D3.156 - Pulmonary embolism in a young asthma patient

Background

Pulmonary embolism (PE) is a rare, life-threatening condition. Risk factors include lower limb fracture, trauma, hormonal therapy, and malignancy. There are numerous conditions that can mimic PE, such as heart failure, pneumonia, asthma. Diagnosis is difficult as symptoms are nonspecific. D-dimer testing is used mostly in the primary care and emergency settings. D-dimer has low positive but high negative predictive value in the early phase, though its reliability diminishes after 3–7 days. In case of high grade of suspicion or positive D-dimer in low risk patients, CT pulmonary angiography should be performed as first line radiological diagnostic. Ventilation/perfusion scintigraphy should be considered if the computed tomographic pulmonary angiography is inconclusive, in pregnant women or if contrast media cannot be used.

Case presentation

A 23-year-old woman with allergic asthma presented with a 2-day history of chest pain and easily provoked shortness of breath. Examination and vital signs were normal; CRP and D-dimer were within range. Asthma exacerbation was suspected, and inhalation therapy was intensified. Two months later, she visited A&E with similar symptoms; tachycardia was noted, other parameters were normal. After short-acting muscarinic agonist treatment, she improved subjectively, and oral steroids were prescribed for presumed uncontrolled asthma. Five days later, due to persistent pain and dyspnoea, she returned to primary care. No oedema or abnormal auscultation was noted. Oxygen saturation was 99% at rest but dropped to 91% after mild exertion. She was referred again to A&E. Labs showed leukocytes 11.4 G/L, platelets 454 G/L, normal troponin (8 ng/L) and Pro-BNP (82 ng/L). CT pulmonary angiography was performed due to oral contraceptive use; no PE was seen. ECG revealed tachycardia, but not other pathological signs. Symptoms worsened, with severe dyspnoea on minimal effort. The case was reviewed with cardiology, allergy, and infectious disease specialists. Viral infection was considered but not confirmed. Spirometry, impulse oscillometry, HRCT, and echocardiography were normal. Because of symptom–test discrepancy, a ventilation/perfusion scan was done, revealing PE in the left lower lobe. Anticoagulation with tinzaparin followed by rivaroxaban was started. Thrombophilia testing revealed heterozygous Factor V Leiden. The patient’s condition improved markedly.

Conclusion

PE is rare and often overlooked in young patients due to atypical clinical signs and fewer risk factors. D-dimer levels, vital signs, and CT pulmonary angiography may appear normal in case of small or peripheral emboli, which can delay diagnosis. PE should always be ruled out when asthma symptoms are sudden, unexplained, or unresponsive to treatment. Awareness of risk factors like hormonal contraception or inherited thrombophilia is crucial for early detection.