921 - Calf pain: Muscle strain or AVM?

26-year-old patient who was misdiagnosed for several years with a calf strain found to have an arteriovenous malformation (AVM).


Case Description: A 26-year-old female presents with chronic right calf pain. She reports cramping pain whenever her leg hangs off of a bed. Initially evaluated on 4/14/22 for possible trigger point injections on the right calf. In 2017, an orthopedic evaluation diagnosed her with a partially torn calf from extensive running, with physical therapy (PT) proving unhelpful. In 2018, after further evaluation at Wake Forest for the same problem, she was diagnosed with a calf strain and again referred to PT. Point-of-care ultrasound (POCUS) shows a heterogeneous structure in the distal medial gastrocnemius head, with mixed echogenicity and varicosity. MRI reveals an AVM in the right soleus muscle, leading to a referral for embolization.

Discussions: POCUS allows providers to utilize dynamic imaging and easily visualize soft tissue and vascular structures. The patient dealt with chronic right calf pain that was diagnosed as a calf strain by multiple providers without specific diagnostic testing. There may be a component of anchoring bias that carried on to other providers resulting in the same treatment of PT. Anchoring can cause misdiagnoses, delayed treatments, unnecessary procedures, and harm to the patient. If a trigger point injection would have been done blindly without diagnostic confirmation, the patient could have experienced poor outcomes causing more harm. Evidence-based care for calf injuries includes physical exam and ultrasound guided assessment to determine severity of injury or rule out non-muscular etiologies.

Conclusions: Evidence supports a correlation between providers completing their own diagnostic testing and an overall decrease for further workup, harm from unessential procedures, decreased overall healthcare costs, and quicker treatment times. POCUS is a useful tool supporting physical exam findings and has high efficacy in quickly diagnosing various ligamentous, muscular, or vascular injuries.