Lung Infections: Overview and Practice Questions (2025)

Lung infections are a significant public health concern that impact millions of lives globally each year.

Ranging from mild conditions like bronchitis to more severe forms such as pneumonia and tuberculosis, these infections can be caused by various pathogens, including bacteria, viruses, and fungi.

Understanding the underlying mechanisms, risk factors, and available treatment options is critical for both healthcare providers and the general public.

This guide provides a comprehensive overview of lung infections, shedding light on the etiology, symptoms, diagnostic procedures, and therapeutic strategies.

What is a Lung Infection?

A lung infection is a medical condition where harmful microorganisms, such as bacteria, viruses, or fungi, invade the lungs, leading to inflammation and impaired function. The severity can range from mild conditions like bronchitis to more serious forms such as pneumonia or tuberculosis.

Signs and Symptoms

The signs and symptoms of lung infections can vary depending on the type of infection, the causative organism, and the individual’s overall health.

However, common signs and symptoms often include:

• Cough
• Shortness of Breath
• Fever
• Chest Pain
• Fatigue
• Wheezing
• Sputum Production
• Loss of Appetite
• Sweating
• Cyanosis

Types of Lung Infections

Lung infections can be categorized based on the causative agent, location of infection, or clinical presentation. Here are some common types:

• Influenza
• Tuberculosis
• Bronchitis
• Pneumonia

Note: Each type of lung infection has its own set of symptoms, diagnostic criteria, and treatment options, making accurate identification essential for effective management.

Influenza

Influenza, commonly known as the flu, is a viral infection that primarily affects the respiratory system. It is highly contagious and spreads through airborne droplets.

Symptoms can range from mild to severe and may include fever, cough, sore throat, and body aches.

While generally self-limiting, influenza can lead to severe complications like pneumonia, particularly in high-risk populations such as the elderly and immunocompromised individuals.

Tuberculosis

Tuberculosis (TB) is a bacterial infection caused by Mycobacterium tuberculosis. Primarily affecting the lungs, it is transmitted through airborne droplets when an infected person coughs or sneezes.

The disease can be latent or active; active TB presents with symptoms like persistent cough, weight loss, and night sweats. It is a major global health issue, requiring prolonged treatment with multiple antibiotics to cure.

Bronchitis

Bronchitis is an inflammation of the bronchial tubes, which carry air to and from the lungs. It is commonly caused by viral infections, although bacterial infections can also be a culprit. Symptoms include coughing, mucus production, and mild fever.

Acute bronchitis is usually self-limiting and lasts for a short duration, while chronic bronchitis can persist and is often associated with conditions like chronic obstructive pulmonary disease (COPD).

Pneumonia

Pneumonia is an inflammatory condition affecting the lung tissue, specifically the alveoli, where gas exchange occurs.

It can be caused by a variety of organisms, including bacteria, viruses, and fungi. Symptoms include high fever, cough with phlegm, shortness of breath, and chest pain.

Pneumonia is a serious condition that can lead to respiratory failure and requires prompt medical attention. Treatment often involves antibiotics, antivirals, or antifungals, depending on the causative agent.

Lung Infection Practice Questions

1. What is the most common cause of community-acquired pneumonia?
S. pneumonia

2. What are the most common causes of nosocomial pneumonia?
Gram-negative bacilli and S. aureus

3. What does a sputum gram stain do?
It provides valuable information about the adequacy of the specimen and the predominance of potential pathogens.

4. What was instituted to monitor and reduce ventilator-associated complications?
The VAE surveillance program

5. What is used for the treatment of nosocomial pneumonia?
Pathogen-specific antibiotic therapy

6. What plays an adjunctive role in the treatment of pneumonia?
Inhaled antibiotics

7. What is a major strategy for preventing community-acquired pneumonia?
Immunizing high-risk individuals against influenza and S. pneumoniae

8. What is important regarding a patient with tuberculosis?
Recognition, appropriate isolation, and diagnostic evaluation

9. What is an effective way to prevent nosocomial pneumonia?
Handwashing

10. What is the primary treatment method for influenza?
Antiviral medications

11. Which type of lung infection has the most serious prognosis?
Tuberculosis

12. A patient with a lung infection may experience what?
Body aches and chills

13. Which type of lung infection is caused by a virus?
The flu

14. What is the primary treatment method for tuberculosis?
Antibiotics

15. What is the primary treatment method for pneumonia?
It depends on the cause but may include antibiotics, antiviral medications, or antifungal medications.

16. What is the best way to prevent a lung infection?
Vaccination and good hygiene practices

17. What are the common signs and symptoms of a lung infection?
Coughing up mucus, shortness of breath, wheezing, chest pain or tightness, fever, chills, fatigue, body aches, and loss of appetite; in severe cases, a patient may also experience hallucinations, confusion, and an inability to stay awake

18. What are the different types of lung infections?
The flu, tuberculosis, bronchitis, and pneumonia

19. How is influenza primarily spread?
It is typically spread through coughing or sneezing and can also be contracted by touching an infected surface and then touching your mouth or nose.

20. How is tuberculosis spread?
It is spread through the air and can be contracted by breathing in infected droplets from a cough or sneeze.

21. How is pneumonia primarily spread?
It is typically spread through coughing or sneezing and can also be contracted by aspirating (breathing in) contaminated food or liquids.

22. What organs does influenza primarily affect?
The respiratory system

23. What causes bronchitis?
It is typically caused by a virus.

24. What is influenza?
It is a viral infection (also called “the flu”) that is spread via droplets. It attacks the respiratory system, including the nose, throat, and lungs.

25. What is pneumonia?
It is an inflammatory process of the lung parenchyma that is usually infectious in origin. It can be caused by bacteria, fungi, or a virus. Many factors can affect how serious pneumonia is, including the germ causing the infection.

26. What is tuberculosis?
It is a disease caused by a bacteria known as mycobacterium tuberculosis that attacks the lungs. It’s an airborne disease that is spread when a person with TB coughs, sneezes, or talks.

27. What is bronchitis?
It’s a viral infection of the airways of the lungs that causes them to become irritated and inflamed.

28. What are the three infection control strategies?
(1) Interrupting routes of transmission, (2) eliminating the source of pathogens, and (3) specialized equipment processing

29. Knowing if the infection is gram-negative or positive helps with what?
It helps with selecting the proper antibiotic.

30. What three elements must be present for the transmission of an infection in a healthcare setting?
A source (or reservoir) of pathogens, a susceptible host, and a route of transmission

31. What is the name for infections that are acquired in the hospital?
Nosocomial infections

32. What is the term for inanimate objects that transfer pathogens from one person to another?
Fomites

33. What precautions are used to prevent a form of transmission that occurs when droplets are propelled short distances?
Droplet precautions

34. What are the four categories of expanded precautions?
Contact precautions, droplet precautions, airborne infection isolation, and a protective environment

35. Hand hygiene involves handwashing for at least how many seconds?
At least 15 seconds

36. What precautions are applied to all patients?
Standard precautions

37. What is a substance that kills bacteria?
Bactericidal

38. How many hospital-acquired infections (HAIs) occur annually?
An estimated 2 million

39. What is the best choice for the high-level disinfection of semi-critical respiratory care equipment?
Glutaraldehyde

40. Which type of respiratory care equipment has the greatest potential to spread infection?
Large-volume nebulizers

41. What is the best way to prevent the spread of an infection in the ICU?
Handwashing after every patient contact

42. What should be worn when treating patients with tuberculosis?
N-95 mask

43. What are pneumatoceles?
Small cavities that develop from severe staph or gram-negative bacteria

44. What is MRSA?
Methicillin-resistant S. Aureus

45. What percentage of pneumonia goes undiagnosed?
25-50%

46. What is a healthcare-associated infection (HAI)?
It’s an infection that patients acquire during the course of medical treatment. Approximately 5% of all patients admitted to a hospital develop an HAI, with 15% of them being pneumonia.

47. What is the aim of an infection control procedure?
To eliminate the source of infectious agents, create barriers to their transmission, and monitor and evaluate the effectiveness of control

48. What three elements must be present for transmission within the healthcare setting?
(1) Source of the pathogens, (2) Susceptible host, and (3) Route of transmission

49. What is the primary source of infections in the healthcare setting?
Humans are the primary source; however, inanimate objects have also been proven to cause transmission.

50. Where do most cases of nosocomial pneumonia occur?
Most cases occur in surgical patients, particularly if they have had a chest or abdominal procedure. In these patients, normal swallowing and clearance mechanisms are impaired, which allows bacteria to enter and remain in the lower respiratory tract.

51. Why are patients with an artificial tracheal airway at high risk for nosocomial pneumonia?
Typically, they require prolonged intubation and may already have one or more factors predisposing them, such as COPD. Another risk factor may be increased upper airway colonization with gram-negative bacteria. Also, handling these tubes increases the likelihood of cross-contamination.

52. What are the three major routes of transmission of pathogens in the healthcare setting?
(1) Contact (direct/indirect), (2) Respiratory droplets, or (3) Airborne droplet nuclei

53. What are the sources of infectious agents?
Humans are the primary source, and inanimate objects (e.g., contaminated medical equipment)

54. How can healthcare workers interrupt the route of transmission of pathogens?
Special equipment handling, barrier/isolation precautions using both standard and transmission-based precautions, and standard precautions

55. What are standard precautions?
They are intended to be applied to the care of all patients in the healthcare setting at all times. Standard precautions apply to blood, body fluids, non-intact skin, and mucous membranes.

56. What does PPE stand for?
Personal protective equipment

57. When must sterile gloves be worn?
Whenever performing invasive procedures

58. What must be worn to protect against droplet diseases?
Masks

59. What is the N-95 respirator?
Intended for protection against airborne diseases

60. What are droplet precautions?
They are in place to prevent transmission that occurs when droplets are propelled short distances, such as influenza that is generated via coughing, sneezing, suctioning, bronchoscopy, and cough induction. For these precautions, a surgical mask must be worn.

61. What is airborne infection isolation?
It involves isolation techniques that are intended to reduce the risk of selected infectious agents transmitted by “small droplets” of aerosol particles, such as M. tuberculosis. In this case, you should use an N-95 respirator mask. The room must have negative-pressure ventilation with two air exchanges per hour, and HEPA filters must be used.

62. What are some equipment handling procedures that help prevent the spread of pathogens?
Maintenance of in-use equipment, processing of reusable equipment, application of one-patient-use disposables, and fluid and medication precautions

63. What are some in-use respiratory care equipment that can spread pathogens?
Nebulizers, ventilator circuits, bag-valve-mask devices, and suction equipment

64. What are four infections that are spread by indirect contact transmission?
(1) Pseudomonas aeruginosa, (2) Enteric bacteria, (3) Hep B and Hep C, and (4) HIV

65. What infections are spread by droplet transmission?
Pneumonia, neisseria meningitides (pneumonia), diptheria, pertussis, influenza, and MMR

66. What infections are spread by airborne transmission?
Legionellosis, TB, varicella, measles, and smallpox

67. What factors can enhance the susceptibility of an infection?
Diabetes, age, obesity, or an underlying HIV infection

68. Which patients are more at risk for pneumonia?
Elderly, obese, COPD, and patients with an artificial airway

69. What is the most difficult and least feasible approach to infection control?
Decreasing host susceptibility

70. What vaccine does OSHA mandate that employers provide to healthcare workers?
Hepatitis B vaccine

71. What is the best way to decrease host susceptibility to a device-related infection?
Limit device use and ensure that the devices are placed and maintained properly

72. What do infection control procedures aim to do?
Eliminate the source of agents, create barriers to their transmission, and monitor the effectiveness of control

73. What is disinfection?
It describes a process that destroys the vegetative form of all pathogenic organisms on an inanimate object, except bacterial spores. Disinfection can involve either chemical or physical methods.

74. What is high-level disinfection?
It is the inactivation of all microorganisms except bacterial spores; however, with sufficient exposure time, spores may also be destroyed.

75. What is sterilization?
It is the process that destroys all microorganisms. It can be achieved with physical and chemical approaches. Steam sterilization is the easiest and most common. Low-temperature sterilization technology includes ethylene oxide, which is a colorless and toxic gas.

Final Thoughts

Lung infections are a diverse group of conditions that vary in severity, causative agents, and treatment approaches.

Despite advancements in diagnostic methods and therapeutics, they remain a leading cause of morbidity and mortality worldwide. Early diagnosis and appropriate treatment are key to reducing the health burden they impose.

As we continue to battle existing and emerging respiratory pathogens, fostering a deeper understanding of lung infections and improving public awareness remain paramount in mitigating their impact on global health.