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723 - Unexpected Growth: A Case Report on a Rare Trigger of Heterotopic Ossification

Friday, February 28, 2025

5:00 PM - 6:30 PM MST

Presenting Author(s)

SS

Semiat O. Shafau, BS

Medical Student
Michigan State University College of Osteopathic Medicine
sterling heights, Michigan, United States
AS

Amaan Sheikh, DO

Resident Physician
Johns Hopkins School of Medicine
Baltimore, Maryland, United States

Co-Author(s)

DK

Daniel Krasna, MD

Assistant Professor
Johns Hopkins University School of Medicine
Baltimore, Maryland, United States
DF

Dorianne Feldman, MD

Physician
Johns Hopkins Univeristy School of Medicine
Baltimore, Maryland, United States

Case Diagnosis: Heterotopic Ossification (HO) Secondary to Malignant Catatonia

Case Description: A 68-year-old male with a history of anxiety and depression was hospitalized in late May due to altered mental status, hypotension, hyperthermia, and respiratory failure. His response to IV dantrolene suggested malignant hyperthermia linked to malignant catatonia. Examination revealed a diffuse, velocity-independent, non-selective increase in muscle tone. He received lorazepam and underwent multiple electroconvulsive therapy sessions. By late July, he showed gradual improvement and was more alert and interactive. However, he remained immobile throughout his hospitalization due to severe catatonia. He was less catatonic by early September. Recurrent fevers prompted an infectious workup, where CT of the abdomen and pelvis incidentally revealed HO adjacent to the left femur. Follow-up x-rays showed HO around both hips and popliteal fossae.

Discussions: HO is the abnormal formation of bone tissue within soft tissues, often as a complication of spinal cord injury, traumatic brain injury, arthroplasty, fractures, and burns. It commonly develops around joints, causing significant pain, restricting movement, and potentially limiting therapy if not identified and managed promptly. This case describes a patient with malignant catatonia who uncharacteristically developed HO, which has not been well reported in such patients. Communication barriers secondary to catatonia delayed the identification of HO. Importantly, the patient had no history of the common causes that would raise suspicion for HO.

Conclusions: This case underscores the need for heightened awareness of HO in atypical presentations. Symptoms of HO are non-specific, making diagnosis difficult. While immobility due to critical illness and dysautonomia in the setting of malignant catatonia likely led to HO, it is salient to remember that aggressive mobilization after extended immobilization may also trigger its development. Early diagnosis and treatment may result in desirable functional outcomes. Our findings emphasize the importance of proactive management of HO to prevent further functional decline and morbidity.