Iraqia University College of Medicine Surgery
3
rd
stage Wed. 16
th
– Mar – 2016 Dr. Firas Fadhil
Gangrene
Gangrene is the necrosis of tissue with superadded
putrefaction or it is death with putrefaction of macroscopic
portions of tissue.
The foul smell is due to putrefaction and the black color is
due to slow drying and oxidation of hemoglobin and
myoglobin in the tissues and formation of iron sulphide.
Sites
The commonest external sites are toes and feet and to a
lesser extent upper limb and fingers, and the internal ones
are appendix, gallbladder, strangulated hernia and
strangulated intestine.
Causes of gangrene
1. Gangrene secondary to
A. Arterial occlusion:
Thrombus like atherosclerosis.
Embolism like fat, air or drug abuse.
Raynaud’s disease.
Thromboangiitis obliterans or Buerger’s disease.
diabetic gangrene.
B. Venous occlusion— deep vein thrombosis.
C. Nerve diseases, e.g. Peripheral neuritis (including
diabetes), hemiplegia, paraplegia, Leprosy, etc.
2. Traumatic gangrene
I. Direct trauma (trauma to the tissue itself)
A. Physical, e.g. Crushing of tissues, Pressure sores.
Iraqia University College of Medicine Surgery
3
rd
stage Wed. 16
th
– Mar – 2016 Dr. Firas Fadhil
B. Chemical — acids and alkalies.
C. Thermal burns and scalds.
D. Electrical injury.
E. Irradiation.
II. Indirect trauma — for example crushing of the tissues or
fractures when bone fragments press on the main artery, e.g.
in case of supracondylar fracture of the humerus.
3. Infective gangrene
• carbuncle.
• gas gangrene.
• fournier’s gangrene.
• postoperative synergistic gangrene, Which usually follows
the drainage of deep abscess like empyema thoracis.
Clinical features
The classical criteria of gangrene
1. Loss of arterial pulsation, venous return and capillary
refill.
2. Loss of normal body temperature(cold)
3. The colour of the part changes through a variety of shades
(pallor, dusky grey, mottled, purple) until finally taking on
the characteristic dark-brown, greenish-black or black
appearance.
4. Loss of function (paralysis).
5. Loss of sensation.
Clinical types
Clinically there are two main types of gangrene.
1. Dry gangrene.
2. Wet (Moist) gangrene.
Iraqia University College of Medicine Surgery
3
rd
stage Wed. 16
th
– Mar – 2016 Dr. Firas Fadhil
Dry gangrene
The characteristic features are:
1. It is caused by slow occlusion of arteries.
2. The involved area is dry shriveled and mummified.
3. Infection is not usually present.
4. The conditions which produce dry gangrene are:
atherosclerosis, Buerger’s disease, frostbite, etc.
5. Crepitus is absent and there is no odor.
6. Line of demarcation is usually present.
7. Conservative amputation is done as treatment.
Wet gangrene
The characteristic features are:
1. The principal difference between dry and wet gangrene is
that in the latter there is bacterial infection as well as venous
occlusion.
The venous occlusion produces the exudate.
2. The involved area is swollen and edematous.
3. presence of infection.
4. The conditions which produce wet gangrene are:
diabetes, bed-sores, gas gangrene, strangulated hernia, etc.
5. Crepitus may be present and there is foul smell due to
hydrogen sulphide produced by putrefactive bacteria.
6. the line of demarcation is absent due to infection and if
present it is diffuse not sharp.
7. Treatment is major amputation.
Separation of gangrene
It is the natural attempt of the living tissue to get rid of the
dead tissue. Thus there is Development of a layer of
granulation tissue Between the living and dead or
gangrenous Part.
Iraqia University College of Medicine Surgery
3
rd
stage Wed. 16
th
– Mar – 2016 Dr. Firas Fadhil
Line of demarcation
It is the line of division between the living tissue and the
granulation tissue.
Line of separation
It is the line separating the granulation tissue from the dead
or gangrenous tissue.
Investigations
1. Blood investigations:
A. Estimation of blood sugar (diabetes)
B. Estimation of serum cholesterol (atherosclerosis).
2. Wound culture
3. plain x-ray
A. May show gas bubbles (gas gangrene).
B. May show calcification of arteries (atherosclerosis).
C. May show the cervical rib.
4. Doppler ultrasound
a hand held Doppler Ultrasound probe is most useful in
patients with occlusive arterial Disease.
The ankle brachial pressure index (abpi) is The ratio of the
systolic pressure at the ankle With that at the arm.
The resting abpi is Normally ≥ 1. Values below 0.9 indicate
some degree of arterial obstruction and a value less than 0.3
suggests imminent gangrene.
This doppler probe is also useful to get an idea about the site
of stenosis.
5. Duplex scanning
this implies two forms of ultrasound B – mode which
typically allows moving structures like red blood within a
vessel to be imaged.
The modern duplex scanners display the moving structures
as a color map proportional to the flow velocity and as an
auditory signal.
6. Arteriography this is the most reliable method of
determining the state of the main arterial tree.
Iraqia University College of Medicine Surgery
3
rd
stage Wed. 16
th
– Mar – 2016 Dr. Firas Fadhil
This procedure gives Information about
the size of the lumen of the artery,
the course of the artery,
Constriction and dilatation present and
The condition of the collateral circulation.
7. Digital subtraction angiography (dsa)
This technique is preferred nowadays in a specialized center.
In this technique, The contrast image is subtracted from
The non required surrounding images in a computer system.
8. The most sophisticated is the magnetic resonance
angiography (MRA) without the need of the direct arterial
puncture.
Treatment
General treatment
This includes diet, control of diabetes and relief of pain.
Care of the affected part
1. The part should be kept dry and every effort is made to
convert wet gangrene into dry gangrene.
Exposure of the part and use of fan may help in
keeping the part dry.
2. The part should be protected from local pressure,
especially the malleoli, toes, heel, etc.
Otherwise patches of gangrene may develop in these
areas.
3. The affected part is kept elevated to reduce pain.
Surgical treatment
1. Lumbar sympathectomy — done in case of Buerger’s
disease alternatively destruction of the lumbar sympathetic
chain with Phenol injection (chemical sympathectomy)
which may increase the blood flow to the skin.
Iraqia University College of Medicine Surgery
3
rd
stage Wed. 16
th
– Mar – 2016 Dr. Firas Fadhil
2. Amputation
• as a life saving measure — in case of a crushed limb or a
rapidly spreading wet gangrene and gas gangrene.
• as a limb saving measure — amputation may be required
when gangrene has developed, but a conservative approach
should be adopted.
3. Direct arterial surgery
Revascularization may heal the gangrene or at least
considerably limit the level of amputation.
Also it has a definite place in embolism or thrombosis in the
form of embolectomy or thrombectomy.
Specific types of gangrene:
Diabetic gangrene
This occurs as a consequence of the following Three factors:
1. Trophic changes due to peripheral neuropathy.
Sensation is impaired and patient Cannot realize or neglect
minor trauma Which invites infection.
2. Angiopathy — this affects both large and small vessels
(macro and microangiopathy) leading to ischemia and
necrosis.
3. The sugar laden tissues serve as a medium for the bacteria
to grow.
Special investigations
1. Blood and urine sugar estimation.
2. X-ray of the local part to exclude osteomyelitis.
3. Pus for culture and sensitivity test.
Treatment
1. Wound debridement.
2. Diet and/or insulin for control of diabetes.
3. Broad spectrum antibiotics are given on the basis of
culture and sensitivity.
Iraqia University College of Medicine Surgery
3
rd
stage Wed. 16
th
– Mar – 2016 Dr. Firas Fadhil
4. Amputations may be required.
Pressure sores (bed sores)
Pressure sores are a common cause of morbidity in bed
ridden patients and in those with paraplegia.
Predisposing factors
• anemia.
• malnutrition.
• moisture is particularly damaging in a patient with urinary
and fecal incontinence.
• increased pressure—this is an important factor.
Normally the end arterial pressure is 32 mmhg and when the
patient is supine or sitting the pressure on areas like the
sacrum, ischium, occiput and heel is About 60 mm hg.
Normally an individual feels pain and shifts the position
thereby relieving the pressure. This does not occur in a
paraplegic or bed ridden patient and unrelieved pressure
more than 2 hours results in necrosis.
Muscle is more sensitive to ischemia than skin. Hence the
area of muscle necrosis is always wider and deeper than the
overlying skin.
Clinical features
The common sites affected are sacral area, ischial tuberosity,
greater trochanters, heels, malleoli and occiput.
The pressure sore initially appears as an area of erythema
which does not change color on applying pressure.
Progression is rapid with ulceration and deep muscle
necrosis up to the bone.
Prevention
1. The skin is to be kept clean and dry.
2. To relieve pressure by change of posture every 1.5 hours.
3. Pneumatic beds or ripple beds can be used to avoid
pressure on bony prominences.
Treatment
• necrotic tissue is removed.
• silver sulphadiazine cream is applied.
Iraqia University College of Medicine Surgery
3
rd
stage Wed. 16
th
– Mar – 2016 Dr. Firas Fadhil
• parenteral antibiotics.
Frostbite
Frostbite is caused by exposure to cold.
Vessel walls are damaged, leading to transudation and
oedema.
The sufferer experiences a severe burning pain in the
affected part, blistering and then gangrene follow.
Frostbitten parts must be warmed gradually.
Amputations should be delayed after re-assessment.
Venous gangrene
Although deep vein thrombosis is common, venous gangrene
is surprisingly rare.
It occurs when the circulation of a limb (usually the leg) is
disrupted by overwhelming outflow obstruction and this
requires massive deep vein thrombosis at a proximal site.
Treatment
full anticoagulation with heparin
effective elevation of the swollen leg
some would advocate venous thrombectomy in extreme
circumstances using a Fogarty catheter.
GAS GANGRENE
Gas gangrene is caused by Clostridium perfringens (welchii).
These gram positive anaerobic spore-bearing bacilli are
widely found in nature, particularly in soil and feces.
This is relevant to military, traumatic surgery and colorectal
operations.
Patients who are immunocompromised, diabetic or have
malignant disease are at greater risk, particularly if they
Iraqia University College of Medicine Surgery
3
rd
stage Wed. 16
th
– Mar – 2016 Dr. Firas Fadhil
have wounds containing necrotic or foreign material
resulting in anaerobic conditions.
Clinical Features
Severe local wound pain and crepitus (gas in the tissues
may be located in the plain radiographs).
Edema and spreading gangrene due to release of
collagenase, hyaluronidase, other proteases and α-
toxin.
The wound produces a thin, brown, sweet smelling
exudates serosanguinous in colour, in which Gram
staining will reveal bacteria.
Systemically, the exotoxins cause severe haemolysis
and, combined with the local effects, this leads to rapid
progression of the disease, hypotension, shock, renal
failure and acute respiratory distress syndrome
(ARDS).
Treatment
The treatment consists of
admission to ICU and aggressively treated with careful
monitoring.
High-dose penicillin G and clindamycin, along with
third-generation cephalosporins, should be given
intravenously until the patient’s toxicity abates.
wide excision of all necrotic and Ischemic tissue with
free drainage
The use of hyperbaric oxygen is controversial.
Antitoxin has been used in military practice
Amputation may be required.
Mortality ranges from 25 to 70 percent.
Iraqia University College of Medicine Surgery
3
rd
stage Wed. 16
th
– Mar – 2016 Dr. Firas Fadhil
NECROTI SING FASCITIS
Synergistic spreading gangrene
(synonym: subdermal gangrene)
It is a surgical emergency.
is caused by polymicrobial infections.
Abdominal wall infections are known as Meleney’s
synergistic gangrene and scrotal infection as Fournier’s
gangrene.
Necrotizing fasciitis represents a rapid, extensive infection of
the fascia deep to the adipose tissue.
Predisposing conditions include:
• diabetes;
• smoking;
• penetrating trauma;
• pressure sores;
• immunocompromised states;
• intravenous drug abuse;
• skin damage/infection (abrasions, bites and boils).
Clinical Features
Severe wound pain,
Early on patients may be febrile and tachycardic, with a
very rapid progression to septic shock.
signs of spreading inflammation with crepitus and smell are
all signs of the spreading infection.
Untreated, it will lead to widespread gangrene and MSOF
(multi-system organ failure).
The subdermal spread of gangrene is always much more
extensive than what appears from initial examination.
Treatment
• broad spectrum antibiotic with aggressive circulatory
support.
Iraqia University College of Medicine Surgery
3
rd
stage Wed. 16
th
– Mar – 2016 Dr. Firas Fadhil
• agressive excision of the necrotic tissues and laying open of
affected areas.
The debridement may need to be extensive and patients who
survive may need large areas of skin grafting.
Mortality about 30–50%
Fournier's Gangrene( Idiopathic scrotal
gangrene )
Fournier's gangrene is a nasty necrotizing fasciitis of the
male genitalia and perineum that can be rapidly progressing
and fatal if not treated promptly.
Mortality has been reported as high as 30 to 40%.
Risk factors for Fournier's include
urethral strictures,
perirectal abscesses,
poor perineal hygiene,
diabetes,
cancer,
HIV, and
other immunocompromised states.
Prompt debridement of nonviable tissue and broad-
spectrum antibiotics is necessary to prevent further spread.
If there is damage to the external sphincter, patients may
require a colostomy.
As the testes have a separate blood supply, they are usually
not threatened and do not need to be removed.
Patients may frequently require return trips to the operating
room for further debridement.