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 Creutzfeld-Jakob
Disease (CJD) is a frightening but nonetheless intriguing disease.
It occurs in most populations at approximately 1 case per million
per year. It is referred to as classical or sporadic CJD to distinguish
it from new variant CJD (nvCJD) of which there have been to date
a total of 25 cases and which is thought to be the human equivalent
of bovine spongiform encephalopathy (BSE). Classical CJD is not
contagious but has been transmitted by transplantation of cornea
1 (world total of 3 cases), dura mater, pituitary growth
hormone and by comtaminated neurosurgical instruments and cortical
electrodes. Although there is rapidly progressive dementia invariably
leading to death usually within months of onset, it is a diagnosis
that is only confirmed postmortem by characteristic spongiform change
or immunochemical identification of the pathological isoform of
the prion protein in the brain. Although it has long been an absolute
contraindication to corneal donation its exclusion can only be achieved
by a low threshold of suspicion as there is as yet no serological
screening test. 2
Adverse
Incident
In
November 1997 it was revealed that a donor in Scotland who had died
from histologically proven carcinoma of the lung also had CJD, a
fact which only came to light some months later as a result of a
routine neuro pathological post mortem evaluation, although there
had been some neurological symptoms shortly before death. By this
time her eyes had been processed by the Corneal Transplant Service
(CTS) Eye Bank in Manchester, the tissue having passed the normal
tests for HIV, Hepatitis C, Hepatitis B, and bacterial and fungal
contamination. Having healthy endothelia the corneas were transplanted
into two recipients and both scleras into a third individual in
a total of three different centres.
When
the information bacame available to CTS the first action taken was
to inform all three transplanting surgeons once the destination
of the tissue had been thoroughly checked. This was only achieved
just as the story reached the national and international press.
It proved to be a difficult time not only for the patients but also
eye bank staff, surgeons and UKTSSA who were actively involved.
There are no Department of Health guidelines for action under such
circumstances and consequently there is uncertainty as to where
responsibility lies. Not surprisingly, the press, somewhat confused
over the difference between classical CJD and nvCJD against a background
of major public concern about BSE, were keen to establish if and
where blame could be apportioned. The incident prompted a useful
editorial 3 which put the risk of such an event occurring
into context.
The
implications of the incident are far reaching and a number of changes
have already been made.
Action
So Far
- After
receiving expert advice from the Spongiform Encephalopathy Advisory
Group in December 1997, all surgeons offered the three patients
explantation of ocular tissue. Two patients accepted the advice
and had further surgery by January 1998. All three remain well.
- The
Duty Office at UKTSSA now routinely asks if a postmortem on a
donor is pending. No tissue is issued form the CTS Banks in Bristol
and Manchester until such time as the result is known (December
1997).
- The
CTS Eye Bank policy on sclera has been changed to ensure that
sclera cannot be held in stock and that sclera from any single
eye is not transplanted into more than one individual and can
always be traced to a named recipient (i.e. a policy which is
in line with corneal transplantation)
- Sir
William Stewart chaired an expert group who undertook and subsequently
published on behalf of the governemnt (April 1998) an independent
review of the incident which contains 18 recommendations. Copies
can be obtained from Margaret
Hallendorff at the College.
- Guidelines
for retrieval of donor eyes have now been accepted by the College
and are available, through this link.
All ophthalmic units are expected to have read this document.
- A
re-designed ocular tissue donor information form and contrainidication
list are now issued with UKTSSA retrieval boxes (July 1998).
College
Response
The
recommendations of the Stewart report are under active consideration
principally by the Ocular Tissues Standards and Audit Group (OTSAG).
This Group was established in 1996 and seeks to define essential
and best practice in the fields of ocular and non-ocular tissue
transplantation. The following proposals are currently under consideration:
- The
Royal College of Ophthalmologists should develop a portfolio of
documents defining standards in the transplantation of the cornea,
sclera and all other ocular and non-ocular tissues into the human
eye.
- The
portfolio should be compiled and updated by OTSAG which is accountable
to the Royal College of Ophthalmologists and to the Corneal Advisory
Group at UKTSSA.
- All
units regularly undertaking ocular tissue transplantation should
contribute to the supply of ocular tissue for transplantation
and research nationwide.
For
the first time during 1997-98 procurement rates appear to be falling.
Units should aim to procure preferably twice as many eyes as those
of which they use any part. To do so would compensate for the significant
discard rate that occurs during eye banking which ensures that only
corneas with high endothelial cell counts are issued for transplantation.
(The Department of Health recognises the time and commitment given
to eye retrieval and a scheme has operated for some years to reimburse
those units who contribute a significant net supply of donor tissue).
- Retrieval
should be undertaken according to guidelines, by trained medical
or non-medical staff.
- All
consultant ophthalmic surgeons who undertake ocular tissue transplantation
should have knowledge of the procedure of eye procurement and
banking, understand the unique risks involved and accept that
they have ultimate responsibility for their patients who should
be well informed.
- All
Medical Directors of Eye Banks should ensure that all ocular tissue
is traceable to its destination. This includes tissue that is
used in research or is discarded as unsuitable or surplus to requirement
in addition to that used in recipient patients.
- All
consultant ophthalmologists and their junior staff who undertake
transplantation of any kind should actively take part in routine
long term follow-up of clinical outcome. Revised forms for transplant,
six month and annual follow-up thereafter are currently being
evaluated.
Andrew
Tullo
All
constructive comments are welcome:
Mr. Andrew Tullo,
Manchester Royal Eye Hospital,
On behalf of OTSAG,
Fax: 0161 272 6618
References:
1 Hogan
RN and Cavanagh HD. Transplantation of corneal tissue from
donors with disease of the central nervous system . Cornea
1995; 14: 547-53
2 Otto
M, Wiltfaug J, Schutz E et al. Diagnosis of Creutzfeld-Jacob
Disease by measurement of 5100 protein in serum: a prospective case
control study. Brit Med J 1998; 316: 577-82
3.
Allan B, Tufts S. Transmission of Creutzfeld-Jacob Disease
in corneal grafts. Brit Med J 1997; 315:1553-4
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