WOUNDS
Definition:
Wound is a discontinuity or break in the surface epithelium.
A wound is simple when only skin is involved.
It is complex when it involves underlying nerves, vessels and tendons..
CLASSIFICATION OF WOUNDS:
I A. Closed wounds
• Contusion
• Abrasion
• Haematoma
B. Open wounds
• Incised
• Lacerated
• Penetrating
• Crushed
II Tidy and untidy wounds
A. Tidy wounds: Incised, clean, healthy tissue and seldom associated with tissue
loss..
B. Untidy wounds: Crushed or avulsed, contaminated, devitalised tissues and
often with tissue loss.
Ill Acute wound and chronic wound
A. Acute wound: Stab wounds, following RTA and blast injuries.
B. Chronic wound: Leg ulcers, pressure sores.
Closed wounds:
Contusion:
Can be minor soft tissue injury without break in the skin, or major such as when being run
over by a vehicle. Generally, it produces discolouration of the skin due to collection of blood
underneath.
Abrasion:
In this wound, epidermis of the skin is scraped away exposing the dermis. They are painful
as dermal nerve endings are exposed. These wounds need cleaning, antibiotics and proper
dressings.
Haematoma:
This refers to collection of blood usually following injury.
It can occur spontaneously in patients who have bleeding tendencies such as haemophilia.
Depending upon the site, it can be subcutaneous, intramuscular or even subperiosteal.
A knee joint haematoma may need to be aspirated followed by application of compression
bandage.
Small haematomas get absorbed.
If not, they can get infected.
Open wound:
Incised wounds:
They are caused by sharp objects such as knife, blade, glass, etc. This type of
wound has a sharp edge and is less contaminated.
Lacerated wounds:
They are caused by blunt injury such as fall on a stone or due to road traffic
accidents (RTA). Edges are jagged.
The injury may involve only skin and subcutaneous tissue or sometimes deeper
structures also.
Due to the blunt nature of the object, there is crushing of the tissue which may
result in haematoma, bruising or even necrosis of the tissue.
Penetrating wounds:
Stab injuries of abdomen are very notorious.
All penetrating wounds of the abdomen should be admitted and observed for at
least 24 hours.
Crushed or contused wounds:
They are caused by blunt trauma due to run over by vehicle, wall collapse,
earthquakes or industrial accidents.
These wounds are dangerous as they may cause severe haemorrhage, death of
the tissues and crushing of blood vessels.
General principles of management of open wounds
• Admission or observation in the hospital.
• Monitoring of temperature, pulse and respiration.
• Systemic antibiotics depending upon the contamination of wound.
• Injection tetanus toxoid for prophylaxis against tetanus.
• Treatment of the wound in the form of cleaning, dressing or suturing.
Healing of the wound
Healing by primary intention occurs in a clean incised wound such as a surgical
incision wherein there is only a potential space between the edges. It produces a
clean, neat, thin scar.
Healing by secondary intention refers to a wound which is infected, discharging
pus or wound with skin loss. Such wounds heal with an ugly scar.
Components of wounds healing:
I. Inflammatory phase (lag phase)
• Injury results in the release of mediators of inflammation, mainly histamine from
platelets, mast cells and granulocytes. This results in increased capillary
permeability.
Later kinins and prostaglandins act and they play a chemotactic role for white cells
and fibroblasts.
• In the first 48 hours, polymorphonuclear (PMN) leukocytes dominate. They play
the role of scavengers by removing the dead and necrotic tissue
II. Proliferative phase (collagen phase)
• Between 3rd and 5th days, polymorphonuclear leukocytes diminish in number
but monocytes increase. They are the specialised scavengers.
• By 5th or 6th day, fibroblasts appear, proliferate and eventually give rise to a
protocollagen which is converted into collagen in the presence of an enzyme
• Epithelialisation occurs mainly from the edges of the wound by a process of cell
migration and cell multiplication. This is mainly brought about by marginal basal
cells.
Ill. Remodelling phase (maturation)
It starts after 4 days and is usually completed by 14 days.
It is brought about by specialised fibroblasts.
Because of their contractile elements, they are called myofibroblasts.
It is the nature's way of reducing the size of defect, thereby helping the wound
healing.
Wound contraction readily occurs when there is loose skin as in back and gluteal
region.
IV. Phases Of Scar Formation
Following changes take place during scar formation
• Fibroplasia and laying of collagen is increased
• Vascularity becomes less (devascularization)
• Epithelialisation continues
• Ingrowth of lymphatics and nerve fibres takes place
• Remodelling of collagen takes place with cicatrisation, resulting in a scar.
Complications of wound healing
1. Infection: It is the most important complication which is responsible for delay in
wound healing. Majority of bacteria are endogenous. Depending upon pus/culture
sensitivity report, appropriate antibiotics are given.
2. Ugly scar: It is the result of infections
3. Keloid and hypertrophic scar
4. Incisional hernia and wound dehiscence
5. Pigmentation of the skin
6. Marjolin's ulcer
FACTORS AFFECTING WOUND HEALING
General factors
1. Age: In children, wounds heal faster. Healing is delayed in old age.
2. Vitamin deficiency: Vitamin C is necessary for the synthesis and maintenance of
collagen. Zinc deficiency is known to delay the healing of pilonidal sinus.
3. In diabetic patients, wound healing is delayed because of several factors such
as microangiopathy, atherosclerosis, decreased phagocytic activity, proliferation of
bacteria due to high blood sugar, etc.
4. Jaundiced and uraemic patients have poor wound healing because fibroblastic
repair is delayed.
5. Cytotoxic drugs such as doxorubicin and malignancy delay healing
6. Generalised infection: Pus in some part of body delays wound healing.
7. Corticosteroids given early may delay wound healing because of their
anti-inflammatory activity. Once healing is established, they do not interfere.
Local factors:
1. Poor blood supply: Wound over the knee and shin of tibia heals very slowly but
wound on the face heals fast.
2. Local infection: Organisms eat away the suture material, destroy granulation
tissue and causes slough and purulent discharge.
3. Haematoma precipitates infection.
4. Faulty technique of wound closure.
5. Tension while suturing.
6. Hypoxia: Killing property of macrophages and production of fibroblasts can
decrease due to hypoxia.
