Acute Pleurisy

Acute pleurisy is acute inflammation of the visceral and parietal pleura causing sharp, localised chest pain that worsens on inspiration, coughing and movement (pleuritic pain). Pleurisy may be dry (fibrinous, with no fluid) or associated with a pleural effusion, and inflammation can occur with or without the underlying lung disease.

• The pain arises from the parietal pleura, which is supplied by intercostal nerves (the visceral pleura is insensitive). Pain in the shoulder tip indicates diaphragmatic pleural involvement through the phrenic nerve.
• Causes:
  • Infections: viral (coxsackievirus B causing epidemic pleurodynia, influenza, parainfluenza, adenovirus, cytomegalovirus), bacterial pneumonia (the commonest cause, with parapneumonic effusion), tuberculosis, and, less often, fungal and parasitic disease.
  • Pulmonary embolism with infarction (pleuritic pain in about 60% of patients).
  • Autoimmune and connective tissue disease: systemic lupus erythematosus, rheumatoid arthritis, Sjogren syndrome, systemic sclerosis, and vasculitis.
  • Drug induced lupus (hydralazine, procainamide, isoniazid, methyldopa, minocycline), and drug induced pleural disease (nitrofurantoin, amiodarone, methotrexate, bleomycin).
  • Malignancy (lung cancer, mesothelioma, metastases and lymphoma), asbestos exposure, and radiation.
  • Pericarditis and post-myocardial infarction or post-cardiac injury syndromes, pancreatitis, subphrenic abscess, familial Mediterranean fever, and inflammatory bowel disease.
  • Trauma, rib fracture and pneumothorax, and uraemic or dialysis associated pleuritis.
• Incidence is high among young adults, with most cases viral and self-limiting. Older adults and those with risk factors have more serious causes.
• Risk factors: respiratory infection, smoking, immobility, recent surgery, malignancy, pregnancy and oestrogen use (embolism), autoimmune disease, and exposure to asbestos.

• Sudden, sharp, stabbing, localised chest pain on one side, worse with deep breathing, coughing, sneezing, laughing, and relieved by holding the breath, shallow breathing or lying on the affected side (splinting). Pain may radiate to the shoulder, neck or abdomen.
• Other symptoms depend on the cause: fever, cough and sputum in pneumonia; a recent viral prodrome with myalgia in viral pleurisy; haemoptysis and leg swelling in pulmonary embolism; joint pain, rash and photosensitivity in lupus; and weight loss in tuberculosis and cancer.
• Examination: rapid shallow breathing, guarded chest movement on the affected side, a pleural friction rub (a scratching sound at the end of inspiration and early expiration, loudest at the base), and, with effusion, dull percussion and reduced breath sounds. Fever and tachycardia are present with infection.
• Differential diagnosis: pulmonary embolism, pneumothorax, pneumonia, pericarditis, acute coronary syndrome, aortic dissection, musculoskeletal pain (costochondritis, rib fracture, intercostal muscle strain), herpes zoster (before the rash), oesophageal rupture or spasm, pancreatitis, cholecystitis, subphrenic abscess, and sickle cell chest crisis.
• Red flags: breathlessness at rest, oxygen saturation below 94%, heart rate above 110 per minute, haemoptysis, hypotension, unilateral leg swelling, a history of cancer, recent surgery or immobility, tearing pain radiating to the back, severe chest pain with sweating, fever with rigors, pain that does not respond to analgesia, a large effusion, and pleurisy in a patient with immunosuppression.
• Complications: pleural effusion, empyema, pleural thickening and fibrosis, respiratory failure, and complications of the underlying disease (for example infarction, sepsis).

• Clinical, with an aim to find the cause and exclude life threatening conditions. Record the onset, character, associated symptoms, risk factors for embolism, infection, tuberculosis exposure, medicines, occupation (asbestos), and autoimmune symptoms.
• Examine vital signs (including oxygen saturation), chest, heart, legs (deep vein thrombosis signs), joints, skin and lymph nodes.
• First line tests:
  • Chest X-ray (posteroanterior and lateral): pneumonia, effusion, pneumothorax, rib fracture, mass. It is normal in early viral pleurisy and in many cases of pulmonary embolism.
  • Electrocardiogram: pericarditis (diffuse ST elevation with PR depression), ischaemia, right heart strain.
  • Full blood count, C-reactive protein, urea and electrolytes, and troponin.
  • D-dimer when the pretest probability of pulmonary embolism is low or moderate (a negative result excludes it), and CT pulmonary angiography when the probability is high or the D-dimer is raised.
• Further tests as indicated:
  • Pleural ultrasound to detect small effusions and guide aspiration.
  • Diagnostic pleural aspiration for all effusions of unclear cause or with fever. Send fluid for pH, protein, lactate dehydrogenase, glucose, cell count and differential, Gram stain, culture, cytology and adenosine deaminase when tuberculosis is possible. An exudate has a fluid to serum protein ratio above 0.5, a fluid to serum lactate dehydrogenase ratio above 0.6, or a fluid lactate dehydrogenase above two thirds of the upper limit of the serum value. A pleural pH below 7.2 or a glucose below 3.3 mmol/L suggests complicated parapneumonic effusion or empyema.
  • Sputum and blood cultures, and sputum acid fast bacilli or a rapid molecular test in suspected tuberculosis.
  • Antinuclear antibody, anti-double stranded DNA antibody, rheumatoid factor, complement levels, and anti-cyclic citrullinated peptide antibody when autoimmune disease is suspected.
  • CT of the chest with contrast for persistent pain, effusion of unknown cause, or suspected tumour, with thoracoscopy or pleural biopsy when diagnosis remains uncertain.
  • Viral testing (influenza, COVID-19) when relevant.

• Treat the cause and relieve the pain:
  • Analgesia is first line: ibuprofen 400 to 600 mg orally 8 hourly with food for 1 to 2 weeks, or naproxen 500 mg orally 12 hourly with food, or diclofenac 50 mg orally 8 hourly with food. Add omeprazole 20 mg orally once daily when there is a risk of gastrointestinal bleeding. Avoid NSAIDs in renal impairment, peptic ulcer disease, heart failure, and in patients taking anticoagulants.
  • Paracetamol 1 g orally 6 hourly (maximum 4 g per day, or 3 g in patients under 50 kg, and 2 g in liver disease), alone or added.
  • Codeine 30 mg orally 6 hourly, or tramadol 50 mg orally 6 to 8 hourly, for severe pain for 3 to 5 days, with laxatives, and cautious use in respiratory failure.
  • Heat packs over the area and splinting the chest with a pillow when coughing. Encourage regular deep breathing and coughing to avoid atelectasis and secondary pneumonia, and avoid prolonged shallow breathing.
• Viral pleurisy: rest, NSAIDs, and fluids. The pain resolves in 3 to 7 days (up to 2 weeks), and no antibiotic is needed.
• Bacterial pneumonia with pleurisy:
  • Mild community acquired pneumonia: amoxicillin 500 mg to 1 g orally 8 hourly for 5 days, with clarithromycin 500 mg orally 12 hourly added for 5 days for suspected atypical infection. Penicillin allergy: doxycycline 200 mg on day 1, then 100 mg once daily for 4 days.
  • Moderate to severe pneumonia or effusion: admit, with co-amoxiclav 1.2 g IV 8 hourly and clarithromycin 500 mg IV or orally 12 hourly, adjusted to culture. Drain an effusion with pH below 7.2, pus, or positive culture (chest drain 12 to 14 French by Seldinger technique, with intrapleural therapy in specialist care), and treat empyema for 2 to 6 weeks.
• Pulmonary embolism: give anticoagulation at once when suspicion is high (apixaban 10 mg orally 12 hourly for 7 days, then 5 mg 12 hourly, or rivaroxaban 15 mg orally 12 hourly for 21 days, then 20 mg once daily with food, or low molecular weight heparin enoxaparin 1.5 mg/kg subcutaneously once daily, or 1 mg/kg 12 hourly, followed by an oral anticoagulant). Treat for at least 3 months. Admit for severe features (hypotension, right heart strain, raised troponin, hypoxia) and consider thrombolysis for haemodynamic instability.
• Pericarditis: ibuprofen 600 mg orally 8 hourly for 1 to 2 weeks (or aspirin 750 to 1000 mg 8 hourly), with colchicine 500 micrograms orally once daily (weight below 70 kg) or 12 hourly (weight 70 kg or more) for 3 months, a gastric protectant, and a tapering NSAID. Restrict strenuous exercise until recovered.
• Tuberculosis: isoniazid, rifampicin, pyrazinamide and ethambutol for 2 months, then isoniazid and rifampicin for 4 months, as fixed dose combinations adjusted for weight, with pyridoxine 10 mg daily with isoniazid, and monitoring of liver function. A corticosteroid course (prednisolone 20 to 40 mg daily for 4 weeks, tapered) may be added for tuberculous pleurisy in specialist care.
• Autoimmune pleurisy: prednisolone 0.5 mg/kg orally once daily (typically 20 to 40 mg) for 1 to 2 weeks and then tapered, with rheumatology input and steroid sparing agents. Stop drugs causing lupus like pleurisy.
• Malignant effusion: therapeutic drainage, an indwelling pleural catheter or pleurodesis with talc (4 to 5 g), and oncology referral.
• Pleurodynia (viral): NSAIDs, warmth, and reassurance. Duration is 2 to 14 days.
• Rib fracture or trauma: analgesia, breathing exercises and exclusion of pneumothorax and haemothorax.
• Special groups:
  • Children: paracetamol 15 mg/kg orally every 4 to 6 hours (maximum 60 mg/kg per day) and ibuprofen 5 to 10 mg/kg every 6 to 8 hours (maximum 40 mg/kg per day). Pleurisy usually indicates pneumonia with effusion, which needs a chest X-ray, ultrasound and antibiotics (amoxicillin 40 to 90 mg/kg per day in 3 divided doses).
  • Pregnancy: use paracetamol, and avoid NSAIDs from 20 weeks of gestation. Maintain a high index of suspicion for pulmonary embolism and treat with low molecular weight heparin (enoxaparin 1 mg/kg subcutaneously 12 hourly). Avoid direct oral anticoagulants and warfarin in pregnancy.
  • Elderly: lower threshold for admission and imaging, because of pneumonia, embolism and cancer. Avoid NSAIDs in those with renal impairment, heart failure and cardiac risks. Use lower doses of opioids.
  • Renal impairment: avoid NSAIDs and adjust doses of antibiotics (amoxicillin, co-amoxiclav) and anticoagulants (apixaban dose reduced in severe impairment).
  • Immunosuppressed: consider tuberculosis, fungal and opportunistic infections, and admit early.
• Follow up: review at 1 week, and arrange a chest X-ray at 6 weeks for patients over 50 years, smokers and those with effusion, to confirm resolution. Refer to respiratory medicine for effusion of unknown cause, empyema, suspected cancer or tuberculosis, and recurrent pleurisy. Refer to cardiology for pericarditis with complications.