITIS 8 Chapter

Endophthalmitis

stage for microbiology and histopathology. Avoid systemic steroids that may mask ongoing inflammation.

■The Endophthalmitis Vitrectomy Study (EVS)1 was a large randomized, controlled trial that suggested early vitrectomy with intravitreal antibiotics may improve the final VA for patients with PL vision. Recent local experience suggests that early vitrectomy results in a worse prognosis for those with PL vision but many other centres follow the EVS recommendations.

Some reports advocate intravitreal ceftazidime 2 mg in 0.1 mL instead of amikacin for Gram-negative cover, because of the risk of aminoglycoside retinal toxicity. Avoid combining vancomycin and ceftazidime in the same syringe.

Some reports advocate intravitreal dexamethasone 0.4 mg but the evidence is not clear.

Follow-up Manage patients as day-cases if they can cope; otherwise admit. If admitted, consider discharge when there is clinical improvement, typically after 48 hours, and then review within 2 weeks. Follow up all patients for 3–6 months, as they may require additional procedures, e.g. vitrectomy for vitreous debris. Final VA is <6/60 in 22–77%. Patients with an acute presentation, good presenting VA, and negative cultures tend to have a better prognosis.

Box 8.1: Aqueous and vitreous tap and intravitreal antibiotic injection

1.Contact the microbiology department to ensure Gram staining is done the same day.

2.Instil G. proxymetacaine then tetracaine (amethocaine), then povidone-iodine 5% into the conjunctival sac and on the lid margins. Allow dwell time for bacterial/fungal killing.

3.Administer subconjunctival or more usually peribulbar anaesthesia (lidocaine 2%).

4.Prepare then draw up the required concentration of antibiotics, combined into a 1 mL syringe (change the needle, as this gets blunt going through the rubber bungs):

a.Vancomycin : 2.0 mg in 0.1 mL.

b.Amikacin : 0.4 mg in 0.1 mL (beware dilution errors).

c.Amphotericin B : 5–10 mcg in 0.1 mL only if fungi are suspected.

5.Scrub and don gloves. A drape and mask are not required. Insert the lid speculum but do not further manipulate the lashes. Wash away excess povidone-iodine with saline.

6.Aqueous sampling (may be done with patient at the slit lamp or

lying down). Using a 1 mL syringe (not an insulin syringe) with an orange 25-gauge needle, aspirate 0.1–0.2 mL of aqueous via a limbal paracentesis. A larger needle may be used if a lot of pus is present. Place the needle into the sheath left resting on a flat surface, without touching the tip of the needle (be mindful of needle-stick). Label and leave to one side.

7.Vitreous sampling (do in a sterile environment with the patient lying flat). Use a 5 mL syringe and blue 23-gauge needle and insert 4 mm (phakic) or 3.5 mm (pseudophakic/aphakic eyes) behind the limbus into the midvitreous cavity. Aspirate 0.2– 0.4 mL. If the tap is dry, carefully move the needle within the vitreous cavity. If still dry, try a larger 21-gauge needle. Place

the sheath on the needle as above. Label and leave to one side.

8.Inject the 0.2 mL of combined intravitreal antibiotics in the 1 mL syringe in a sterile manner and through the same area as the vitreous sampling. As the eye can be very soft, counter pressure helps get the needle through the sclera.

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UVEITIS 8 Chapter

Endophthalmitis

Box 8.1: Aqueous and vitreous tap and intravitreal antibiotic injection—cont’d

9.Plate out immediately, as per local protocol, for example:

a.Blood agar: place one drop from the syringe on an eccentric one-third of the plate and then streak with a loupe. Do not cut into the agar, as the organisms will not grow. Use a separate blood agar plate for aqueous and vitreous. Close with tape, and label.

b.Robertson’s cooked meat broth and brain heart infusion: put one drop in each bottle (avoid touching the rim). Close, mix, and label.

10.Send specimens immediately to the microbiology department for Gram (± Giemsa) stain, and then culture. If the laboratory is closed, incubate the plates and transfer at the first opportunity, but this may reduce the yield so avoid if possible.

Fig. 8.23: Candida endophthalmitis extending from the retina into the vitreous.

Optometry and General

Practice Guidelines

General Comments

Accurate diagnosis and assessment of patients with uveitis requires slit lamp examination. This is not usually available in general practice and topical steroids should not be initiated owing to their potential side effects including raised intraocular pressure, cataract, and exacerbation of dendritic corneal ulcers. All suspected intraocular inflammation should therefore be referred within 24 hours to an ophthalmologist.

Acute anterior uveitis accounts for 90% of all intraocular inflammation presenting to general practitioners but it accounts for a minority of patients with red eye.

General Practice

Photophobia and pain are the predominant complaints in patients with uveitis, with conjunctival injection centred primarily around the cornea (circumcorneal injection). It is usually possible to distinguish anterior uveitis from conjunctivitis from the history (p. 142).

Posterior uveitis is more difficult to diagnose from the history and is reliant upon proficient dilated fundoscopy. Symptoms of acute onset of floaters, with or without blurred vision, are far more likely to be related to posterior vitreous detachment than inflammation, but in either event urgent referral is required.

Optometrists

Optometrists who suspect anterior uveitis should take a careful history and look for anterior chamber cells. These are best seen against a dilated pupil, using a thin, maximally illuminated slit beam passed at 45º through the anterior chamber. Inflammatory cells can be seen to percolate upward in the back of the anterior chamber, and downwards immediately behind the cornea (see Fig. 8.1). Look for anterior vitreous activity using the same slit beam focused behind the lens. For patients with suspected posterior uveitis, look for vitreous haze, macular oedema, and perivascular infiltrates. Pars planitis may be difficult to detect without indentation. Any anterior or posterior segment inflammation requires same-day review by an ophthalmologist.

References

UVEITIS 8 Chapter

Fig. 9.5: Primary acquired melanosis.

develop prominent feeder vessels can be biopsied to rule out malignant melanoma.

2.Primary acquired melanosis (PAM) (Fig. 9.5): a. Benign (premalignant).

b. Diffuse, patchy foci of increased conjunctival pigmentation. Sometimes extends to the eyelid skin and is occasionally nonpigmented. Acquired in middleage and found in light-skinned patients.

c.Manage by observation every 6 months with or without multiple incisional biopsies.

d. Confirmed areas of PAM with atypia may be treated with cryotherapy although it is not certain whether freezing reduces a 50% risk of developing conjunctival melanoma.

e.Dark-skinned patients may have diffuse racial pigmentation seen near the limbus, which is generally benign and does not require treatment or follow-up.

3.Malignant melanoma (MM) (Fig. 9.6): a. Malignant.

b. May arise from a naevus, PAM, or de novo.

c.Typically, darkly pigmented and focal, but variations include nonpigmented and diffuse forms. Feeder

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