A 55-year-old woman presents to the ER complaining of sudden onset of shortness of breath associated with pain on inspiration. She is 2 weeks post total knee replacement surgery and has been recovering without any complication. However, she did not attend her prescribed physical therapy sessions. Her medications are oxycodone for pain management and hormone replacement therapy. Her temperature is 38.0° C, pulse rate is 120/min, respiratory rate is 30/min, blood pressure is 110/75 mm Hg, and oxygen saturation is 89% by pulse oximetry. The ER physician ordered a chest X-ray which came out to be normal, and ECG/EKG which showed evidence of sinus tachycardia.

​

1. What is the most probable diagnosis?

   • Pulmonary Embolism:

     1. It is basically a blood clot that forms in the venous system traveling to the lung causing obstruction of the pulmonary vasculature.

     2. Which is suggested by the presence of acute onset of dyspnea, pleuritic chest pain, hypoxia, hemoptysis, low-grade fever, and tachycardia.
         

2. What risk factors are associated with this condition?

   • The risk factors can be summarized in the Virchow’s Triad:

     1. Endothelial cell injury: due to trauma, surgery, fracture, or previous DVT.

     2. Hypercoagubility state: due to estrogen, malignancy, or genetic condition e.g: Factro V leiden mutation.

     3. Stasis: immobility especially postoperatively.
         

3. How are you going to confirm your diagnosis?

   • Chest X-ray:

     1. Usually normal in majority of the patients.

     2. If abnormality is present, then the most common abnormality associated with PE is atelectasis.

   • ​EKG/ECG:

     1. The most common finding is sinus tachycardia or non-specific ST-T waves changes.

     2. S1Q3T3 is the classic finding of PE, which indicated the presence of right heart strain although it is not usually seen (rarely seen).

   • Arterial blood gases (ABGs):

     1. Might show hypoxemia along with respiratory alkalosis because of the high respiratory rate the CO2 will washout!

   • Serum D-dimer:

     1. It is highly sensitive for the presence of hypercoaguable state.

     2. However, not specific for PE. It can be DVT for example.

     3. So, a negative test will definitely rule out PE/DVT. On the hand, a positive test is not confirmatory for PE.

   • Lower limb Doppler: to identify the source of the emboli.

     1. Because most of the pulmonary emboli originate from DVTs.

   • Spiral CT scan/ CT Angiogram: (VQ scan is not done nowadays):

     1. It is the standard of care in term of confirming the diagnosis of PE.

   • V/Q scan is first initial test to confirm PE only in cases of pregnancy.

   • Pulmonary angiography is the gold standard test for diagnosis, however, it is not done anymore due to the invasiveness and complications of the procedure.

   • In summary for diagnosis:

     1. CXR, ECG, and ABGs are the best initial tests for a patient presenting with the symptoms we mentioned before.

     2. Pulmonary angiography is the gold standard test for confirming the diagnosis; however, it is not used any more due to the fatality of the procedure.

     3. Instead, spiral CT/ CT angiogram is the considered the best next step after the initial tests.
         

4. What is the most appropriate treatment for this patient?

   1. Heparin is the best initial therapy for PE.

   2. And at the same time you should start Warfarin in order to achieve an INR 2-3 as soon as possible because the cornerstone of PE management is long-term anticoagulation therapy.

   3. Anticoagulant therapy should be between 6-9 months.
       

5. When should you consider inferior vena cava (IVC) filter as part of your management plan?

   1. If there is any contraindication for anticoagulants e.g.: melena, or any CNS bleeding.

   2. Or the patient is having recurrent episodes of PE while on heparin or in the fully therapeutic INR of Warfarin.

   3. Or the presence of the right ventricular dysfunction with evidence of enlarged right ventricle on echo.
       

6. When should you consider thrombolytic therapy as a treatment for a PE patient?

   1. Only if the patient is hemodynamically unstable (low SBP<90mmHg), and in cases of acute right ventricular dysfunction. 

 

 

In summary:

1. We have a 55 years old female patient presented with the classical symptoms & signs of PE which include acute onset of dyspnea, acute onset of dyspnea, pleuritic chest pain, hypoxia, hemoptysis, low-grade fever, and tachycardia.

2. This patient has two important risk factors which are hormone replacement therapy, and the fact of having a recent major surgery and not compliant to the prescribed physical therapy sessions.

3. ECG, CXR, ABGs are best initial test to perform in such patient, and spiral CT/ CT angiogram is the best test to confirm your diagnosis of PE.

4. The management plan will be heparin and warfarin as the patient doesn’t have any apparent contraindications and she is hemodynamically stable.