. 2013 Jul 4;29(3):717–756. doi: 10.1016/j.ccc.2013.03.015

Table 8.

Diagnostic features of anthrax

Syndrome (Route)	Typical Time Course	Symptoms	Physical Findings	Laboratory Findings^a	Radiographic Findings
Cutaneous (transdermal)	Incubation period range 1–12 d Lesion usually begins 3–5 d after infection Edema rapidly develops over 12–24 h Eschar sloughs within 1–2 wk Resolution may take months without treatment	Painless lesion, which may be pruritic Dysphagia or dyspnea if face involved and major edema	Lesion beginning as a pustule, develops significant surrounding edema rapidly, evolves into a necrotic center Respiratory distress (if head/neck involved) Regional lymphadenopathy Septic shock (infrequent) Meningitis (rare)	Histology: lymphocytic infiltrate with edema and necrosis General laboratory results may show only leukocytosis unless patient progresses to a systemic illness	CT or MRI shows extensive soft tissue edema in the immediate area of the lesion and may show regional lymphadenopathy
GI (ingestion)	Oropharyngeal: Incubation period 42 h Lower GI: 3 phases 1. Fever and constitutional symptoms (onset) 2. Abdominal symptoms begin (∼24 h after onset) 3. Worsening abdominal symptoms and shock	Oropharyngeal: Oral or esophageal ulcer Cervical adenopathy which may be painful Dysphagia Hoarse voice Lower GI: Nausea Vomiting Malaise Abdominal pain ± distension	Oropharyngeal: Necrotic ulcer ± pseudomembrane Local edema Regional lymphadenopathy Lower GI: Fever Abdominal mass Ascites Acute abdomen features if perforation of viscus Bowel obstruction Septic shock (common) Meningitis (rare)	Leukocytosis Hemoconcentration	CT: ascites, thickening of bowel wall, lymphadenopathy
Thoracic (inhalation)	3 phases 1. Constitutional/flulike symptoms (hours–4 d) 2. Latent stage (brief) 3. Rapid onset of high fever and shock (death usually within 24 h if untreated) Incubation period (1 d–6 wk)	1. a. Chills b. Malaise c. Headache d. Nausea/vomiting e. Dyspnea f. Nonproductive cough 2. None 3. Dyspnea	1. Fever 2. Minimal 3. a. High fever b. Drenching sweats c. Septic shock d. Respiratory failure e. Meningitis (common)	Hypocalcemia Hypoglycemia Hyperkalemia Lactic acidosis Elevated hematocrit	CXR: hilar prominence often greater on the right, pleural effusions and widened mediastinum (common) [note: lung consolidation is not a feature) CT: mediastinal adenopathy with changes suggesting intermodal hemorrhage, peribronchial parenchymal opacification (suggests lymphatic involvement)

Syndrome (Route)

Typical Time Course

Symptoms

Physical Findings

Laboratory Findings^a

Radiographic Findings

Cutaneous (transdermal)

Incubation period range 1–12 d
Lesion usually begins 3–5 d after infection
Edema rapidly develops over 12–24 h
Eschar sloughs within 1–2 wk
Resolution may take months without treatment

Painless lesion, which may be pruritic
Dysphagia or dyspnea if face involved and major edema

Lesion beginning as a pustule, develops significant surrounding edema rapidly, evolves into a necrotic center
Respiratory distress (if head/neck involved)
Regional lymphadenopathy
Septic shock (infrequent)
Meningitis (rare)

Histology: lymphocytic infiltrate with edema and necrosis
General laboratory results may show only leukocytosis unless patient progresses to a systemic illness

CT or MRI shows extensive soft tissue edema in the immediate area of the lesion and may show regional lymphadenopathy

GI (ingestion)

Oropharyngeal:

Incubation period 42 h
Lower GI:
3 phases
- 1.
  Fever and constitutional symptoms (onset)
- 2.
  Abdominal symptoms begin (∼24 h after onset)
- 3.
  Worsening abdominal symptoms and shock

Oropharyngeal:

Oral or esophageal ulcer
Cervical adenopathy which may be painful
Dysphagia
Hoarse voice
Lower GI:
Nausea
Vomiting
Malaise
Abdominal pain ± distension

Oropharyngeal:

Necrotic ulcer ± pseudomembrane
Local edema
Regional lymphadenopathy
Lower GI:
Fever
Abdominal mass
Ascites
Acute abdomen features if perforation of viscus
Bowel obstruction
Septic shock (common)
Meningitis (rare)

Leukocytosis
Hemoconcentration

CT: ascites, thickening of bowel wall, lymphadenopathy

Thoracic (inhalation)

3 phases
- 1.
  Constitutional/flulike symptoms (hours–4 d)
- 2.
  Latent stage (brief)
- 3.
  Rapid onset of high fever and shock (death usually within 24 h if untreated)
Incubation period (1 d–6 wk)

1.
- a.
  Chills
- b.
  Malaise
- c.
  Headache
- d.
  Nausea/vomiting
- e.
  Dyspnea
- f.
  Nonproductive cough

2.
None

3.
Dyspnea

1.
Fever
2.
Minimal
3.
- a.
  High fever
- b.
  Drenching sweats
- c.
  Septic shock
- d.
  Respiratory failure
- e.
  Meningitis (common)

Hypocalcemia
Hypoglycemia
Hyperkalemia
Lactic acidosis
Elevated hematocrit

CXR: hilar prominence often greater on the right, pleural effusions and widened mediastinum (common) [note: lung consolidation is not a feature)
CT: mediastinal adenopathy with changes suggesting intermodal hemorrhage, peribronchial parenchymal opacification (suggests lymphatic involvement)

Abbreviations: CT, computed tomography scan; CXR, chest radiograph; MRI, magnetic resonance imaging.

For microbiological findings, refer to Table 7.

Data from Refs.7, 11, 12, 19, 52