A Rare Consequence of Digital Isolation: Bilateral Femoral Neck Fractures Induced by Hypocalcemic Seizure in a Hikikomori Adolescent

Prolonged social withdrawal, conceptualized as Hikikomori, is increasingly recognized for its potential impact on physical health in adolescents because of profound lifestyle alterations. This report describes the case of a 16-year-old male patient who sustained bilateral femoral neck fractures following a hypocalcemic seizure, potentially associated with prolonged indoor confinement and lack of sunlight exposure. The patient presented to the emergency department following a first-time generalized tonic-clonic seizure. Laboratory investigations revealed profound hypocalcemia (5.3 mg/dL), severe vitamin D deficiency (5.7 ng/mL), and secondary hyperparathyroidism (219 pg/mL), leading to a diagnosis of nutritional rickets/osteomalacia. Despite initial metabolic stabilization, persistent hip pain and impaired mobility prompted further imaging. Radiographic and magnetic resonance imaging (MRI) assessments identified bilateral displaced femoral neck fractures. A detailed psychosocial history revealed that the patient had been in a state of severe social withdrawal for the preceding three years, confined to a single room with negligible sunlight exposure. A Hikikomori Questionnaire (HQ-25) score of 70 further characterized the severity of his social isolation. This case illustrates a potential clinical association between Hikikomori behavioral patterns and significant metabolic bone disturbances. Although bilateral femoral neck fractures are a rare complication of convulsive episodes, the underlying skeletal fragility in this patient may have been exacerbated by chronic, isolation-related vitamin D deficiency. This report suggests that extreme social withdrawal should be considered a potential contributing factor in atypical presentations of metabolic bone disease in the modern digital era.