1.7 Method of diagnosis
Culture of
C. diphtheriae from the infected site. Direct microscopy is of no value.
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Guidelines for the Control of Diphtheria in the Northern Territory March 2004
2.1 Collection of specimens from a suspected case
•
membrane and the membrane itself.
The preferred specimen is a cotton tipped swab of the eroded epithelium underneath the
•
and should be obtained with a flexible alginate (wire) swab that reaches deep into the
back of the nose.
Nasopharyngeal cultures are indicted in children who do not have an obvious membrane
•
wounds are taken, lesions should be cleansed with sterile normal saline and crusted
material removed. A cotton-tipped applicator should then be firmly applied to the base of
the wound.
Any chronic, crusting, cutaneous lesion should also be swabbed. Before cultures of
•
Transport in ordinary semi-solid transport medium, such as Amies or Stuarts.
•
Specimens should be collected prior to administration of antibiotics.
2.2 Case management
2.2.1 Clinical systemic diphtheria / results of toxigenicity pending
Confirm with the local laboratory that the specimen has been sent to the reference
laboratory for urgent PCR toxigenicity testing. A result should be available in 24-48
hours.
Since clinical systemic diphtheria is usually caused by a toxigenic strain it is a
emergency
includes the administration of antibiotics (to eliminate infection and prevent spread) and
equine diphtheria antitoxin on the basis of clinical diagnosis alone. Administration of
antitoxin is the most important aspect of treatment in this situation and must not be
delayed until bacteriological/toxigenicity confirmation. Life support measures,
including endotracheal intubation or emergency tracheotomy may be necessary to
overcome respiratory obstruction.
medical. Management involves seeking advice from an experienced physician, and
Section 2 Clinical Management
CDC must be urgently notified by telephone if disease is suspected on clinical grounds
(while waiting for laboratory confirmation)
Management of cases is based on the clinical condition
and the toxigenicity of the infection, if known.
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Guidelines for the Control of Diphtheria in the Northern Territory March 2004
Cases should remain in strict respiratory isolation until 2 cultures from both the nose
and throat taken not less than 24 hours apart, and not less than 24 hours after ceasing
antibiotic therapy, are negative for diphtheria bacilli. If culture is impractical, isolation
may be ended after 14 days of appropriate antibiotic treatment.
2.2.2 Toxigenic infection
The same isolation criteria apply as for systemic disease above. The management of
toxigenic infections in the absence of systemic disease involves seeking advice from an
experienced physician, as it may involve the administration of equine diphtheria
antitoxin. Vigorous cleansing of wounds, if present, and the administration of
antibiotics is recommended.
Diptheria infection does not necessarily confer immunity
stage of their illness, fully immunised individuals should receive a booster dose of
diphtheria containing vaccine (unless they have received a dose within the last 12
months).
‘catch-up’ vaccination and receive/complete the primary course and boosters in
accordance with the
4 so during the convalescent5 Unimmunised or incompletely immunised individuals should commenceAustralian Immunisation Handbook recommendations.
2.2.3 Non-toxigenic infection
Treatment of non-toxigenic infection will depend on the local manifestations of the
infection, and a decision on whether to treat will need to be made on individual
circumstances. Unimmunised or incompletely immunised individuals should
commence “catch-up’ vaccination and receive/complete the primary course and
boosters in accordance with the
Australian Immunisation Handbook recommendations.
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Guidelines for the Control of Diphtheria in the Northern Territory March 2004
3.1 Case Definition and Notification
NT case definitions are the same as the National Notifiable Diseases Surveillance System
(NNDSS) definitions. Both confirmed and probable cases should be reported.
3.1.1 Confirmed case
A confirmed case requires laboratory definitive evidence only.
•
Laboratory definitive evidence – isolation of toxigenic C. diphtheriae or
toxigenic
C. ulcerans
3.1.2 Probable case
A probable case of diphtheria disease requires either:
laboratory suggestive evidence
AND clinical evidence
OR
Clinical evidence
AND epidemiological evidence
•
production unknown)
Laboratory suggestive evidence – isolation of C diphtheria or C ulcerans (toxin
•
pharyngitis and/or laryngitis (with or without a membrane);
Clinical evidence – at least one of the following :
OR
toxic (cardiac or neurological) symptoms
•
contact between 2 people involving a plausible mode of transmission at a time
when :
Epidemiological evidence – an epidemiological link is established when there is:
more than 4 weeks after onset of symptoms)
one of them is likely to be infectious (usually 2 weeks or less and seldom
AND
contact
the other has an illness which starts within approximately 2-5 days after the
AND
involve many cases) is laboratory confirmed
at least 1 case in the chain of epidemiologically linked cases (which may
Section 3 Public Health Management
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Guidelines for the Control of Diphtheria in the Northern Territory March 2004
3.2 Active Surveillance
Active surveillance includes follow-up of contacts, as detailed below. In addition,
community members with symptoms compatible with diphtheria up to 2 weeks after
diagnosis of the index case should be investigated. This includes anyone presenting with a
sore throat or runny nose, particularly if the nasal discharge is blood stained or only apparent
on one side.
3.3 Definition of a contact
•
index case.
All household members and other persons with history of habitual, close contact with the
•
during the previous week (i.e. mouth kissing or mouth to mouth resuscitation).
Anyone who has had significant contact with nasopharyngeal secretions of the index case
•
hours with the index case in the week preceding the onset of illness (e.g. contacts in child
care centres, schools etc).
Anyone who has spent 4 hours or more a day for 5 consecutive days, or more than 24
3.4 Management of asymptomatic contacts
3.4.1 Contact management when the index case has:
•
clinical systemic diphtheria OR
•
confirmed toxigenic strain (with or without systemic disease)
•
ordinary semi-solid transport medium.
Take nasopharyngeal swabs (or nose and throat swabs) for culture and place in
•
containing vaccine. (NB a booster dose is not required if the last dose was given
less than 5 years earlier).
Fully immunised contacts should be given a booster dose of a diphtheria4
•
immunisation following the recommendations in the
Immunisation Handbook.
Unimmunised or incompletely immunised contacts should commence ‘catchup’Australian
Management of contacts is based on the clinical condition of the index case
and the toxigenicity of the infection, if known.
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Guidelines for the Control of Diphtheria in the Northern Territory March 2004
•
Antibiotic prophylaxis (see section 3.5).
•
association with children should be excluded from work until swabs prove them
not to be carriers or 48 hours post commencement of antibiotic prophylaxis.
Adult contacts whose occupations involve handling food/milk products or close
•
them not to be carriers or 48 hours post commencement of antibiotic
prophylaxis.
Child contacts should be excluded from school, day care etc until swabs prove
•
Observe all asymptomatic contacts closely for 7 days.
3.4.2 Contact tracing is NOT required when the index case has:
•
organism
no evidence of systemic disease with a confirmed non-toxigenic4,5 OR
•
no evidence of systemic disease with toxigenicity pending*
*If the laboratory result comes back as a toxigenic strain, refer to section 3.4.1.
3.5 Antibiotic prophylaxis for contacts of systemic diphtheria and/or
toxigenic infection
Antibiotic prophylaxis should be given regardless of the immunisation status of the
contact.
Weight < 30 kg: Benzathine penicillin (Bicillin LA), 600,000 units (450mg/1ml)
1ml as a single intramuscular dose.
Weight
2ml as a single intramuscular dose.
≥ 30 kg: Benzathine penicillin (Bicllin LA), 1,200,000 units (900mg/2ml)
If penicillin allergy present or compliance assured:
Erythromycin orally for 7 days in 4 daily divided doses
Children 40mg / kg / day
Adults 1gm / day
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Guidelines for the Control of Diphtheria in the Northern Territory March 2004
References
1. U.S Department of Health and Human Services. Centers for Disease Control and Prevention.
Manual for surveillance of vaccine preventable diseases 3rd Edition, 2002. URL: http://www.
cdc.gov/nip/publications/surv-manual/chpt01_dip.pdf accessed 29/09/2003.
2. Chin J, editor. Control of Communicable Diseases Manual. 17
American Public Health Association, 2000.
3. National Health and Medical Research Council. The Australian Immunisation Handbook. 8
th edition. Washington:th
edition. 2003. URL: http://immunise.health.gov.au/handbook.htm accessed 29/09/2003.
4. U.S Department of Health and Human Services. Centers for Disease Control and Prevention.
Epidemiology and Prevention of Vaccine-Preventable Diseases. 8th Edition. URL: http://www.
cdc.gov/nip/publications/pink/dip.pdf accessed 12/03/2004.
5.
disease control. 1999. U.K Public Health Laboratory Service. URL: http://www.hpa.org.uk/
infections/topics_az/diphtheria/guidelines.pdf accessed 29/09/2003.
Bonnet JM and Begg NT. Control of diphtheria: guidance for consultants in communicable
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Guidelines for the Control of Diphtheria in the Northern Territory March 2004
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Guidelines for the Control of Diphtheria in the Northern Territory March 2004
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Guidelines for the Control of Diphtheria in the Northern Territory March 2004
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