Introduction
Pneumonia in immunocompromised people is a severe infection and inflammation of the lower respiratory tract, exacerbated by the widespread multi-drug antibiotic resistance. However, the condition is made more accessible by the advancements in the field of medical science, which include better diagnostic techniques and immunosuppressive drugs. Despite improvements in overall patient survival, pneumonia remains the most frequent invasive infection in immunocompromised patients. It is associated with a high death and morbidity rate.
What Is Pneumonia?
An infection of one or both lungs is known as pneumonia. It accumulates fluid or pus in the lungs' air sacs, called alveoli. Viruses, bacteria, or fungi may bring on pneumonia. A cough with or without mucous, a fever, chills, and breathing difficulties are a few of the symptoms that can range in severity from moderate to serious. Newborns and young children, adults over 65, and those with health conditions or weaker immune systems are the most vulnerable.
Who Are Immunocompromised Patients?
An individual with an impaired or weakened immune system and cannot react to an infection is typically referred to as an immunocompromised host. Numerous factors, such as illnesses (such as diabetes or human immunodeficiency virus infection), malnutrition, and medications, can contribute to this incapacity to fight infection.
There might not be the typical signs; immune-compromised patients might not exhibit the typical symptoms of infection, such as swelling and redness at the site of infection. Fever is not always an infection's main symptom. Without white blood cells that can fight infections, an illness may quickly advance from a simple fever to sepsis and death. Hence, patients with compromised immune systems and low white blood cell counts should report any fever immediately. If these individuals develop a fever, they are frequently given intravenous (IV) antibiotic therapy. Patients with a weakened immune system may struggle to recover from infections. For instance, a patient with a weakened immune system may require more time to recover from a viral infection like the "flu" than someone with a robust immune system.
What Are the Causes of Pneumonia in Immunocompromised Patients?
New immunosuppressive treatments, the emergence of multi-drug-resistant organisms, and enhanced diagnostic techniques have all increased the number of possible lung pathogens. The risk of infection from encapsulated bacteria like Hemophilus influenza and Streptococcus pneumoniae is higher in patients with compromised humoral immunity. Neutropenia makes people more vulnerable to infections from S. aureus, gram-negative bacteria, and fungi. A variety of infections can result from impaired T-cell immunity. Another significant risk factor for acquiring pneumonia is malignancy, particularly hematologic malignancy. The degree and length of neutropenia are connected to the pathogenicity and severity of the illness. Other groups of people that are highly vulnerable are those undergoing solid organ and bone marrow transplants.
What Are the Symptoms of Pneumonia in Immunocompromised Patients?
In immunocompetent patients, the symptoms and signs may be the same as those of community-acquired pneumonia. However, immunocompromised people are less likely to have purulent sputum if they are neutropenic and may not have a fever or respiratory symptoms. Fever is the only symptom in some people. The commonly observed symptoms may include:
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Malaise.
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Chills.
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Rigidity.
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Cough.
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Dyspnea (difficulty in breathing).
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Chest discomfort.
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Chest pain.
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Anorexia (loss of appetite).
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Weight loss.
How Is Pneumonia in Immunocompromised Patients Diagnosed?
A detailed history and a thorough physical examination help to diagnose the condition. This also helps in deciding the type of investigations to be carried out. Examining a patient's sexual habits, intravenous drug usage, history of cancer, organ transplantation, corticosteroid use, or any illness requiring long-term immunosuppressive medication can help determine the reason for immunodeficiency. Laboratory tests can include
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Complete Blood Count (CBC): If the cause of the infection is bacterial, leukocytosis (increased leukocyte count) may also be present in addition to an elevated neutrophil count, provided the patient does not already have immunodeficiency brought on by neutropenia (decreased neutrophil count). The leukocyte count may be increased, reduced, or normal in viral pneumonia.
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Inflammatory Markers: Due to continuous inflammation, levels of C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and procalcitonin will increase. Procalcitonin and CRP can also aid in early-stage pneumonia prognosis and severity prediction. Sputum smear, blood cultures, and CD4 count can help to diagnose the condition early.
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Chest X-Ray: When a suspected case of pneumonia is being evaluated, this is the first-line imaging technique of choice should be a chest X-ray. Radiographs of the posterior-anterior (PA) and lateral planes should be taken. In immunocompromised patients, despite symptoms, a chest X-ray may be normal for up to 72 hours.
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Computed Tomography (CT) of Chest: CT of the chest should be obtained in individuals with a strong suspicion of pneumonia but who have normal results in chest X-ray.
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ELISA (Enzyme-Linked Immunosorbent Assay) and PCR (Polymerase Chain Reaction): In patients suspected of Herpes simplex virus (HSV), influenza A and B, and cytomegalovirus (CMV), ELISA or PCR is recommended.
How Is Pneumonia in Immunocompromised Patients Managed?
Both pneumonia prevention and treatment of pneumonia are essential in the management of pneumonia in immunocompromised people. Empiric antibiotics are the mainstay of pharmacologic therapy while waiting on the outcome of diagnostic tests. To customize treatment to the most likely organism and avoid overusing anti-microbe medication, a restricted differential diagnosis can be made by considering each patient's features and risk factors. According to studies, early adjunctive corticosteroid treatment may lower mortality risk in HIV-infected patients with P Jiroveci pneumonia by 0.55 times compared to patients who do not receive the supplementary therapy.
One strategy for preventing pneumonia in immunocompromised people is to optimize therapy of the underlying immunocompromise. HAART (highly active anti-retroviral therapy), chemotherapy, radiation therapy, and other interventions, depending on the type of immunocompromise, are included in this. However, even with the best treatment, opportunistic and endemic lung infections can be challenging to prevent. Other prevention strategies include prophylaxis against bacteria, viruses, and fungi, pneumococcal and influenza vaccinations, and both. The optimum amount of immunosuppression is just as crucial as prophylaxis against microbial infection in rheumatologic illnesses, where corticosteroids or immunomodulators like TNF (tumor necrosis factor) inhibitors play a role in symptom control.
Conclusion
Patients who have compromised immune systems are especially prone to quickly getting pneumonia. Due to this, the initial evaluation must include a thorough history-taking procedure and a high degree of clinical suspicion. An interdisciplinary team approach is required to treat pneumonia in immunocompromised patients effectively. Positive outcomes can be attained with evaluation across numerous disciplines, a team approach, and early action.
