Ophthalmic Surgery and Creutzfeldt- Jakob Disease

446 COMMENTARY Br J Ophthalmol: first published as 10.1136/bjo.2003.028373 on 18 March 2004. Downloaded from Series editor: David Taylor We analysed the surgical history of ....................................................................................... sCJD and vCJD cases with specific reference to ophthalmic surgery. Cases of CJD were identified in the current Ophthalmic surgery and Creutzfeldt- prospective UK national surveillance project (1990-October 2002) by direct Jakob disease notification or from death certificates,10 and were classified as definite, probable, P S-Juan, H J T Ward, R De Silva, R S G Knight, R G Will or possible cases of sCJD or vCJD according to published diagnostic cri- ................................................................................... teria. Only definite or probable cases Although the evidence does not suggest that contaminated were included in this analysis. All cases with a history of ophthalmic surgery ophthalmic instruments represent a risk of onward transmission of were identified from the database, sporadic CJD, this conclusion should be treated with caution which has a specific code for this type of surgery. Information on past ophthal- he occurrence of variant the anterior chamber of the eye in mic surgery was obtained from relatives, Creutzfeldt-Jakob disease (vCJD) guinea pigs.8 general practitioner records, and/or Tand the probable causal link with Recently it has been shown that the copies of case notes. Case files were bovine spongiform encephalopathy experimental transmission of metallic examined to identify the type of surgery, (BSE) in cattle have increased interest suface bound prions is highly efficient.9 date of surgery, and hospital in which in the search for possible environmental Steel wires in contact with the brain of the surgery had taken place. In cases in sources of sporadic CJD (sCJD). pre-symptomatic mice needed only which the surgery was carried out after Presumed iatrogenic CJD is rare. Up to 5 minutes to acquire an infectious load the onset of clinical symptoms of CJD the year 2000 there had been 267 cases equivalent to the injection of a 1% detailed information on the clinical reported worldwide: three cases second- homogenate of brain. Infected wires course was extracted. ary to human corneal grafting (one were inserted transiently into the brains The frequency of a history of eye confirmed, one probable, and one pos- of healthy mice and only 30 minutes of surgery in sCJD and vCJD was com- sible case), 114 related to human dura exposure was sufficient to result in pared with data on the frequency of past mater grafts, 139 related to human infection. The same wires remained eye surgery in age and sex matched growth hormone treatment, four related infective when reintroduced into control groups. During the period of the to human pituitary gonadotrophin ther- another set of healthy mice. Although, study the case-control study has apy, and seven linked to neurosurgical to our knowledge, there have been no evolved. Between 1990 and 1998 a procedures or stereotactic EEG electro- documented cases of CJD secondary to single hospital control was obtained for des.1 Because of the marked resistance ophthalmic surgery other than corneal the sCJD cases and from 1999–2002 a of the infectious agent of CJD to transplantation, there is a possibility single community based control was conventional sterilisation techniques, that ophthalmic surgery might be a risk identified. From 1996–2002 a single there is concern about the possibility of procedure for the accidental iatrogenic hospital control was obtained for vCJD cases and since 1998 attempts have been transmission of infection via surgical transmission of CJD. http://bjo.bmj.com/ instruments in contact with infected Precautions to minimise the risks of made to obtain four community based tissue, especially in neurosurgery or iatrogenic transmission of CJD are vital controls per case of vCJD. Because of the ophthalmic surgery. and the Department of Health has limited numbers of controls and the infrequency of past eye surgery this The presence of infection in the eye established an incidents panel to pro- study reports on unmatched compari- in sCJD was first demonstrated follow- vide advice in cases of all forms of sons of the frequency of past eye ing the intracerbral inoculation of human prion diseases in which there is the possibility for cross infection. surgery. pooled sCJD eye tissue in non-human on September 26, 2021 by guest. Protected copyright. primates.2 Recently the infectious form However, an important question is Fifty eight cases of sCJD (11%) out of of prion protein (PrPSc) has been iden- whether the concerns raised by experi- 510 with information available had a tified in the neural retina, optic nerve, mental work translate into an actual history of intraocular surgery, with an average of 1.34 interventions per and in retinal pigmented epithelium risk in the clinical setting. This com- patient. The types of operation (n = 78) in variant and sporadic CJD using mentary reviews the data on ophthalmic in the total of 58 cases having under- immunohistochemistry or western surgery in sCJD and vCJD from the gone any form of ocular surgery are blot,34 with comparable levels to those archives of the UK National CJD listed in table 1 and the years of found in brain. PrPSc was not detected Surveillance Unit from 1990 to 2002, including information on both sCJD and operation in figure 1. Ten cases of in other ocular tissues. Although this vCJD. sCJD underwent eye surgery during suggests that there may be a greater risk of contaminating surgical instruments in procedures involving the Table 1 Types of operation on cases of sporadic CJD posterior segment of the eye, infectivity has been demonstrated in animal Number of 5 Number of operations operations on Number of operations and human cornea, and circumstan- on sCJD cases hospital controls on community controls tial evidence has implicated corneal (n = 78) (n = 39) (n = 20) transplantation as a mechanism of 6 Intraocular surgery* 55 (70%) 29 (74%) 17 (85%) transmission of iatrogenic CJD. Experi- Extraocular surgery 17 (22%) 6 (16%) 3 (15%) mental infection has been achieved Laser therapy 4 (5%) 2 (5%) — following conjunctival installation of Information not available 2 (3%) 2 (5%) — scrapie infectivity in mice7 and by *Cataract, trauma, and glaucoma. inoculation of an adapted agent into www.bjophthalmol.com COMMENTARY 447 Br J Ophthalmol: first published as 10.1136/bjo.2003.028373 on 18 March 2004. Downloaded from the prodromal (within 3 months of onset) or early symptomatic phase of the disease, the majority cataract operations. Four out of these 10 patients had the Heidenhain variant of sCJD, with visual onset and early development of cortical blindness (table 2). Figure 2 shows the time interval between last eye surgery and the onset of symtoms in sCJD patients. The frequency of past eye surgery was compared with the control groups in sCJD (table 3) and vCJD. In the hospital control group for sCJD, 31 (14%) out of 226 had a history of ophthalmic surgery, with an average of 1.26 procedures per Figure 1 Year of eye surgery in sCJD. patient and in the community control group for sCJD 14 (13%) out of 106, with an average of 1.43 procedures per patient. Eight patients with vCJD (6%) out of 125 with information available Table 2 sCJD patients with ophthalmic surgery after clinical onset had a history of eye surgery and all were squint corrections in childhood, with Heidenhain Case Date of surgery Intervention variant Diagnosis the exception of one case with a history of open surgery for retinal detachment 1 1992 Cataract Definite carried out 15, 17, and 20 months before 2 1992 Laser therapy * Definite 3 1992 Cataract * Definite the development of symptoms (this case 4 1993 Cataract Definite predated the establishment of the CJD 5 1996 Cataract Definite incidents panel). In the hospital control 6 1998 Dacryocystorhinostomy Definite group for vCJD (15%) 10 out of 67 had a 7 1998 Cataract Definite 8 1999 Cataract * Definite history of ophthalmic surgery and in the 9 1999 Laser therapy * Definite community control group for vCJD five 10 2000 Cataract Definite (3%) out of 155 had had eye surgery. There were no significant (at the 5% * Heidenhain variant: cases with isolated cortical visual symptoms at onset. level) differences between the frequen- cies of past eye surgery in the cases and any of the control groups. Details of the year and hospital of each surgical procedure were listed and in the great majority there was no http://bjo.bmj.com/ temporal or geographic link between operations. A group of six cases of sCJD had been operated on in one hospital and in two pairs of cases the procedures had been carried out in the same year. Inquiry about the specific dates of these procedures, however, indicated that the on September 26, 2021 by guest. Protected copyright. operations had been carried out months apart. The aim of this article is to document the frequency of past eye surgery in CJD and to determine whether there is evidence of transmission of CJD through contaminated ophthalmic instruments. About 10% of cases of sCJD have a history of eye surgery, of Figure 2 Interval between last eye surgery and onset of symptoms in sCJD (n = 54). which about 70% involved open surgery on the anterior chamber of the eye. In the great majority of cases the surgical instruments were reused on subsequent Table 3 Past ophthalmic surgery in sCJD compared with control groups patients, usually because CJD developed years after the original procedure. Cases Hospital controls Community controls Despite this, the evidence in this paper (n = 510) (n = 226) (n = 106) does not suggest that there is onward Patients with eye operations 58 (11%) 31 (14%) 14 (13%) iatrogenic transmission of sCJD through Total number of operations 78 39 20 eye surgery, a finding consistent with Average per patient 1.34 1.26 1.43 some previous studies.11 12 An important question is whether cases of CJD caused by this type of www.bjophthalmol.com 448 COMMENTARY Br J Ophthalmol: first published as 10.1136/bjo.2003.028373 on 18 March 2004.

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