SURGICAL INFECTIONS

BACKGROUND
• Surgical infection has been documented for at least 4000-5000 years.
• It is clear that the Egyptians know about infection.
• They were certainly able to prevent putrefaction, which is testified in their skills of
mummification.
• The ‘Prophylaxis’ had also been known earlier by the Assyrians & the Greeks,
although it is less documented.
• The Hippocratic teachings described clearly the use of antimicrobials such as
Wine, Vinegar which were used to irrigate open infected wounds before
secondary closure at a later date.
• Common to all their cultures, & the later Roman practitioners, was a dictum that
whenever pus developed in an infected wound it wasto be drained.
BACKGROUND
• Many practitioners actually promoted suppuration in wounds by
application of many noxious substances including faeces, in the misbelieve
that healing could not occur without pus formation.
• The understanding of the causes of infection came in the 19 th century.
• Koch laid down the first definition of infective disease (Koch’s Postulates).
• Louis Pasteur recognized the micro-organisms spoilt wine and Joseph Lister
applied this knowledge to the reduction of organisms in compound
fractures allowing surgery without infection.
• The concept of “Magic Bullet” that could kill microbes but not their host
first became a reality with the discovery of sulphonamide in the mid-
twentieth century.
• The discovery of the antibiotic Penicillin is attributed to Alexander Fleming
but it was isolated by Florey & Chain.
 PHYSIOLOGY
• Bacteria are prevented from causing infection in the tissue by intact
epithelial surfaces

• They are broken down in trauma and by surgery

• In addition to this mechanical barrier, there are other protective

mechanisms like –

– Chemical : low gastric pH

– Humoral : antibodies, complements & opsonins
– Cellular : phagocytic cells, polymorphs

• All these natural mechanisms may be compromised by surgical

interventions & treatments
 Factors that determine whether a wound will
become infected
Host response
Virulence and inoculum of infective agent
Vascularity and health of tissue being invaded (including local
ischaemia as well as systemic shock)
Presence of dead or foreign tissue
Presence of antibiotics during the ‘decisive period’
 The decisive period
There is up to a 4-hour interval before bacterial growth becomes
established enough to cause an infection after a breach in the
tissues, whether caused by trauma or surgery. This interval is
called the ‘decisive period’ and strategies aimed at preventing
infection from taking a hold become ineffective after this
time period. It is therefore logical that prophylactic antibiotics
should be given to cover this period and that they could be
decisive in preventing an infection from developing, before
bacterial growth takes a hold. The tissue levels of antibiotics
during the period when bacterial contamination is likely to
occur should be above the minimum inhibitory concentration
(MIC90) for the expected pathogens.
Causes of Reduced Resistance to Infection

• Metabolic :
– Malnutrition
– DM
– Uraemia
– Jaundice

• Disseminated disease :
– Cancer
– AIDS

• Iatrogenic :
– Radiotherapy
– Chemotherapy
– Steroid
Local & Systemic Manifestation
• Infection may be define as invasion and
multiplication of microorganisms in body tissues
and the reaction of host tissues to these
organisms and the toxins they produce.

• Sepsis is the systemic manifestation of a

documented infection, the signs & symptoms of
which may also be caused by multiple trauma,
burns, pancreatitis etc.
Invasion:
Invasion is the simple, harmless entrance of
bacteria into the body or their deposition in
tissue.
SURGICAL INFECTIONS
A surgical infection is an infection that (1) is
unlikely to respond to nonsurgical treatment
(usually its need excision or drainage) and
(2) occurs in an operated site.
Common examples of the first group
1. Appendicitis,
2. Empyema,
3. Abscesses.
 Sepsis
• Systemic inflammatory response syndrome (SIRS) :
Two of
• Tachycardia (>90/min) or Tachypnea (>20/min)
• Hyperthermia (>38*C) or Hypothermia (<36*C)
• White cell count >12000/cc or <4000/cc

• Sepsis is SIRS with a documented infection

• Severe sepsis or sepsis syndrome is sepsis with evidence of one or

more organ failure ( ARDS, ARF, CVS, CNS)

• Systemic manifestations [ multi organ dysfunction syndrome –

MODS] are mediated by the release of cytokines such as IL, TNF and
other substances from polymorph nuclear and phagocytic cells
 Infected States
• SSSI (Superficial Surgical Site Infection) is an infected wound

• SIRS (Systemic Inflammatory Response Syndrome) is the body’s

systemic response to an infected wound

• MODS (Multi Organ Dysfunction Syndrome) is the effect that the

infection has on the whole body

• MSOF (Multi System Organ Failure) is the end stage of

uncontrolled MODS
 Classification of Sources of Infection

• Primary
– Acquired from community or
– Endogenous

• Secondary
– Acquired from operation theatre or
– From Ward or
– Contamination of surgery
• PRESENTATION OF SURGICAL
INFECTION

• Major and minor surgical site

infection (SSI)
Infection acquired from the environment or the staff following
surgery or admission to hospital is termed hospital acquired
infection (HAI).
There are four main groups:
1. respiratory infections (including ventilator-
associated pneumonia),
2. urinary tract infections (mostly related to urinary
catheters),
3. bacteraemia (mostly related to indwelling vascular
catheters) and
4. SSIs.
A major SSI is defined as a wound that either
discharges significant quantities of pus
spontaneously or needs a secondary procedure to
drain it.
systemic signs such as tachycardia, pyrexia
and a raised white cell count.

Minor wound infections may discharge pus or

infected serous fluid but are not associated with
excessive discomfort, systemic signs or delay in
return home
• Localised infection
 Abscess
Definition:
An abscess is a localized collection of pus.

Types
1. Pyogenic abscess
2. Pyaemic abscess
3. Metastatic abscess
4. Cold abscess
 Pyogenic Abscess

Definition:
Abscess may be define as localized
collection of pus confined within a
pyogenic membrane.
Pus:
Pus Is a semi liquid debris of dead / dying
polymorphonuclear leukocytes, necrotic tissue cells
and microorganism.

Pyogenic Membrane:
Area immediately around the abscess which is
composed of an inner layer of neutrophils & bacteria
and an outer zone of vascular granulation tissue.
Abscess
 Abscess
Bacteria causing abscess
o Staphylococcus aureus.
o Streptococcus pyogenes.
o Gram-negative bacteria (E. coli, Pseudomonas)
o Anaerobes
Mode of infection or port of entry
o Direct
o Haematogenous
o Lymphatics
o Extension from adjacent tissues
Pathogenesis of abscess
Focus of infection,

Nutrophils are attracted by chemotaxis,

Release of proteolytic enzymes,

Liquefaction necrosis

At periphery hemorrhage from blood vessels

Activation of platelets

Fibroblastic proliferation
 Sites of Abscess

External Sites Internal Abscess

1. Fingers and hand. 1. Abdominal: Subphrenic/
2. Neck. pelvic abscess, amoebic/
3. Axilla. pyogenic liver abscess,
splenic abscess
4. Breast.
2. Perinephric abscess.
5. Foot, thigh
3. Retroperitoneal abscess.
6. Ischiorectal and
perianal region. 4. Lung abscess.
7. Abdominal wall. 5. Brain abscess.
Abscess
 C.F of pyogenic abscess
A. Symptoms: B. Signs:
1. Local pain a. General:
(Throbbing) 1. Fever
2. Local swelling 2. Tachycardia
3. Fever a. Local:
1. Overlying skin red &
edematous,
2. Visible (pointing) pus.
3. Local rise of temperature,
4. Tender
5. Flactuation may posetive
 Abscess
Investigations
• CBC - Total count is increased.
• Urine sugar and blood sugar
 Abscess
Treatment:
1. Incision and drainage ( Pus should sent
for C/S)
2. Antibiotics
3. Analgesics
4. Control of associate disease(e.g: DM)
 Abscess
Hilton’s method of draining an abscess:
1. Under general anesthesia or regional block anesthesia, after cleaning
and draping.
2. Skin & superficial fascia are incised adequately, in the most dependent
position.
3. Abscess cavity is opened by thrusting of a Sinus forceps

4. Blades of forceps are separated in two direction(×)

5. All loculi are broken up.
6. Abscess cavity is cleared of pus and washed with saline.
7. A drain (either gauze drain or corrugated rubber drain) is placed. Wound
is not closed.
8. Wound is allowed to granulate and heal. Sometimes secondary suturing.
Hilton’s method of draining an
abscess
 Abscess
Complication of abscess:
1. Bacteraemia, septicaemia, and pyaemia.
2. Multiple abscess formation.
3. Metastatic abscess.
4. Antibioma formation (common in breast abscess).
5. Sinus and fistula formation
6. Complication of specific abscess
a) Abdominal abscess may brust and cause peritonitis.
b) Brain abscess can cause intracranial hypertension, epilepsy, neurological
deficit.
c) Liver abscess can cause hepatic failure, rupture, jaundice.
d) Lung abscess can lead to bronchopleural fistula or septicaemia or
respiratory failure or ARDS.
 Abscess
BACTERAEMIA
Presence of bacteria in blood with no clinical menifestation.
SEPTICAEMIA
Presence of overwhelming and multiplying bacteria in blood with
toxins causing SIRS (Systemic Inflammatory Response
syndrome).
PYAEMIA
Presence of multiplying bacteria in blood as emboli which spread
and lodge in different organs in the body causing multiple
abscess.
 Abscess
Pyemic Abscess:
Multiple abscesses are developed in different part of
body as a result of circulating infected emboli in
blood.
Metastatic abscess:
Metastatic abscess is an abscess which occurs as a
spread from other abscess. For example, lung
abscess causing metastatic abscess in the brain
 Abscess
Cold Abscess:
It is a sequelae to tubercular infection
anywhere in the body, commonly in lymph
nodes, bone.
 Differences between Pyogenic
Abscess
Pyogenic abscess and Cold Abscess
Cold abscess

(a) Red, warm, tender, with signs of (a) No signs of acute inflammation
acute inflammation
(b) Pyogenic bacteria are nonspecific (b) Tuberculous bacteria
organisms (Streptococcus,
Staphylococcus
(c) For drainage, dependent incision (c) Nondependent incision is used
is used
(d) Suturing of the wound is not done (d) Wound is sutured

(e) Drain is placed (e) Drain is not placed (otherwise

sinus will form which is difficult to
treat)
Cold Abscess
 BOIL
Definition:
It is an acute staphylococcal infection of a
hair follicle with perifolliculitis which usually
proceeds to suppuration and central
necrosis.
 Boil
Furuncle:
Boil in external ear. It is very painful
because of rich cutaneous nerves.
Furunculosis:
Multiple recurrent furuncle.
Stye / Hordeolum:
Boil in the eyelash follicles.
 Boil
Pathogenesis:

Obstruction of hair follicle by keratin or sebum plug.

↓
Content become infected.
↓
Inflammation.
↓
Suppuration and subsequent necrosis.
 Boil
Sites:
Any hairy place of body

Etiological factors:
– Obesity, smoking.
– Poor hygiene.
– Diabetes mellitus.
– Steroids
 Boil
Complications
1. Cellulitis.
2. Lymphadenitis.
3. Abscess
4. Carbuncle
5. Hidradenitis (Infection of group of hair
follicles).
6. Boil in dangerous zone can cause cavernous
sinus thrombosis.
 Boil
Treatment:
1. Depilation / Drainage
2. Antibiotic
 Carbuncle( পদ্মরাগ ফুল)
Definition:
Curbuncle is the infective gangrene of the
skin and subcutaneous tissue composed
of boil with multiple formed or incipient
discharging sinuses usually due to
staphylococcous.
 Carbuncle
Common sites:
1. Nap of the neck
2. Back of the shoulder
3. Buttock
 Carbuncle
Common in: Complication
1. Male 1. Septicemia
2. Diabetic patient 2. Epidural abscess
3. >20yrs age 3. Meningitis
4. Chronic illness
5. Immunodeficiency
 Carbuncle
Treatment:
1. Control of diabetes is essential using insulin.
2. Antibiotics like penicillins, cephalosporins or
depending on C/S is given.
3. Drainage is done by a cruciate incision and
debridement of all dead tissues is done.
Excision is done later.
4. Once wound granulates well, skin grafting may
be required.
 Cellulitis
Definition:
It may be define as acute, diffuse,
spreading, non-suppurative inflammation
of the subcutaneous tissue and fascial
planes.
Causative organism:
1. β Hemolytic Streptococcus
2. Staphylococcus
3. Clostridium perfringens
Pathology:

Streptococcal infection

Inflammation

Production of Hyaluronidase & Streptokinase

Dissolve intracellular matrix & fibrin

Loss of inflammatory barrier

Spread of inflammatory exudates

Portal of entry:
1. Accidental wound
2. Operative wound
3. Burn
4. Scratch
5. Bite
Susceptible group:
1. Diabetic patient
2. Immunocompromized
3. Debilitated
4. Poor nutrition
C.F:
Symptoms:
1. Pain, Fever, Swelling, Restricted movement
Signs:
a. Local:
1. Diffuse swelling, red & shiny area
2. Increased temp, tenderness
3. Regional Lymphadenopathy
b. Systemic:
1. Fever, Tachycardia, tachypnoea,
2. Toxemia
Treatment:
1. Rest
2. Elevation of affected part
3. Broad spectrum antibiotics
4. If needed I&D (Abscess / Compartment
syndrome)
Sequelae:
1. Infection can get localized to form
pyogenic abscess.
2. Infection can spread to cause
bacteraemia, septicemia, pyaemia.
3. Often infection can lead to local gangrene
Danger area of cellulites:
1. Face: Infected embolus can give rise to
cavernous sinus thrombosis.
2. Orbit: Orbital cellulites will lead to blindness.
3. Neck & submaxillary region: Ludwig’s angina
4. Hand
 ERYSIPELAS

Definition:
Acute superficial form of cellulites involving
the dermal lymphatics and dermis caused
by Streptococcus pyogenes
It is a spreading inflammation of the skin and subcutaneous
tissues due to infection caused by Streptococcus pyogenes.
There will be always cutaneous lymphangitis with
development of rose pink rash with cutaneous lymphatic
oedema.
Causative Organism:
Group A (β Hemolytic) Streptococcus
Susceptible group:
1. Poor hygienic condition
2. Recurrent upper RTI
3. Debilitating illness
4. Extremes of life
C.F:
1. A rapid onset of toxemia associated with local
infection.
2. Rose pink rash which extends into adjacent skin
rapidly.
3. Rashes have clear edge
4. Following fading of the rash, brownish
discoloration remain.
5. Localized cutaneous and subcutaneous
gangrene are the dangerous problems.
Treatment: