Ms. Smith is a 52-year-old woman 6 weeks status post knee replacement surgery presenting to the ED following two episodes of sharp chest pain lasting 5-10 minutes and accompanied by dyspnea.
Vitals
Her vital signs are reassuring. Temperature and blood pressure are within normal limits; pulse and respiratory rate are mildly increased; oxygen saturation is on the lower end of normal. While her symptoms warrant urgent workup, she is hemodynamically stable and you should proceed with a history and physical exam.
History of Present Illness
Important clues:
Ms. Smith recently had knee replacement surgery, and, subsequently, immobility in her postoperative period. She endorses shortness of breath; sharp, left-sided pleuritic chest pain, unrelieved by rest; and acute-onset lower extremity swelling and pain.
Ms. Smith, a 52 year old woman, goes to the Emergency Department because she felt a sharp pain in her chest while she was at work. She has been working as a manager at a hair salon in the mall for the past 6 years. She was admitted about 6 weeks ago for a left knee replacement. She had to go back to work after the knee surgery sooner than expected. Today she has been having trouble moving around because she is easily fatigued. She was able to keep up despite the fatigue until about an hour into the job, when she suddenly started feeling sharp, 5/10 pain on the left side of her chest. She tried sitting and resting without much relief. The pain worsens when she takes a deep breath. Her discomfort was accompanied by shortness of breath, but she has had no sweating, nausea, or vomiting.
The first episode of chest pain occurred when she was cooking dinner yesterday. The pain lasted for approximately 5-10 minutes and disappeared. She sat down for a while and felt better so did not think much more about it. Since that episode of chest pain, this is the first time she has experienced similar pain. At no time has she attempted any specific measures to relieve her pain, other than rest. She becomes short of breath during these episodes, but describes no other exertional dyspnea , orthopnea, or nocturnal dyspnea. Otherwise, she describes no other associated symptoms during these episodes of pain, including dizziness, nausea, diaphoresis, or palpitations.
She thought the recovery from the knee surgery was going well. The swelling in her knee and leg had gotten much better, the pain was almost gone, and she has been working hard at physical therapy to increase her range of motion. However, since she’s had to start working again, she hasn’t been keeping up with PT as well. She also noticed the swelling getting worse.
This presentation is concerning for provoked acute deep vein thrombosis (DVT) causing a pulmonary embolism (PE). A provoked DVT is associated with a clear inciting risk factor (immobility following surgery in this case), whereas an unprovoked DVT occurs without any known precipitating factors. Other risk factors for provoked thrombosis include trauma, smoking, malignancy, and use of oral contraceptives. The clinical presentation can be scored using the Wells’ criteria* to give a pre-test probability for risk of DVT. A score of 3 or higher suggests that DVT is likely. In this case, Ms. Smith has a Wells’ score of 3 (+1 each for: major surgery within 12 weeks of presentation, left leg swelling, and left leg swelling of 3 cm greater than right).
* Please note that there is also a separate Wells’ criteria for PE, with different scoring.
Review of Systems
| General | No fever, chills, or sweats. No nausea, vomiting or sweating during incident. Acute-onset leg swelling and pain; some spider veins on left leg. |
| Vision | No changes in vision. |
| Head and Neck | No headaches. |
| Pulmonary | No other exertional dyspnea, orthopnea, paroxysmal nocturnal dyspnea. No sputum production. No hemoptysis. |
| Cardiovascular | No dizziness or palpitations. |
| Gastrointestinal | No changes in stool pattern, consistency, or color. |
| Genitourinary | No dysuria, nocturia, polyuria, hematuria, or vaginal bleeding. |
| Neurological | No weakness, numbness, or incoordination. No complaints of dysphagia. |
| Musculoskeletal | Feeling weak recently. No left arm pain or radiation. |
Medications and Supplements
| Medication | Dosage |
|---|---|
| Enoxaparin | 40 mg twice daily for 2 weeks after surgery (patient no longer taking) |
| Ibuprofen | 800 mg every 8 hours as needed for post-op pain (patient no longer taking as of 2 weeks ago) |
| Over-the-counter multivitamin | Daily |
| Over-the-counter Tums | As needed for heartburn |
Past Medical History
| Medical History | None |
| Surgeries |
Left knee replacement six weeks ago. She took her prescribed post-op DVT prophylaxis. The patient was prescribed appropriate prophalaxis against venous thromboembolism. It is common practice to provide preventative therapy following Orthopedic surgery. While this reduces the risk of VTE it does not eliminate it. |
| Hospitalizations | Once for knee replacement surgery. Preoperative labs including BMP and CBC were normal. |
| Allergies | No known drug allergies. |
| Screening Tests |
Normal colonoscopy at age 50, normal pap screen at age 52, and normal mammography at age 52. Malignancy is a significant risk factor for thrombosis. |
| Immunizations | Up to date per patient. |
| Last Contact | 2 months ago for pre-operative evaluation. |
The HPI and ROS strongly suggest an initial diagnosis, but it’s important to review the rest of the history, as there is information found here that could change our diagnostic strategy.
Family History
| Relation | Notes |
|---|---|
| Father | Passed away at 62 due to coronary artery disease. |
| Mother | Currently 75 years old and healthy. |
| Grandmother | 87 years old and had a hip surgery three years ago. |
| Siblings | 49-year-old brother who is in good health. |
| Children |
Two adult children. Both healthy. Both deliveries were vaginal and normal. No spontaneous abortions. A personal or family history of recurrent spontaneous abortions can be concerning for a clotting disorder. This could trigger additional workup. |
| Other Blood Relatives | None. No family history of sudden death, clotting disorders, or spontaneous abortions. |
Physical Exam
| GEN | Well-nourished female appearing stated age. |
| HEENT | Normal. Moist mucus membranes, sclera clear, good dentition. |
| Neck | Normal. Carotid pulses symmetric, no bruits auscultated. No jugular venous distention. No lymphadenopathy. |
| Chest | Clear to auscultation bilaterally. Mild dyspnea. |
| Cardio | Normal S1 and S2. Mild tachycardia. No murmurs, rubs, or gallops. Point of maximal impulse not displaced. |
| Abdomen | Soft, non-tender, non-distended. No organomegaly. |
| Extremities |
Left leg with 2+ pitting edema. Left leg diameter 3 cm larger than right leg. Lower left leg erythematous and warm. TKR incision site is not tender or erythematous. Varicose veins present on left. Right leg with 1+ pitting edema but no erythema or tenderness. The physical exam is strongly suggestive of a DVT in the left lower extremity. The key finding here is unilateral calf swelling and pitting edema. While not described here, the Homan’s sign test is a classic test for DVT, and is positive if the patient experiences calf pain with passive dorsiflexion of the ankle. However, this test has low sensitivity and specificity, and cannot be used alone to make a diagnosis. |
| Neurologic | Alert and oriented x4, cranial nerves 2-12 grossly intact, normal finger to nose, normal tandem gait, normal strength throughout, normal speech. Sensory intact to light touch in bilateral lower extremities. |
What else could be on your differential?
The presentation of a pulmonary embolism (PE) can be quite variable, and as such the differential can be extensive. Based on Ms. Smith’s chest pain and shortness of breath, the etiology is likely cardiovascular or pulmonary. Other than PE, other key diagnoses to consider include:
- Acute coronary syndrome
- Cardiac arrhythmia
- Acute pericarditis
- Heart failure
- Pneumonia
- Pneumothorax
- Pleural effusion
- Asthma or bronchospasm
Ordering Diagnostics
| Order Name |
|---|
Lab Results
| Lab | Patient Value | Normal Range |
|---|---|---|
|
BMP: Calcium |
Sodium: 139 mmol/L Potassium: 4.9 mmol/L Chloride: 103 mmol/L Bicarbonate: 27 mmol/L BUN: 18 mg/dL Creatinine: 1.0 mg/dL Glucose: 89 mg/dL Calcium: 8.9 mg/dL |
Sodium: 136-145 mmol/L Potassium: 3.5-5.1 mmol/L Chloride: 98-107 mmol/L Bicarbonate: 22-29 mmol/L BUN: 6-20 mg/dL Creatinine: 0.67-1.17 mg/dL Glucose: 70-99 mg/dL Calcium: 8.5-10.6 mg/dL |
|
Complete Blood Count (CBC) |
WBC: 8.7 thousand/mm3 Hemoglobin: 14.1 g/dL Hematocrit: 42.5% Platelets: 298 thousand/mm3 |
WBC: 4-10 thousand/mm3 Hemoglobin: 13.2-16.6 g/dL for men, 11.6-15 g/dL for women Hematocrit: 41-50% for men, 36-44% for women Platelets: 140-370 thousand/mm3 |
|
CBC Differential |
WBC: 8.7 thousand/mm3 Hemoglobin: 14.1 g/dL Hematocrit: 42.5% Platelets: 298 thousand/mm3 Neutrophils: 66% Lymphocytes: 28% Monocytes – 3% Eosinophils – 2% Basophils – 1% |
WBC: 4-10 thousand/mm3 Hemoglobin: 13.2-16.6 g/dL for men, 11.6-15 g/dL for women Hematocrit: 41-50% for men, 36-44% for women Platelets: 140-370 thousand/mm3 Neutrophils: 40-60% Lymphocytes: 20-40% Monocytes: 2-8% Eosinophils: 1-4% Basophils: 0.5-1% |
|
Comprehensive Metabolic Panel (CMP) A CMP will give you the same information as a BMP, but also includes liver function tests. This may be useful if there is concern for liver pathology, but in this case the BMP is adequate (and less expensive). |
Sodium: 139 mmol/L Potassium: 4.9 mmol/L Chloride: 103 mmol/L Bicarbonate: 27 mmol/L BUN: 18 mg/dL Creatinine: 1.0 mg/dL Glucose: 89 mg/dL Calcium: 8.9 mg/dL AST: 22 U/L ALT: 38 U/L Alkaline phosphatase: 88 U/L Total bilirubin: 0.4 mg/dL Total protein: 7.7 g/dL Albumin: 3.8 g/dL |
Sodium: 136-145 mmol/L Potassium: 3.5-5.1 mmol/L Chloride: 98-107 mmol/L Bicarbonate: 22-29 mmol/L BUN: 6-20 mg/dL Creatinine: 0.67-1.17 mg/dL Glucose: 70-99 mg/dL Calcium: 8.5-10.6 mg/dL AST: 0-40 U/L ALT: 0-41 U/L Alkaline phosphatase: 40-129 U/L Total bilirubin: <1.2 mg/dL Total protein: 6-8 g/dL Albumin: 3.5-5.2 g/dL |
|
Blood type and screen A CMP will give you the same information as a BMP, but also includes liver function tests. This may be useful if there is concern for liver pathology, but in this case the BMP is adequate (and less expensive). |
O+ (antibody negative) |
N/A |
| PT/INR | PT: 14 seconds INR: 1.0 | PT: 11-13.5 seconds INR: 0.8-1.1 |
| PTT | 25 sec (normal) | PTT: 21-35 seconds |
|
APC resistance screen These are all tests that could be ordered as part of a thrombophilia workup. Several of these tests (ex: protein C, protein S, and ATIII activity) are inherently abnormal in the setting of an acute clot, so their diagnostic utility is limited in this setting. There is evidence [link] that testing for inherited thrombophilia does not reduce recurrence of DVTs and PEs. For Ms. Smith in particular, who does not have a history of recurrent thromboses and a clear inciting risk factor for her DVT, ordering extensive thrombophilia testing is a poor use of resources. Even when a diagnostic investigation for thrombophilia is indicated, it is best pursued at the completion of the initial therapy, when the patient is recovered and off anticoagulation. |
Negative | Negative |
| Factor V Leiden | Normal | Normal |
| Factor V Activity | 152% (normal) | 50-200% |
| Antiphospholipid antibody panel | Normal | Normal |
| RVVT | 34 sec (normal) | 30-50 seconds |
| PT G20210A mutation | Negative | Negative |
| Protein C activity | 102% (normal) | 70-150% |
| Protein S level | 98% | 60-150% |
| ATIII activity | 92% | 80-120% |
| MTHFR mutation | Normal | Normal |
| Homocysteine level | 15 micromoles/L | 5-15 micromoles/L |
|
D-dimer D-dimer is an acute-phase reactant, meaning that it is elevated in response to many sources of inflammatory stimuli, including infection, trauma (including surgery), autoimmune disorders, and malignancy. As such, an elevated D-dimer alone is insufficient to make a diagnosis of PE. A normal D-dimer can be used to rule out PE in patients with a low or intermediate probability of PE. For Ms. Smith, who has a clinical presentation highly consistent with PE, a D-dimer would not be useful. A negative result would not be sufficient to rule out the diagnosis of PE. |
6.45 mg/L | <0.5 mg/L |
|
Fibrinogen A fibrinogen test is unlikely to be helpful for diagnosis of PE, as fibrinogen levels could be variable based on a number of factors. Fibrinogen, like D-dimer, is an acute-phase reactant. However, fibrinogen could also be lowered postoperatively as a result of appropriate clot formation during surgical healing. |
322 mg/dL | 200-400 mg/dL |
Imaging Results
| Image | Result |
|---|---|
|
EKG An EKG is essential for ruling out other dangerous conditions—such as ACS—that may resemble the presentation of PE, though it will not confirm a diagnosis of PE. The most common EKG finding in the setting of PE is sinus tachycardia. |
Sinus tachycardia |
|
Chest X-ray A chest X-ray will be unremarkable in the setting of a PE, but is important for ruling out other conditions—such as pneumonia or pneumothorax—that may present similarly to PE. |
Normal |
|
CT pulmonary angiogram A CT pulmonary angiogram is the diagnostic modality of choice when PE is suspected. It would not be appropriate if the clinical suspicion for PE was low, as it would expose the patient to unnecessary radiation. |
Pulmonary embolus in right main pulmonary artery |
|
V/Q scan A V/Q scan is appropriate for diagnosing PE in patients with a contraindication to CT angiogram, such as a severe contrast allergy or high risk of contrast nephropathy. In the absence of a contraindication, however, a CTA is usually preferred for diagnosis (as it is significantly faster to perform and has a higher diagnostic accuracy). |
High probability V/Q scan by PIOPED criteria |
|
Lower extremity ultrasound A lower extremity ultrasound is the standard imaging test for diagnosing DVT. While outside the scope of this case, there are different approaches for ordering a CT angiogram vs. a lower extremity ultrasound to diagnose DVT and PE. Just remember that you could make a case for ordering either test, but you generally would not order both. |
Non-occlusive thrombus in distal femoral vein |
|
Knee X-ray 3 views A knee X-ray would have been appropriate if there were concerns specifically relating to the implant (ex: loosening, misalignment). However, it is not useful in the diagnosis of DVT, and represents a poor use of resources. Additionally, ordering unnecessary testing can lead to delay in making a proper diagnosis. |
Left knee prosthesis in appropriate position, no fracture, normal soft tissue |
How did you do?
You spent a total of $
Those that are absolutely indicated to manage and treat the clinical scenario:
| Labs | Imaging |
|---|---|
| BMP | EKG |
| PT | Chest X-ray |
| PTT | Lower extremity ultrasound |
| CBC | CT pulmonary angiogram |
Those that are not indicated and would not change management but have minimal harm to patient:
| Labs | Imaging |
|---|---|
| Type and screen | Knee X-ray |
| CMP | |
| D-dimer |
Those that should not be done and may harm the patient:
| Labs | Imaging |
|---|---|
| APC resistance screen | V/Q Scan |
| Factor V Leiden | |
| Factor V activity | |
| Antiphospholipid antibody panel | |
| RVVT | |
| PT G20210A mutation | |
| Protein C activity | |
| Protein S level | |
| ATIII activity | |
| MTHFR mutation | |
| Homocysteine level | |
| Fibrinogen |
Takeaways
Venous thromboembolism (VTE)—representing a spectrum of disease from DVT to PE— is a common and potentially dangerous condition that leads to significant morbidity, mortality, and expenditure within our health care system. One study estimates that there are 900,000 cases of PE and DVT per year. In 2012, Medicare paid $6,000 per hospitalization, for a total of almost $250 million dollars. It is important to accurately diagnose and treat this condition while minimizing health care expenditure.
Remember that high-value care means practicing in a manner that is patient-centered and evidence-based, while refraining from using resources in way that is likely to be wasteful or harmful. Of course, we recognize that in a real-world clinical setting, patient presentations and questions around resource utilization are not nearly as clean-cut as displayed here. Patient preferences, goals of care, and unique circumstances must all be accounted for. As such, the goal should not be to exactly match the minimum cost that we’ve provided for each case, but instead to use these cases as an exercise to develop a pattern of thinking about why or why not you would order a given test, procedure, or medication, and what value it is likely to add to your care plan.
Note: Click or hover over the comment boxes or highlighted text to view the full content.
Adapted from case written by Dr. Amit Pahwa and Dr. Danelle Cayea (John Hopkins University School of Medicine). Edited by Michelle Chen, Emma Williams, Nicole Xu, Kiersten Gabaldon, and Dr. Greg Seymann (UC San Diego School of Medicine).
Disclaimer: This case is intended to be used for educational purposes only. Medical science is continuously evolving, and we try to keep up by reviewing our cases on a regular basis. This case was last reviewed August 2024. If you notice an error or inconsistency with current guidelines, please let us know through the feedback function.
T
Temperature is within normal limits.
P
Pulse is mildly increased.
RR
Resiratory rate is mildly increased.
BP
Blood pressure is within normal limits.
O2 Sat
Oxygen saturation is on the lower end of normal.
BMI