Part 4
Infection Control of CJD and Related Disorders in the Healthcare Setting
Introduction
Scope
4.1 This section provides advice on safe working practices to prevent the transmission of CJD and related disorders in hospital and community healthcare, diagnostic laboratory, and post mortem room settings. Whilst the evidence to date does not suggest that CJD and related disorders are spread from person to person by close contact, it is known that transmission can occur in specific situations associated with medical interventions (known as iatrogenic infections). A number of cases of CJD have been associated with the administration of hormones prepared from human pituitary glands and dura mater preparations, and three cases have been reported associated with corneal grafts. Iatrogenic transmission has also been identified following neurosurgical procedures with inadequately decontaminated instruments. Consequently, there are particular groups of patients who present a greater risk of potential exposure to the CJD agent for attending healthcare staff. Likewise, there are specific occupations which place the worker at a greater exposure risk, e.g. neuropathologists and those workers involved in post mortem examination of known or suspected CJD cases.
4.2 This section also includes and updates earlier advice from the Department of Health on preventing iatrogenic transmission.2,3 It also provides guidance aimed at preventing the remote possibility of transmission of infection from patients to healthcare workers. The occupational infection control advice issued to post mortem rooms and anatomy departments given in the Department of Health circular, PL(94)CO/2, remains current and should be followed where appropriate (copies available from the Department of Health). This circular advises anatomy departments not to accept for teaching or research purposes bodies or brain, spinal cord or eyes from donors currently identified as being at higher risk from developing CJD or a related disorder (see Table 4). It suggests questions which might be used by anatomy departments when formulating their own guidance on exclusion criteria for prospective donors, e.g. whether the patient showed signs of dementia or other progressive neurological defect.
Patient confidentiality
4.3 There has been increased media and press interest in patients suffering from CJD, and whilst it is important that staff are aware of the risks so that appropriate precautions can be taken, healthcare staff are reminded of the need to maintain patient confidentiality and to avoid unnecessary disclosure of patient names and clinical details. For example, the use of a code number rather than a name on clinical samples could be considered.
Standard infection control procedures
4.4 The epidemiological evidence to date does not suggest that, in the majority of situations, there is need for particular precautions beyond those used for other patients. Guidance on the management of infection control in hospitals and residential and nursing homes has been published previously (see bibliography). This guidance is not re-iterated here, but it is emphasised that the use of routine standard infection control practices will minimise the exposure of individuals involved in the healthcare of patients who have, or may develop TSE, and protect them from the very remote possibility of infection. An important aspect of this is to ensure that the appropriate procedures are being adhered to. Employers and managers will therefore need to ensure that effective management systems are in place. Guidance on the management of health and safety in the health services has been prepared by the Health Services Advisory Committee (see bibliography).
Occupational exposure
4.5 Currently there is no evidence of any specific occupational risk of transmission. However, available information is limited and, as CJD remains a rare disease, it is not possible to draw firm conclusions. It is prudent therefore to take a precautionary approach. Within the general healthcare setting, workers from a range of occupational groups may potentially be exposed to tissues from patients known or suspected to have CJD, or those who may be at risk of developing CJD, that may contain the agents responsible for CJD or related disorders. Therefore, any healthcare worker who attends patients in these groups, and might come into contact with tissues that may contain the CJD agent, should be aware of the risks of exposure.
Patient risk groups (referred to below as known, suspect or at risk patients)
4.6 When considering measures to prevent transmission to patients or staff in the healthcare setting, it is useful to make a distinction between those patients who are known or suspected to have CJD or a related disorder, i.e. those with clinical symptoms, and those who are potentially at risk of developing one of these diseases, i.e. asymptomatic, but having a clinical or family history which places them in one of the risk groups. Table 4 sets out these groups in more detail. It is important to note that the requirements set out below apply only to the relatively small number of patients in the risk groups.
4.7 In most routine clinical contact, no additional precautions are needed for the care of patients in the risk groups. However, when certain invasive interventions are performed there is the potential for exposure to the agents of TSE. In these situations it is essential that control measures are in place to prevent the iatrogenic transmission of TSE. The tissues that present the highest risk of exposure to the agents of TSE are the brain, spinal cord, and eyes. Therefore, special precautions need to be taken for interventions involving these tissues for known, suspect or at risk patients, i.e. all the groups identified in Table 4. Furthermore, special precautions need to be considered for all clinical interventions on known or suspect patients. This is partly because known or suspect patients will, by definition, have clinical symptoms, and therefore there may be a greater likelihood of the infectious agent being present in their tissues, but most importantly because of the added uncertainties about the tissue distribution of the agent in cases of nvCJD. Specific advice on clinical procedures for the various patient risk groups identified in Table 4 is given in paragraphs 4.21-4.36, and is presented as a flow chart on page 35.
Table 4
Patient Risk Groups |
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| Known or suspect patients | | At risk patients |
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| Patients diagnosed as having CJD or a related disorder* | Asymptomatic patients who are potentially at risk of developing CJD or a related disorder*: |
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| Patients suspected of having CJD or a related disorder* i.e. whose clinical symptoms are suggestive of CJD but where the diagnosis has not yet been confirmed. | - recipients of hormone derived from human pituitary glands, e.g. growth hormone, gonadotrophin;
- recipients of human dura mater grafts; |
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| - people with a family history of CJD, i.e. close blood line relatives (parents, brothers, sisters, children, grandparents and grandchildren). |
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| * ie. classical sporadic CJD, nvCJD, GSS, FFI and kuru |
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4.8 It has been noted already that nvCJD is quite distinct from classical forms of CJD. This difference appears to extend to the pathogenesis of the disease, and it has been suggested that in nvCJD there is more involvement of lymphoreticular tissues possibly involving circulating lymphocytes. The risk tissues may therefore need to be redefined as further research findings emerge and as the estimation of the numbers of nvCJD cases becomes clearer. At present, the number of people incubating nvCJD is not known.
4.9 Transfusions of whole blood, component blood or blood derivatives have not been shown to transmit the classical CJD agent. However some experimental evidence suggests that intracerebral inoculation of some blood components can occasionally transmit the CJD agent. Further studies are in progress to investigate these findings. To avoid the theoretical possibility of transmission of CJD by transfused blood, recipients of human growth hormone were excluded from donation in 1989, and recipients of other human-derived pituitary hormones excluded since 1993. Work is underway to assess the risk of transmitting nvCJD by blood transfusion and, in the interim, the National Blood Authority is working towards the possible extension of leucodepletion of blood as a precautionary measure.
Hospital Care
4.10 The following advice is for those involved in the care of patients known, suspect or at risk of developing CJD or related disorders. This advice should be taken into consideration in the development of local infection control policies. The responsibilities for infection control policies should be clearly defined locally in line with existing Department of Health guidance (HSG(95)10, see bibliography for details). In general, this will be the responsibility of the infection control team.
Ward Procedures
4.11 Available epidemiological evidence suggests that normal social or routine clinical contact with a CJD patient does not present a risk to healthcare workers, relatives and the community. Isolation of patients with CJD is not considered necessary, and they can be nursed in the open ward with no particular precautions beyond the routine infection control used for all other patients.
4.12 The distribution of TSE infectivity in natural disease has been discussed earlier. In the main, most infectivity is likely to be concentrated in the central nervous system (CNS), and particular care should be taken with such specimens from known, suspect or at risk patients. For example, use disposable gloves, aprons and single-use disposable instruments when performing a lumbar puncture for the collection of cerebrospinal fluid (see sample collection below). It is important to ensure that only trained staff, aware of the hazards, should carry out such procedures. At present, there is no evidence of infectivity in saliva, body secretions or excreta and, therefore, any potential exposure to these body fluids should be handled as for any patient, i.e. treated as potentially infectious in line with standard infection control procedures. As mentioned previously, there are uncertainties about the risks of TSE transmission from blood. However, careful attention to standard infection control procedures will minimise any such risk.
4.13 Drug administration by injection and the collection of blood specimens should involve the precautions used for all work of this type with any patient, i.e. avoidance of sharps injuries and other forms of parenteral exposure, and the safe disposal of sharps and contaminated waste by incineration. Again, these procedures should be carried out by trained personnel aware of the hazards involved.
4.14 In the event that a known, suspect or at risk patient becomes pregnant, childbirth should be managed using standard infection control procedures. The placenta, other associated material and fluids should be treated as if infected, and disposed of as infectious clinical waste by incineration, unless they are needed for investigation, in which case the precautions for dealing with infected tissue should be followed (see below). Instruments should be handled following the advice below on clinical procedures.
4.15 Used or fouled bed linen (contaminated with body fluids or excreta), should be removed from the bed and washed and dried in accordance with current practice and advice (Department of Health HSG(95)18, see bibliography). No further handling or processing requirements are necessary.
4.16 Spillage in the ward of potentially CJD-infectious materials should be removed using absorbent material, the surface disinfected with an appropriate disinfectant, and any waste disposed of as clinical waste by incineration. Disposable gloves and an apron should be worn when removing such spillage(s) and disposed of by incineration. See Annex B for further advice on disinfection.
4.17 Waste material should be handled as for all clinical waste, and disposed of by incineration in line with standard practice “Safe disposal of clinical waste.” HSAC 1992. New edition due mid-1998).
4.18 Any accident involving sharps, or contamination of abrasions with blood or body fluid, should be gently encouraged to bleed, gently washed (avoid scrubbing) with warm soapy water, rinsed, dried and covered with a waterproof dressing, or further treatment given appropriate to the type of injury4. Splashes into the eye or mouth should be dealt with by thorough irrigation. The accident should be reported to the accident supervisor and an accident or incident form completed. See also the section on page 8 on accident reporting and health surveillance.
Sample collection and labelling
4.19 Biopsy and lumbar puncture samples from known, suspect or at risk patients should only be taken by trained personnel who are aware of the hazards involved. Disposable gloves and eye protection should be worn where splashing may occur. Samples should be marked with a ‘Biohazard’ label and, because of the increased media interest in CJD, particular consideration should be given to the need to maintain patient confidentiality. For example, the use of a code identifier rather than labelling with the patient name might be appropriate.
4.20 Because of the unusual resistance of the TSE agents, single-use disposable equipment should be used wherever practicable, and all small items contaminated by such specimens destroyed by incineration. Where this is not possible, the advice in Annex B on decontamination should be followed.
Clinical procedures
General measures
4.21 The use of standard infection control procedures during any clinical intervention will reduce the risk of infection. There are particular concerns regarding surgical and other clinical procedures on known, suspect or at risk patients because of the potential for onward transmission to other patients via contaminated surgical instruments. The following guidance should also serve to protect healthcare staff involved in such clinical procedures.
4.22 For the care and clinical management of known, suspect or at risk patients it may be necessary to undertake a range of clinical procedures. In these situations every effort should be made to plan carefully not only the procedure, but also the practicalities surrounding the procedure, e.g. instrument handling, storage, cleaning and decontamination or disposal. It may be useful to plan that the patient is last on the day’s operating list. No other discrimination should be permitted.
4.23 For non-invasive investigations, e.g. certain imaging or X-ray procedures, no specific precautions, other than those that would normally be applied to safeguard patient well-being are required.
4.24 Whilst the risk of transmission of infection via surgical or clinical procedures is generally accepted as small, there is still a need for specific precautions when undertaking certain procedures on known, suspect or at risk patients. This will depend first on whether the patient is symptomatic, i.e. known or suspected of having CJD, or non-symptomatic but falls into one of the at risk categories. The second consideration is about the type of procedure. In general, for known or suspect patients, whatever the clinical procedure, disposal of all instruments is recommended. Whereas, for at risk patients, disposal is recommended only where there is contact with a high risk tissue, i.e. brain, spinal cord or eye, and less stringent precautions are generally acceptable when there is contact with other tissues which are unlikely to contain the agent of CJD. This is illustrated by the algorithm chart on page 35.
4.25 All staff directly involved in procedures on patients in the risk groups, or in the subsequent re-processing or disposal of potentially contaminated items, should be aware of the specific precautions, and adequately trained. These staff should also be made aware of any clinical intervention in sufficient time to allow the necessary preparations for the procedure; this should include notification to the Sterile Services Department (SSD) or re-processing units, where appropriate. This will also allow time to obtain the most suitable instruments and equipment, which may not be those used routinely. Single-use items or components, such as patient circuits used in renal support equipment, should be used wherever possible.
Precautions during clinical procedures on known or suspect patients
4.26 The following precautions should be taken for all clinical procedures on known or suspect patients:
- wherever appropriate and possible, the intervention should be performed in an operating theatre;
- where procedures are performed at the bedside, e.g. a lumbar puncture, care should be taken to ensure the environment may be readily cleaned should a spillage occur (see Annex B). The protective clothing described below should be worn by the healthcare personnel performing diagnostic procedures;
- perform the procedure at the end of the list to allow normal cleaning of theatre surfaces before the next session;
- involve only the minimum number of healthcare personnel required;
- wear the following single-use protective clothing:
-liquid repellant operation gown, over a plastic apron
-gloves
-mask
-visor or goggles;
- maintain a one-way flow of instruments;
- use single-use disposable surgical instruments and equipment where possible.
Note: If single-use disposable items are not available the instruments should under no circumstances be re-used;
- destroy all used instruments and protective clothing by incineration.
Note: Instruments that will not be entirely destroyed by incineration should be subject to a process to ensure surface decontamination. These items may then be considered fit for disposal via landfill.
4.27 Some expensive items of equipment, such as drills, may be prevented from being contaminated by using shields, guards or coverings, so that the entire items do not need to be destroyed. The drill bit, other parts in contact with high risk tissue, and the protective coverings would then need to be incinerated. However, in practice, it may be difficult to ensure effective protective covering, and advice should be sought from neurosurgical staff and the manufacturer to determine practicality. For example, the screws of neurosurgical stereotactic frames, which are placed in the cranium, should be considered as being in contact with high risk tissue and therefore should be destroyed. However, there is a potential risk of the frame being contaminated as the screws are removed through it, therefore the frame should also be discarded.
4.28 Instruments that have been used on a suspect CJD patient, e.g. to take biopsy material for diagnosis of CJD, may be quarantined by securely storing in a rigid, sealed container after use, until the diagnosis is confirmed. If the case is confirmed as CJD, or if after testing the diagnosis remains ‘suspected CJD’, the instruments should be disposed of by incineration. Only if a definitive alternative diagnosis is confirmed may the instruments be cleaned and decontaminated following the usual routine procedures.
Precautions during clinical procedures on at risk patients
4.29 If the clinical intervention involves brain, spinal cord, or eyes, the precautions recommended above for procedures on known or suspect patients should be taken.
4.30 If the clinical intervention does not involve brain, spinal cord, or eyes, the following precautions should be taken:
- wear the following protective clothing (i.e. the same as above but may be re-processed if not designated single-use):
-liquid repellant operation gown, over a plastic apron
-gloves
-mask
-visor or goggles;
- use single-use surgical instruments and equipment wherever reasonably practicable;
- destroy all single-use items by incineration;
- re-usable surgical instruments and equipment must not be re-used until one of the recommended decontamination procedures has been carried out (see Annex B).
4.31 Where there is no exposure to high risk tissues, instruments which are not single-use can be re-processed as described in this guidance, providing that they are able to tolerate the process (e.g. stainless steel surgical instruments such as forceps, cutters, retractors).
Labelling and transportation of instruments
4.32 All instruments and items of equipment that have been in contact with known, suspect or at risk patients should be clearly identified. Items used on known or suspect patients should be labelled for disposal. Items used on at risk patients, where there has been contact with brain, spinal cord or eye, should also be labelled for disposal, whilst those used on other tissues should be labelled either for re-processing or disposal as appropriate.
4.33 Items for re-processing should be securely contained in a robust, leak-proof container, and transferred to the re-processing unit or SSD as soon as possible after use. Items should be transferred to the reprocessing unit by a designated person from the theatre team.
4.34 Items for disposal by incineration should be isolated in a rigid clinical waste container and transported to the incinerator as soon as practicable, in line with the current disposal of clinical waste guidance.
Cleaning and decontamination
4.35 The nature of the agents of TSEs is such that standard methods such as autoclaving cannot be relied upon to inactivate the agents completely. The emphasis must, therefore, be on removal of the agents by thorough cleaning, followed by an appropriate decontamination process. Detailed advice on cleaning and decontamination is given in Annex B. However, this does not apply to instruments that have been used in procedures on known or suspect patients, or those used on at risk patients where there has been contact with brain, spinal cord or eye, as these items must be disposed of by incineration.
Instrument use on subsequent patients
4.36 After decontamination as described above, surgical instruments (if incineration is not required) should be put through the standard hospital procedures for re-processing instruments, i.e. cleaned again, inspected, function tested, packed and sterilized, before being made available for use on another patient.
2DA(81)22 and DA(84)16 "The management of patients with spongiform encephalopathy (Cruetzfeldt-Jakob Disease CJD)", 1981 and 1984, Department of Health and Social Security.
3PL(92)CO/4 "Neuro and ophthalmic surgery procedures on patients with or suspected to have, or at risk of developing CJD or GSS", 1992, Department of Health.
4The use of concentrated disinfectants and/or surgical excision of the site of exposure has been suggested (Aguzzi and Collinge Lancet 1997). However, because of the lack od data at this stage, these views were not supported by the working group, but the situation will be kept uder review.
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