5.1. Bone and Soft Tissue Infection - Acute (and Subacute) Osteomyelitis Flashcards
What are the 4 categories of Osteomyelitis?
- Acute (Subacute) Osteomyelitis
- Chronic Osteomyelitis
- Specific Osteomyelitis
- Non-Specifc Osteomyelitis
What are the Risk Factors for having Haematologenous spread of infection, causing Acute Osteomyelitis?
- Children and Elderly
- Boys > Girls
- History of Trauma
- Other Diseases (e.g. Diabetes, Rheumatoid Arthritis, Immune compromise, Long-term Steroid Treatment, Sickle Cell Anaemia)
How does Haematologenous spread, causing Acute Osteomyelitis occur?
Local spread from Contiguous Site of infection:
- Trauma (open fracture)
- Bone Surgery (ORIF)
- Joint Replacement
What are the most common sources of infection, causing Acute Osteomyelitis, in infants?
Infected umbilical cord
What are the most common sources of infection, causing Acute Osteomyelitis, in children?
- Boils (Furunculosis)
- Tonsilitis
- Skin abrasions
What are the most common sources of infection, causing Acute Osteomyelitis, in adults?
- Urinary Tract Infections
2. Arterial Line
What are the most common infective organisms, causing Acute Osteomyelitis, in Infants (<1 year)?
- Staph. Aureus
- Group B Streptococci
- E. Coli
What are the most common infective organisms, causing Acute Osteomyelitis, in Older Children?
- Staph. Aureus
- Strep Pyogenes
- Haemophilus Influenzae
What are the most common infective organisms, causing Acute Osteomyelitis, in Adults?
- Staph. Aureus
- Coagulase Negative Staphylococci
- Propionibacterium spp
- Streptococcus Pyogenes
- Mycobacterium Tuberculosis
- Pseudomonas Aeroginosa
What type of Organism is likely to cause Acute Osteomyelitis, from a Diabetic Foot patient?
Mixed infection including Anaerobes
What type of Organism is likely to cause Acute Osteomyelitis, from a Pressure Sore patient?
Mixed infection
What type of Organism is likely to cause Acute Osteomyelitis, from a Vertebral Osteomyelitis patient?
- Staph. Aureus
2. Tuberculosis
What type of Organism is likely to cause Acute Osteomyelitis, from a Sternal Osteomyelitis patient?
Coagulase Negative Staphylococci (post-cardiac surgery)
What type of Organism is likely to cause Acute Osteomyelitis, from a Sickle-Cell Anaemia patient?
Salmonella Spp
What type of Organism is likely to cause Acute Osteomyelitis, from a Sexually Transmitted Disease patient?
Gonococcus
What is the pathology of Acute Osteomyelitis?
- Trauma causes acute inflammation and vascular stasis
- Pus forms and Bone reformation occurs
- If infection gets into the bone during this time - granulation tissue “walls off” the diseased bone tissue (sequestrum)
- Bacterial proliferation results in further destruction, and abscess formation in the bone
What are the clinical features of Acute Osteomyelitis in an infant?
- Minimal signs / may be very ill
- Failure to thrive
- Drowsy / Irritable
- Metaphyseal tenderness / swelling
- Decreased Range of Movements + positional change
What are the clinical features of Acute Osteomyelitis in a Child?
- Severe pain - reluctance to move / not weight bearing
- Fever (swinging Pyrexia)
- Tachycardia
- Malaise (Fatigue, Nausea, Vomiting)
- Toxaemia
What are the clinical features of Primary Acute Osteomyelitis in an Adult?
This is seen commonly in the Thoracolumbar Spine:
- Fever
- Backache
- History of UTI or Urological procedure
- Old
- Diabetic / Immunocompromised
What are the clinical features of Secondary Acute Osteomyelitis in a Adult?
This is more common the Primary Osetomyelitis - often seen after:
1. An open fracture
2. Surgery
Note - this often contains a mixture of organisms
What Clinical (Blood) Investigations are done to diagnose Acute Osteomyelitis?
- Full Blood Count + Diff. WBC
- Inflammatory markers - ESR + CRP
- 3 x Blood Cultures
- Urea & Electrolytes
What Radiological Investigations are done to diagnose Acute Osteomyelitis?
- X-Ray
- Ultrasound
- Aspiration
- Isotope Bone Scan
- Labelled White Cell Scan
- MRI
What is found on an X-Ray of a suspected Acute Osteomyelitis patient?
- It appears normal in the first 10-14 days
- Late Metaphysial Destruction
- Late Medullary Changes - Lytic Areas
- Late Osteonecrosis - Sequestrum
- Late Periosteal New Bone - Involucrum
How is a Microbiological diagnosis of Acute Osteomyelitis arrived at?
- Blood Cultures
- Bone Biopsy
- Tissue Swabs from up to 5 sites around an implant at debridement in prosthetic infection
What is the differential diagnosis for Acute Osteomyelitis?
- Cellulitis
- Eryipelas
- Necrotising Fasciitis
- Gas Gangrene
- Toxic Shock Syndrome
- Acute Septic Arthritis
- Trauma
- Acute Inflammatory Arthritis
- Transient Synovitis
What is the treatment for Acute Osteomyelitis?
- Analgesia
- Rehydration Therapy
- Rest and Splintage
- I.V. / Oral Antibiotics for 4-6 weeks (Flucloxacillin + Benzylpenicillin until know more specifics)
- Surgery
What are the indications for surgery in Acute Osteomyelitis?
- Abscess drainage
2. Debridement of Dead / Infected / Contaminated Tissue
What are the complications of Acute Osteomyelitis?
- Septicemia, death
- Metastatic Infection
- Pathological Fracture
- Septic Arthritis
- Altered Bone Growth
- Chronic Osteomyelitis
When does Subacute Osteomyelitis occur?
- Increased Host Resistance
- Lowered Bacterial Virulence
- Antibiotic Usage
What are the Clinical Features of Subacute Osteomyelitis?
- Long history (weeks-months)
- Variable Pain / Limp
- Local Swelling / Warmth
- Local Tenderness
What is the Differential Diagnosis for Subacute Osteomyelitis?
- Tumour (Ewing;s Sarcoma, Osteoid Osteoma)
2. Tuberculosis
What is the name of the Abscess which forms during Subacute Osteomyelitis?
Brodie’s Abscess - A well defined cavity in Cancellous Bone
What are the Clinical Features of Subacute Osteomyelitis?
- Painful Limp
- No systemic Features
- Most commonly seen in older children
What is seen on Radiographical Imaging, when Subacute Osteomyelitis is present?
Luency in a Long Bone Metaphysis
What is the treatment of Subacute Osteomyelitis?
- Prolonged course of Antibiotics
2. Surgery - Curettage