Endophthalmitis
is one of the most devastating eye complications that can occur following
intraocular surgery. If the outcome is to be successful, it is essential
that the diagnosis is recognised and not denied. Once the diagnosis is
made, treatment should begin without delay to avoid further erosion of
visual acuity.
Signs
and symptoms
Symptoms
may include pain, loss of vision, swelling or redness of the eye and discharge
following surgery, but some cases may be asymptomatic. Signs may include
injection or chemosis, corneal oedema, flare and cells or frank hypopyon,
or fibrin clot in the anterior chamber. A relative afferent defect may
be found. Vitreous cells or abscess may be seen but often no view of the
posterior segment is possible; sheathing of retinal vessels may occasionally
be seen. When the signs are pronounced, the diagnosis is not in doubt,
but sometimes only a relatively low-grade inflammation is observed. If
these signs cannot be explained, or if there is any doubt, the eye should
be treated as if it were infected.
Treatment
A 'therapeutic
trial of steroids' can be particularly misleading since, even in endophthalmitis,
there may be an initial favourable response. If in doubt proceed to vitreous
biopsy and anterior chamber tap.
To
date, there has only been one large prospective randomised study on the
management of endophthalmitis. The Endophthalmitis Vitrectomy Study (EVS)1,
recently completed in the USA, has greatly simplified our approach to treatment,
which should begin immediately diagnosis is made.
In
all cases, where the acuity is better than light perception, a single-port
vitreous biopsy via the pars plana should be performed using a vitreous
cutting-suction device. (Disposable devices are now available which allow
the procedure to be done outside the operating theatre if necessary with
even less delay. this can be useful in outreach clinics). The specimens
are directly smeared, for Gram stain etc, and plated for culture.
The
space created by the biopsy is sufficient for direct intravitreal injection
of antibiotics. In the EVS, amikacin and vancomycin were used. Gentamicin
and cefuroxime would have supplied virtually the same degree of broad spectrum
cover. The study showed that there was no advantage in the concurrent administration
of intravenous antibiotics. The antibiotics may be made up as detailed
later.
Only
when the visual acuity is perception of light is there an advantage in
performing a formal three port vitrectomy, from the point of view of both
final acuity and media clarity. Intensive topical antibiotics are not required,
unless there are specific wound-related problems or co-existing microbial
keratitis.
The
EVS did not address the specific question of intravitreal steroids and
to date their use remains unsubstantiated. In general terms, high dose
systemic prednisolone may be given eg 60-80mgs daily, rapidly reducing
to zero over a week to 10 days. Steroids are contraindicated if there is
a fungal infection. If the clinical course warrants it, the biopsy and
intravitreal antibiotic injection may be repeated after 48 to 72 hours.
this may allow review of the choice of antibiotic in light of the culture
results as well as the clinical progress.
Prophylaxis
No study
to date has effectively looked at the question of antibiotic prophylaxis.
Proper pre-assessment of the patient, identifying and treating risk factors
such as blepharitis, mucocoele of the lacrimal sac, or conjunctivitis is
probably more useful than blunderbuss prophylaxis.
Skin
and conjunctival sac preparation with 5% aqueous povidone iodine, at least
five minutes before surgery, is safe and effective in significantly reducing
ocular surface flora. Instillation of this material into the sac at the
end of the procedure may be additionally effective.
The
use of antibiotics in irrigating solutions has been widely condemned and
the choice of vancomycin can be especially criticised from a public health
stance because resistance to vancomycin has been encountered in MRSA.
Active
prophylaxis by intravitreal injection of antibiotics after repair of penetrating
trauma is probably beneficial.2 The EVS did not consider the
management of endophthalmitis developing other than post-operatively. It
may be reasonable, however, to adopt a similar approach to management in
these other cases but no firm guidelines can be given.
References
1. Results
of the Endophthalmitis Vitrectomy Study. The Endophthalmitis Vitrectomy
Study Group. Arch Ophthalmol 1995; 113; 1479-1496.
2.
The
criteria for intravitreal antibiotics during surgery for removal of intraocular
foreign bodies. Seal DV, Kirkness CM. Eye 1992; 6: 465-468.
| 1.
Gentamicin
200µg
in 0.1ml
1.
Take 0.5ml from a vial of gentamicin containing 40mg/ml
2.
Make up to 10mls with normal saline or balanced salt solution (BSS) in
a syringe.
3.
0.1ml of this solution=200µg
NB
Minims of gentamicin are unpreserved and contain 3000µg per ml. These
may be used. |
| 2.
Amikacin
0.4mg
in 0.1ml
1.
Reconstitute one vial - 500mg - and make up to 10ml with BSS
2.
Withdraw 0.8ml (using 1ml syringe) and make up to 10ml with BSS
3.
Withdraw 0.1ml of this - 0.4mg |
| 3.
Cefuroxime or Vancomycin
1000µg
in 0.1ml
1.
Reconstitute a 250mg vial with 8mls of saline or BSS
2.
Withdraw entire contents and make up to 10mls with saline or BSS
3.
Inject 2mls back into vial and make up to 5mls in the vial with saline
or BSS
4.
0.1ml of this solution - 1mg (1000µg)
For
smaller doses adjust the volumes accordingly. |
| 4.
Amphotericin
5µg
in 0.1ml
1.
Reconstitute a 50mg vial with 10mls of saline or BSS
2.
Withdraw 0.1ml of this and make up to 10mls in a syringe.
3.
0.1ml of this = 5µg
Alternatively
inject entire contents of a 50mg ampoule into a 1 litre bag of Ringer-Iactate
and 0.1ml of this contains 5µg. |
| 5.
Clindamycin
1000µg
in 0.1ml
1.
Draw up the contents of a 2ml ampoule (300mg) and make up to 3ml in a syringe
with normal saline or BSS
2.
Withdraw 1ml of that and make up to 10ml in another syringe with normal
saline or BSS
3.
0.1ml of that contains 1000µg |
Intravitreal
Drugs
NB The
intravitreal dose is given in 0.1ml except when combination therapy is
used and 0.2ml are given. In emergencies it may be necessary to prepare
drugs for intravitreal injection without the assistance of the pharmacist.
Avoid solutions or preparations containing preservatives. The quantities
for intravitreal injection may be drawn up in 1ml syringes, and injected
with a 25 or 27 gauge needle. Make sure to fill the dead space with antibiotic
solution.
Focus
Published by the Royal College of Ophthalmologists 17 Cornwall Terrace,
London NW1 4QW
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