Pneumonia is a prevalent and potentially life-threatening respiratory infection that poses a significant global health challenge.
It is characterized by inflammation of the alveoli in one or both lungs and can be caused by various infectious agents, including bacteria, viruses, and fungi.
Its symptoms range from mild to severe and often include cough, fever, and difficulty breathing.
Understanding the causes, symptoms, and treatment options for pneumonia is crucial in effectively managing this condition and reducing its impact on public health.
What is Pneumonia?
Pneumonia is an infection that inflames air sacs in one or both lungs, causing them to fill with fluid or pus, leading to symptoms like cough, fever, and difficulty breathing. It can be caused by bacteria, viruses, or fungi and ranges from mild to severe, sometimes requiring hospitalization for treatment.
Causes
Pneumonia is caused by various infectious agents, including bacteria, viruses, and fungi, which lead to the inflammation of the lungs’ air sacs.
Here are the main causes categorized by the type of pathogen:
- Bacterial Pneumonia: Streptococcus pneumoniae is the most common cause of bacterial pneumonia in adults. Mycoplasma pneumoniae causes “walking pneumonia,” a milder form. Legionella pneumophila causes Legionnaires’ disease, often found in contaminated water systems.
- Viral Pneumonia: Influenza (the flu) virus is a common cause, especially in the elderly and young children. Respiratory syncytial virus (RSV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes COVID-19, are other notable causes.
- Fungal Pneumonia: Common in immunocompromised individuals, such as those with HIV/AIDS or cancer. Caused by fungi from soil or bird droppings, including Pneumocystis jirovecii, Cryptococcus species, Histoplasma species, and Coccidioides species.
- Aspiration Pneumonia: Occurs when food, saliva, liquids, or vomit is inhaled into the lungs, leading to infection.
Note: These pathogens can invade the lungs in various ways, including inhalation of airborne droplets containing the pathogens, aspiration of food or liquids, or via the bloodstream from other parts of the body.
Signs and Symptoms
The signs and symptoms of pneumonia can range from mild to severe, depending on factors such as the type of germ causing the infection, the patient’s age, and their overall health.
Common symptoms include:
- Productive cough
- Fever
- Chills
- Diaphoresis
- Tachypnea
- Shortness of breath
- Chest pain
- Diaphoresis
- Fatigue
- Weakness
- Cyanosis
- Loss of appetite
- Nausea
- Vomiting
- Confusion
Note: Children and infants might not show the typical symptoms described above. Instead, they may appear lethargic, have difficulty feeding, or have a lower-than-normal body temperature.
Diagnosis
Diagnosing pneumonia typically involves a combination of clinical examination, medical history, and diagnostic tests.
The process includes:
- Medical History and Physical Examination: The doctor will ask about the symptoms, medical history, and any recent exposure to illnesses. During the physical exam, they listen to the patient’s lungs with a stethoscope for any abnormal sounds, such as crackling, bubbling, or rumbling.
- Chest X-ray: This is a key diagnostic tool for detecting pneumonia and determining its extent and location in the lungs.
- Blood Tests: Blood tests may be done to confirm an infection and to try to identify the type of organism causing the infection, though blood tests alone cannot identify all types of pneumonia-causing organisms.
- Sputum Test: Analysis of a sample of sputum (the mucus that is coughed up from the lungs) can sometimes reveal the organism causing the pneumonia.
- Pulse Oximetry: A simple test that measures the oxygen level in the blood and can help determine if there’s a need for supplemental oxygen.
- CT Scan: In some cases, especially if complications are suspected, a CT scan of the chest may provide more detailed images than an x-ray.
- Pleural Fluid Culture: If there is fluid in the pleural space around the lungs, a sample may be taken through a needle (thoracentesis) to look for the presence of infection.
Note: Additional tests might be necessary to ensure an accurate diagnosis in children, older adults, or those with weakened immune systems.
Treatment
Treatment for pneumonia depends on the type and severity of the pneumonia, as well as the patient’s overall health.
Here’s an overview:
- Bacterial Pneumonia: Antibiotics are the mainstay of treatment, and the choice of antibiotic depends on the presumed causative organism and local antibiotic resistance patterns. It’s crucial to complete the prescribed course, even if symptoms improve before the medication is finished.
- Viral Pneumonia: Often, viral pneumonia resolves on its own. However, in some cases, antiviral medications may be prescribed, especially for influenza or severe cases, such as those caused by SARS-CoV-2 (COVID-19). Supportive care, including rest, hydration, and fever management, is important.
- Fungal Pneumonia: Treatment involves antifungal medications. The specific choice depends on the type of fungus causing the infection and the patient’s overall health.
- General Supportive Care: Rest and hydration are important for recovery. Fever reducers and pain relievers (like acetaminophen or ibuprofen) can help manage symptoms. Oxygen therapy may be necessary for patients experiencing difficulty breathing. In severe cases, hospitalization may be required, especially if there are complications such as respiratory failure or sepsis.
- Preventive Measures: Vaccinations, such as the pneumococcal vaccine and flu vaccine, can help prevent some types of pneumonia. Good hygiene practices, including frequent handwashing and avoiding smoking, can also reduce the risk.
Note: It’s essential for patients with pneumonia to follow their healthcare provider’s instructions closely, including taking all medications as prescribed and attending follow-up appointments.
Types of Pneumonia
Pneumonia is classified into several types based on its cause, how it was acquired, and where it was contracted.
The main types include:
- Community-Acquired Pneumonia (CAP): Occurs outside of hospitals or other healthcare facilities.
- Hospital-Acquired Pneumonia (HAP): Develops in patients during their stay in the hospital, particularly in those not on mechanical ventilation.
- Ventilator-Associated Pneumonia (VAP): Occurs in people who have been on a mechanical ventilator for more than 48 hours.
- Aspiration Pneumonia: Results from inhaling food, liquid, gases, or dust into the lungs.
Each type can be caused by different pathogens, including bacteria, viruses, fungi, or a combination of these, and the treatment approach may vary accordingly.
Pneumonia Practice Questions
1. What is the definition of pneumonia?
Pneumonia is an inflammatory respiratory condition that primarily affects the alveoli, typically caused by an infection with viruses, bacteria, or other microorganisms.
2. What are the symptoms of pneumonia?
High fever and chills, headache, loss of appetite, mood swings, cough with sputum, shortness of breath, joint pain, fatigue, and body aches.
3. What are some ways to diagnose pneumonia?
Chest x-ray, sputum culture, CBC, and ABG.
4. What is the assessment of viral pneumonia?
It typically has a low-grade fever, a non-productive cough, and a normal (or slightly increased) WBC. It is typically less severe than bacterial pneumonia.
5. What is the assessment of bacterial pneumonia?
High fever, productive cough, WBC elevated, and severe infiltrates on the chest x-ray.
6. What methods can be used for the therapeutic management of pneumonia?
Antibiotic medications, oxygen therapy, bed rest, airway clearance therapy, hyperinflation therapy, and fluid management.
7. What medications can be used for the treatment of pneumonia?
Antibiotics, bronchodilators, and corticosteroids.
8. What type of pneumonia is frequently undiagnosed?
Nonbacterial pneumonia
9. What are the three key signs of bacterial pneumonia?
Yellow sputum, increased white blood cell count, and the presence of fever.
10. What type of anatomic alteration leads to aspiration pneumonia?
Alveolar consolidation, atelectasis, and inflammation of the alveoli.
11. What term refers to the filling of the alveolar spaces due to pneumonia?
Effusion
12. The term “walking pneumonia” is generally used to describe what type of pneumonia?
Mycoplasma pneumonia
13. What is the most common bacterial cause of pneumonia?
Streptococcus pneumonia
14. What are the clinical manifestations of patients with severe pneumonia?
Chest pain, tachycardia, hemoptysis, cyanosis, hypoxia, tachypnea, and dyspnea.
15. What is breathing like for a patient with pneumonia?
They will likely show signs of tachypnea, and pulse oximetry will likely reveal hypoxemia.
16. What causes “walking pneumonia,” and who typically gets it?
It is caused by atypical organisms like mycoplasma pneumonia and chlamydophila. It affects young, healthy adults and presents with a dry, hacking cough.
17. What viruses can cause pneumonia?
Influenza A or B, respiratory syncytial virus (RSV), rhinovirus, and coronavirus (SARS, MERS-CoA).
18. What fungi can cause pneumonia?
Cryptococcus, histoplasma, coccidiosis, aspergillus, and mucor.
19. What are the non-infectious etiologies of pneumonia?
Carcinomas, lymphomas, vasculitis, sarcoidosis, heart failure, and pulmonary embolism.
20. What are the causes of pneumonia?
Bacteria, viruses, mycoplasma, fungi, parasites, and fluid stasis of the lungs caused by the accumulation from secondary conditions such as asthma and COPD.
21. What is the problem with pneumonia?
Even with antibiotics, patients with pneumonia still have high morbidity and mortality rates.
22. What are the primary types of pneumonia?
Community-acquired pneumonia, hospital-acquired pneumonia, and aspiration pneumonia.
23. What is community-acquired pneumonia (CAP)?
A type of pneumonia that is acquired prior to hospitalization.
24. What kind of therapy is required to treat pneumonia?
Antibiotic medications
25. What is hospital-acquired pneumonia (HAP)?
A type of pneumonia that is acquired at least 48 hours after admission to the hospital.
Access our quiz with sample TMC practice questions and detailed explanations to help you master the key concepts of pathology.
26. What is the pathophysiology of pneumonia?
Microorganisms enter the alveoli of the lungs, which leads to an infection and inflammatory response.
27. What inflammatory response occurs with pneumonia?
Neutrophils are activated, which results in edema of the airways, and fluid leaks from the capillaries into the alveoli, which affects normal oxygen transport.
28. What are the mechanical barriers of a bacterial infection?
Air filtration, epiglottis, cough reflex, mucociliary response, reflex bronchoconstriction, and the secretion of immunoglobulins and alveolar macrophages.
29. What are the risk factors of pneumonia?
Risk factors for pneumonia include smoking, having a weakened immune system, chronic lung diseases such as COPD or asthma, recent respiratory infections, being very young or elderly, and exposure to pollutants or chemicals. Additionally, hospitalization, especially when requiring mechanical ventilation, significantly increases the risk of developing hospital-acquired pneumonia.
30. What is aspiration pneumonia?
A type of pneumonia that occurs when bacteria is aspirated into the lungs.
31. What is opportunistic pneumonia?
A type of pneumonia commonly seen in immunocompromised individuals (e.g., HIV), those receiving radiation therapy, chemotherapy, and long-term corticosteroid therapy.
32. What are the sudden symptoms of pneumonia?
Sudden symptoms include fever, shaking, chills, shortness of breath, tachypnea, cough, purulent sputum, and pleural cerebral palsy.
33. What is consolidation?
Consolidation refers to the filling of the lung’s alveoli with fluid, which appears as a solid white area on a chest x-ray or CT scan. It is commonly seen in bacterial pneumonia and is indicative of an active lung infection.
34. Why is antibiotic therapy beneficial for pneumonia?
Antibiotic therapy is beneficial for pneumonia because it effectively targets and kills the bacteria causing the infection, reducing symptoms, preventing complications, and accelerating recovery, particularly in bacterial forms of pneumonia where antibiotics are essential for successful treatment.
35. What are the diagnostic tests for pneumonia?
Chest x-ray, sputum culture, sputum gram stain, blood cultures, WBC, and ABG.
36. What are the standard treatment options for pneumonia?
Antibiotics, IVF and PO hydration, supplemental O2, analgesics, antipyretics, frequent small meals, and a balance between rest and physical activity.
37. What are the standard practices that patients with pneumonia should learn?
Hand hygiene, cough etiquette, a balanced diet, adequate rest, and to stop smoking.
38. What are the various complications of pneumonia?
Atelectasis, pleurisy, bacteremia, meningitis, acute respiratory failure, sepsis, septic shock, and empyema.
39. What event can trigger the clinical syndrome of pneumonia?
The host’s immune response leads to the inflammatory mediators that create an alveolar-capillary leak. This leak results in rales on auscultation, hypoxemia, and chest x-ray infiltrates.
40. What are the physical examination findings of pneumonia?
Crackles, rhonchi, or wheezes on auscultation; tachypnea; and dullness to percussion.
41. What is the one-year mortality rate of someone with pneumonia older than 65?
40%
42. What chest x-ray finding indicates that pneumonia may be life-threatening and difficult to treat?
Lung abscess
43. What is the most common chest x-ray finding with pneumonia?
Consolidation
44. What chest x-ray finding is usually associated with an empyema?
Parapneumonic effusion
45. What is a bronchogram on a chest x-ray?
Air-filled bronchi made visible by opacification of surrounding alveoli and peribronchial thickening.
46. What will you usually see on a CBC with pneumonia?
Leukocytosis and an L shift
47. What will the ABG typically show for a patient with pneumonia?
Respiratory alkalosis (hyperventilation) with hypoxemia
48. What biomarkers are used to help diagnose pneumonia?
CRP and Procalcitonin (PCT)
49. What is a typical workup for a patient with suspected pneumonia?
Medical history, physical examination, laboratory tests, PA and lateral chest x-ray, microbial studies, culture and gram stain, and blood cultures in hospitalized patients with sepsis.
50. What should true sputum show when trying to find the cause of pneumonia?
An abundance of inflammatory cells, no squamous epithelial cells, and large numbers of a single organism.
51. What pattern of pneumonia will have entire lobe consolidation?
Lobar pneumonia
52. What pattern of pneumonia is typically multifocal and patchy?
Bronchopneumonia
53. What pattern of pneumonia is caused by viruses?
Interstitial
54. What are the four most common symptoms of pneumonia?
Productive cough, shortness of breath, chest pain, and fever/chills.
55. What are the different categories of pneumonia?
Acute vs. chronic (time), typical vs. atypical (clinical characteristics), alveolar vs. interstitial (x-ray pattern), and community-acquired vs. nosocomial (location of illness onset).
56. What are the types of hospital-acquired pneumonia (HAP)?
Ventilator-associated pneumonia (VAP) and healthcare-associated pneumonia (HCAP)
57. What type of pneumonia is considered community-acquired (CAP)?
Pneumonia that develops outside of the hospital setting.
58. What causes considered community-acquired (CAP)?
It is most commonly caused by bacteria that traditionally has been divided into two groups (typical and atypical).
59. Can COVID-19 cause pneumonia?
Yes, some infected with coronavirus can develop pneumonia in one or both lungs.
60. What factors impair the pulmonary clearance of pneumonia?
Viral upper respiratory tract infection, smoking, alcohol, uremia, and bronchial obstruction.
61. What is an early symptom of pneumonia?
Breathlessness
62. Can pneumonia lead to acute respiratory distress syndrome (ARDS)?
Yes, pneumonia can lead to ARDS in severe cases.
63. What would the PFT results of a patient with pneumonia show?
Decreased lung volumes and capacities.
64. What bacteria can cause pneumonia?
Streptococcus, mycoplasma, haemophilus influenzae, and legionella pneumophila.
65. What can cause hypoxemia in a patient with pneumonia?
Alveolar consolidation
66. What are the typical vital signs for pneumonia?
Typical vital signs in pneumonia may include fever, increased respiratory rate, and sometimes a higher heart rate. Oxygen saturation levels might be lower than normal, indicating impaired gas exchange due to the infection and inflammation in the lungs.
67. What is the most common causative agent of bacterial pneumonia in adults?
Streptococcus pneumoniae
68. What are the signs of dying from aspiration pneumonia?
Signs of dying from aspiration pneumonia may include severe respiratory distress, persistent hypoxemia (low blood oxygen levels), altered mental status, multi-organ failure, and a significant increase in respiratory secretions, indicating the body’s inability to fight the infection and maintain vital functions.
69. What role do leukocytes play in the body’s response to pneumonia?
Leukocytes, or white blood cells, play a crucial role in fighting off the infection in pneumonia by attacking and destroying the invading pathogens.
70. Is pneumonia an obstructive or restrictive lung disease?
Pneumonia is classified as a restrictive lung disease because it restricts the expansion of the lungs due to inflammation and fluid accumulation in the alveoli, leading to reduced lung volume and impaired gas exchange. This contrasts with obstructive lung diseases, which involve airflow obstruction.
71. When is intubation required for pneumonia?
Intubation is required for pneumonia when patients experience severe respiratory distress, have a significantly lowered ability to maintain adequate oxygen levels, or are unable to protect their airway due to decreased consciousness, ensuring mechanical support to maintain breathing and oxygenation.
72. What breathing pattern is common with pneumonia?
Tachypnea
73. Are narrow-spectrum antibiotics used to treat pneumonia?
Yes, narrow-spectrum antibiotics can be used to treat pneumonia, particularly when the specific bacterial pathogen responsible for the infection has been identified. These antibiotics target a specific type of bacteria, thereby minimizing disruption to the body’s normal bacterial flora and reducing the risk of resistance.
74. What can lobar atelectasis occur with pneumonia?
Lobar atelectasis can occur with pneumonia when inflammation and mucus production lead to blockage of the airways, causing a collapse of part or all of a lung lobe.
75. What is the difference between pneumonia and pulmonary edema?
Pneumonia is an infection of the lungs causing inflammation and fluid-filled alveoli, primarily caused by microorganisms. Pulmonary edema, on the other hand, involves fluid accumulation in the lungs due to heart problems or other non-infectious causes, affecting gas exchange.
Final Thoughts
Pneumonia continues to present a substantial burden on global healthcare systems, contributing to significant morbidity and mortality rates.
Timely diagnosis, appropriate treatment, and preventive measures such as vaccination remain pivotal in combating this respiratory infection.
Public health efforts focused on education, early intervention, and promoting healthy behaviors are essential in reducing the incidence and impact of pneumonia on individuals and communities worldwide.
Written by:
John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.
References
- Jain V, Vashisht R, Yilmaz G, et al. Pneumonia Pathology. [Updated 2023 Jul 31]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024.