Biomedical Engineering Reference
In-Depth Information
types A-E is available as an investigational new
drug (IND). Stool and serum should be obtained
from patients. In cases where botulism factors high
among diagnostic possibilities, electromyography,
using repetitive stimulation at 40 Hz or greater, may
be considered. Moreover, cerebrospinal fluid may
be examined for white blood cells and protein, and
a Tensilon challenge test can be performed. The
patient's vital capacity should be monitored [1,5].
Supporting evidence can be obtained by finding
“safety-pin”-shaped Gram-negative coccobacillary
organisms on stained sputum, lymph node aspirate,
blood, or spinal fluid. Confirmation is by culture
of these same specimens, which should only be
attempted under BSL-3 conditions [5,10].
4.3.4 Differential Diagnosis
The differential diagnosis for the bubonic
form includes ulceroglandular tularemia, staphy-
lococcal or streptococcal adenitis, meningococ-
cemia, enteric Gram-negative sepsis, gas gangrene,
cat-scratch disease, scarlet fever, Rocky Moun-
tain spotted fever, necrotizing fasciitis, and rick-
ettsioses. In tularemia or cat-scratch disease, the
inoculation site is usually more evident than in
bubonic plague, and the patient is not usually
septic. The differential diagnosis for pneumonic
plague includes other etiologies of fulminant
pneumonia, tularemia, trench fever, anthrax and
staphylococcal enterotoxin B (SEB) inhalation.
Continued deterioration without stabilization rules
out SEB. Patients with plague have a cough
productive of bloody sputum, while those with
tularemia generally have a non-productive cough.
Secondary spread may occur with pneumonic
plague [5,10].
4.3 Disease: Plague
4.3.1 Causative Agent
Yersinia pestis
, a Gram-negative bacillus, may
be inhaled as an aerosol (pneumonic plague), or
contracted by the bite of infected fleas (bubonic
plague). The incubation period for pneumonic
plague is from 2-3 days, and is 2-10 days for the
bubonic form of the disease [5,10].
4.3.2 Clinical Description
In the pneumonic form, the onset of symp-
toms is acute and fulminant with high fever,
chills, headache, malaise, myalgia, and cough. The
patients may have lymphadenopathy and blood-
tinged sputum. Pneumonia progresses rapidly,
resulting in dyspnea, stridor, and cyanosis.
Terminal events are respiratory failure, circula-
tory collapse, and hemorrhage; mortality is 100%
in untreated patients. In the bubonic form, initial
symptoms include malaise, high fever, and one
or more painful swollen lymph nodes (“buboes”).
The vast majority of buboes occur in the groin,
cervical, and axillary lymph nodes may also be
involved. Up to 80% of patients with bubonic
plague also become septic (“septicemic plague”);
5-15% develop pneumonia. Circulatory collapse,
hemorrhage, and peripheral thrombosis are the
terminal events. About half of untreated bubonic
cases die [10].
4.3.5 Medical Management
For pneumonic plague, streptomycin 30mg/kg/day
IM in 2 divided doses for 10 days or gentam-
icin 2.0mg/kg IV loading dose, then 1.7mg/kg IV
q8h or 5mg/kg once daily (in children, 2.5mg/kg
IV q8h is recommended). Alternate treatments are
doxycycline 200mg IV initially, then 100mg q12h
IV (2.2mg/kg IV q12h in children) for 10-14 days;
or chloramphenicol 1000mg qid IV (25mg/kg IV
q6h in children) for 10-14 days (preferred for
plague meningitis). Supportive therapy is provided
as required.
Plague prophylaxis is achieved with tetracy-
cline 500mg qid po or doxycycline 100mg bid
po (2.2mg/kg po q12h in children) for 7 days
or duration of exposure, whichever is longer.
Ciprofloxacin 500mg bid po (20mg/kg po q12h in
4.3.3 Diagnosis
As prompt therapy is critical to survival for plague
victims, an initial diagnosis should be made clin-
ically in patients with severe, rapidly progres-
sive pneumonia accompanied by hemoptysis.
