Types of Wound and Healing process

Definition of Wound

A wound is a cut or break in the continuity of any tissue.

Classification of wound

Wounds are classified according to the extent of injury, the causes ,the type of wounds and presence or absence of pathogens.

Open wound

• ·         An open wound is one in which there is a cut or break in the continuity of skin or mucus membranes.
• ·         caused by a sharp blow or object.
• ·         allows the entry of foreign particles and organisms and loss of fluid from the body.

Closed wound

• ·         A closed wound is one in which there is no break in the continuity of skin or mucus membrane.
• ·         accompanied by the damage of tissues under the skin.
• ·         caused by direct blow or by some blunt instruments  or by crushing.
• ·         Unusual straining or twisting can also cause closed wounds.
• ·         Also called as ‘contused wound’
• ·         The blood vessels may be damaged and bleeding may take place into the tissues.
• ·         The discoloration caused by the extravasations of blood in the tissues is called as ‘echymosis’.
• ·         A ‘haematoma’ may occur if the bleeding into the area is localized and significant.
• ·         Exudate collection can lead to swelling, loss of function and pain may accompany both closed and open wounds.

Surgical and Traumatic wounds

• ·         A surgical wound is an intentional type of wound, usually performed by the surgeons during the surgical procedures, under aseptic precautions. They are usually called ‘incisions’
• ·         A traumatic wound is an unexpected wound usually caused by accidents. They occur in septic conditions.

Incised and Lacerated wounds

• ·         When the wound is clean cut with a sharp, smooth and regular edges that can be readily approximated, it is called as incised wound.
• ·         When the wound has torn and irregular edges, it is called lacerated wound. The incised wound bleed more profusely than the lacerated wound.

Abrasions and penetrating wounds

• ·         An abrasion is  a superficial wound  caused by scraping or sliding of the skin surface over a firm and fixed surface.
• ·         A penetrating wound is caused by an object or instrument passing through the skin and mucus membrane into the deeper tissues or organs. A penetrating wound can be a ‘perforating wound’ if the instrument or object cuts open the whole thickness of the wall of a cavity or organ.

Puncture Wound

• ·         A ‘puncture wound' is produced by a sharp pointed object piercing the deep tissues, leaving a very small opening on the surface.
• ·         These wounds are potentially dangerous because of the anaerobic organisms may enter into the injured area.

Clean, Contaminated and Infected wound

• ·         A clean wound contains no pathogenic micro organisms. A surgical wound is considered to be a clean wound because it is made under aseptic conditions.
• ·         A contaminated wound is one in which there is a great likelihood of pathogenic micro organisms invading the wound. A wound may become contaminated by the foreign bodies that have entered through the injured surfaces during the injury.
• ·         An infected wound is one in which  pathogens have invaded and overcome the body’s first line of defense, producing clinical signs of infection.
• ·         The infected wound is also called ‘septic wound’.

Healing Process:

The healing process takes place in three ways:

• ·         Healing by first intention (primary union)
• ·         Healing by second intention (delayed union)
• ·         Combination of above two processes (healing by third intention)

Healing buy first intention takes place when the wound heals without infection or separation of the wound edges. The clean surgical wounds are healed by this process.

When the wound edges are not approximated, granulation tissue or connective tissues fill in the gap and the wound is closed , it is described as healing by second intention or delayed union . Contaminated and infected wound are  healed by this method. When there is combination of the above two processes ,namely, the wound edges initially left opened and later approximated or initially sutured and later break open, and healing takes place by filling in by granulation tissues, it is known as healing by third intention. The healing process takes place in different stages. Within few seconds after injury, the blood escapes into the injured area with the loss of function of the organ. There will be bacterial and foreign body contamination of the wound if it is open to the outside.

• ·         Within few minutes the blood starts clotting
• ·         Acute localized inflammatory response
• ·         Local edema by collection of transudate
• ·         The white blood cells(phagocytes) migrate into the injured site.
• ·         The plasma cells produces specific antibodies against the particular organisms that have entered the wound.
• ·         The phagocytes together with the specific antibodies attack the invading organisms and the infection is brought under control.
• ·         If the bacteria is defeated, the phagocytes clear the bacteria and foreign bodies from the injured area and healing takes place.
• ·         If bacteria are virulent, and the resistant of the host is poor, the infection may settle.
• ·         Pus formation.
• ·         If the infection is under control within 4-5 days, healing process starts (proliferate phase)
• ·         a scab is formed over the wound which protects the underlying tissues from contamination.