Inhalational Anthrax - All You Need to Know

Introduction

Anthrax spores have recently generated a lot of concern due to the possibility of deliberate release into the environment. Skin disease, pulmonary disease brought on by inhaling anthrax spores, and gastrointestinal disease are the most typical clinical manifestations of anthrax. The progression of inhalational anthrax is dramatic with vague influenza-like symptoms and progressing to severe dyspnea, hypotension, and hemorrhage within days. It is not unusual for a patient's condition to deteriorate quickly, leading to septic shock, respiratory distress, and death within 24 hours. The high mortality rate in inhalational anthrax is partly due to delay in diagnosis. Widening of the mediastinum and pleural effusions are typical findings on the chest radiograph.

The 2001 bioterrorism attack in the United States was one of the few documented cases of non animal transmission. After being exposed to anthrax spores sent through the mail, twenty-two people became ill and five of them passed away.

What Are Anthrax Infections and Their Types?

Anthrax is a rod-shaped bacterium, Bacillus anthracis, that produces spores and is frequently found in tropical soil. Anthrax has many desirable characteristics that make it an ideal biologic weapon as it has:

1. High rates of morbidity and mortality.

2. Low-infectious dose.

3. Lack of quick diagnostic tests.

4. Lack of widely accessible effective vaccines.

5. Ability to incite fear and anxiety.

6. Widespread pathogen availability.

7. Production viability.

8. Environmental stability.

9. Potential for weaponization.

10. Inhalational, gastrointestinal, and cutaneous anthrax infections are the three types.

Based on the organism's mode of entry into the host, the disease manifests in these different ways.

Gastrointestinal Anthrax (GI): After the spore is consumed in GI anthrax, the symptoms appear one to six days after incubation. Anthrax then clings to the gastrointestinal epithelium, germinating and producing superficial ulcerations that are visible on endoscopic examination. However, from these small superficial ulcerations, vegetative cells can move into the bloodstream, quickly multiplying to cause septicemia and lead to more severe symptoms. They might have no symptoms at all in a small percentage of patients. Others could experience fulminant upper and lower GI bleeding, septicemia, and even death. Survival gives patients some natural immunity.

Cutaneous Anthrax: The incubation period is about one to five days. It appears clinically as a papule that develops into a large blister. As a result of the exotoxin's release, the lesion becomes edematous, and the patient develops associated regional lymphadenitis. The lesions rupture about a week later, and an eschar forms. While the skin lesions appear impressive, they are described as non-tender and painless. The eschar sloughs off over the next few weeks, and the patient either recovers or develops signs of disseminated disease. Untreated mortality is less than 20 percent in this case. However, antibiotic treatment reduces the risk of spread and death.

Inhalational Anthrax: Of the three exposure types, inhalational anthrax is the deadliest. The spores germinate in the tracheobronchial lymph nodes and multiply after being inhaled and phagocytized by macrophages. The patient exhibits influenza-like symptoms, including fever, malaise, and a nonproductive cough during an incubation period of two to ten days. The presentation may be postponed for longer than a month. In addition, patients may experience sudden deterioration, shock, hemorrhagic mediastinitis, and airway compromise. Within 72 hours of symptom onset, it is estimated that there is a 50 percent mortality rate.

What Signs and Symptoms Can Be Observed in Cases of Inhalational Anthrax?

The early symptoms of inhalational anthrax are typically vague and last several days, including fever, myalgias, and malaise. Patients might only seek care if there has been known exposure to anthrax spores. Due to the lack of distinguishing clinical signs and symptoms, the diagnosis would typically only be considered with known exposure. More concerning symptoms like dyspnea, respiratory distress, high fever, shaking chills, and hypotension may appear as the symptoms, and the disease gradually enters a second stage. Death happens 24 to 72 hours after the presentation if patients are not given the proper care.

It has never been documented that anthrax inhalation is accompanied by pneumatosis or portal venous gas. In some clinical circumstances, the presence of portal venous gas along with bowel wall pneumatosis can indicate bowel ischemia or infarction and may warrant immediate surgical intervention. The first radiographic sign, according to some reports, is mediastinal widening. Before the appearance of mediastinal widening, nodal enhancement may be a precursor to infection.

What Is the Treatment for Inhalational Anthrax?

Appropriate decontamination procedures should be in place for every case of anthrax inhalation and treated as a bioterrorist incident. The proper protective gear for healthcare workers should be provided, including masks, gloves, and splash shields. Individuals who have come into contact with contamination should immediately cleanse their hands using soap and water, and the clothing should be placed in a plastic bag for further analysis.

A multidrug regimen containing one bactericidal agent and one protein-synthesis inhibitor is required to treat inhalational anthrax. The preferred medications are Linezolid or Ciprofloxacin, to be administered intravenously.

A three-drug regimen consisting of two bactericidal medications from various drug classes (Fluoroquinolone and beta-lactam) and one protein-synthesis inhibitor is advised for meningitis patients. An antitoxin product, which includes monoclonal and polyclonal antitoxins, may be suggested as a treatment adjunct in addition to a multidrug antimicrobial regimen. Anthrax vaccine available for specific population. Since the vaccine does not include live bacteria, infection cannot result from it. The vaccine may, however, have unintended consequences, ranging from minor soreness to more severe allergic reactions.

What Is the Differential Diagnosis of Inhalational Anthrax?

The differential diagnosis includes,

• Community-acquired pneumonia.

• Respiratory syncytial virus.

• Influenza.

• Tularemia.

• Pneumonic plague.

Conclusion

Anthrax is a life-threatening infection that requires the coordinated efforts of an interdisciplinary team specialized in bioterrorism treatment, given its potential for quick fatality. Only a small group of highly qualified nurses and clinicians should be in charge, and the patient must be kept in isolation. Blood samples and all patient body fluids must have distinct labels. Cleaning all spills with bleach and decontaminating clothing is imperative to prevent outbreaks. Educating the patient and family regarding the symptoms should be a collaborative effort between the nurses and clinicians. The evaluation and treatment of patients with an anthrax infection should be done in a multidisciplinary manner for the best results.