Candida Pneumonia - An Overview

Introduction:

Pneumonia due to Candida is rare and is associated with a fatal outcome with up to 70 percent mortality rates. It is predominant among immunocompromised patients or people receiving broad-spectrum antibiotic therapy. Candida pneumonia was first described by Nils Rosen von Rosenstein in 1984 and later by Castellani in 1927. Diagnosis of candida pneumonia is challenging because of its rare occurrence and manifestation.

What Is Candida Pneumonia?

Candida is commonly found as a part of the normal microbial flora of the skin, oral cavity, respiratory tract, gastrointestinal tract, and genitourinary tract. There is no effective method to illustrate Candida species' commencement, colonization, and infection. Among the immunocompromised patients, Candida is isolated from respiratory samples such as sputum or bronchoalveolar lavage (BAL) and is interpreted cautiously.

Candida pneumonia is a type of fungal infection that affects the lungs. The yeast-like fungus Candida, a common inhabitant of the human body, causes it. It mostly affects the immunocompromised patients admitted to the intensive care unit (ICU). The incidence of candida pneumonia is rare and uncommon, ranging from 0.2 percent to 0.4 percent, mainly in high-risk groups or critically ill patients.

What Are the Symptoms of Candida Pneumonia?

The symptoms are similar to viral and bacterial pneumonia, including the following:

• Fever.

• Chills.

• Shortness of breath.

• Cough with thick phlegm.

• Pain during breathing or coughing.

• nausea and vomiting

• Diarrhea.

• Fatigue.

What Are the Routes of Infection?

The routes of infection of Candida pneumonia can be primary and secondary.

1. Primary Candida Pneumonia: The accompanying Candida esophagitis and upper respiratory tract colonization are frequently found in primary Candida pneumonia. The aspiration of esopharyngeal contents presumes the mechanism of pulmonary infection. Under certain circumstances, Candida organisms are supposed to reach and invade distal air spaces. Hence, the spread of Candida in the airspaces without vascular invasion.

2. Secondary Candida Pneumonia: In secondary Candida pneumonia infection, the inoculation occurs by spreading microorganisms into the bloodstream from any distant site. This includes dissemination from the skin, translocation from the gastrointestinal tract, or spread from extensive mucositis.

What Are the Risk Factors for Candida Pneumonia?

The risk factors include:

• Immunocompromised Individuals: Organ transplant recipients, immunomodulation in rheumatoid arthritis, malignancies, infections (human immunodeficiency virus, granulomatous diseases, or ICU), sepsis, and malnutrition cases.

• Diabetes mellitus.

• Nicotine and alcohol abuse individuals.

• People use steroids and prior antibiotic use.

• Intensive care unit patients.

• Aspiration of gastric fluids.

• Diverticulum of the esophagus.

What Is the Diagnosis?

The diagnosis is challenging due to its rare occurrence and common symptom manifestations. The diagnosis depends on clinical, radiological, and histological examinations–

Clinical examination: involves patient history and physical examination.

• Patient History:

  • Fever.

  • Cough.

  • Chest pain.

  • Progressive dyspnea resulting in respiratory failure.

  • Hypersensitivity or allergic reactions such as bronchial asthma, allergic bronchopulmonary mycoses, and extrinsic allergic alveolitis (farmer’s lung).

  • Extrapulmonary symptoms.

• Physical Examination:

  • Temperature: In case of fever.

  • Tachycardia: Pneumonia can cause abnormal heartbeats, such as atrial fibrillation or tachycardia (heart rates higher than 150 beats per minute).

  • Tachypnea: It can be a symptom of sepsis or acidosis commonly presented by pneumonia patients.

  • Respiratory distress.

  • Pleural rub.

  • Signs of pulmonary consolidations.

  • Allergic findings.

  • Skin lesions (papules, pustules, ulcers)

• Laboratory Tests:

  • The positive cultures of sputum and bronchoalveolar lavage (BAL) fluid are used as definitive diagnoses of Candida pneumonia.

  • Biopsy: Lung biopsies show extensive suppurative granulomatous lung inflammation.

  • Sputum cultures, bronchoalveolar lavage fluids, pericardial fluid, and biopsies show positive cultures for Candida albicans.

  • Blood cultures are negative in these cases.

• Imaging Tests:

  • Chest X-Ray: The radiography shows patchy infiltrates, nodules, or pleural effusion.

  • Chest CT Scan: The chest CT (computed tomography) scan shows lung opacity or halo sign, progressively confluent airspace opacities, and mediastinal lymphadenopathy.

What Is the Treatment for Candida Pneumonia?

Treatment for candida pneumonia:

• Indication: All patients with invasive dissemination are essential to reverse the factors affecting the immune system.

• Treatment Or Antifungal Therapy:

  • Removing infected intravenous lines or catheters in hematogenous spread settings.

  • Reducing the dosages of immunosuppressive agents and corticosteroids.

  • Amphotericin B is the drug of choice. Flucytosine + Amphotericin B will be beneficial.

  • Echinocandins can be used as an alternative.

What Is the Significance of Candida Pneumonia?

Significance of candida pneumonia:

• Critically Ill Patients: The rate of isolation of Candida species is relatively high in the respiratory tract, especially in mechanical ventilation individuals. Pneumonia caused by ventilator-associated pneumonia or Candida species remains challenging due to

  • Lack of pathologic evidence, nonspecific diagnostic criteria, and difficulty differentiating colonization and infection.

  • The research studies do not explain the co-existence of bacteria and fungi, and further analysis is not conducted for the rapid growth of Candida isolated from respiratory tract samples.

  • A threshold value is not yet established for the presence of pathogenic Candida species.

Hence, Candida pneumonia is rare in critically ill patients, and antifungal therapy is not advised unless there is clear evidence of histopathological reports of infection.

• Colonization and Drug Resistance: Candida colonization changes bacterial colonies virulence and hosts immune function. An experiment showed that though the percentage of candida is small, the bacteria occupy a higher percentage of alveoli, and the presence of Candida protects the bacteria from clearance through normal alveolar macrophages.

The presence of biofilms increases the resistance of bacteria to drugs. It is reported that Staphylococcus aureus forms a biofilm in serum, but its integrity is less and dissociates easily. In the case of the co-existence of bacteria and fungi, S. aureus form microcolonies on the fungal biofilm, connected to fungal hyphae ‘scaffold’, and forms a multi-bacterial biofilm or polymicrobial biofilm. This biofilm shows matrix staining with different phenotypes and single-cell membranes encapsulated in the matrix secreted by Candida albicans, resulting in antibiotic resistance.

Although candida pneumonia is rare, Candida colonization in the airway affects bacterial colonization and antibacterial resistance patterns, playing a vital role in developing bacterial pneumonia. Further studies are needed to show the existence of candida pneumonia and its characteristics.

Conclusion:

Candida pneumonia is a rare fungal infection caused by Candida species and occurs mainly in immunocompromised and critically ill patients, long-term antibiotic therapy individuals, low-birth weight and premature individuals, and people on immunosuppressive drugs and corticosteroids. The diagnosis of Candida pneumonia is challenging due to its rare occurrence and existing evidence of its presentation and symptoms. The definitive and confirmative diagnosis is based on histopathological reports. Treatment includes anti-fungal medication and supportive care for ICU patients.