Pulmonary Embolism in Pneumonia: Still a Diagnostic Challenge? Results of a Case-Control Study in 100 Patients

Abstract

This study evaluated the diagnostic value of D-dimer, CRP, and leucocytes count to detect an underlying pulmonary embolism (PE) in patients with pneumonia. A predictive model of an underlying PE, based on laboratory markers and clinical symptoms, was our ultimate objective. Overall 100 patients underwent a computed tomography angiography (CTA) of the lung: 54 with coexistence of PE and pneumonia (cases) and 46 with pneumonia without PE (controls). Cases and controls were matched 1 : 1. Symptoms and paraclinical findings were registered on admission. Receiver operating characteristic (ROC) curves, search for an optimal threshold, and conditional logistic regression analysis were conducted. D-dimer has a moderate ability to detect PE in pneumonia. Sensitivity of D-dimer was estimated at 97.78% and specificity at 11.11%. No optimal cut-point has acceptable diagnostic ability. After excluding patients with sepsis, sensitivity was reduced to 96.97%, whereas specificity increased to 16.13%. Consolidation in chest X-ray and positive D-dimer predict better an underlying PE as D-dimer itself. Thus, discriminatory power of the prediction model (AUC of 0.740) is not much greater than D-dimer (AUC of 0.703). No threshold that could increase the diagnostic value of D-dimer or a prediction model which is significantly better than D-dimer itself was identified.

Diagnostic management of inpatients with a positive D‐dimer test: developing a new clinical decision‐making rule for pulmonary embolism

“…1,2 In addition, because it has nonspecific clinical manifestations and lacks a specific auxiliary examination, PE is associated with high rates of misdiagnosis and missed diagnoses, which has been a common source of medical disputes. 3 Therefore, it is imperative to achieve an accurate and early diagnosis of PE.…”

Incidence of Pulmonary Embolism in Patients with Positive D-Dimers and Chest X-ray Evidence of Pneumonia: A Retrospective Study

“…Our sample size was too small to make any statistically significant predictors of which patients are at high risk and need a CTA to further rule out pulmonary embolism in the setting of an elevated D-dimer and pneumonia based on CXR. Paparoupa M et al performed a case control study on 100 patients, approximately half with PE in addition to pneumonia and the other half without PE and were also unable to determine a prediction rule [13].…”

Plućni embolizam u pneumoniji

“…Plućni embolizam (PE) i pneumonija obilježeni su brojnim sličnostima u rizičnim faktorima, kliničkim, laboratorijskim i radiološkim obilježjima, zbog čega uspješna distinkcija među ovim patološkim zbivanjima može predstavljati dijagnostički izazov. Poseban dodatni problem leži u mogućoj istovremenoj prisutnosti PE i pneumonije, osobito u specifičnim populacijama bolesnika [1][2][3] .…”