Painful Spasms and a Cognitive Bias

1University of California, San Francisco, San Francisco, CA

Meeting: Hospital Medicine 2014, March 24-27, Las Vegas, Nev.

Abstract number: 281

Case Presentation:

A 14‐year‐old boy with athetoid cerebral palsy (CP) and spastic quadriplegia presented with intractable pain and spasms. Four weeks prior to his presentation, he had a right proximal femoral resection for hip pain and stiffness from subluxation. He was discharged home on postoperative day four. During the next two weeks, he was readmitted twice for painful right lower extremity spasms. The spasms were rhythmic, lasted several minutes to hours, and were occasionally relieved with intravenous lorazepam and morphine in addition to his baseline spasticity regimen consisting of diazepam, cyclobenzaprine, and baclofen. He additionally demonstrated tachycardia to the 150s, mild swelling of his right thigh, and a fluctuating hemoglobin between 7 and 8. These signs were attributed to a postoperative state, and he continued to receive symptomatic management. On postoperative day 32, he acutely developed worsening pain, thigh swelling, and a decrease in hemoglobin to 4.7. An ultrasound revealed a 22‐centimeter thigh hematoma surrounding a 4‐centimeter pseudoaneurysm of the proximal profunda femoris artery. Computed tomography angiography demonstrated active extravasation adjacent to the edge of the remaining femur. He was taken to the operating room for a repair of his artery and a two‐liter hematoma evacuation. He remained stable postoperatively. His spasms resolved, and he was discharged home.


CP is the most common motor disability in childhood and a disorder frequently encountered by pediatric hospitalists. Spastic CP is the most common type of CP, affecting approximately 80% of people with CP. His postoperative muscle spasms likely disrupted his surgical repair, which enabled the sharp edges of his femoral stump to mechanically damage the adjacent artery. The pseudoaneurysm grew over time, as did the extravasated blood, causing more pain and spasms. In the setting of his multiple admissions and ongoing pain and spasms, the pseudoaneurysm was a missed diagnosis. It came to attention only after it ruptured and caused a clinically obvious hematoma. Anchoring bias — locking on a diagnosis and failing to adjust to new information — contributed to this diagnostic error. His spasms were attributed solely to his underlying spasticity disorder. Despite subsequent information that these spasms were more severe and less responsive to therapy than his baseline spasticity, the differential was not broadened to include specific surgical complications.


Despite the unusual occurrence of a pseudoaneurysm following proximal femoral resection (this is the first documented case), the lessons learned are universal. While spasticity is a common presentation of patients with CP, spasms may represent a physiologically independent entity. Postoperative pain and swelling may trigger spasms, which can subsequently lead to complications of their own. Clinicians should be aware of anchoring bias, which can contribute to diagnostic errors.

To cite this abstract:

Rosenthal J, Suarez D, Ward D, Monash B. Painful Spasms and a Cognitive Bias. Abstract published at Hospital Medicine 2014, March 24-27, Las Vegas, Nev. Abstract 281. Journal of Hospital Medicine. 2014; 9 (suppl 2). Accessed April 1, 2020.

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