Burns

burns is a wound  in which there is  coagulative necrosis of  the tissues. The following are the types of burns:-
    1). Ordinary burns- usually caused by dry heat with fire, open flame, hot metal, bomb injury, or   aeroplane crush etc.
    2). Scalds burns- are caused by moist heat like hot liquid or steam.
    3). Electric burns- result as result higher or lower electrical voltage contact.
    4). Chemical burns- caused by either strong base or strong acid
    5). Radiation burns- occurs usually due to X-ray or radium

Pathology of burns:- for better understand pathology of burns are divided into the following form
    a). local changes
    b). systemic changes
  
Local changes are further subdivide into:-
 1. Severity 2. The extent of burns 3. Vascular changes and 4.Infection.

1.SEVERITY OF BURNS.
The severity of the burn are subdivided into three degree or grades depend on depth of tissue damage/necrosis.
  -first degree is the one inwhich there only area of hyperaemic on the skin plus slightly oedema of the epidermis.

-second degree is the one in which entire area of the epidermis thickness is destroyed and vesicles are formed by dermis and epidermis. The hall mark of this type of burn is vesiculation.

-third degree is the one in which there is destruction of both epidermis and dermis depth thickness. In this form of burn , there irreversible destruction of dermis appendages and epithelial include sensory nerves end. Skin grafting become an important management to cover area of burns.

Another classification of severity of burns include-

a). partial thickness burn- is the one in which superficial part of skin involve the epidermis and partly part of dermis has bee destroyed, but sweat glands and enough epithelial remain intact which enable regeneration of destroyed skin.

b). full thickness burns- occur when the entire depths thickness of both dermis and epidermis has been destroyed. Epithelial layers and sweat glands has been destroyed and so no possible regeneration of the damaged area.

2.EXTENT OF BURNS:
The extent of burns is clinically estimated by using the rule of nines. The length and widths of the burn is expressed in percentage of the total body surface area. Usually used on second and third degree burns. To understand the rule of nines for adults and pediatric patients check the image below.
 



3. VASCULAR CHANGES.
Its of very important in the burns area. There is main two changes observed
 a). dilation of small vessels- due to direct  injury of blood vessel walls and through the release of histamine. This increase blood flow to the affected area without stasis as in case of the inflammation. 
 b). capillary permeability- is greatly increased.  plasma rich in protein released continously in large amount. Exudate collect in blister or form a dry crust to protect the wound.

4. INFECTION.
In case of first degree, the skin is intact and act as barrier to infection. In case of second or third degree of burns, the skin is destroyed and therefore, the burns wound is like to be infected from virulent organism.

SYSTEMIC CHANGES.
The following changes are observed -
1). shock 2). biochemical changes 3). changes in blood.

1.SHOCK- is one of  most important outcome of the burns. Different types of shock related to burns has observed, but the mostly important is oligaemic shock which is reported to cause death related to burns i most of the people.

a). oligaemic shock- follow damage of blood vessel walls as a result of  burns, there an increase of capillary permeability, which allow loss of fluid and proteins from intra-vascular to exra-vascullar compartment. Due to excessive loss of fluid, the blood become very concentrated and interfere with oxygen transport to the tissue and hence shock may develop.

b). neurogenic shock- occur likely due to severe pain 
c). cardiogenic shock- occur following a decreased in cardiac output due to marked peripheral vascular resistance, later due a decreased blood volume, and increased in viscosity due to increased in haematocrit and aggregation of RBC , white cells, and platelets.
d). bacteremic shock- occur following infection and toxic released on the burn area which are then absorbed into the body.

2. BIOCHEMICAL CHANGES-
     a). electrolyte imbalance- lower sodium and lower chloride, high potassium level in blood.
     b). hypoproteinaemia- occur following greatly loss of plasma proteins.
     c). hyperglycemia- are likely to develop in burns.
     d). rise in urea and creatinine due to acute kidney damage by burns.

3. CHANGES IN BLOOD.
     a). rise in Hb level following outpouring of serum.
     b). increase in number of RBC due to outpouring of serum.
     c). blood sludging due to aggulitation of RBC intravascularity.
     d). falling in eosinophic count within the first 12 hours which begin to rise after 24 hours.




TREATMENTS:
 1.Treatment of shock- the treatment of burn shock include the following method
        a). Sedation- sedatives and anti-pain is always required in burns victim. Usually morphine 1/4th or less is injected iv in order to avoid depression of cardiopulmonary function. Barbiturate is preferred  for children patients.
        b). fluid resuscitation- iv fluid should be given early for patients with 15% or more burns total body surface area  and 10% burns body area for children should be given fluid resuscitation.  When the burns involve more than 20% of full thickness  or 40% of partially thickness.
       c). maintenance of airway- victim of burns usually develop sign and symptoms of hypoxia like tachypnoea, respiratory arrest and coma. Patient should be given 100% oxygen with ventilator support.


GENERAL TREATMENT:-Include the following
1). Escharotomy and fasciotomy, 2). Tetanus prophylaxis, 3). Antibiotics, 4). Nutritional support, 5). Gastric decompression and 6. Treatment of G.I. complication.