Diagnostic algorithm and history taking
The first stage of diagnosis always begins with taking a patient history. The typical cutaneous form is characterized by specific local symptoms: against the background of gelatinous soft tissue edema, a painless ulcer forms, at the base of which a characteristic black eschar develops.
It is crucial to trace the strict staging in the development of the anthrax carbuncle:
- Macule (macula).
- Papule (papula).
- Vesicle (vesicula).
- Pustule (pustula).
- Ulcer (ulcus).
Symptoms of general intoxication (fever, sleep disturbance, headache, loss of appetite, vomiting) typically appear precisely at the ulcer stage.
A decisive role is played by epidemiological history. The physician must investigate contacts with infected animals or livestock products, assess occupational risks (handling animal products), and the likelihood of a localized outbreak. Underlying conditions such as skin microtraumas, immunodeficiencies, or chronic pulmonary and gastrointestinal pathologies significantly facilitate infection penetration.
Differential diagnosis
Pulmonary and intestinal forms of the disease are significantly harder to recognize due to the non-specificity of early symptoms.
- Pulmonary form: Without compelling epidemiological data at the initial stage, it is indistinguishable from influenza and other acute respiratory viral infections. At the height of the disease, it must be differentiated from primary pneumonic plague (which is clinically virtually identical and requires bacteriological confirmation), tularemia pneumonia (characterized by an indolent course, focal bronchopneumonia, and leukopenia), and pneumonia of other etiologies. The main feature distinguishing pulmonary anthrax is the production of abundant serosanguineous sputum and extremely severe general intoxication.
- Intestinal form: The most difficult to diagnose due to clinical polymorphism. Accompanied by profuse diarrhea, recurrent copious vomiting, and cramping periumbilical pain. Requires differentiation from abdominal tularaemia (periumbilical pain, hepatosplenal syndrome), food-borne toxic infections, and typhoid-paratyphoid diseases (gradual onset, roseolous rash on days 8–9, "coated" tongue). The most important specific sign of intestinal anthrax is the absence of pathological impurities in the stool throughout the entire disease, despite severe gastroenteritis and the threat of dehydration or infectious-toxic shock (ITS).
Principles of anthrax treatment
Patients must be hospitalized in an infectious diseases ward. Comprehensive treatment is prescribed, including diet therapy (Diet No. 1 or No. 4abd for the intestinal form; Diet No. 13 or No. 15 for the cutaneous and pulmonary forms).
Etiotropic therapy:
- Uncomplicated cutaneous form: The drug of choice is ciprofloxacin (500 mg twice daily per os, 7–10 day course) or latest-generation fluoroquinolones. Doxycycline is an alternative. Penicillins are used only when strain susceptibility is proven by laboratory testing due to rising resistance.
- Severe and pulmonary forms, bioterrorism threat: The earliest possible combination therapy administered intravenously is required (ciprofloxacin + rifampicin + clindamycin/vancomycin or benzylpenicillin). For pulmonary and intestinal forms, as well as inhalation exposure, treatment lasts at least 60 days due to the risk of prolonged spore persistence in the lungs.
Additional treatment methods:
- Specific immunotherapy: Simultaneously with antibiotics, equine anti-anthrax immunoglobulin is administered intramuscularly (20 to 80 mL/day). Human serum from vaccinated donors is no longer used due to the risk of transmitting blood-borne infections (HIV, HBV, HCV).
- Pathogenetic therapy: Intravenous infusions of colloidal and polyionic solutions, fresh frozen plasma.
- Glucocorticoids: Prescribed for desensitization in cases of extensive neck and facial edema, meningitis, or pulmonary edema, strictly under antibacterial cover.
- Local treatment: Limited to the application of aseptic dressings. Any surgical interventions for cutaneous forms are strictly contraindicated due to the extremely high risk of generalized infection.
Outcomes, discharge, and prevention
Complications of the intestinal form include exicosis (grade I–III dehydration), seizures, arterial hypotension, collapse, and septic shock. Complications are managed using standard intensive care protocols. In some cases, rapid recovery occurs with simultaneous resolution of toxic symptoms.
Convalescents after the cutaneous form may be discharged only after complete epithelialization and scarring of the ulcer at the site of the rejected eschar. Following the pulmonary or intestinal forms, discharge occurs after complete clinical recovery. Dispensary follow-up for recovered patients is not currently regulated.
Prevention includes routine vaccination of risk groups, control over animal-origin raw materials, as well as veterinary surveillance of pastures and burial sites, and scheduled immunization of livestock.
Briefly: answers to topical questions
What laboratory methods are used to confirm the diagnosis of anthrax?
Bacteriological and serological methods are used to confirm the diagnosis of anthrax.
- Bacteriological method — isolation of a pure culture of Bacillus anthracis upon inoculation onto nutrient media.
- Serological method — detection of specific antibodies to pathogen antigens using indirect hemagglutination assay (IHA), ELISA, fluorescent antibody technique, etc.
- Allergological method — an auxiliary method involving skin allergy tests with a specific allergen (anthraxin) to detect sensitization.
What pathogen causes anthrax and what are its morphological properties?
The disease is caused by the Gram-positive spore-forming bacterium Bacillus anthracis.
- Shape — rod-shaped morphology.
- Spore formation — the ability to form heat-resistant endospores that possess exceptional environmental stability.
- Capsule formation — the bacterium forms an antiphagocytic capsule that impedes phagocytosis and the development of an immune response in the body.
To memorize the developmental stages of the anthrax carbuncle: Macule — Papule — Vesicle — Pustule — Ulcer (Macula — Papula — Vesicula — Pustula — Ulcus).
Class and exam questions
Why is surgical excision of the anthrax carbuncle strictly contraindicated?
Surgical intervention is strictly contraindicated because it destroys the protective tissue barriers surrounding the primary lesion and inevitably leads to rapid generalization of the infection with the development of sepsis.
How to distinguish the initial stage of pulmonary anthrax from common ARVI?
Clinically, at early stages, they are practically indistinguishable. Only the epidemiological history plays a key role, and at the height of the disease, the appearance of abundant serosanguineous sputum and extremely severe intoxication.
Can penicillin be prescribed empirically when anthrax is suspected?
No. Due to the rise of penicillin-resistant strains, penicillins are used only after laboratory proof of susceptibility of the isolated strain. Ciprofloxacin is the initial drug of choice.
What else to study on this topic
- Features of laboratory diagnostics and rules for collecting pathological specimens
- Mechanism of action of Bacillus anthracis exotoxin
- Pathogenesis of anthrax meningitis and sepsis
- Management tactics for patients with septic shock
- Safety protocols in anthrax foci and disinfection
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