History

Fact Explanation
Limping or inability to walk Due to pain caused by the underlying inflammatory process of the bone and the marrow, cortex, periosteum and surrounding soft tissues.
Fever Systemic reaction to microbial infection. Illness duration is 2 weeks in acute presentation and up to 3 months in sub acute presentation. [1]
Visible erythema and swelling Due to the underlying inflammation of the long bones. More often seen in legs than arms. [1]
Back pain Manifestation of vertebral osteomyelitis. [1]
Symptoms of vascular insufficiency [2] eg: claudication, rest pain etc. Impaired blood supply makes under perfused tissue susceptible to microbial invasion. [2] Often associated with diabetes mellitus or peripheral vascular disease.
History of trauma Open fractures allow for direct inoculation of microbial organisms in to the bone. [2]
History of diabetes mellitus 15% of patients with diabetic foot ulcer may develop acute osteomyelitis. [2]
Immunocompromised state Hypoxemia, chronic renal or hepatic insufficiency, malignancy, diabetes or use of immunosuppressive medication can hinder the normal immune function and healing. [2]
References
  1. PELTOLA Heikki, PAAKKONEN Markus. New England Journal of Medicine. Massachusetts Society of Medicine. 23 January 2104 vol:370 (4). 352-360 [viewed 5 March 2014] Available from doi:10.1056/NEJMra1213956
  2. Clinical Key. Elsevier [viewed 5 March 2014]. Available from : https://www.clinicalkey.com/topics/orthopedic-surgery/osteomyelitis-in-adults.html#679590

Examination

Fact Explanation
Erythema Caused by underlying inflammatory process.
Focal tenderness Usually inflammation in osteomyelitis is limited to regions of long bone particularly the metaphysis.
Multi-focal tenderness Commonly seen in neonates, where acute hematogenous osteomyelitis can affect multiple foci. [1]
Diabetic foot ulcer Commonly causes osteomyelitis of meta tarsal or tarsal bones. Risk is increased in large (>2cm) in diameter and deep (>3mm) wounds. [1]
Paucity of movements Can be observed in neonates and young children. Due to the pain, movement is avoided in the affected limb.
Edema Due to the underlying inflammatory process.
Features of vascular insufficiency Poorly perfused tissue is more susceptible to microbial invasion.
Surgical scars Orthopedic implants, previous open fractures increase risk of direct inoculation by microbes.
Features of septic arthritis of adjacent joint Usually seen in neonates and young children. Due to spread of metaphyseal infection through the epiphyseal plate. [2]
Pain on Digital Rectal Examination (DRE) Suggestive of sacral osteomyelitis [3]
References
  1. Clinical Key. Elsevier [viewed 5 March 2014]. Available from : https://www.clinicalkey.com/topics/orthopedic-surgery/osteomyelitis-in-adults.html#679590
  2. ABUAMARA S, LOUIS JS, GUYARD MF, BARBIER-FREBOURG N, LECHEVELLIER J. Osteoarticular infection in children: evaluation of a diagnostic and management protocol. Rev Chir Orthop Reparatrice Appar Mot. December 2004, vol.90(8) 703-13 [viewed 5 March 2014]. Available from : http://www.ncbi.nlm.nih.gov/pubmed/15711488 [PMID 15711488]
  3. PELTOLA Heikki, PAAKKONEN Markus. New England Journal of Medicine. Massachusetts Society of Medicine. 23 January 2104 vol:370 (4). 352-360 [viewed 5 March 2014] Available from doi:10.1056/NEJMra1213956

Differential Diagnoses

Fact Explanation
Cellulitis [1] A soft tissue infection caused by Streptococcus pyogenes, will cause similar features of inflammation.
Trauma [1] A soft tissue injury or fracture may mimic acute osteomyelitis as it also causes pain and loss function of the limb.
Septic arthritis [1] Also causes loss of function, pain, swelling and erythema. May co-exist with osteomyelitis.
Gout [1] Acute onset sudden pain. Classically affects the first metatarso phalangeal joint. Usually seen in obese middle aged men and often follows a bout of heavy drinking.
Spinal cord neoplasm [1] Also gives rise to back pain, but is usually accompanied by sensory, motor or autonomic symptoms.
References
  1. HATZENBEUHLER J, PULLING TJ. Diagnosis and management of osteomyelitis. American Family Physician. American Academy of Family Physicians. 1 November 2011. vol 84(9) 1027-1033 [viewed 5 March 2014]. Available from: http://www.aafp.org/afp/2011/1101/p1027.html

Investigations - for Diagnosis

Fact Explanation
Blood culture and antibiogram [1] Determination of the causal organism is vital in diagnosis and in further management. Many organisms have been implicated in the etiology of osteomyelitis but Staphylococcus aureus is the most commonly isolated organism. Exclusion of MRSA (Methicillin resistant Staphylococcus aureus) by performing an antibiogram is important in subsequent choice of antibiotics. [2]
Bone Biopsy Blood cultures are usually only positive in 50 percent of patients. A bone biopsy allows for direct aspiration of the sequestrum to obtain samples of microbial pathogens. Should be performed through uninfected skin, it is indicated if cultures are persistently negative with a high clinical suspicion of osteomyelitis.
C Reactive Protein (CRP) Always elevated; a normal CRP effectively rules out acute osteomyelitis. [1]
Complete Blood Count (CBC) Shows a neutrophil leucocytosis with increased left shift. Characteristic of bacterial infection.
Plain X-Ray Useful in ruling out other possible pathologies such as osteoporotic fractures. Shows changes two weeks after onset of osteomyelitis, when half of the bone mineral content has been lost. [1] Shows a periostial (concentric ring pattern) reaction and osteolysis.
Magnetic Resonance Imaging (MRI) Shows changes within 3 to 5 days. [1]
Technetium 99 bone scintigraphy Positive within days of onset of osteomyelitis. Sensitivity is comparable to MRI but specificity is poor. [1]
References
  1. HATZENBEUHLER J, PULLING TJ. Diagnosis and management of osteomyelitis. American Family Physician. American Academy of Family Physicians. 1 November 2011. vol 84(9) 1027-1033 [viewed 5 March 2014]. Available from: http://www.aafp.org/afp/2011/1101/p1027.html
  2. PELTOLA Heikki, PAAKKONEN Markus. New England Journal of Medicine. Massachusetts Society of Medicine. 23 January 2104 vol:370 (4). 352-360 [viewed 5 March 2014] Available from doi:10.1056/NEJMra1213956

Investigations - Followup

Fact Explanation
C Reactive Protein (CRP) To monitor response to antibiotics. Declining levels of CRP usually suggest a favorable response to treatment, even if the fever doesn't subside. [1]
References
  1. PELTOLA Heikki, PAAKKONEN Markus. New England Journal of Medicine. Massachusetts Society of Medicine. 23 January 2104 vol:370 (4). 352-360 [viewed 5 March 2014] Available from doi:10.1056/NEJMra1213956

Investigations - Screening/Staging

Fact Explanation
Magnetic Resonance Imaging (MRI) Osteomyelitis is staged based on degree of infiltration into the bone. [1] Stage 1: medullary osteomyelitis Stage 2: superficial osteomyelitis Involves the cortex Stage 3: localized osteomyelitis Stage 4: diffuse osteomyelitis extensive disease
References
  1. Clinical Key. Elsevier [viewed 5 March 2014]. Available from : https://www.clinicalkey.com/topics/orthopedic-surgery/osteomyelitis-in-adults.html#679590

Management - General Measures

Fact Explanation
Analgesia Extremely painful, adequate pain relief is indicated. Can be achieved with pharmacotherapy (Coxibs, NSAIDS or opioids) or splinting of the affected limb. [1]
Anti pyretic medication Symptomatic treatment of fever.
Nutrition Ensure adequate nutrition and hydration as osteomyelitis causes a loss appetite due to the systemic reaction to infection.
References
  1. RAO N, ZIRAN BH, LIPSKY BA. Treating osteomyelitis: antibiotics and surgery. Plastic Reconstructive Surgery. January 2011. vol 127(1).177S-187S[viewed 5 March 2014]. Available at doi: 10.1097/PRS.0b013e3182001f0f

Management - Specific Treatments

Fact Explanation
Emprical parenteral antibiotics Instituted empirically on clinical suspicion. [1] Frequent and large doses are used in order to achieve penetration into the bone. Usually first generation cephalosporins, anti staphylococcal penicillins are used. Clindamycin or Vancomycin is indicated where there is >10% prevalence of MRSA in the community. [1] Alternatively ampicillin should be first line in children who have not been vaccinated for H.influenzae type b.
Parenteral antibiotics guided by culture and antibiogram Should be guided by the results of microbiological cultures. Parenteral therapy is continued until the patient improves clinically and CRP normalizes. However uncomplicated cases may require parenteral antibiotics for only a week and subsequent treatment is continued with oral antibiotics. [1]
Oral antibiotics Oral antibiotics are used once patients improve clinically and the CRP normalizes. Most cases benefit from a 20 day regimen of antibiotics provided that clinical response is good and the CRP normalizes within 7 to 10 days. [2] However in acute MRSA infection treatment for 4 to 6 weeks is recommended. [3] Shorter regimens are advocated to reduce healthcare expenditure though many clinicians prefer the traditional six week regimen.
Surgical debridement Indicated when a patient fails to improve following parenteral antibiotic therapy for 48 hours. Drainage of pus and excision of non viable tissue is performed. [4]
Ilizarov method If surgical debridement is performed and a large section of bone is removed it is possible to promote bone growth through distraction osteogenesis using a specialized device.
Bone graft Vascularized bone grafts retain their intrinsic blood supply and enable the surgeon to achieve sound bony union irrespective of the length of the bone defect that occurs due to debridement and suppuration. [5]
References
  1. PELTOLA Heikki, PAAKKONEN Markus. Acute Osteomyelitis in Children. New England Journal of Medicine. Massachusetts Society of Medicine. 23 January 2104 vol:370 (4). 352-360 [viewed 5 March 2014] Available from doi:10.1056/NEJMra1213956
  2. PELTOLA H, PAAKKONEN M, KALLIO P, KALLIO MJ. Short- versus long-term antimicrobial treatment for acute hematogenous osteomyelitis of childhood: prospective, randomized trial on 131 culture-positive cases. Paediatric Infectious Diseases Journal. 29 December 2010 vol:29(12).1123-8 [viewed March 5 2014]. Available from doi: 10.1097/INF.0b013e3181f55a89
  3. LIU C, BAYER A, COSGROVE SE, et al. Clinical practice guidelines by the Infectious Diseases Society of America for the treatment of methicillin-resistant Staphylococcus aureus infections in adults and children. Clinical Infectious Diseases. Oxford Journals. 1 February 2011 vol:52(3) e18-e55 [viewed March 5 2014]. Available from doi: 10.1093/cid/ciq146.
  4. COLE WG, DALZIEL RE, LEITL S. Treatment of acute osteomyelitis in childhood. Journal of Bone and Joint Surgery (British volume). April 1982 vol: 64-B(2) 218-223. [viewed March 5 2014]. Available from: http://www.bjj.boneandjoint.org.uk/content/64-B/2/218.short
  5. DINH Paul , HUTCHISON BK, STEVANOVIC MV. Reconstruction of Osteomyelitis Defects. Seminars in Plastic Surgery,Thieme Medical Publishers.May 2009 vol: 23(2): 108–118. [viewed March 5 2014]. Available from doi: 10.1055/s-0029-1214163