Ultrasonographic diagnosis of septic arthritis secondary to porcupine quill migration in a dog

A 7-year-old 45-kg (99-lb) castrated male German Shepherd Dog was referred to the Ontario Veterinary College (OVC) at the University of Guelph because of lethargy, icterus, and sepsis.One month prior to referral, 15 porcupine quills had been removed from the dog' s face.Right forelimb lameness developed 2 days after removal of the quills.Examination of the dog by the referring veterinarian revealed swelling in the region of the right elbow joint and proximal portion of the antebrachium.The dog was treated with enrofloxacin a (3.3 mg/kg [1.5 mg/lb], PO, q 12 h) for 7 days without improvement.Two weeks after the quill incident, radiography revealed soft tissue swelling and joint effusion of the right elbow joint (Fig 1).Meloxicam b was administered (0.1 mg/kg [0.05 mg/lb], PO, q 24 h) for 7 days with no improvement of the dog's lameness.Arthrocentesis of the right elbow joint was performed 3 weeks after removal of the quills by the referring veterinarian and yielded a large quantity of cloudy synovial fluid.Cytologic evaluation of the synovial fluid confirmed suppurative synovitis compatible with sepsis, but no bacteria were identified.A CBC revealed mild nonregenerative anemia (Hct, 36%; reference range, 37% to 55%) and mild thrombocytopenia (154 X 10 9 platelets/L; reference range, 200 to 500 X 10 9 platelets/L).Bacteriologic culture of the synovial fluid yielded growth of Staphylococcus aureus; results of antimicrobial susceptibility test-ing indicated that this organism was resistant to penicillin.A diagnosis of septic arthritis of the right elbow joint was made.Treatment with amoxicillin and clavulanate potassium c (14 mg/kg [6.4 mg/lb], PO, q 12 h) was initiated.Despite antimicrobial treatment, the dog' s lameness continued to progress.One month after removal of the quills, the dog was evaluated by the referring veterinarian because of anorexia and lethargy.Physical examination revealed that the dog was approximately 7% dehydrated, icteric, and had developed a heart murmur.Hematologic and serum biochemical analyses revealed a PCV at the high end of the reference range (0.50 L/L; reference range, 0.37 to 0.54 L/L) and high total solids (80 g/L; reference range, 55 to 75 g/L), high serum urea (27.8 mmol/L; reference range, 2.5 to 8.9 mmol/L), and high creatinine (282 µmol/L; reference range, 27 to 124 µmol/L) concentrations indicative of dehydration and prerenal azotemia.Blood glucose concentration was 4.1 mmol/L (74 mg/dL; reference range, 3.3 to 6.1 mmol/L [59 to 110 mg/dL]).The activated clotting time was prolonged at 170 seconds (reference range, 90 to 120 seconds).Fluids, enrofloxacin a (6.6 mg/kg [3 mg/lb], q 24 h), ampicillin d (11 mg/kg [5 mg/lb], q 8 h), and ranitidine e (0.5 mg/kg [0.23 mg/lb],