Multimodal imaging characteristics and case management of intraspinal Spirocerca lupi infection in a dog

A 1-year-old female spayed mixed breed dog was ambulatory with paraparesis and proprioceptive ataxia, absent conscious proprioception in pelvic limbs, and spinal pain with a T3-L3 neurolocalization on presentation. Thoracic radiographs revealed caudal mediastinal mass, pneumothorax, and pleural effusion. Magnetic resonance imaging revealed multiple mediastinal masses with vertebral canal extension, extradural compression at T5-T6, intramedullary T2 hyperintensities at T5 and T9, esophageal compression and dilation, and aortic aneurysmal dilation. Transdiaphragmatic ultrasonography was suggestive of parasitic involvement. A right T5-T8 hemilaminectomy and parasitology confirmed Spirocerca lupi. Treatment with ivermectin (400 mcg/kg SC q24h for 3 days followed by once a week for 6 weeks), prednisone (0.7 mg/kg/day), and clindamycin (10.7 mg/kg PO q12h) was initiated. Recovery of independent ambulation occurred 2 months after treatment. Computed tomography revealed resolution of mediastinal and esophageal nodules with progressive aortic aneurysmal dilation. Multimodal imaging was essential for the management of spinal spirocercosis.