Clinical Assistant Professor Stanford Palo Alto, California, United States
Case Diagnosis: This is the first reported case of bilateral hip heterotopic ossification (HO) in neuroinvasive West Nile Virus associated with Guiillan-Barre Syndrome (GBS).
Case Description: A healthy 58-year-old male developed fevers and rapidly progressive ascending paralysis while traveling in France in August. He was diagnosed with GBS and eventually found to be positive for WNV. After a complicated 7 week hospital stay, he completed 6 weeks of acute rehabilitation.
Six months after symptom onset, he presented to our PM&R clinic with presumed spasticity non-responsive to Baclofen. His exam was notable for tightness and decreased range of motion in his bilateral hip flexors/adductors and knee flexors, with absent reflexes. His restricted range of motion severely interfered with his ambulation and sitting positioning. Hip radiographs showed extensive bilateral Brooker grade IV HO, and triple phase bone scan demonstrated osteogenically active HO surrounding the proximal femoral head and neck bilaterally.
After neurology consultation, the patient was deemed to have suffered from neuroinvasive WNV with a resultant inflammatory polyradiculopathy, mild thoracic myelitis with residual spasticity, and bilateral hip HO.
Discussions: While HO is an established sequelae of spinal cord injury, traumatic brain injury, burns, and total hip arthroplasty, its prevalence in other neurologic conditions is less well known. It’s estimated that HO at the hip may occur in up to 6% of patients admitted to acute rehab with GBS. To our knowledge, HO has never previously been reported in a case of neuroinvasive WNV.
Conclusions: This case highlights the importance of considering HO in patients with WNV, as this patient had already developed significantly decreased hip range of motion and functional limitations by the time of diagnosis.