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Author: Admin | 2025-04-28
A contraindication to anticoagulation).Pleuritic chest pain may result from pleural irritation.Low-grade fever may result from tissue necrosis. Fever is usually (10631196)Isolated dyspnea may be the only symptom.radiology of pulmonary infarctionAnatomic distribution:Infarction creates a wedge-shaped opacity that is always pleural-based. However, the opacity may be based in the fissure or mediastinal pleura, so it won't always appear wedge-shaped on chest radiograph.Lesions are usually present in the lower lobe.Multiple lesions can be present (which can mimic multinodular lung disease).CT scan appearances of pulmonary infarction may include:Consolidation (which may represent necrotic lung tissue).Ground-glass opacities (which may represent local pulmonary hemorrhage).Reverse halo sign 📖 may occur (a rim of consolidation, containing a central area of ground-glass opacity; figure below).(Cavitation may occur, but it's rare.)(Walker 2019)Evolution: Over ~3-5 weeks, the infarct slowly decreases in size. On CT scan, the resolving infarct may appear to have a “melting ice cube sign:”Pneumonia resolves in a patchy fashion.Pulmonary infarct decreases in size while maintaining a homogeneous appearance – like an ice cube.Reverse halo sign occurring in the context of a pulmonary infarction due to pulmonary embolism. (24957589)radiology of pulmonary infarction: accompanying pleural effusionPulmonary infarction produces a small pleural effusion in ~60% of patients. (9377961)Effusion is usually ipsilateral to the pulmonary infarct.The pleural effusion is often unimpressive and easily overlooked (e.g., causing mild blunting of the costophrenic angle).(More on pleural effusion due to pulmonary embolism: 📖)(4) DVT (deep vein thrombosis) DVT may occur by itself, or in combination with pulmonary emboli.symptoms of DVTHalf of DVTs are asymptomatic.Pain is the most common symptom.Other symptoms may include swelling, redness.signs of DVT may includeTenderness may be present.Asymmetric pitting edema.Discoloration (erythema or cyanosis).Dilation of superficial veins.Warmth.sensitivity of D-dimerD-dimer is very sensitive for acute PE/DVT (~98% sensitive).D-dimer will fall over time, following acute PE/DVT. Patients presenting two weeks after the acute DVT/PE may have a false-negative D-dimer.specificity of D-dimerAn elevated D-dimer is highly nonspecific. Causes of elevated D-dimer include:Infection (e.g., COVID).Inflammatory states (e.g., pancreatitis).Malignancy.Surgery/trauma.Pregnancy (D-dimer tends to elevate over time as pregnancy progresses).Older age.Cirrhosis.Among patients admitted to a medical ICU who don't have venous thromboembolic disease, ~80% will have an elevated D-dimer. (10708176) Thus, in the context of critical illness, D-dimer has extremely low specificity.D-dimer units & cutoffsD-dimer is typically expressed in FEU (fibrin-equivalent units), but some labs use assays that express D-dimer in terms of DDU (D-dimer units). FEU are roughly twice as high as DDU:FEU = ~2(DDU)Typical cutoff values for D-dimer are:FEU
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