A localised area of pus formation within the lung tissue, usually due to infection and tissue destruction, is referred to by which of the following terms?

Introduction / Context:
The lungs can be affected by various pathological conditions, each with distinct features and clinical implications. When describing diseases of the lungs, precise terminology is important because it guides diagnosis and treatment. One such condition involves a localised pocket of pus within the lung parenchyma, usually caused by severe infection and tissue breakdown. This question asks you to identify the correct term for a localised area of pus formation in the lungs.

Given Data / Assumptions:

The lesion is localised within lung tissue, not just in the pleural space. It consists of pus, indicating infection and suppuration. Options include pulmonary embolism, pulmonary abscess, pleurisy, pulmonary oedema and bronchial asthma. We assume standard clinical definitions of these respiratory conditions.

Concept / Approach:
A pulmonary abscess is a localised collection of pus within the lung parenchyma caused by microbial infection and subsequent tissue necrosis. It often appears as a cavity on imaging and may be associated with fever, cough, foul smelling sputum and systemic signs of infection. Pulmonary embolism is a blockage of pulmonary arteries by a clot or other material, not a pus filled cavity. Pleurisy refers to inflammation of the pleura lining the lungs and chest wall, typically causing sharp chest pain, but not a pus pocket in lung tissue. Pulmonary oedema involves fluid accumulation in the alveoli due to heart failure or other causes. Bronchial asthma is a chronic inflammatory condition with reversible airway narrowing, not pus formation.

Step-by-Step Solution:
Step 1: Focus on the key phrase in the question: localised area of pus formation within the lungs. Step 2: Recall that an abscess, in general medicine, means a confined pocket of pus in tissue, so pulmonary abscess fits this description in the lungs. Step 3: Compare pulmonary embolism, which is related to blood clots and sudden shortness of breath, not pus. Step 4: Evaluate pleurisy, which denotes inflammation of the pleural membranes and painful breathing, without necessarily forming pus filled cavities in lung parenchyma. Step 5: Recognise that pulmonary oedema is fluid (often frothy, serous) in alveoli and bronchial asthma is airway narrowing; neither describes a pus filled cavity. Therefore pulmonary abscess is the correct term.

Verification / Alternative check:
In respiratory medicine references, pulmonary abscess is described as a necrotising infection of the lung, often forming a cavity containing pus. Imaging such as chest X ray or CT scan may show a cavity with an air fluid level. Clinical descriptions emphasise chronic productive cough and fever. Pulmonary embolism, on the other hand, is discussed in the context of deep vein thrombosis and sudden obstruction of pulmonary arteries. Pleurisy is characterised by pleuritic chest pain and pleural rub, while pulmonary oedema is associated with heart failure and frothy sputum. These contrasting descriptions confirm that the term matching a localised pus collection in lung tissue is pulmonary abscess.

Why Other Options Are Wrong:
Pulmonary embolism involves blockage of lung blood vessels and does not refer to pus accumulation in the lung tissue. Pleurisy describes inflammation of the pleural surfaces and may involve fluid in the pleural space but not necessarily an abscess within the lung parenchyma. Pulmonary oedema is the accumulation of fluid, not pus, in the lungs. Bronchial asthma is a chronic inflammatory airway disease characterised by bronchospasm, wheezing and reversible airflow obstruction; it does not form localised pus pockets in lung tissue. These conditions differ significantly from a pulmonary abscess.

Common Pitfalls:
A common pitfall is to confuse pleurisy with all types of lung infection because both can cause chest pain and cough. Another is to mix up pulmonary abscess with tuberculosis cavities or lung cancer lesions on imaging, without noting the pus filled nature of an abscess. For exam questions, focus on key words: abscess implies pus; embolism implies blockage; oedema implies fluid; and asthma implies airway narrowing. This keyword strategy helps you quickly match clinical terms with their core pathological features.

Final Answer:
A localised area of pus formation within lung tissue is called a pulmonary abscess.