Development of Bilateral Heterotopic Ossification After Survival of Life Threatening Purpura Fulminans.

Heterotopic ossification has been reported in patients who have undergone traumatic amputations, burn injuries, and total hip arthroplasty; however, the incidence of heterotopic ossification following purpura fulminans has only been reported in one case with unilateral involvement. Here we present a bilateral lower extremity case of heterotopic ossification as sequelae of purpura fulminans.  A 34-year-old male smoker with a past medical history of stab wounds to the chest and abdomen requiring emergent exploratory laparotomy, diaphragmatic repair, and splenectomy 15 years ago presented to the emergency department with a rapid onset of high fevers, chills and myalgia. He did not receive post-splenectomy prophylactic vaccinations for , , and . The patient presented clinically in septic shock with disseminated intravascular coagulation. The patient was admitted to the Medical Intensive Care Unit and subsequent workup suggested  bacteremia. Over the next 48 hours, the patient developed extensive necrosis of the bilateral upper and lower extremities concerning for purpura fulminans. The decision was made to perform a right transradial forearm amputation as well as bilateral transtibial amputations. He tolerated these procedures and was discharged to an inpatient rehabilitation facility. Approximately four months following his bilateral below knee amputations, the patient had difficulty wearing the prosthetics secondary to pain and eventually discontinued use altogether. At home, he continued to ambulate by bearing weight on his knees while wearing kneepads. He continued to report significant tenderness and pain along the bilaterally, below knee amputation stumps. His physical examination was concerning for significant distal bone formation in his bilateral amputation stump sites without evidence of skin breakdown. Intraoperatively, extensive bony formation was found bilaterally within his soleus muscle flaps, concerning for heterotopic ossification. Postoperatively, the patient was refitted for lower extremity prosthetics.  Similar to burns and trauma, the development of heterotopic ossification in patients with purpura fulminans may be directly related to the inflammatory process and amount of tissue damage. In some cases, heterotopic ossification could be caused from daily living activities, so the timing of diagnostic imaging techniques and clinical intervention is crucial.