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38 Cards in this Set
- Front
- Back
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OSTEOMYELITIS
Definition? Onset: Prognosis? |
Definition - osteomyelitis is an infection of bone that is progressive and results in destruction of bone and new bone formation
It can be acute ( days to weeks) or chronic (months) Difficult to diagnose and treat, especially chronic osteomyelitis Medical and surgical approaches are necessary Antibiotics have changed osteomyelitis from a disease of high mortality to a disease of high morbidity |
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MECHANISMS OF DISEASE - BONE
Bacteria cause _________, inflammatory reaction (PMN’s) which compresses __________ _________ This causes _________, tissue _________ Inflammation penetrates through _______ into _________ area, stripping _________ from underlying bone; stimulates ____________ formation ________ _________ to a segment of bone is cut off forming a _________( dead bone) . _________ cannot penetrate this (dead bone) – NEED ___________ Extension of _________, necrotic material through cortical bone creates _________, sinus tract to skin |
Bacteria cause suppuration, inflammatory reaction (PMN’s) which compresses vascular channels
This causes ischemia, tissue necrosis Inflammation penetrates through cortex into subperiosteal area, stripping periosteum from underlying bone; stimulates new bone formation Blood supply to a segment of bone is cut off forming a sequestrum ( dead bone) . Antibiotics cannot penetrate this – NEED SURGERY Extension of sequestrum, necrotic material through cortical bone creates fistula, sinus tract to skin |
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MECHANISMS OF DISEASE- ORGS
Initial event is ________, plays central role |
Initial event is adhesion, plays central role
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What is most common etiology of osteomyelitis?
What do these guys express that interact with host proteins? |
Staph Aureus:
Staphylococcus aureus most common, expresses several adhesins (MSCRAMMs) that interact with host proteins - fibronectin, collagen, fibrinogen. |
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Antibiotics can't penetrate through what that's usually on staph aureus?
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slime
Biofilms – Staph aureus, coagulase negative staph form biofilms that help attachment to foreign bodies. Organisms are embedded in a matrix (slime) of extracellular polymeric substance; antibiotics can’t penetrate into slime. |
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KEY POINTS PATHOGENESIS
Inflammation causes _______, ______ Penetrates _______, strips periosteum, stimulates ____ _______ _________ Dead bone (_________) extruded, leads to fistula and sinus tract Bacterial _________ important ( S aureus has many ______); other virulence factors _________ - S aureus, coag negative staph embedded in glycocalyx, resist host defenses; important in infected prostheses |
Inflammation causes ischemia, necrosis
Penetrates cortex, strips periosteum, stimulates new bone formation Dead bone (sequestrum) extruded, leads to fistula and sinus tract Bacterial adhesion important ( S aureus has many adhesins); other virulence factors Biofilms - S aureus, coag negative staph embedded in glycocalyx, resist host defenses; important in infected prostheses |
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CLASSIFICATION OF OSTEOMYELITIS
(3) |
Hematogenous – frequent in children; in adults it involves vertebrae
Contiguous infection – trauma, surgery, infected prostheses increasing; biofilms important. Vascular insufficiency, diabetes – neuropathy, poor vascular supply to bone. |
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ACUTE HEMATOGENOUS OSTEOMYELITIS
What organism? In children what bones are involved? |
Mainly in children; staphylococcus aureus
Involves metaphysis of long bones; tibia, femur |
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ACUTE HEMATOGENOUS OSTEOMYELITIS
In neonates what is not formed? and so it spreads where? Otherwise infection can spread where? |
Neonates – epiphysis not closed, spreads into joint
Infection can spread laterally through bone cortex |
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OSTEO IN CHILDREN
Age <1 presentation? Age > 1 presentation? |
Age <1: blood vessels between the epiphysis and metaphysis communicate - focus of infection in the metaphysis can enter the joint space
Age >1: infection contained by epiphyseal growth plate, spreads laterally, may involve subperiosteal space ( subperiosteal abscess) |
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BRODIE’S ABSCESS
this is a complication of acute/chronic osteomyelitis? organism? how do you manage it? |
Complication of acute osteomelitis
Staphylococcus aureus Pus filled cavity surrounded by sclerotic bone Drainage needed |
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VERTEBRAL OSTEOMYELITIS
Hematogenous, in adults Seeding of ________ disc (discitis) and both ___________, as ________ __________ bifurcates (HALLMARK) Lumbar __%, thoracic __%, cervical __% Sources – ? If infection spreads through vertebrae, what complications? |
Hematogenous, in adults
Seeding of intervertebral disc (discitis) and both adjacent vertebrae, as segmental artery bifurcates Lumbar 45%, thoracic 35%, cervical 20% Sources – gram positive from skin, soft tissue, infected catheters; gram negative from urine , abdomen Epidural, paravertebral abscess complications |
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KEY POINTS HEMATOGENOUS OSTEO
_____ ________ in children, ________ in adults Spreads into _____ ______ in neonates Bacteremia from what sources? Sx:4? Neurologic involvement? Lab findings? IV antibiotics for __-__ weeks( high dose for ____ _______); surgery when? Early _____ switch in children |
Long bones in children, vertebrae in adults
Spreads into joint space in neonates Bacteremia from any source (skin, GI, GU, IV) Pain, limited movement, fever, chills Neurologic involvement – evaluate urgently Blood cultures positive 50%; ESR, CRP up IV antibiotics for 4-6 weeks( high dose for bone penetration); surgery rare Early oral switch in children |
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OSTEO - CONTIGUOUS FOCUS
Occurs around what medical context? Age affected? bones involved? Organism frequent? If foreign body infection, think which organism? Are sequestrum formation common? Associated with what insults is increasing? Management? |
Trauma, surgery, joint replacement
Occurs any age, involves any bone S. aureus most frequent ; if foreign body infection, think coagulase negative staph Sequestrum formation is common Osteo associated with infected prostheses, hardware ( nail, screw, rod) increasing Low virulence pathogens ( coag neg staph, proprionibacter ) stick, produce biofilm Surgical removal foreign body is necessary |
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CHRONIC OSTEOMYELITIS
Which bones affected? |
Destruction of femoral head, acetabulum, fusion of hip joint, sclerosis of bone
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Osteo associated with prosthesis
What is first sign of infection? |
loosening of prosthesis
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Osteo associated with prosthesis
High/low virulence orgs? Biofilm formation? Antibiotic effectiveness? Management? |
Low virulence orgs – coag neg staph, proprionibacter
Biofilm formation Loosening prosthesis Poor penetration of antibiotics Surgical removal prosthesis, hardware |
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OSTEO DUE TO VASCULAR INSUFFICIENCY
Mostly seen in _________ patients – ___% develop foot ulcers, small number require amputation ________, _________ result in poor wound healing Osteomyelitis likely if persistent _____, or if _____ is exposed, can be probed Polymicrobial organisms – (3) Every ________ patient should have their feet examined carefully and frequently – watch for (3) |
Mostly seen in diabetes – 15% develop foot ulcers, small number require amputation
Neuropathy, poor vascular supply result in poor wound healing Osteomyelitis likely if persistent ulcer, or if bone is exposed, can be probed Polymicrobial organisms – Staphylococcus aureus, gram negatives, anaerobes Every diabetic should have their feet examined carefully and frequently – watch for ingrown toenails, cellulitis, foot ulcers |
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If bone is exposed or can be probed think ___________
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osteomyelitis
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OSTEO IN DIABETICS
Skin breakdown over ________ points Good/Poor vascular supply? Infection tracks through _________ bone to ________ Sequestra, sinus tracts common/uncommon? Avoid ? |
Skin breakdown over pressure points
Poor vascular supply Infection tracks through cortical bone to medulla Sequestra, sinus tracts common Avoid ill fitting shoes |
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KEY POINTS CONTIGUOUS OSTEO
Seen in what context? ____________ in diabetics Organisms? Presentations? __________ diagnostic of osteo _________ _________ to identify pathogen; ESR, CRP _________ to debride infected tissue IV antibiotics for __ weeks or longer |
Trauma, surgery, prostheses (biofilms)
Vascular insufficiency in diabetics S aureus, coag neg staph; polymicrobial in diabetics Pain, draining sinus tracts, ulcers; fever rare Exposed bone diagnostic of osteo Bone biopsy to identify pathogen; ESR, CRP Surgery to debride infected tissue IV antibiotics for 6 weeks or longer |
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MICROBES / CLINICAL ASSOCIATIONS
Most frequent organism, any osteo |
Staphylococcus aureus
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MICROBES / CLINICAL ASSOCIATIONS
Foreign body |
Coagulase neg staph, proprionibacter
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MICROBES / CLINICAL ASSOCIATIONS
Diabetic foot infection |
S. aureus, gram negatives, anaerobes
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MICROBES / CLINICAL ASSOCIATIONS
Sickle – cell disease |
Salmonella, S. pneumo
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MICROBES / CLINICAL ASSOCIATIONS
Sneakers |
Pseudomonas
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MICROBES / CLINICAL ASSOCIATIONS
Human, animal bites |
Pasturella, Eikinella
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MICROBES / CLINICAL ASSOCIATIONS
Nosocomial |
Gram negatives
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MICROBES / CLINICAL ASSOCIATIONS
Endemic populations |
TB, Blasto, Histo, Cocci
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CLINICAL MANIFESTATIONS OF OSTEOMYELITIS
____ ____________ – child will not move limb, pain on passive movement; erythema, warmth indicate cellulitis; fever, chills _______ - pain, draining sinus tracts; no fever __________ – back pain; neurologic complications need urgent investigation __________ – ulcer with pain, soft tissue infection, exposed bone ________ – pain, drainage, loosening prosthesis |
Acute hematogenous – child will not move limb, pain on passive movement; erythema, warmth indicate cellulitis; fever, chills
Chronic - pain, draining sinus tracts; no fever Vertebral – back pain; neurologic complications need urgent investigation Diabetic – ulcer with pain, soft tissue infection, exposed bone Prosthetic – pain, drainage, loosening prosthesis |
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DIAGNOSIS OF OSTEOMYELITIS
Acute – positive ______ cultures ( 50%) ; Inflammatory markers? Xray – periosteal reaction, soft tissue swelling; takes __-__ days to show destruction (will acute process show up?) Bone scans very sensitive, positive before/after xrays?; specificity? Labeled ____ scan - occasionally helpful CT scan? MRI? Gold standard? |
Clinical suspicion, history, examination
Acute – positive blood cultures ( 50%) ; ESR, CRP elevated. Xray – periosteal reaction, soft tissue swelling; takes 10-14 days to show destruction (acute process will not show up) Bone scans very sensitive, positive before xrays; limited specificity (tumors and fractures will also be positive) Labeled WBC scan - occasionally helpful CT scan good definition bone, useful for biopsy; metal artifact MRI very sensitive, good for soft tissue; bony edema persists for many months; expensive BONE BIOPSY is gold standard |
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DIAGNOSIS OF OSTEOMYELITIS
What is the gold standard? |
Bone biopsy
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BONE BIOPSY
How important? What organisms found? Histopathology of tissue samples > ___ PMN’s per HPF indicate infection Are sinus tract cultures helpful? except when? Which type of therapy is most useful? |
EXTREMELY IMPORTANT!
Aerobic and anerobic cultures Mycobacterial, fungal cultures if indicated Histopathology of tissue samples > 5 PMN’s per HPF indicate infection Sinus tract cultures not helpful, represent colonization ( except if S. aureus isolated) Pathogen directed therapy most useful |
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KEY POINTS DIAGNOSIS OSTEO
__________ is gold standard Xray positive in __-__ days _______ _______ + before xray, not specific ___ especially for biopsy ____ very sensitive, edema persists for many months _____ _________ _______ not helpful, unless _________ is isolated |
Bone biopsy is gold standard
Xray positive in 10-14 days Bone scan + before xray, not specific CT especially for biopsy MRI very sensitive, edema persists for many months Sinus tract cultures not helpful, unless S aureus is isolated |
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MANAGEMENT OF ACUTE OSTEOMYELITIS
_________ __________ often sufficient to eradicate infection ________ rarely needed – may have to drain ________ __________ Long term _________ to penetrate bone – minimum __ weeks ( animal studies), usually __-__ weeks Early switch to _____ _________ in children Switch to _______ if poor compliance with IV therapy or other problems |
Intravenous antibiotics often sufficient to eradicate infection
Surgery rarely needed – may have to drain intramedullary abscess Long term antibiotics to penetrate bone – minimum 3 weeks ( animal studies), usually 4-6 weeks Early switch to oral antibiotics in children Switch to oral if poor compliance with IV therapy or other problems |
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MANGEMENT OF CHRONIC OSTEOMYELITIS
Chronic osteomyelitis is a huge problem Get ______ _________ to choose pathogen- directed therapy Surgery very important- remove ________, __________ infected tissue, _____ _______ management High dose ___ _________ for 6 weeks or longer _____ __________ requires monitoring |
Chronic osteomyelitis is a huge problem
Get bone biopsy to choose pathogen- directed therapy Surgery very important- remove sequestrum, debride infected tissue, dead space management High dose intravenous antibiotics for 6 weeks or longer Home infusion requires monitoring |
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KEY POINTS MANAGEMENT OSTEO
_______ for culture, sensitivity very helpful for pathogen- directed therapy Need high dose, prolonged (4- 6weeks) antibiotic treatment; home IV therapy Surgery for ________, _________ management especially in chronic osteo Early switch to _____ antibiotics in children |
Tissue for culture, sensitivity very helpful for pathogen- directed therapy
Need high dose, prolonged (4- 6weeks) antibiotic treatment; home IV therapy Surgery for debridement, dead space management especially in chronic osteo Early switch to oral antibiotics in children |
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Antibiotics for Infections of Bone and Joints
MSSA (methicillin sensitive) MRSA Strep Pneumo Grap A Beta Hemolytic Strep Enterococci H. Influ (Beta lactamase negative) H. Influ (Beta lactamase positive) Klebsiella Pneumo E.coli P. Aeruginosa |
MSSA (methicillin sensitive) = Nafcicillin and oxacillin
MRSA = Vancomycin Strep Pneumo = Penicillin Grap A Beta Hemolytic Strep = Penicillin Enterococci = Ampicillin H. Influ (Beta lactamase negative) = ampicillin H. Influ (Beta lactamase positive) = Ceftriaxone E.coli = Cefazolin P. Aeruginosa = Ciprofloxacin or Ceftazidine |
