L1 Pathology Acute Osteomyelitis (Locomotor System).pdf

Level 2 Semester 3 ▪ Module locomotor system (LOM413)  Lecture Title -Fracture bone -Acute osteomyelitis  Instructor information Dr/ Sarah Nabil Nasif MD Assistant professor of Pathology email: [email protected]  Lecture...

Level 2 Semester 3 ▪ Module locomotor system (LOM413)  Lecture Title -Fracture bone -Acute osteomyelitis  Instructor information Dr/ Sarah Nabil Nasif MD Assistant professor of Pathology email: [email protected]  Lecture Title Fracture bone ILOs by the end of this lecture you will be able to: -classify types of bone fracture -identify causes of bone fracture -discuss pathogenesis of bone healing -identify factors affecting bone healing Types of fracture 1. Simple fracture 2. Comminuted fracture (multiple bone fragments) 3. Compound fracture (open fracture breaking through overlying skin) 4. Pathological fracture(fracture of bone weakened by disease) Causes of fractures Fractures in normal bone are the result of substantial trauma, such as direct violence or a sudden unexpected fall Repeated episodes of minor trauma, for example, after marching, marathon running or training for sport, can produce small but often painful stress fractures Fractures occur more easily in bone that is structurally abnormal ( pathological fractures ) Repair of bone fracture 1- heamatoma 2- inflammation 3- fibrovascular tissue (soft calus) 4-bone formation 5- remodeling Assignment What are the factors which affect bone healing?  Lecture Title Acute osteomyelitis  Case scenario A 11 years old boy , went to orthopedic surgeon complaining of severe pain in his left shin (front of leg). Her mother said he was playing football 6 days ago and his friend hit his shin(leg) during the match, then they went to emergency department and had X-ray which was free from fracture. The physician prescribed to him analgesic only. Now he developed severe pain , swelling, hotness , redness and tenderness maximum on proximal tibia. His temperature is 37.7, C reactive Protein (CRP) is 48mg/L (normal up to 5 ). ESR is 50mm/h in first hour( normal 0- 10). The orthopedic surgeon suspected that the boy has acute hematogenous osteomyelitis and prescribed IV antibiotic and told them if no response he will need surgical drainage. ILOs by the end of this lecture you will be able to: -define osteomyelitis, predisposing factors and causative organisms of pyogenic type -discuss routes of infection, pathogenesis, morphology, diagnosis and complications of acute osteomylitis Osteomyelitis Definition: inflammation of bone and bone marrow Incidence: *In children: long bones are mostly affected *In adults: vertebrae are mostly affected. Classification A-Acute osteomyelitis Acute hematogeous osteomyelitis Acute non hematogeous osteomyelitis B-Chronic osteomyelitis Non specific: chronic suppurative osteomyelitis Specific: TB, Syphilis, Sarcoidosis Parts of long bone Acute Hematogenous Osteomyelitis Acute Hematogenous Osteomyelitis Definition: it is blood-borne infection of the metaphysis of long bones Incidence :children and adolescents Causative organisms: Staphylococcus aureus in 90% of cases, Staph albus, streptococci, and pneumococci: rarely Predisposing factors: Septic focus (abscess, upper respiratory or urinary tract infections) Pathogenesis Pathogenesis Pathology 1. transient bacteraemia, for example, S. aureus 2. focus of acute inflammation in metaphysis of long bone (subperiosteal abscess) 3. necrosis of bone fragments, forming the sequestrum 4. reactive new bone forms, the involucrum 5. if untreated, sinuses form, draining pus to the skin surface via cloacae. Clinical features Systemic manifestation : illness with malaise, fever, chills, leukocytosis. Local manifestation : intense throbbing pain over the infected bone In other instances, the presentation is subtle, with only unexplained fever (infants) or localized pain (adults). X-ray: The characteristic radiographic finding of a lytic focus of bone destruction surrounded by sclerosis strongly suggests osteomyelitis Investigation : bone culture & biopsy may be required Treatment : The combination of antibiotics and surgical drainage is usually curative Complications 1. Blood spread: Toxemia, septicemia, and pyemia. 2. Direct spread to surrounding tissue 3. Septic arthritis (spread to the joint in children only) 4. Chronic suppurative osteomyelitis2ry amyloidosis, Squamous cell carcinoma (on the epithelialized sinus tract 5. Pathological fracture 6. Affection of the epiphyseal plate  alteration in the growth rate Acute Non-Hematogenous Osteomyelitis Definition: Suppurative inflammation of the bone due to direct infection. Incidence : common in adult Etiology: 1- Direct spread from septic lesion (otitis media, sinusitis). 2- Direct infection of the bone in compound fractures. 3-surgical infection. Assignment What are the different in the pathology between acute hematogenous osteomyelitis and acute non hematogenous osteomyelitis?  Recommended references https://www.clinicalkey.com/student/content/book/3-s2.0- B9780702072123000256#hl0000990 https://www.clinicalkey.com/student/content/book/3-s2.0- B9780323531139000261#hl0001946 https://www.clinicalkey.com/student/content/book/3-s2.0- B9780702072123000256#hl0001273