Infections-Hall Flashcards
A 12 year old female soccer player sustained a nasty bruise below her R knee during a particularly physical game. Two weeks later she complained of increased pain over the area accompanied by a low grade fever and sweats. She didn’t tell her parents. Her coach told her to quit complaining. However, her symptoms persisted and 2 weeks later she went to her pediatrician. Physical exam revealed a temperature of 101 F and a slightly swollen and warm left proximal tibia.
Differential?
staph-local infection
trauma-contusion to tibia
fracture
What tests should be done?
xray
CBC
blood culture
sedimentation rate
T/F Findings on X-rays are relatively late.
True.
What tests might have been positive at the time of the trauma?
bone scan
MRI
higher sensitivity
What is a bone scan?
radioactive tracer injected into patient. Images taken at various times after injection. Tracer absorbed by bone. Look for areas of increased uptake.
What is the most likely organism for this infection?
probably staph aureus
or strep
Does this patient need a needle biopsy?
it would be helpful for her
great to know which organism you’re dealing w/ & whether it is resistant
**for this pt blood culture prob won’t show organism b/c she is young & healthy
Which antibiotics do you want to use?
3rd generation cephalosporin
sulfa another option
dual therapy good for penicillin resistance
A 26 year old thrill-seeker suffered an open fracture of his right tibia and fibula while roller-blading behind a motorcycle driven by his ex-girlfriend. The fracture was reduced and fixed with the placement of screws, plates and rods. He did remarkably well until 4 months later when he noted a pimple followed by a little drainage from one of wounds. Four days later he was chasing his ex-girlfriend up some stairs and heard a loud crack and looked down to find hardware and bone protruding through his right leg.
Why did he break his leg a second time?
pathologic fracture
What is the most likely organism?
staph or strep
What do you send to the lab?
bone cultures
not sinus tract
Usu you don’t trust the superficial culture. What is an exception?
when the culture yields a single organism.
What do you do with the hardware?
take them out until the infection resolves & then put it back in.
Which antibiotic should be used?
vancomycin-make them IV for deep infection. Eventually transition to oral antibiotics.
What is the medical term for a bone infection?
osteomyelitis
Usu what do you do with transplants that get infected?
remove the hardware.
resolve the infection.
put the hardware back.
Are there situations when the prosthesis can be retained after debridement?
sometimes if symptoms less than 3 weeks
stable implant
easy to treat organism
maybe a strep–just use a penicillin
Are there indications for a single stage replacement?
remove old hardware & same day put in a new one. sometimes if symptoms less than 3 weeks soft tissue in good shape no co-morbidities easy to treat organism **very rare situation
A 39 year old IV drug user reports to the ER with fever and back pain. He mixes his drugs with dirty tap water and does not prep his skin before injecting. On exam his temperature is 39 C, he has a 3/6 holo-systolic murmur and tenderness over his thoracic spine on percussion. Neurological exam is initially normal.
Possible diagnosis?
endocarditis
vertebral osteomyelitis
epidural abscess
probably staph>strep>GNR>fungi
can use MRI for imaging
Which antibiotics should be used?
nafcillin gentamycin vancomycin gentamycin no advantage of IV over oral
What is mid-thoracic radicular pain indicative of?
spinal ache-first sign of epidural abscess
What are the indications for debridement of vertebral osteomyelitis?
Instability Abcess Cord compression Cervical infection Medical failure Neurological signs or symptoms
What follow up imaging should be done for this patient?
Focus on epidural & soft tissue changes. Don’t focus on MRI too much.
A 56 year old diabetic man visits his PCP for a routine visit. He is noted to have a 2.5 cm ulcer on the plantar surface of his foot at the first metatarsal head, extending up to the great toe. He was unaware of the ulcer; although, in retrospect, he recalls that his socks have been stained and foul smelling lately. He has not noted fevers or chills. His physician notes a hard, gritty surface at the base of the ulcer.
What is the recommended work up?
X-rays
CBC, ESR, CRP
MRI
Blood CUlture
**think bone involvement b/c >2 cm ulcer that is deep
What is the best imaging available for diabetic foot infections?
plain film
CT
MRI
Nuclear medicine studies
How long does it take to see X-ray evidence of a bone abnormality? How much mineral loss is required?
30-50% mineral loss
14 days at least
**not sensitive for acute osteomyelitis
What is a CT good for detecting?
small areas of necrosis, gas, foreign bodies
T/F Seeing a midfoot joint-centered lesion with no ulcer on MRI indicates an osteo problem.
False. Charcot foot.
Usu with an infected ulcer you think staph or strep Group B…but with chronically infected ulcers what do you think?
staph aureus Group B strep enterococci enterobacteria pseudomonas
With necrotic malodorous fetid foot…what organisms are responsible?
staph aureus Group B strep enterococci enterobacteria pseudomonas anaerobes
What is the recommended treatment for these extreme diabetic foot infections?
surgical debridement
revascularization
long term antibiotics
YOu should always include gram + coverage for ulcers…when should you include gram negative coverage?
coverage for chronic wounds
When should you add coverage for anaerobes?
for obviously necrotic wounds or those with a feculent odor
HOw long does it take to treat a mild infection? A moderate-severe infection?
Mild Infection: 1-2 weeks
Moderate-Severe Infections: 2-4 weeks
How long does it take to treat osteomyelitis?
4-6 weeks
A 43 year old male immigrant from Pakistan reports to urgent care complaining of back pain for the last 12 months. He has lost ~15 pounds. During the last 2 weeks he noticed some mild weakness in his right leg. Examination reveals a thin, stooped, muscular male with normal vital signs. His back has a tender deformity at T6. His right knee is tender and swollen. Plain films of his T-spine show anterior wedge-shaped collapse of T6.Which organism is required?
TB>Staph>Other
What diagnostic tests should be done for this patient?
MRI spine PPD and CXR Blood cultures Biopsy HIV Leg films **needs anti-TB therapy **surgery
What are indications for surgery in Pott’s disease?
Neurological deficits
Instability
Cervical disease
Medical failure including non-adherence
What is the pathogenesis of skeletal TB?
US adults–skeletal TB reactivation of an old focus infection
Developing World–skeletal TB in patients with acquired TB, occurs in childhood
What are the symptoms of skeletal TB?
local swelling
pain
fluctuance
systemic symptoms (fever, sweats)
What is another name for Pott’s disease? It is responsible for 1/3 of skeletal TB cases. How does the infection go?
aka tuberculous spondylitis
begins in anterior aspect of vertebral body leading to anterior collapse & spread of infection along the anterior ligament
usu in the lumbar & lower thoracic spine
A 43 year old female with a long history of rheumatoid arthritis requiring multiple joint replacements complains to her rheumatologist of a flare of her disease with pain and swelling in one of her IP joints and her right wrist. Her temperature is 37.5C, her right wrist is warm, swollen and red as is one of her IP joints on the same hand.
Why isn’t this just a flare of her RA?
too few joints
if infected–drain.
A 23 year old female reports to the ER with 2 days of diffuse arthralgias, low grade fever and then the development of swelling and increased pain in her right knee and wrist. She has a new boyfriend.
gonorrhea–>reactive arthritis
will see skin lesions
she needs ceftriaxone for 7-10 days
If you are less than 3 mo old which organism is responsible for pyogenic arthritis? What are the initial meds?
staph aureus
enterobacteria
Group B strep
Meds: PRSP + 3rd gen cephalosporin
If you are 3 mo-6years in age…what organism is likely responsible for pyogenic arthritis? What are the initial meds?
staph aureus H influenza strep enterobacteria Meds: PRSP or 1st gen cephalosporin + 3rd gen cephalosporin
If you are an adult which organisms are responsible for pyogenic arthritis? Initial meds?
staph aureus Group A strep enterobacteria Initial Meds: PRSP or 1st gen cephalosporin + cipro or Timentin etc.
If you have a joint replacement & then get pyogenic arthritis…which organism is likely responsible? WHat are the initial meds?
staph epidermis
staph aureus
enterobacteria
pseudomonas
Meds:
vanco + cipro or aztreonam or APAG
