Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Burns and Plastic Surgery PPT 2 Burns Epidemiology Extent Pathophysiology And Prevention Lecture Notes
A burn is an injury to the skin or other organic tissue primarily caused by heat
or due to radiation, radioactivity, electricity, friction or contact with
Thermal (heat) burns occur when some or all of the cells in the skin or other
tissues are destroyed by:
hot liquids (scalds)
hot solids (contact burns), or
flames (flame burns).
Epidemiology of Burns
The global scenario
Burns are a global public health problem, accounting for an estimated 265 000
deaths annually. The majority of these occur in low- and middle-income countries
and almost half occur in the WHO South-East Asia Region.
Non-fatal burns are a leading cause of morbidity, including prolonged hospitalization,
disfigurement and disability, often with resulting stigma and rejection.
Burns are among the leading causes of disability-adjusted life-years (DALYs) lost in low-
and middle-income countries.
In 2004, nearly 11 million people worldwide were burned severely enough to require
Who is at risk?
Females and males have broadly similar rates for burns. according to the most
recent data. (In contrast to other injuries where males have a higher rate)
children are particularly vulnerable to burns. Burns are the 11th leading cause of
death of children aged 1?9 years and are also the fifth most common cause of
non-fatal childhood injuries.
There are important regional differences in burn rates.
Children under 5 in the WHO African Region have almost 3 times the incidence of
burn deaths than infants worldwide
People living in low- and middle-income countries are at higher risk for burns than
people living in high-income countries.
Within all countries however, burn risk correlates with socioeconomic status.
Other risk factors
occupations that increase exposure to fire;
poverty, overcrowding and lack of proper safety measures;
placement of young girls in household roles such as cooking and care of small
underlying medical conditions, including epilepsy, peripheral neuropathy, and
physical and cognitive disabilities;
alcohol abuse and smoking;
easy access to chemicals used for assault (such as in acid violence attacks);
use of kerosene (paraffin) as a fuel source for non-electric domestic appliances;
inadequate safety measures for liquefied petroleum gas and electricity.
In which settings do burns occur?
Burns occur mainly in the home and workplace.
Community surveys in Bangladesh and Ethiopia show that 80?90% of burns occur at home.
Children and women are usually burned in domestic kitchens, from upset receptacles containing
hot liquids or flames, or from cookstove explosions.
Men are most likely to be burned in the workplace due to fire, scalds, chemical and electrical
Classification of Burn Injuries
By mechanism of cause
result of breathing in superheated gases, steam, hot liquids or noxious
products of incomplete combustion.
cause thermal or chemical injury to the airways and lungs.
Thermal burns involve the skin and
may present as: ?
a) scalds ? hot liquid or steam
b) contact burns ? hot solids or items
such as hot pressing irons and
cooking utensils, as well as lighted
c) flame burns ? flames or
incandescent fi res, such as those
started by lighted cigarettes,
candles, lamps or stoves
caused by an electrical current passing from an electrical outlet, cord or
appliance through the bodyfrom one point to another, creating "entry"
and "exit" points.
The tissue between these two points can be damaged by the current.
Can be high voltage or low voltage injuries
High voltage injuries:
True high tension injury
Electrocardiogram after electrocution
showing atrial fibril ation
caused by exposure to reactive
chemical substances such as
strong acids or alkalis
These burns tend to be deep, as
the corrosive agent continues to
cause coagulative necrosis until
Alkalis tend to penetrate deeper
and cause worse burns than acids.
Cement is a common cause of
By the degree and depth of a burn
First degree Burn
Cause: Flash flame.
Surface appearance: Dry, no
blisters, no or minimal edema
Pain level: Painful
Second Degree Burn(Superficial partial
Cause: Contact with hot liquids or
solids, flash flame to clothing,
direct flame, chemical. Ultraviolet
Surface appearance: Moist blebs,
Colour: Mottled white to pink,
Pain level: Very Painful
Third degree Burns (Deep Partial
Cause: Contact with hot liquids or
solids, flame. chemical, electrical
Surface appearance:Dry with
leathery eschar until
debridement; charred vessels
visible under eschar
Colour:Mixed white, waxy. pearly;
dark, khaki, mahogany; charred
Pain level: Little or no pain; hair
pulls out easily
Fourth degree Burn
Cause: Prolonged contact with
Surface appearance:Same as
third degree, possibly with
exposed bone, muscle, or tendon
Colour: Same as third degree
Pain level: Same as third degree
Currently burn depth assessment is
Future: multisensor heatable laser
Assessing the extent of burn
This is calculated as a percentage of Total body surface area(TBSA)
Rule of 9
Lund and Browder chart
The Rule of 9's provides a simple
method of estimating
total body surface area burned.
Due to differences in body
the percentage for each body
area is different in adults and
The Lund and
provideo a more
precise estimate of
bum TBSA for each
body part based on
the individual's age.
Pathophysiology of Burn
Body's response to burn injury
Burn injuries result in both local and systemic responses.
The three zones of a burn were described by Jackson in 1947.
Zone of coagulation--This occurs at the point of maximum damage. In this
zone there is irreversible tissue loss due to coagulation of the constituent
Zone of stasis--The surrounding zone of stasis is characterised by decreased
tissue perfusion. The tissue in this zone is potentially salvageable. The main
aim of burns resuscitation is to increase tissue perfusion here and prevent
any damage becoming irreversible. Additional insults--such as prolonged
hypotension, infection, or oedema--can convert this zone into an area of
complete tissue loss.
Zone of hyperaemia--In this outermost zone tissue perfusion is increased.
The tissue here will invariably recover unless there is severe sepsis or
These three zones of a burn are three dimensional, and loss of tissue in the
zone of stasis will lead to the wound deepening as well as widening.
Clinical image of burn
zones. There is central
necrosis, surrounded by
the zones of stasis and of
The release of cytokines and other inflammatory mediators at the site of
injury has a systemic effect once the burn reaches 30% of total body
Capillary permeability is increased, leading to loss of intravascular proteins
and fluids into the interstitial compartment.
Peripheral and splanchnic vasoconstriction occurs.
Myocardial contractility is decreased, possibly due to release of tumour
necrosis factor .
These changes, coupled with fluid loss from the burn wound, result in
systemic hypotension and end organ hypoperfusion.
and in severe burns
Atrophy of the small bowel mucosa occurs within 12 hours of injury in
proportion to the burn size
reduced uptake of glucose and amino acids, decreased absorption of
fatty acids, and a reduction in brush border lipase activity
Intestinal permeability to macromolecules, which are normally repelled by
an intact mucosal barrier, increases after a burn.
splanchnic hypoperfusion occurs
early and aggressive enteral feeding to decrease catabolism and maintain
The basal metabolic rate increases up to three times its original rate.
A stress such as a severe burn induces the release of inflammatory
hormones, which results in
Non-specific down regulation of the immune response occurs, affecting
both cell mediated and humoral pathways.
BURNS ARE PREVENTABLE
Prevention strategies: forming a burn
Prevention strategies should address the hazards for specific burn injuries, education for vulnerable
populations and training of communities in first aid.
An effective burn prevention plan should be multisectoral and include broad efforts to:
develop and enforce effective policy
describe burden and identify risk factors
set research priorities with promotion of promising interventions
provide burn prevention programmes
strengthen burn care
strengthen capacities to carry out all of the above.
Recommendations for individuals,
communities and public health officials
1. Enclose fires and limit the height of open flames in domestic environments.
2. Promote safer cookstoves and less hazardous fuels, and educate regarding
3. Apply safety regulations to housing designs and materials, and encourage
4. Improve the design of cookstoves, particularly with regard to stability and
prevention of access by children.
5. Lower the temperature in hot water taps.
6. Promote fire safety education and the use of smoke detectors, fire
sprinklers, and fire-escape systems in homes.
7. Promote the introduction of and compliance with industrial safety
regulations, and the use of fire-retardant fabrics for children's sleepwear.
8. Avoid smoking in bed and encourage the use of child-resistant lighters.
9. Promote legislation mandating the production of fire-safe cigarettes.
10.Improve treatment of epilepsy, particularly in developing countries.
11.Encourage further development of burn-care systems, including the training
of health-care providers in the appropriate triage and management of
people with burns.
7. Support the development and distribution of fire-retardant aprons to be
used while cooking around an open flame or kerosene stove.
This post was last modified on 07 April 2022