P3A358: Painless Presentation of Multiple Fractures in a Child

Introduction: An 8-year-old male presented to the emergency department for left foot swelling. He had a past medical history of right knee fracture seven months prior that required a bone graft, which became infected and required washouts and IV antibiotics. Prior to this fracture, patient was reported as healthy. He had no primary care provider.

Case Description: Regarding the left foot, one week prior to presentation, patient fell after doing a cartwheel, and landed with his left foot inverted. He heard a “pop” but was able to ambulate immediately without pain. There was no obvious injury initially. However, he developed progressive swelling of his left foot, which is why family sought medical attention.

Review of systems was otherwise negative. Exam was remarkable for right knee edema, with healed incision and no tenderness. His left foot was edematous, non-tender to palpation, and with full range of motion. Left foot x-ray revealed fractures involving the 1st-4th metatarsals and medial cuneiform, in various stages of healing. Right knee x-ray showed findings consistent with prior fracture and surgery history. Screening labs were overall unremarkable.

Upon further history, father reported patient had always appeared to not feel pain. Due to his unusual presentation, genetics was consulted, and he was presumptively diagnosed with congenital insensitivity to pain. Patient’s foot was splinted and he was made non-weight bearing.

One week later, patient followed up in Sports Medicine Clinic. His left foot was non-tender, without instability, and had intact strength and sensation to light tactile stimulation. He was placed in a cast and made non-weight bearing.

Three weeks later, patient returned to the emergency department after his cast broke from walking on it. He was now noted to have ulcers on his left 5th toe and knee. Father reported difficulty restricting his activity. He followed up in Orthopedic Clinic and was placed in a walking boot. Social work was consulted to provide resources, he was referred to wound care clinic, and education about nightly skin assessments was provided.

Discussion: Congenital insensitivity to pain is a rare, autosomal recessive disorder characterized by lack of pain perception and presence of abnormal sensory nerves. This is now distinguished from congenital indifference to pain, in which nerve histology is normal and pain is perceived without affective response.

When the mechanism of injury, presentation, and exam do not align, it is important to further investigate why. Differentials to consider for initial presentation included cellulitis, juvenile idiopathic arthritis, malignancy, septic arthritis, osteomyelitis, and abusive trauma.

Conclusion: Patients with congenital insensitivity to pain, or other sensory and autonomic neuropathies, may not present with fractures or typically-painful diagnoses as expected. They may require closer follow up than usual, and more resources during recovery and when well.