Differential diagnosis: Pneumonia must be differentiated from CAPs, atypical pneumo-
nias, tuberculosis, psittacosis, Q fever, pneumonic plague, inhalation anthrax, and SARS.
Typhoidal disease, especially if prolonged, must be differentiated from other forms of sepsis,
including typhoid fever, enteric fever, brucellosis, Legionella, Q fever, disseminated
mycobacterial or fungal disease, rickettsial disease, malaria, and endocarditis.
Ulceroglandular disease may be mistaken forMycobacterium marinumor sporotrichosis
infections. Because lymphadenopathy may be present without the skin lesion and persist for
long periods of time, bacterial infection, cat scratch disease, syphilis, chancroid, lymphogranu-
loma venereum, tuberculosis, nontuberculous mycobacteria, toxoplasmosis, sporotrichosis, rat-
bite fever, anthrax, plague, and herpes simplex must be included in the differential diagnosis.
Oculoglandular disease with predominantly tender preauricular, submadibular, and
cervical nodes may be mistaken for mumps.
Pharyngeal tularemia may mimic other forms of exudative tonsillitis (streptococcal,
infectious mononucleosis, adenovirus), and diphtheria.
Treatment: Streptomycin or gentamicin for 7 to 14 days. Treatment with doxycycline
200 mg PO daily for 14 days is often used in Europe, but the risk of relapse is higher.
Fluoroquinolones appear to be efficacious for the subspeciesholarctica(limited experience).
Third-generation cephalosporins clinically fail in spite of in vitro susceptibility testing results.
Chloramphenicol is not recommended because of the risk or relapse and hematologic toxicity.
The bacterium appears to be resistant to clindamycin and co-trimoxazole.
Anthrax (23,27)
Incubation period:Cutaneous anthrax: five days (range: 1 to 10 days). Gastrointestinal disease:
The precise incubation period is unknown. In one case, symptoms developed 48 hours after
consumption of well-cooked meat from an infected cow.
Contagious period: Direct contact with skin lesions represents a risk.
Clinical disease:Inhalation anthrax: In addition to pulmonary symptoms patients more
frequently have nausea, vomiting, pallor or cyanosis, diaphoresis, confusion, tachycardia
110 beats/min, temperature>100.9 8 F, and hemoconcentration. Patients with fulminant
disease had 97% mortality. Hemorrhagic meningoencephalitis was present in 50% of autopsy
deaths after the accidental release of anthrax in Sverdlovsk.
Hemorrhagic Meningoencephalitis
Neurologic spread of infection may occur with inhalation disease, cutaneous disease, or
gastrointestinal disease. Patients also develop cerebral edema, intracerebral hemorrhages,
vasculitis, and subarachnoid hemorrhages. There is 95% mortalitywithtreatment.
Cutaneous Anthrax (Also Known as Malignant Pustule)
This is the most common form of anthrax. It is a consequence of skin contact with anthrax
spores. There is localized edema that evolves into a pruritic macule and papule. In 24 hours,
this ulcerates and is surrounded by small (1 to 3 mm) vesicles. A painless black eschar with
local edema is seen, which eventually dries and falls off in one to two weeks. Sometimes there
is lymphangitis and painful local lymphadenopathy.There is 20% mortality without treatment.
Gastrointestinal Anthrax
Presents with severe gastrointestinal symptoms. Patients may succumb from necrotizing
enterocolitis with hemorrhagic ascitic fluid.
Differential diagnosis: Cutaneous anthrax: plague, tularemia, scrub typhus, rickettisal
spotted fevers, rat-bite fever, ecthyma gangrenosum, arachnid bites, and vasculitis.
Diagnosis: Blood cultures before antibiotics (growth in 6 to 24 hours). Antibiotics will
rapidly sterilize blood cultures. Confirmatory tests by special laboratories are available (special
staining, ELISA for protective antigen, gamma-phage lysis, PCR, and real-time PCR).
Treatment: Ciprofloxacin or doxycycline for the initial intravenous therapy until
susceptibility is reported. Prophylaxis is necessary for those exposed to the spores (usually
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