Diagnosis
of Smallpox
Diagnosis (19:10)
Three major
criteria and five minor criteria have been developed to assist
clinicians in determining whether or not a disease is smallpox.
Based on the major and minor criteria that describes the patients
symptoms, or a combination thereof, the likelihood of the patients
illness being smallpox can be evaluated.
There
are three major smallpox criteria. The first criterion is that
the person had a significant febrile prodrome 1 to 4 days before
rash onset. A significant febrile prodrome is described as having
a fever that must be greater than or equal to 101° Fahrenheit,
and at least one of the following systemic complaints: prostration,
headache, backache, chills, vomiting or abdominal pain. The second
criterion is that the rash lesions are deep in the skin, firm,
or hard to the touch and well circumscribed. They have a “shotty” feel,
like rolling a pea around under the skin. (22:V4:9) The
third criterion is that on any one part of the body, all the lesions
are in the same stage of development. This means that all lesions
on the arm or all lesions on the trunk would be all vesicles, all
pustular, or all crusting – not a mixture of different skin
lesions. (22:V4:9)
There are five
minor smallpox criteria. The first criteria is that the distribution
of the rash is centrifugal. The second criteria is that first lesions
of the rash appeared on the oral mucosa or palate, or on the face
or forearms. The third is that the patient appears toxic or moribund
(typically a patient is so sick that they are bed ridden). The
fourth is that lesions progressed slowly, in other words they evolved
from macules to papules to pustules over several days. The final
minor criteria is that there are lesions on the palms or soles.
Evaluation based
on Major and Minor Criteria will determine whether the patient
is considered high, moderate or low risk for smallpox.
A
person is considered at high risk for smallpox if he or she meets
all three major criteria. Immediate action should be taken to make
sure that contact precautions and respiratory isolation are in
place. These patients should be reported to local health authorities
immediately. High Risk Response.
A
person is considered at moderate risk of smallpox must have had
a febrile prodrome and either one other major criterion or at least
4 minor. Patients should be isolated and be evaluated urgently
to determine the cause of illness. Persons classified as high or
moderate risk be seen in consultation with a specialist in infectious
diseases and/or dermatology whenever possible. Moderate
Risk Response.
Any
person who did not have a febrile prodrome is considered low risk,
as are persons who had a febrile prodrome and less than 4 minor
criteria. These patients should be managed as clinically indicated. Low
Risk Response.
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