Anthrax Findings

The following information is from the Centers for Disease Control and Prevention (CDC) Emerging Infectious Diseases: Bioterrorism-related inhalational anthrax: the first 10 cases reported in the United States, November 8, 2001, available at: www.cdc.gov/ncidod/eid/vol7no6/jernigan.htm. Additional resources and references are available at www.ochealthinfo.com/epi/bio and at http://www.bt.cdc.gov.

Inhalational Anthrax

There have been 10 inhalational anthrax patients identified from October 4 to November 2, 2001. The time from exposure to onset of illness (known for 6 of the 10 cases) ranged from 4-6 days with a median of 4 days. Only one of the cases had rhinorrhea.

Symptom Number Symptom Number

Fever, chills

10

Myalgias

6

Sweats, often drenching

7

Headache

5

Fatigue, malaise, lethargy

10

Confusion

4

Cough* (minimally or non-productive)

9

Abdominal pain

3

Nausea or vomiting

9

Sore throat

2

Dyspnea

8 Rhinorrhea

1

Chest discomfort or pleuritic pain 7

*1 case with blood-tinged sputum

Other findings

  • WBC: Median of 9.9 (7.5-13.3 x 103 /cumm); 7 of 10 cases had neutrophilia (>70%). None of the patients had a low WBC count or lymphocytosis when initially evaluated.
  • Chest: Chest radiograph was abnormal in all patients, but in two an initial reading was interpreted as within normal limits. Mediastinal changes including mediastinal widening, paratracheal fullness, hilar fullness, and mediastinal lymphadenopathy were noted in all eight patients who had CT scans. Mediastinal widening may be subtle, and careful review of the chest radiograph by a radiologist may be necessary. Pleural effusions were present in 8 patients and were a feature of the two patients who did not have mediastinal changes on chest radiograph or did not have a CT scan. Pleural effusions eventually developed in all cases, often were large and hemorrhagic, reaccumulated, and required repeated thoracentesis or chest tubes. Pulmonary infiltrates were observed in 7 patients and were multilobar in some cases.
  • Confirmation of Bacillus anthracis infection: Blood cultures grew B. anthracis in seven patients and in all who had not received antimicrobials. Diagnosis in the patients with negative cultures was confirmed by bronchial or pleural biopsy and specific immunohistochemical staining, by PCR of material from a sterile site, or by a fourfold rise in IgG to the protective antigen (confirmed by antigen inhibition).