LAUSR

A man aged 65 years with a history of polysubstance abuse, currently on 80 mg daily of methadone in addition to ongoing intravenous drug use (IVDU) presents with 1 week of left arm pain. Patient reports gradual onset of swelling, erythema and pain of the left arm that began shortly after ‘muscling’ heroin (injecting heroin into the muscle instead of into a vein) into that site. He denies fever, chills, palpitations, chest pain, shortness of breath or other symptoms on review of systems. Medical history: hepatitis, polysubstance abuse. No surgical history. Home medications: methadone 80 mg daily. No known allergies. ### Triage vital signs BP: 146/84 mm Hg, HR: 77 bpm, temperature: 36.8°C, RR: 18 per min, SpO2: 98%. ### Physical examination Non-toxic male lying in bed comfortably. Exam benign apart from left arm soft tissue exam. Left arm with swelling, erythema and tenderness overlying the lateral bicep. No visible lesion or ulceration. Full range of motion of the shoulder and elbow (figure 1). Figure 1 Left upper extremity examination findings. ### Laboratory data Laboratory data revealed a leucocytosis of 14.6 and elevated lactate of 2.3. The rest of the laboratory values were within normal limits. Figure 2 shows the point-of-care ultrasound (POCUS) in the diagnosis of left upper extremity. Figure 2 Left upper extremity short axis plane. 1. What are the indications for performing a POCUS of the soft tissue? If there is clinical concern based on warmth, erythema, pain, induration or fluctuance, POCUS can aid in the diagnosis of cellulitis and abscess. 2. What clinical questions can be answered when assessing the soft tissue with POCUS ? Are there sonographic findings pointing to cellulitis, abscess, pyomyositis or necrotising …