Last modified on 15 November 2012, at 04:49

Septic arthritis

Septic arthritis in a 6-month-old Labrador Retriever, showing deep bony erosion of the lateral femoral condyle[1]

Septic arthritis is an acute suppurative arthritis of the dog characterised by infection with bacteria, viruses, fungi or other infectious agents.

Septic arthritis occurs with higher frequency in large breed dogs, twice as often in males as in females and there is no age predisposition[2].

It usually appears as an acute onset joint swelling with heat, pain, fever and lameness observed clinically. Depending on the inciting cause, systemic illness may be associated with the condition such as lethargy, toxemia, endocarditis and icterus[3].

Osteomyelitis is a common sequel in the neighboring subchondral bone and marrow[4].

Primary initiation is usually through trauma, penetrating foreign bodies (sticks, awns, quills, etc) or post-operative infections, but hematogenous spread can occur, especially in young, or debilitated dogs. As the disease progresses, the joint space becomes distended with exudate which may be observed radiographically. This is inexorably followed, without intervention, by subluxation, destructive arthritis and vascular compromise to the epiphysis.

Bacteria are commonly involved, including Streptococcus pyogenes[5], Staphylococcus aureus[6], Pasteurella spp[7], Klebsiella spp and Chlamydophila spp[8], but fungi (e.g. Blastomyces dermatitidis[9]), viruses (e.g. canine distemper virus[10]) and even aberrant nematode migrations (Dirofilaria immitis) have been reported[11].

Diagnosis requires aseptic aspiration of joint fluid, which is usually serosanguinous. Cultures are not always rewarding but the presence of toxic, degranulated, or ruptured neutrophils should strongly suggest an infectious etiology[12].

A leucocytosis is usually evident on blood sampling and hematological analysis.

Septic arthritis occurs less frequently than immune-mediated arthritis, but may be difficult to differentiate clinically. Septic arthritis most often affects only one or two joints, while immune-mediated arthritis usually affects many joints[13].

Treatment usually requires arthroscopic[14] or exploratory curettage and lavage of the affected joint, if possible, augmented with parenteral broad-spectrum antimicrobial drugs such as enrofloxacin, clindamycin, amoxycillin/clavulanate or gentamycin.

These infectious should be treated aggressive to eliminate persistent and recurrent infections, thus avoiding permanent lameness, particularly in young dogs.

In most cases, the response to immediate medical and surgical intervention is good, but diminution of full joint function is common[15].

References

  1. Uni of Pennsylvania
  2. Bennett D & May C (1995) Joint diseases of dogs and cats. In: Ettinger SJ, Feldman EC, eds. Textbook of Veterinary Internal Medicine. 4th ed. vol. 2. Philadelphia: WB Saunders. pp:2032-2040
  3. Brisson BA et al (2004) Ultrasonographic diagnosis of septic arthritis secondary to porcupine quill migration in a dog. J Am Vet Med Assoc 224(9):1467-1470
  4. Pratt JN et al (1999) Osteomyelitis of the atlanto-occipital region as a sequela to a pharyngeal stick injury. J Small Anim Pract 40(9):446-448
  5. Hewes CA & Macintire DK (2011) Intra-articular therapy to treat septic arthritis in a dog. J Am Anim Hosp Assoc 47(4):280-284
  6. Owen MR et al (2004) Management of MRSA septic arthritis in a dog using a gentamicin-impregnated collagen sponge. J Small Anim Pract 45(12):609-612
  7. Fearnside SM & Preston CA (2002) Arthroscopic management of septic polyarthritis in a dog. Aust Vet J 80(11):681-683
  8. Lambrechts N et al (1999) Chlamydia-induced septic polyarthritis in a dog. J S Afr Vet Assoc 70(1):40-42
  9. Marcellin-Little DJ et al (1996) Chronic localized osteomyelitis caused by atypical infection with Blastomyces dermatitidis in a dog. J Am Vet Med Assoc 209(11):1877-1879
  10. Bell SC et al (1991) Canine distemper viral antigens and antibodies in dogs with rheumatoid arthritis. Res Vet Sci 50(1):64-68
  11. Hodges S & Rishniw M (2008) Intraarticular Dirofilaria immitis microfilariae in two dogs. Vet Parasitol 152(1-2):167-170
  12. Morrow M (1988) Urinary tract infection as nidus for systemic spread and septic arthritis. Can Vet J 40(9):666-668
  13. Bennett D & Taylor DJ (1988) Bacterial infective arthritis in the dog. J Small Anim Pract 29:207-230
  14. Ridge PA et al (2011) A retrospective study of the rate of postoperative septic arthritis following 353 elective arthroscopies. J Small Anim Pract 52(4):200-202
  15. Clements DN et al (2005) Retrospective study of bacterial infective arthritis in 31 dogs. J Small Anim Pract 46(4):171-176