A 58-year-old man was skiing while vacationing in Utah when he fell forward over his skis and injured his right calf. Immediately following the injury, he sought care at a local emergency department (ED); while no imaging studies were obtained, he was diagnosed with a calf strain and instructed to follow-up with his primary care provider upon returning to the East Coast.
Back home and 1 wk since the injury, the patient presented to the sports medicine clinic where he described a change in the quality and location of his calf symptoms. He complained of nonradiating mid-to-proximal calf pain that was exacerbated by walking and ascending stairs. He denied any weakness, numbness, tingling, chest pain, fever, chills, or shortness of breath.
On examination, trace edema was subjectively noted in the right calf compared with the left calf, though both measured equal in circumference. The medial aspect of the midcalf and the medial head of the gastrocnemius muscle were tender to palpation with no palpable cords. There were no sensation, strength, range of motion, or distal pulse deficits.
Musculoskeletal point-of-care ultrasound (MSK POCUS) of the right lower extremity (LE) performed by the sports medicine fellow revealed numerous large noncompressible gastrocnemius veins (deep veins of the muscle distal to the popliteal vein) filled with hyperechoic debris and lacking flow on color Doppler (Fig). The gastrocnemius and soleus appeared intact without any evidence of tear, discontinuity, or hematoma; muscle tissue maintained normal “starry night” and “feathered” appearance in short and long axes, respectively. The patient was then referred for formal vascular studies after coordination with the ED to expedite workup and treatment. At that point, he was diagnosed with a right calf deep vein thrombosis (DVT) on formal LE Doppler and started on anticoagulation.
In the above case, MSK POCUS for a calf injury yielded an alternate diagnosis. While the provider in this case considered DVT prior to scanning due to the patient’s recent travel, relative immobilization due to injury, and evolution of symptoms, there also were findings that made DVT less likely: minimal calf swelling, no palpable cords, and low Wells Score (−1) (1). In this case, the noncompressible venous structures in the calf containing obvious debris, most likely representing a clot, made the diagnosis of DVT highly probable; these findings overrode the Wells Score and other examination findings for this clinician's decision making; without POCUS, the proper diagnosis of DVT would have been delayed in this patient.
In the ambulatory setting, is the identification of a noncompressible LE vein or lack of blood flow by point-of-care Doppler ultrasound sufficient to diagnose and begin treatment for a DVT?
For a provider without formal vascular training, the answer is no. Currently, the standard for diagnosing LE DVT is formal LE Doppler examination to reveal noncompressible veins or lack of color flow (2,3). The American Medical Society for Sports Medicine's recommended ultrasound (US) curriculum for sports medicine fellowships does not include assessment for or diagnosis of DVT (4); as such, it is likely that many fellowships do not impart this skill formally to their graduates. As a result, providers without formal training and comfort in assessing for LE DVT should send such patients for same-day formal radiologic confirmation (5). If a formal study cannot be performed within 24 h and a patient is suspected of having a DVT, the American College of Chest Physicians recommends starting patients on anticoagulation, even in low-risk patients, until a formal US can be performed (2).
Although the standard of care is to obtain a LE Doppler examination for a suspected DVT, there is still a lack of consensus on which LE US protocol should be performed. For example, in 2016, the American Academy of Family Physicians created a recommended training guideline for POCUS for family medicine residents. These guidelines state that for a low-risk patient (per Wells Score), two-zone discrimination compression (proximal femoral and popliteal vein zones) should be performed, as opposed to complete compression of the LE from the popliteal to the common femoral vein (6). Alternatively, the Society of Radiologists in Ultrasound recommends a complete duplex ultrasound (CDUS) for diagnosis of acute DVT. This consists of compression of the deep veins in the LE from the inguinal ligament to the ankle with left and right common femoral vein and popliteal spectral Doppler waveforms and color Doppler. If a CDUS is not available in a timely manner, compression US from the thigh to the knee can be performed with CDUS follow-up, if negative, within 5 d to 7 d (3).
Of note, in this patient, a two-point compression US would have missed his distal DVT. Although distal LE DVTs are usually self-limited with a low-risk of embolization, approximately 20% do progress to proximal DVTs, which then carries an increased risk for pulmonary embolization (7).
In sum, current standard of care dictates that unless otherwise formally trained, noncompressible veins found on MSK POCUS require formal assessment for confirmation and appropriate treatment; in situations of suspected DVT such as that encountered in the described case, sports medicine physicians with formal training in formal LE Doppler examinations could expedite definitive diagnosis by performing the evaluation themselves.
The authors declare no conflict of interest and do not have any financial disclosures.
1. Modi S, Deisler R, Gozel K, et al. Wells criteria for DVT is a reliable clinical tool to assess the risk of deep venous thrombosis in trauma patients. World J. Emerg. Surg
. 2016; 11:24.
2. Bornemann P, Jayasekera N, Bergman K, et al. Point-of-care ultrasound: coming soon to primary care? J. Fam. Pract
. 2018; 67:70–80.
3. Needleman L, Cronan JJ, Lilly MP, et al. Ultrasound for lower extremity deep venous thrombosis: multidisciplinary recommendations from the Society of Radiologists in Ultrasound Consensus Conference. Circulation
. 2018; 137:1505–15.
4. Finnoff JT, Berkoff D, Brennan F, et al. American Medical Society for Sports Medicine (AMSSM) recommended sports ultrasound curriculum for sports medicine fellowships. PM R
. 2015; 7:e1–11.
5. Jacobson JA, Berkoff D, Brennan F, et al. AIUM practice parameter for the performance of a musculoskeletal ultrasound examination. 2017. [cited 2020 March 16]. Available from: www.aium.org/resources/guidelines/musculoskeletal.pdf
6. American Academy of Family Physicians. Recommended Curriculum Guidelines for Family Medicine Residents Point of Care Ultrasound AAFP Reprint No. 290D. 2016. [cited 2020 March 16]. Available from: www.aafp.org/dam/AAFP/documents/medical_education_residency/program_directors/Reprint290D_POCUS.pdf
7. Philbrick JT, Becker DM. Calf deep venous thrombosis. A wolf in sheep's clothing? Arch. Intern. Med
. 1988; 148:2131–8.