Surgical infections Flashcards
When can we diagnose an infection as a surgical site infection?
any infection at surgical site up to 1 month after surgery
how many types of SSIs exist?
Incisional - superficial - deep Organ Space - generalized (peritonitis) - abscess
Which surgeries are considered clean-contaminated surgeries?
cholecystectomy
appendectomy
elective bowel resection
hernia repair and breast biopsy are considered as which type of surgeries?
clean surgery
which surgery is a contaminated surgery?
Emergency bowel resection
emergency appendectomy
perforation or abscess require what type of surgery?
dirty/infected surgery
mention some host related risk factors for SSIs
- diabetes
- hypoxia
- hypothermia
- leukopenia
- smoking
- immunosuppression
- malnutrition
- poor skin hygiene
what are some surgical related risk factors for SSIs?
- early operative site shaving
- breaks in operative sterile techniques
- improper antimicrobial prophylaxis
- prolonged hypotension
- contaminated operating room
- poor wound care post-op
- hyperglycemia
- wound closure technique
How do we prevent the occurrence of SSIs?
PATIENT
- correct predisposing factor
- avoid elective surgeries in patients with active infections
TECHNICAL
- minimize pre-op stay
- shave or clip hair just before incision
- surgeon should scrub appropriately
- adequate hemostasis
- adequate drainage of infected wounds
ANTIBIOTIC
- selected according to suspected pathogen, tissue concentration, patient’s general condition
- single dose prophylactic antibiotic given 1 hour prior to surgical incision
- if surgery exceeds 2 hours another dose should be administered
- discontinue 24hrs after surgery in CLEAN surgeries
acute non-suppurative infection of loose connective tissue best describes what skin infection?
Cellulitis
What is the causative organism of cellulitis?
Steptococci
a patient presents to your clinic with a red, hot, indurated, and painful lesion. The lesion has ill-defined edges and she described that it spread rapidly. The patient had a fever and edema.
What is the diagnosis?
cellulitis
what occurs in a severe case of cellulitis?
patches of skin necrosis with sloughing of subcutaneous tissue
What are the complications of cellulitis?
may suppurate
may spread locally, through lymphatics, or hematogenously
How do we treat ANY non-suppurative inflammation?
- antibiotic
- analgesic and NSAID
- rest & elevation of affected organ
- hot fomentation
rapidly spreading non-suppurative inflammation of dermal lymphatics. What is your diagnosis?
Erysipelas
What is the causative agent of erysipelas?
Streptococci hemolyticus
How is erysipelas different from cellulitis?
- the color of the skin is fiery red
- the edge is well defined
- islets of inflammation beyond the margins
What is the most important complication of erysipelas?
lymphedema
What are the suppurative inflammatory soft tissue infections?
- boil (furuncle)
- carbuncle
- acute abscess
what is the definition of a boil?
Furuncle: acute suppurative inflammation of the sebaceous gland of the hair follicle
small painful indurated swelling which will eventually point and rupture
What is the causative agent of a furuncle, and who will it affect more?
- staph. aureus
- in diabetics
Which soft tissue infection causes infective gangrene of the subcutaneous tissue?
Carbuncle (complicated furuncle): painful swelling with multiple sinuses discharging pus
the carbuncle is most common in who?
diabetics and immunosuppressed patients
What is the commonest location for a carbuncle to occur?
NAPE
back & gluteal region
How does the infection usually start in a carbuncle?
- infection starts in a hair follicle
- then extends into subcutaneous fat where other hair follicles will get infected
- multiple areas of necrosis and thrombosis of blood vessels occur
- patches of skin undergo sloughing and separate from underlying granulation tissue
What is the most important first-line treatment for a carbuncle?
CORRECT GENERAL CONDITION FIRST
and then surgical debridement of all necrotic tissue
what is an acute abscess?
acute localized suppurative inflammation caused by the coagulase enzyme of staphylococci
What are the manifestations of pus formation?
- change of pain from dull to THROBBING
- persistent fever becomes HECTIC
- LOCALIZATION of inflammatory reaction
- PITTING edema
- fluctuation test becomes positive (dont wait for this)
- shooting leukocytosis
How should we drain an abscess?
general anesthesia incision - adequate - dependent - not crossing skin crease - parallel to important structures evacuation of all the pus open all loculi (either by finger or Hilton's method) pack for 24hrs (hemostasis & drainage) (NEVER SUTURE AN ABSCESS)
Which organism causes diffuse non-suppurative synergistic infection extending to the deep fascia causing its sloughing and necrosis
Synergistic (mainly group A streptococci) causes NECROTIZING FASCIITIS (flesh eating disease)
What are the predisposing factors to necrotizing fasiitis?
- following infected surgical procedure
- immunocompromised
How does the infection spread in necrotizing fasciitis?
through subfacial planes
thrombosis of blood vessels
gangrene and sloughing of overlying tissue
How should necrotizing fasciitis be treated?
- MANDATORY adequate debridement
- ICU to correct general condition
- combined parenteral antibiotics
How can we clinically diagnose necrotizing fasciitis?
sloughing & necrosis
offensive discharge
gangrene
What is the difference between acute lymphangitis and lymphadenitis?
LYMPHANGITIS LYMPHADENITIS
- infection of lymph vessels - infection of lymph nodes
- red painful STREAKS - red hot swelling in usual
beneath skin sites of nodes (multiple)
- usually resolves - may resolve or suppurate
- treat as any non - treat as abscess if its
suppurative infection suppurative
What is the difference between bacteremia and septicemia?
BACTEREMIA SEPTICEMIA
- non-multiplying bacteria - multiplying bacteria in
in blood blood
What is the difference between toxemia and pyemia?
TOXEMIA PYEMIA
- bacterial toxins in blood - infected emboli in blood
What are the specific acute infections?
- tetanus
- gas gangrene
Which organism is responsible for tetanus?
Clostridium tetani which is an anaerobic bacteria
How does clostridium tetani invade tissue?
- contamination of dead or ischemic tissue in wounds
- umbilical stump: tetanus neonatorum
How does the clostridium affect the body?
- exotoxin released in blood attaches to motor nerves
- the toxin is irreversibly attached to the motor cells and anterior horn cells (cant be reversed by antitoxin)
- toxin increases excitability of motor cells so slightest stimuli will cause a violet spasm
What is the incubation period of clostridium tetani?
if non-immunized: 24hrs to 15 days
in immunized: several weeks or months
What are the symptoms during the incubation period of clostridium tetani?
- tenderness
- rigidity of muscles
- swelling at wound site
- local twitches
- restlessness and anxiety
What are the 2 stages that occur in tetanus?
TONIC CLONIC
- pain and tingling - violent muscular contractions
- limitation in jaw movement - relaxation incomplete
- spasm of facial muscles (isolate patient)
- stiffness of neck
- dysphagia
- laryngospasm
- opisthotonus
What is the cause of death in a tetanus patient?
heart failure due to very high work load on heart due to continuous muscle contractions
what are the general measures of prevention of tetanus?
- avoid wound contamination
- debridement of any necrotic tissue
- irrigate wound with saline and H2O2
- liberal drainage of any infected wound
What are the specific measure of prevention of tetanus?
active immunization with tetanus toxoid with booster injection every 7-10 years
How do we immunize an individual who received 3 or more doses the last 10 years?
booster dose of tetanus toxoid
those who received less than 3 doses of tetanus immunization should receive?
booster dose of tetanus toxoid and tetanus immunoglobulin
How do we immunize a patient who has not be previously immunized?
full immunization with tetanus toxoid and tetanus immunoglobulin
how do we treat a patient with tetanus?
isolation in a quite place
neutralize toxin with TIG
wound debridement
muscle relaxant
What other infection is caused by a clostridium bacteria BUT NOT clostridium tetani?
Gas gangrene only caused by contamination of wounds
What is the pathogenesis of gas gangrene?
wound infection spores germinate vegetative cells multiply carbohydrates fermentation (saccharolytic bacteria) gas production distention of tissues ischemia and gangrene (proteolytic bacteria) toxemia and death
What is the clinical picture of a patient that has a gas gangrene infection?
- patient is toxic
- offensive odor
- crepitus
- blackish discoloration
- muscle doesnt bleed or contract when cut
What is the immediate treatment of gas gangrene?
debridement of dead tissue
if gangrene is GROSS amputate
how to treat a patient with a gas gangrene infection?
- hospitalization and ISOLATION
- support general condition
- wound debridement or amputation if gross
- massive parenternal antibiotics
- hyperbaric oxygen
What is a decubitus ulcers?
a pressure ulcer caused by avascular necrosis (bed sore)
localized tissue ischemia due to compression
What are the stages of a bed sore?
Stage I: persistent redness
Stage II: partial thickness skin or tissue loss
Stage III: full thickness skin loss
Stage IV: full thickness tissue loss (exposed bone)
How do we prevent a decubitus ulcer?
- frequent change of position
- air mattress
- improvement of skin care and local hygiene
