Infection, Chapter 12 Flashcards
What is the most responsible organism cause all bone and joint infection in normal host ?
Staphylococcus aureus
What are the responsible organisms cause bone & joint infection in immunocompromised host ?
S. aureus, other organism are ..
- H. influenzae
- Diplococcus pneumoniae
- Mycobacterium
- Pseudomonas
- Fungi
- Gram-negative organism
When the humerus was involved in infant patient, the responsible organism is …
Streptococcus group B
1) How much percentage do pre-existing organ infection occur in bone and joint infection ?
2) And what are the most commonly involved organ ?
50% of cases.
Most commonly involved pre-existing organ are..
- Skin
- Respiratory tract
- Genitourinary tract
Concerning about suppurative osteomyelitis most often occur between age ? and is there gender predilection ? and which gender ?
Between 2 and 12 years with male : female about 3 : 1 ประมาณว่าเด็กชายซนกว่า exposed trauma มากกว่า ไรงิ
Which bones are most commonly involved in suppurative osteomyelitis ?
Large tubular bones of extremities.. - Femur, the most common - Tibia, humerus and radius, favored sites - Rare calvicle as pelvis (but pelvis not rel. trauma)
” Bone infection at pelvis occurs with rarely associate with trauma. “
Does the above statement is true ?
Yeah
chu!
- )3(/// x ////
What is the major predisposing factor to development suppurative osteomyelitis ?
IVDU,
in this pt. group the unusal sites predilection are "S" joints: >> Spine >> SI >> Symphysis pubis >> Sternoclavicular joint
Please described the difference vascular anatomy between
- Infantile pattern
- Childhood pattern
- Adult pattern
that contribute to difference infection pattern of bone and joint …
- Infantile pattern
> เป็นลักษณะ เลือดที่มาเลี้ยงตอนยังเป็น fetus ซึ่งจะยังคงอยู่ ใน tubular bone จนอายุ 1 ปี โดยการที่มีลักษณะดังกล่าวอาจทำให้ยังมี metaphyseal and diaphyseal vessels ทะลุ physis (epiphyseal plate)
> Trueta พบว่า vascular barrier ที่ epiphyseal plate สามารถพบได้ ตั้งแต่อายุ 8 เดือน และโตเต็มที่ตอนอายุ 18 เดือน
> Co’z infantile pattern epiphyseal involvement - Childhood pattern
> เกิดขึ้นช่วง ระหว่าง 1 ขวบ จน epiphyseal ปิด
> เป็นช่วงที่ blood flow บริเวณ metaphysis เป็น turbulence flow และ ช้า ทำให้เกิดสภาวะที่เหมาะสมต่อการเจริญของ microbe
> Co’z infection โดน metaphysis โดยที่ spare joint และ epiphysis - Adult pattern
> ในช่วงที่เป็น adult metaphyseal vessels จะค่อยๆ penetrate ผ่าน ส่วนที่เคยเป็น physis
–> re-establishing communication ระหว่าง metaphysis และ subarticular end of bone (epiphysis)
> Co’z increased incidence of septic arthritis secondary to OM in adult
Does the process of osteolytic lesion in infection and bone metastasis involved osteoclast activity both ?
If not which one involve ?
No, in bone infection, the hyperemia at marginal area promote the osteoclast activity.
In bone metastasis, pressure effect cause bone resorption, not involved osteoclastic activity.
When infection through bone marrow and cortec and at last involved subperiosteal space, why this process in subperiosteal space is readily (เร็ว) ในเด็กทารก
เนื่องจากในเด็ก มี Sharpey’s fibers น้อยกว่าในผู้ใหญ่ จึงทำให้ perisoteal easily detach from bone
What are the “ Sequestrum “ , “ Involucrum “ , “ Cloaca “ and “ Empyema nessitatis “ meanings ?
Sequestrum
» Mean the dead bone,
» In small size may removed by osteoclast
In larger size mat need surgical removal
Involucrum
» Latin “ to wrap or cover “
» As the pus lifts the periosteal, causes new bone formation and pain.
–> The periosteal new bone is the body’s to attempt to well off infectious process
» เห็นเป็น thick bony sleeve หุ้ม shaft of bone ส่วนที่ infected (cortical collar of new bone)
Cloaca
» a defect in involucrum (draining sinus)
» functioning to decompressed or discharge inflammatory product from bone
» Also referred as “ empyema nessitatis “
When developed malignant transformation from the cloaca in chronic osteomyelitis, we called ?
Marjolin’s ulcer
How long is the latent period of Marjolin Ulcer from onset of OM to CA ?
Latent period is about 20 - 30 year
What is the most reliable treatment of Marjolin’s ulcer ?
คำถามไม่ค่อยดีนะ
Amputation
Where is the most common sites in developed Marjolin’s ulcer in osteomyelitis?
Tibia and fibula
From the knowledge of development of Marjolin’s ulcer, when encounter the case of chronic OM what should be performed in all case of chronic ulcer ?
Biopsy งัย ถ้าเป็น CA ก้อตัดเลย
1) How long is the Radiographic latent period in detection of OM ?
2) How long is the Radiographic latent period in detection of OM in spine* ?
[เน้น spine]
1) about 10 days
2) About 3 weeks
Please described early signs and late signs of Osteomyelitis on Radiographs..
[ From Yochum P 1378 ]
Early signs [Latent period 10 d, spine 21 d]
» Soft tissue
- Elevation and displacement of fat plane
- Obliteration of fat plane
- Increased density of soft tissue
» Bone
- Moth-eaten or Permeative bony destruction of medullary and cortical bone
- Periosteal new bone
(Solid, Laminated, Codman’s triangle)
Late signs
>> Soft tissue
- Draining sinus tract (secondary sinus tract carcinoma)
- Debris
>> Bone
- Destruction the adjacent cortex
- Involucrum
- Cloaca
- Sequestrum
- Sclerosis and moth-eaten sclerosis
>> Joints
- Loss of joint space
- Ankylosis
What is the most early detecting image modality in detection bone destruction ?
Bone scan, Positive in a few hour after onset of symptoms
What most common used radiopharmaceutical in detection bone infection ?
Tc 99m MDP
Gallium-67 citrate
–||–||–||–||–||–||–||–||–||–||–||–||–||–
In dynamic (triple phase scan) shows increased uptake all in three phase
(จำไม่ค่อยได้แล้ว)
- Vascular (uptake จาก hyperemia)
- Parenchyma
- Late (uptake ใน bone, ไม่เกิดใน cellulitis)
Please described the change of bone infection in MRI, T1W and T2W signal ?
T1 ดำ
T2 ขาว
อักเสบเลยมีน้ำ
When the T1 low and high T2 involving the “__________” aspect of bone in children, diagnostic of bone infection could be made.
juxta-physeal medullary
When the radiographic sign of bone infection in soft tissue developed ?
Early or later than Bone change ?
3 days,
often early than bone change
(10d, 21d in spine)
When soft tissue change in bone infection occured, the obliteration of myofascial marginal plane will occured in deep myofascial structures first and then affected more superficial levels.
Does the above statement is true ?
Yes ตรงไปตรงมานะ
In obliteration of soft tissue plane between infectious process and neoplastic process, what is the difference ?
In neoplasm usually displaces and deform soft tissue margin w/o obliterating them.
In infect / inflammation usually obliterated soft tissue margin.
When does the bone sequestrum formation occured after initial onset of symptoms ?
About 3 -6 weeks after initial onset of symptoms
How much percentage of spine involvement in OM occured ?
In which patient group does the spinal OM occured ?
In which part of spines is the most common site of spinal OM ?
2-4%
(ต้องจำ จารย์ชอบถาม หนังสือ ชอบเขียนว่า well known)
Debilitated patient in 5th to 6th decade
Male > Female
Lumbar spine followed by thoracic spine
For spinal OM the most common organism is ?
Staphylococcus aureus
1) Other than S.aureus what are the organism cause spinal OM ?
2) Between Gram positve and negative which one are more common organism in general cases and IVDU ?
1)
Gram positive :
- Streptococcus
- Pneumococcus
Gram negative :
- E. coli
- Pseudomonas
- Salmonella
- Klebsiella
- Corynebacterium
2) Gram positive is more common in general cases but Gran negative is more common in IVDU
NOTE
* Brucellosis
(Brucella abortis, B. melitensis, B. suis)
» common causes of joint infection (30%)
» Spine involvement (25-50%)
» SI joint (40-70%)
- What is the most common complaint symptom in spinal OM ?
- Does the following statement in true ?
a. “ In symptom of pain from spinal OM, pt. may presented with radicular pain and aggravated by motion “
b. “ Almost all case do have fever in spinal OM “
c. “ often WBC is normal in spinal OM but more common to elevated in appendicular OM “
d. “ in IVDU patient, increased incidence of cervical spine OM “
- Back pain
- a. True, infective symptom may mimic degenerative change
b. False, fever is infrequent in adult and in children only 1/3 developed fever
c. True, แปลกแต่เจง Yochum เขียนไว้
d. True
Concerning about spinal OM,
» In children age < 20 years, what is the cause of disc involvement before vertebral body.
» In adult, what is the initial focus of infection in spinal OM ?
> > ในเด็กอายุ < 20 ปี,
- Disc vessels still exist, infection can occured before vertebral body
- Initial findings is narrowing disc height with paraspinal edema (abscess)
- Follow by desturction of vertebral end plate then verteebral body
> > ในผู้ใหญ่
- ตำแหน่งแรกของการติดเชื้อ คือ
Anterior vertebral endplate ซึ่ง containing vascular arcade และเป็นที่ให้ nutrition กับ intervertebral disc ร่วมกับเป็นบริเวณที่มี low flow
- จึงทำให้ organism มักมา lodge อยู่บริเวณ subchondral plate ก่อน involve disc
- Later developed vertebral collapse and paraspinal swelling
Does intradisc gas common in spinal infection ?
If intradisc gas occured from infection, what are the responsible organism ?
No
Clostridia, Brucellosis, TB and streptococcus
How can we observed soft tissue swelling in spine infection in plain radiograph in each part (cervical, thoracic and lumbar spines) ?
For cervical spine
» Widening prevertebral soft tissue (retropharyngeal, or retrotracheal space)
For Thoracic spine
» Displacement of paraspinal line
For Lumbar spine
» paravertebral or psoas abscess
Brucella spondylitis exhibits diminish disc height, loss of vertebral end plate and 15% developed paraspinal abscess.
What are the other manifestation of Brucella spondylitis ?
What is most common site of Brucella spondylitis ?
- Anterior discovertebral erosion simulating Schmorl’s node with normal disc
- Ivory vertebra
- Peripheral vacumm phenomenon
- Frequently anterior osteophytes
The most common site is Lower Lumbar spine.
1) What are naming species of Brucellosis that is pathogen in spondylitis ?
2) What are the common DDx of Brucella spondylitis and why ?
1) Brucella abortis, B. melitensis, B. suis
2) Psoriatic arthritis and Reiter’s syndrome
From จาก pattern involvement
» common causes of joint infection (30%)
» Spine involvement (25-50%)
» SI joint (40-70%)
Concerning about Brodie’s abscess
- What is the classical presentation ?
- And from the clinical presentation what is the DDx of the Brodie’s abscess ?
- From radiographic findings of Brodie’s abscess what are the DDx ?
- What is the usual precede history ?
- What patient group is common to developed ?
- Which site of bone is most common involved and what bone commonly affected, please described in decreased order ขอห้าลำดับ (เอง) ?
- Classic presentation: Nocturnal pain, relieve with aspirin
- Clinically Mimic the osteoid osteoma
- a) Osteoid osteoma ถ้าไม่พูดถึงขนาดแยกกันไม่ได้
b) Eosinophilic granuloma มีหลากหลาย radiographic findings ที่ overlap กะ abscess - Recent distant infection or dental Sx
- Common in male children
- Location: Metaphysis of long bone
1st Distal tibia
2nd Proximal tibia
3rd Distal femur
4th & 5th Proximal & distal fibula
6th Distal radius
++ Less frequent effect diaphysis of tubular and flat bone
Concerning about Brodie’s abscess
- อะไร คือ Brodie’s abscess
- Wall of Brodie’s abscess consist of ?
- What are the content of Brodies’s abscess ?
- Are the Brodie’s abscess is common to be sterile or no organism found ?
- In which condition of Brodie’s abscess has negative bacterial cultures ?
- What is the most responsible organism ?
- เป็น localized or aborted form of suppurative OM (ประมาณว่า localized form ของ OM)
- Inflammatory granulation tissue and sclerotic change of surrounding spongy. bone.
- Necrotic debris, purulent or mucoid fluid
- Often sterile or C/S Negative
- When internal content is mucoid fluid.
- S. aureus
Please described radiographic appearance of Brodie’s abscess ..
Abscess…
- Oval, Elliptical or serpiginous radiolucency with no visible matrix
- Surrounded by a halo or doughnut rim of heavy reactive sclerosis
- Radiolucency usually >/= 1 cm with no associated with bony enlargement or cortical break through.
[ ** เป็นจุดที่ใช้แยกกับ Osteoid osteoma มักจะมีขนาด < 1 cm และอาจมี targaet center calcification + Nidus of osteoid osteoma ประกอบด้วย vascular stroma ซึ่งจะแสดง “vascular blush” ใน arteriogram»_space; confirm Dx ได้]
