What to consider for pulmonary embolism symptoms with elevated D-dimer, alkaline phosphatase, and aspartate aminotransferase, but clear computed tomography angiography?

From the Guidelines

For a patient with symptoms suggestive of pulmonary embolism (PE), moderately elevated D-dimer, elevated alkaline phosphatase (Alk Phos) and aspartate aminotransferase (AST), but a clear computed tomography angiography (CTA), I recommend considering alternative diagnoses while maintaining vigilance for PE.

Key Considerations

• Evaluate for other cardiopulmonary conditions like pneumonia, bronchitis, pleurisy, or pericarditis that can mimic PE symptoms 1.
• The liver enzyme abnormalities (elevated Alk Phos and AST) suggest possible hepatobiliary issues that could be contributing to symptoms or represent a separate problem requiring investigation.
• Consider ultrasound of the liver and biliary system to evaluate for cholestasis, hepatitis, or other liver pathology.

Diagnostic Approach

• The moderately elevated D-dimer in the setting of a negative CTA is not unusual, as D-dimer has high sensitivity but poor specificity for PE 1.
• If clinical suspicion for PE remains high despite negative CTA, consider additional testing such as ventilation-perfusion (V/Q) scan or lower extremity ultrasound to evaluate for deep vein thrombosis 1.
• Monitor the patient closely for 24-48 hours with serial vital signs and symptom assessment, as PE can sometimes be missed on initial imaging.

Management

• A systematic approach to diagnosis is necessary, considering the complex clinical picture that may involve multiple organ systems.
• Follow the guidelines for the diagnosis and management of acute pulmonary embolism, which recommend using validated clinical prediction rules to estimate pretest probability in patients in whom acute PE is being considered 1.
• Consider the patient's clinical probability of PE and use age-adjusted d-dimer thresholds to determine whether imaging is warranted 1.

From the Research

Considerations for Pulmonary Embolism Symptoms

• Elevated D-dimer levels can indicate the presence of pulmonary embolism (PE), but may also be elevated in other conditions 2
• Alkaline phosphatase and aspartate aminotransferase levels are not directly related to the diagnosis of PE, but may be elevated in other conditions that need to be considered in the differential diagnosis
• A clear computed tomography angiography (CTPA) result does not necessarily rule out PE, as it may not detect small peripheral emboli or asymptomatic PE of uncertain clinical significance 3

Diagnostic Approach

• A clinical decision rule can be used to determine the pre-test probability of PE, and a D-dimer test can be used to further evaluate patients with a low pre-test probability 4
• If the D-dimer result is normal, PE can be excluded, but if the D-dimer level is elevated, further imaging with CTPA or ventilation-perfusion (V/Q) scan may be necessary 3, 5
• The choice of imaging modality depends on the patient's clinical status, risk factors, and other factors, such as radiation exposure and pregnancy 3

Management and Further Evaluation

• Patients with suspected PE and elevated D-dimer levels should undergo further evaluation, including imaging and possibly other diagnostic tests, to confirm or rule out the diagnosis 6, 2
• A simple clinical model combined with D-dimer assay can be used to manage patients presenting to the emergency department with suspected PE, and can help to exclude PE in patients with low pre-test probability and negative D-dimer result 5