What are the symptoms of diaphragmatic pleuritis?

Symptoms of Diaphragmatic Pleurisy

Diaphragmatic pleurisy presents primarily with sharp, pleuritic chest pain that is localized and worsens with breathing, often accompanied by referred pain to the shoulder tip due to diaphragmatic irritation. 1

Cardinal Symptom: Pleuritic Chest Pain

• Sharp, stabbing, or "knifelike" pain that is provoked or worsened by deep breathing, coughing, or other respiratory movements 1
• The pain is well-localized to the affected area, typically in the lower chest or upper abdomen where the diaphragm is involved 2
• Pain intensity increases with inspiration and may force patients to take shallow breaths 1

Referred Shoulder Pain (Pathognomonic Feature)

• Shoulder tip pain occurs in approximately 14% of patients with diaphragmatic irritation, representing referred pain via the phrenic nerve (C3-C5 distribution) 2
• This referred pain pattern is highly suggestive of diaphragmatic involvement and helps distinguish diaphragmatic pleurisy from other causes of chest pain 2
• The presence of both localized chest pain and shoulder tip pain strongly indicates diaphragmatic pathology 2

Respiratory Symptoms

• Dyspnea is common, particularly when the inflammatory process is extensive or bilateral 3
• Tachypnea (respiratory rate >20/min) may develop as patients attempt to minimize painful deep breathing 4
• Dry cough can occur and typically exacerbates the pleuritic pain 4

Associated Systemic Symptoms

• Fever may be present if the pleurisy is infectious or inflammatory in origin 5
• Influenza-like symptoms including myalgia and malaise can precede or accompany viral pleuritis 3, 5
• Some patients remain asymptomatic in early or mild cases, particularly with small areas of inflammation 3

Important Clinical Pitfalls

Do not assume normal oxygen saturation excludes significant diaphragmatic pleurisy—20-40% of patients with pleural pathology maintain normal arterial oxygen saturation 4. The diagnosis relies on the characteristic pain pattern and physical findings rather than hypoxia.

Beware of misdiagnosis as pneumonia or bronchiolitis, especially when preceded by viral illness with respiratory symptoms 3. The key distinguishing feature is the sharp, positional nature of pleuritic pain versus the dull ache of pneumonia.

Physical Examination Findings

• Pleural friction rub may be audible on auscultation—described as a creaking, leathery sound that occurs during both inspiration and expiration and is not cleared by coughing 1
• Reduced chest wall movement on the affected side due to pain-related splinting 3
• Tenderness to palpation over the lower chest wall where the diaphragm attaches 1

Severity Spectrum

• Mild cases: Intermittent discomfort with deep breathing only, minimal functional impairment 3
• Moderate cases: Constant pain limiting normal respiratory excursion, requiring analgesics 5
• Severe cases: Incapacitating pain preventing adequate ventilation, potentially leading to atelectasis and secondary complications 3

Temporal Patterns

The onset and duration vary by etiology:

• Acute viral pleuritis: Sudden onset over hours to days, typically self-limited 5
• Post-traumatic: May develop immediately after injury or be delayed by days to weeks 3
• Autoimmune (e.g., lupus): Can be recurrent with exacerbations and remissions 6, 7