Introduction:
As per the definition, non-resolving pneumonia is a type of pneumonia with a slow resolution of radiologic infiltrates or clinical symptoms despite adequate antibiotic therapy. The diagnosis of non-resolving pneumonia should not be confused with tuberculosis, malignancies related to the lungs that mimic pneumonia. Bronchoscopies and pulmonary consultations can be done to confirm its diagnosis. Non-resolving pneumonia may develop due to various reasons. However, it does not occur very often.
It is a complex clinical problem with an incidence of ten percent to 15 % among patients hospitalized with community-acquired pneumonia, out of which six percent of cases develop into progressive pneumonia. In around 20 % of the patients with community-acquired pneumonia, the etiology was non-infectious. The mortality rate ranges from 27 % to 49 %. The primary goal in evaluating non-resolving pneumonia is to differentiate between typical and non-resolving pneumonia to avoid unnecessary diagnostic tests. If the abnormal resolution is identified in the radiograph, the next step is to consider the most common infectious and non-infectious factors associated with non-resolving pneumonia.
What Is Non-resolving Pneumonia?
Non-resolving pneumonia is a clinical syndrome characterized by persistent clinical symptoms, with or without fever, and failure of resolution of radiographic features by 50 % in two weeks or entirely in four weeks despite the antibiotic therapy for a minimum of ten days. In addition, the acid-fast bacilli sputum smear remains negative for two consecutive samples—the non-resolving pneumonia results in 15 % of pulmonary consultations and eight percent of bronchoscopies.
According to a recent study in south India, non-resolving pneumonia was caused by tuberculosis in 35.7 % of the cases, and 27 % of cases resulted from malignancies. However, according to the studies conducted in the west, around 11 % of the cases resulted from malignancies. The clinical decision that a patient has non-resolving and progressive pneumonia must consider the facets that affect the expected resolution rate, including comorbidities, the age of the patient, the severity of infection, and the type of infectious agent involved.
What Are the Causes of Non-resolving Pneumonia?
The causes of non-resolving pneumonia include:
1. Inappropriate Antimicrobial Therapy: The therapy remains ineffective if the proper antibiotic dose is not administered or such antibiotics are given to which the organisms have become resistant.
2. Super Infections: Super infections with resistant microorganisms, such as Fungi, and Mycobacterium tuberculosis, can also lead to non-resolving pneumonia.
3. Complications of Initial Pneumonia: Initial foci of pneumonia infection may prevent the desirable amount of antibiotic from reaching the site of infection. Other complications may include para pneumonic effusion or abscess, which requires drainage and further antibiotic therapy.
4. Host Factors: Host factors include the age of the patient. Patients above the age of 50 years are at a greater risk. Patients immunocompromised or with comorbidities are highly prone to the disease. In addition, patients who are intubated may also develop resistant microorganisms that can cause this infection.
5. Delayed Radiological Recoveries: Non-resolving pneumonia indicates failure of clinical or radiological recovery. Clinical improvement may be seen in some patients, but radiological healing is absent.
6. Presence of Resistant Organisms: The presence of drug-resistant Streptococcus pneumonia (DRSP) may lead to non-resolving pneumonia, which can be treated with Beta-lactams within six months.
7. Presence of Unusual Microorganisms: The unique microorganisms include:
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Nocardia (as an oral microflora).
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Atypical mycobacteria.
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Fungi like Aspergillus, Cryptococcus mucor, Histoplasma coccidioides.
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Travel to endemic areas: Hantavirus, Paragonimiasis.
8. Poor Defense Mechanism: Poor defense mechanisms can be due to malnutrition as a result of aging, vitamin B6 or zinc deficiency, or immunocompromised patients.
9. The Disease Mimics Pneumonia: The diseases that mimic pneumonia are:
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Inflammatory disorders.
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Systemic vasculitis (connective tissue diseases).
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Wegener's, including (diffuse alveolar hemorrhage).
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Bronchiolitis obliterans with organizing pneumonia.
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Acute and chronic eosinophilic pneumonia.
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Sarcoidosis (growth of small collections of inflammatory cells in various body parts).
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Acute interstitial pneumonia.
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Drugs-induced lung disease associated with Nitrofurantoin, Amiodarone, Methotrexate, Bleomycin, Mitomycin, Paclitaxel, Docetaxel, or Cyclophosphamide.
How Is Non-resolving Pneumonia Diagnosed?
The diagnosis of non-resolving pneumonia starts with careful history taking, physical examination, and proper medical record review. The clinician should find out whether non-resolving pneumonia has an infectious or non-infectious etiology and if the patient is stable or improving slowly and has comorbidities that can cause a delay in the rate of resolution of pneumonia. Adequate observation and continued antibiotic therapy should be done for four to eight weeks. If there is no resolution of the infection, then a more aggressive diagnosis should be performed.
The diagnostic evaluation is done by re-evaluating the host factors. The possibilities of antimicrobial failures are examined adequately, including patient noncompliance and improper dosage. Antibiotic-resistant, as well as sensitive pathogens are reviewed for correct diagnosis. In addition, the parameters used to describe this infection include both clinical and radiographic criteria.
Sometimes the gram stain and culture of sputum are neither sensitive nor specific due to the contamination by the flora of the upper airway or previous use of antibiotics.
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Radiological Examinations: Shows infiltrates and pleural effusion along with lymphadenopathy.
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CT (Computed Tomography): This scan provides a detailed study of parenchyma, interstitium, pleura, and mediastinum.
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Bronchoscopy: It can also be done to confirm the diagnosis. Fiberoptic bronchoscopy can be done from the collected culture specimens for the detection of common pathogens or tuberculous mycobacteria to diagnose a poorly treated lower tract infection (post-obstructive pneumonia).
What Is the Treatment of Non-resolving Pneumonia?
The treatment of non-resolving pneumonia involves the administration of antibiotics like intravenous Cefoperazone-Sulbactam (1.5 gram), eight hourly, and oral Clarithromycin (500 milligrams) twice daily, along with other supporting antibiotics.
Conclusion:
To conclude, non-resolving pneumonia is often regarded as a significant clinical issue. The commonest etiology is a pyogenic infection, but microbiologically, it differs from community-acquired pneumonia. Tuberculosis, malignancy and other non-infectious causes like vasculitis are other important etiological factors. Fiberoptic bronchoscopy is an advantageous diagnostic method. Biopsies of any significant pleural collections should be performed.
The major problem in defining non-resolving pneumonia is that the standard resolution of pneumonia is not a clearly defined process. Therefore, it is helpful to consider the resolution of pneumonia as a spectrum, including standard resolution, slowly resolving pneumonia and progressive pneumonia.
