Lung Abscesses

Question 1

What is a Lung Abscess?

Answer 1

A localized area of suppuration (pus formation) within the pulmonary parenchyma that results in the formation of one or more large cavities and involves the destruction of lung tissue (alveoli, airways, and blood vessels).

Question 2

What is the most common way organisms are introduced to cause a lung abscess?

Answer 2

Aspiration of infective material, typically from carious teeth, infected sinuses, or tonsils. This is common in patients with depressed cough reflexes, such as those under anesthesia or with alcoholic intoxication.

Question 3

A lung abscess is a common complication of what other condition?

Answer 3

Necrotizing pneumonias (either bacterial or fungal).

Question 4

Name the type of bacteria that are a principal target for treatment and are nearly always present in a lung abscess.

Answer 4

Anaerobic bacteria. They are often exclusive isolates in up to two-thirds of cases, and their source is the oral cavity.

Question 5

If a lung abscess is caused by aspiration, which side of the lung is it most likely to be on, and why?

Answer 5

The right side, because the right bronchus is straighter and more vertical than the left bronchus, making it easier for material to aspirate.

Question 6

How do the number of abscesses typically differ between aspiration, necrotising pneumonia and septic/pyemic causes?

Answer 6

Aspiration: Usually single and large. Septic/Pyemic: Usually multiple and can be scattered throughout the lungs.

Question 7

What is the classic radiographic sign seen in a partially drained lung abscess?

Answer 7

An air and fluid level within the cavity.

Question 8

What is the characteristic feature of the cough/sputum in a patient with a lung abscess?

Answer 8

The patient usually presents with a cough producing large amounts of foul-smelling, purulent sputum (pus).

Question 9

Name two serious complications of a lung abscess.

Answer 9

Empyema (rupture into the pleural cavity) and severe hemoptysis (erosion into adjacent blood vessels). Other complications include brain abscesses/meningitis from septic emboli.

Question 10

What condition must be ruled out when a lung abscess is found in an elderly patient?

Answer 10

Underlying lung cancer (particularly squamous cell carcinoma), as a lung abscess can mask or be a complication of a neoplasm.

Question 11

Question

Answer 11

Correct Answer

Question 12

A 45-year-old male presents with persistent fever, weight loss, and a productive cough. Chest imaging reveals a focal, pus-filled cavity within the pulmonary parenchyma, associated with localized tissue destruction. Which of the following best describes this pathological process?

Answer 12

Localized area of suppuration resulting in cavitation

Question 13

A 68-year-old male with a history of severe alcoholism is admitted after being found unconscious. Three weeks later, he develops a cough productive of large volumes of foul-smelling sputum. Which mechanism is the most likely cause of his lung abscess?

Answer 13

Aspiration of infective material from the oropharynx

Question 14

A 55-year-old patient is diagnosed with a lung abscess following aspiration. The sputum is noted to have a particularly putrid odor. When initiating empiric antibiotic therapy, which class of organisms must be primarily targeted, given their high prevalence in such cases?

Answer 14

Anaerobic bacteria

Question 15

If a lung abscess is caused by aspiration, which side of the lung is it most likely to be on, and why?

Answer 15

Single and large, most often in the right lung

Question 16

A patient with an acute lung abscess suddenly develops sharp, pleuritic chest pain and signs of systemic toxicity. Subsequent imaging confirms the presence of pus within the pleural cavity. This complication is known as:

Answer 16

Empyema

Question 17

In a long-standing or chronic lung abscess, what microscopic feature is expected at the margin of the cavity?

Answer 17

A band of dense fibrous tissue

Question 18

A 75-year-old non-smoker presents with a lung abscess that developed distal to a newly discovered endobronchial mass. The abscess is single and is primarily caused by impaired drainage and distal atelectasis. What must be ruled out as a potential primary cause of the underlying bronchial obstruction?

Answer 18

Malignant neoplasm

Question 19

A 30-year-old intravenous drug user with known infective endocarditis develops multiple small, scattered lung abscesses throughout both lung fields. What is the most likely route of dissemination for the infectious organisms to the lung parenchyma in this patient?

Answer 19

Hematogenous spread via the pulmonary arteries

Question 20

Which of the following complications of a lung abscess is caused by septic emboli traveling to the systemic circulation?

Answer 20

Meningitis or brain abscesses

Question 21

A chest X-ray in a patient with a recently partially drained lung abscess cavity is expected to show which of the following radiological findings?

Answer 21

Air-fluid level