Pleural disease & pneumothorax flashcards
17 high-yield MRCP Part 1 cards from the Intellect Medicos Respiratory Medicine course. Try to answer each question before you open it — then study them properly with spaced repetition, which brings each card back just before you would forget it.
Study these 17 cards Save progress — free account
-
Light's criteria: an effusion is an exudate if pleural/serum protein is > ______, or pleural/serum LDH is > 0.6, or pleural LDH is > two-thirds of the upper limit of normal serum LDH.
Show answer
0.5
Why? Only one criterion is needed. Exudates are due to pleural disease (infection, malignancy); transudates to fluid imbalance (heart failure, cirrhosis, nephrotic syndrome).
-
Light's criteria: an effusion is an exudate if pleural/serum protein is > 0.5, or pleural/serum LDH is > ______, or pleural LDH is > two-thirds of the upper limit of normal serum LDH.
Show answer
0.6
Why? Only one criterion is needed. Exudates are due to pleural disease (infection, malignancy); transudates to fluid imbalance (heart failure, cirrhosis, nephrotic syndrome).
-
What is the most common cause of a transudative pleural effusion?
Show answer
Heart failure.
Why? Raised hydrostatic pressure pushes protein-poor fluid into the pleural space. Course aid: "all failures are transudative".
-
After the chest X-ray, which imaging should guide pleural aspiration or drainage?
Show answer
Thoracic ultrasound.
Why? Ultrasound confirms fluid, shows loculation and reduces complications of aspiration and drain insertion.
-
In a parapneumonic effusion, which pleural fluid findings mean a chest drain is needed?
Show answer
Any one of: frank pus, pleural fluid pH ≤ 7.2, or organisms on Gram stain/culture.
Why? These indicate a complicated parapneumonic effusion or empyema, which will not settle with antibiotics alone. BTS adds: insert the drain if the volume of fluid on ultrasound makes it safe.
-
What antibiotics are suggested for pleural infection in the course notes?
Show answer
Co-amoxiclav, or cefuroxime plus metronidazole.
Why? Pleural infection often involves anaerobes, so anaerobic cover is needed alongside drainage.
-
Which intrapleural drug combination may be used when a chest drain fails to clear pleural infection?
Show answer
Tissue plasminogen activator (alteplase) plus DNase (dornase alfa).
Why? tPA breaks down fibrinous loculations and DNase reduces pus viscosity, improving drainage (MIST-2 trial). Otherwise refer for surgery.
-
What pleural fluid triglyceride level suggests a chylothorax (course notes), and what is its commonest non-traumatic cause?
Show answer
Triglycerides > 1.2 mmol/L (with chylomicrons); lymphoma is the commonest cause.
Why? Chyle leaks from a damaged or blocked thoracic duct, giving milky fluid.
-
Which cause of pleural effusion gives a very low pleural glucose (often < 1.6 mmol/L)?
Show answer
Rheumatoid arthritis.
Why? Low glucose (< 3.3 mmol/L) is also seen in empyema, TB and malignancy, but rheumatoid effusions are classically the lowest.
-
A raised pleural fluid amylase suggests which two conditions?
Show answer
Acute pancreatitis and oesophageal rupture (Boerhaave syndrome).
Why? A pleural/serum amylase ratio > 1 points to these diagnoses.
-
A lymphocytic exudate has a high adenosine deaminase (ADA). What is the likely cause?
Show answer
Tuberculous pleural effusion.
Why? ADA comes from activated lymphocytes; a high level supports TB, especially in high-prevalence settings.
-
What is the maximum volume usually removed in one therapeutic pleural aspiration, and what complication does this limit prevent?
Show answer
Up to 1.5 L per session; it limits the risk of re-expansion pulmonary oedema.
Why? Stop earlier if the patient develops cough, chest tightness, breathlessness or vasovagal symptoms.
-
For a recurrent malignant effusion with a non-expandable (trapped) lung, which is the preferred option?
Show answer
An indwelling pleural catheter (IPC).
Why? Talc pleurodesis needs the visceral and parietal pleura to meet, so it fails when the lung cannot re-expand.
-
Under BTS 2023 guidance, what pneumothorax size on chest X-ray is generally "sufficient" to make intervention safe?
Show answer
About 2 cm or more, measured laterally or apically.
Why? Management also depends on symptoms, high-risk features and the patient's priorities; asymptomatic PSP can be managed conservatively.
-
What are the boundaries of the "triangle of safety" for chest drain insertion?
Show answer
Lateral border of pectoralis major, anterior border of latissimus dorsi, a line at the level of the nipple (5th intercostal space), with the apex below the axilla.
Why? Inserting in this area avoids the internal mammary vessels, major muscles and the diaphragm.
-
A chest drain for pneumothorax is continuously bubbling. Should it be clamped?
Show answer
No — a bubbling drain must never be clamped.
Why? Clamping a drain with an ongoing air leak can cause a tension pneumothorax. Check connections and examine the patient.
-
After a pneumothorax, which activity is permanently contraindicated unless the patient has had definitive surgery?
Show answer
Scuba diving (discouraged permanently unless a secure definitive procedure such as surgical pleurectomy has been done).
Why? Pressure changes during ascent can re-expand trapped air dangerously. Commercial flying is allowed 7 days after a chest X-ray shows full resolution.