WOUND

Wound:

Definition:  A break in the continuity of soft tissues by trauma or surgery.

Classification:

Closed wounds (No break in the continuity of skin or mm but underlying tissues damaged)			Open wounds (Break in the continuity of skin)
Contusion ( By blunt objects, damage to skin or  S/C tissue without break in skin surface) According to the severity and extent of tissue damage: 1.First degree with rupture of capillary vessels of the skin and subcutaneous tissue. 2.Second degree with rupture of larger vessels leading to haematoma formation. 3.Third degree with major damage of tissues leading to gangrene formation.	Bruise (Mild degree of contusion, characterised by rupture of skin capillaries giving reddish blue to purple colour)	Haematoma (Collection of blood in abnormal cavity, by injury to superficial vein in s/c or submucous) Eg: Cattle-Mammary Vein. Horse-External thoracic vein by rider. Dog-Ear flap	1.Incised wounds 2.Lacerated wounds 3.Punctured wounds 4.Penetrating wounds 5.perforating wounds 6.Gun shot wounds 7.Abrasions 8.Avulsions 9.Aseptic wounds 10.Contaminated wounds 11.Infected wounds 12.Granulating wound 13.Ulcerating wounds 14.Bite wounds 15.Virulent wounds

 

·   Incised wounds are caused by sharp cutting instruments such as knives, scalpels, fragments of glass etc with minimum loss to tissue, edges are regular, bleeds freely and painful, heals by first intention.

·   Lacerated wounds are caused by tearing of tissues with torn and uneven edges. Wounds have irregular jagged borders and loss of tissue is limited to skin and subcutaneous tissue e.g.: barbed wire.

·   Punctured wound are caused by sharp pointed objects like nails relatively with a small opening. There might be presence of infection/ foreign particles deep into the wound with inadequate opening for drainage. Ex: Stab wounds.

·   Penetrating wounds are types of deep wounds communicating with cavities like abdomen, thorax, and joints etc. e.g.: stab wounds.

·   Perforating wound is having two opening, one of entrance and other of exit.

·   Gunshot wound is produced by various forms of firearms e.g. injuries caused by bullet.

·   Abrasions are superficial damage to the skin, generally not deeper than the epidermis.

·   Avulsion occurs when an entire structure or part of it is forcibly pulled away. Eg: Horn or Hoof avulsion.

·   Aseptic wound is surgical wound made under aseptic conditions where chances of bacterial contamination are negligible.

·   Contaminated wound is one where there is presence of micro organisms.

·   Infected/ septic wound: A contaminated wound may become infected after a period of 6 -8 hours where bacterial multiplication may occur and liberation of their toxin.

·   Granulating wound is one in which there is a tendency to heal within expected time.

·   Ulcerating wound have no tendency to heal like horn cancer or cancer wounds.

·   Bite wounds are caused by snake; dog or wild animals bite with significant degree of tissue damage.

·   Virulent wounds are caused by bacteria or virus leading to formation of pustules or vesicles e.g.: FMD, anthrax.

Symptoms:

Local	General	Remote
1.Haemorrhage 2.Gaping of wound edges 3.Pain 4.Repair phenomena	1.Febrile disturbance by virulence of infected organisms and degree of injury to tissues and toxemia.	Symptoms observed away from wound part. Abscess formation in dependent lymph gland, paralysis or loss of sensation in the dependent part or neuritis.

 

Healing of an wound:

1.First intention healing-(Primary union)

For primary healing

The wound should be

Clean and fresh wound,

Free of infection,

 No hemorrhage,

No foreign bodies like nails or thorns,

Minimal dead cells,

 Good blood supply to wound edges,

 the part should be given rest by immobilization in which different layers of tissues are properly aligned.

Narrow space between wound edges are filled with blood clot.

Capillaries and fibroblasts grow into this from wound edges and healing completed in 5-14 days.

Little scar tissue is formed.

By 3^rd day, capillaries proliferate in the wound, By 4^th day, fibroplasias is evident.

After fibroplasias, wound has tensile strength, in 10-14 days sufficient tensile strength is obtained.

2.Second intention healing: (Healing by granulation)

By replacement of tissues

In wounds with extensive loss of tissues and edges widely separated.

Granulation tissue has budding capillaries and fibroblasts grow from edges and the bottom of the wound to fill the gap.

Granulation tissue is highly vascular, velvety, soft, moist and pink in appearance, these capillaries grow up and anastamose forming network.

Fibrous tissue proliferates and fibres are interlaid among the capillaries.

Fibrous tissues and capillaries will come to the surface of the wound and surface epithelium also grows from its borders and healing gets completed.

Fibrous tissue contracts causing constriction of capillaries giving pale colour to scar tissue/Cicatrix.

By 2^nd intention healing happens in 14-21 days.

3. Mixed intention healing:

Sutured wound partially disturbed, which heals partly by 1^st intention and partly by 2^nd intention.

4.Third intention healing-(Healing by 2^nd suture)

When granulating surfaces have to heal by 2^nd intention, unite them by sutures to bring quick healing.

 

 

5.Healing under a scab:

In superficial wounds like abrasions, exudates in wound dries up and forms a scab. Under the scab healing process(granulation) takes place, scab automatically separates and falls off.

 

·   The Four phases of wound healing are

• Haemostasis
• Inflammatory phase
• Proliferative phase
• Wound remodeling

·         Haemostasis:

·         The initial vascular response involves a brief and transient period of vasoconstriction and hemostasis.

·               A 5-10 minute period of intense vasoconstriction is followed by active   vasodilatation accompanied by an increase in capillary permeability.

·               Platelets aggregated within a fibrin clot secrete a variety of growth factors and cytokines that set the stage for an orderly series of events leading to tissue repair.

• Inflammatory phase:
• The second phase of wound healing i.e. the inflammatory phase lasts for 1-3 days in uninfected wounds.
• The inflammatory response increases vascular permeability, resulting in migration of neutrophils and monocytes into the surrounding tissue. The neutrophils engulf debris and microorganisms, providing the first line of defense against infection.
• In the late inflammatory phase, monocytes converted in the tissue to macrophages, which digest and kill bacterial pathogens, scavenge tissue debris and destroy remaining neutrophils. Macrophages begin the transition from wound inflammation to wound repair by secreting a variety of chemotactic and growth factors that stimulate cell migration, proliferation, and formation of the tissue matrix.

         Proliferative phase

        The subsequent proliferative phase is dominated by the formation of granulation tissue    and epithelialization.

o    Chemotactic and growth factors released from platelets and macrophages stimulate the migration and activation of wound fibroblasts that produce a variety of substances essential to wound repair, including glycosaminoglycans (mainly hyaluronic acid, chondroitin-4-sulfate, dermatan sulfate, and heparan sulfate) and collagen.

o    These form an amorphous, gel-like connective tissue matrix necessary for cell migration.

· New capillary growth must accompany the advancing fibroblasts into the wound to provide metabolic needs.

o    Collagen synthesis and cross-linkage is responsible for vascular integrity and strength of new capillary beds.

o    Around the third day after wounding the growing mass of fibroblast cells begin to synthesize and secrete measurable amounts of collagen.

o    The amount of collagen secreted during this period determines the tensile strength of the wound

Wound remodeling

·   The final phase of wound healing i.e. remodeling develops 3 weeks following injury and continues up to two years.

·   This phase is characterized by reorganization of new collagen fibers, forming a more organized lattice structure that progressively continues to increase wound tensile strength.

·   The strength of scar tissue formed in this phase is less than the surrounding normal tissue

Factors for delay in wound healing:

1.Improper apposition or dead space.

2.Bacterial infection.

3.foreign bodies like thorns,metal pieces.

4.Devitalization of tissues of wound edges by

a) Lack of blood supply

b) Old age

c) Deficiency of Vitamins like A,D,B-Complex.

d) Dessication of tissue by drying.

e) Overhydration or edema.

f) Malnutrition especially Protien and Glucose.

h) Defi. of Vit C for collagen formation.

i) Defi. Of Vit K for coagulation of blood.

j) Chemical and mechanical trauma.

5. Haematoma/Serum Collection , media for bacteria proliferation.

6. Malignant neoplastic tissue.

7.Lack of immobilization—rupture of newly formed granulation tissue.

8.Presence of dead tissue—debridement is necessary.

Treatment of wounds:

1.Closed wounds:

a)Contusions treated by cold astringent application to minimize extravasation.

(Mag sulf+Glycerine or Creata+Acetic acid)

b) Haematoma-Small one will be absorbed, Large should be opened and treated.

2.Open wounds

For Aseptic wounds-

a)Control Bleeding

b)Sutured for 1^st intention healing.

For Contaminated wound

a)Control bleeding by ligating larger blood vessels.

b)No sutures to be applied for infected wounds

c)Clean the wound by clipping the hair and irrigating with mild,nonirritant antiseptic lotion to remove dirt and dead tissue by 5-10% hypertonic saline solution or 1 in 500 acriflavin solution or by Hydrogen peroxide application.

d) Foot lesions treated with 10 5 formalin foot bath.

4.Control of infection:

Dry wounds—Ointments like Boric or iodine oint or BIPP.

Wet wounds—Powders like Boric or Eupad(Bleaching powder+Boric powder) or sulphanilamide powder.

Antibiotics parenterally.

Tetnus toxoid for horses and goats is essential.

5.Drainage of wounds: ( Sterilized guage/capillary tube/perforated tube)

Pen rose drains for deep wounds to remove tissue exudates/discharges.

6.Immobilization of a wounded area:

If wound is not immobilized, excess granulation tissue ( proud flesh) is formed in wounds below knee/hock joint.

Powdered caustic like Copper sulphate/Potassium permanganate is applied on wound with pressure bandage for 48 hrs and checked for removal of granulation tissue, if not removed then surgical removal is advised.

 

Complications of the wounds:

1.Severe haemorrhage leading to shock

2.Traumatic neuralgia

3.Traumatic emphysema

4.Venous thrombosis and embolism

5.Traumatic fever

6.Erysepelas

7.Septicaemia and pyemia

8.Gas gangrene

9.Tetanus

10.Other infections

11.Adhesions between adjacent structures during healing of the wound.

1. Hemorrhage:

Bleeding from a wound, if larger vessel is wounded no coagulation takes place.

In deficiency of Vit K and Calcium.

By heredity—Haemophilia/Leukemia. Or diseases of liver/heart/blood vessels.

Continuous bleeding leads to shock

Syncope (fainting) by cerebral anaemia and unconsciousness by sudden fall in BP and active vasomotor depression.

Cardiac and respiratory inhibition , and muscle relaxation leads to death by heavy bleeding.

2.Traumatic Neuralgia:

By traumatic injury, severe pain along the course of the nerve is neuralgia.

Primary neuralgic pain starts ever since wound is produced.

Secondary neuralgia pain after few days after wound by pressure and subsequent infection.

Treatment:

Clean the wound with antiseptic lotion.

Anodyne and antiseptic dressing is applied.

Warm and moist fomentation and administration of NSAIDS.

3.Traumatic emphysema:

Emphysema is infiltration of tissue spaces with air.

It is common complication of punctured wounds of respiratory tract and alimentary tract and also punctured wounds of axilla and groin and peri-articular tissues.

During movement air gets trapped in wound and spreads into subcutaneous tissue and forms emphysematous swelling.

Air from digestive tract can give infected emphysema.

If it involves extensive area it may cause general discomfort and dyspnoea.

Treatment: Apply pressure and remove the air through wound and antibiotics.

4.Venous thrombosis:

By injury to a vein at the site of the wound, thrombosis is formed, which may break in vein and curved forward in the blood stream as emboli.Emboli if larger can block pulmonary artery, coronary artery and arterioles in brain producing instant death. Septic emboli can cause general septicaemia.

5.Traumatic fever:

The rise of the body temperature by wounds. Fever  can be produced post operatively also.

Rise of temperature is due to reaction of tissue to the trauma. Fever is characterized by high temperature, pronounced leuckocytosis and neutrophilia.

Persistant fever by secondary bacterial infection requires antibiotics administration.

6.Erisepelas:

By infection of the wound by streptococcus infection in horse and dogs. Erisepals in pigs by E.Rusiopathae,it is cutaneous form.

In 3 forms a) Cutaneous form-Diffuse, hot painful swelling of skin,spreads rapidly with high temperature and lymphangitis.

b)Phlegmatous form-Diffuse suppurative lesions.

c)Gangrenous form-Extensive gangrenous lesions seen.

7.Septicaemia and pyaemia:

Pus in general circulation, so profound depression in general condition and febrile condition. Antibiotics are used.

8.Gangrenous septecaemia(Gas gangrene)

Infection of wound with gas producing bacteria.

Hot painful, edematous swelling develops surrounding the wound, spreads rapidly, putrefactive changes give foetid gas and grayish red discharge.

High temperature followed by subnormal temperature, toxic symptoms are seen.

 Incurable after toxic symptoms develop.

9.Tetanus:

Disease caused by infection of wound by clostridium tetani by anaerobic fermentation, releasing toxins like tetnospasmin and tetnolysin. Produces titanic convulsions.Develops 3 days to 3 weeks after castration /docking.

10.Other infections:

Wound may be infected by other organism like actinomycosis/actinobacillosis, BQ, Anthrax, fracy etc.

11.Adhesions:

Open wound with muscles and tendons form adhesions ,will cause  difficulty in  movement leading to lameness.

Maggot wound : (Traumatic Myiasis)

It comes from greek word Myia=fly.

Myiasis—Condition caused by infestation of the animal body by flies or their larvae(maggots).

Classification:

Primary	Secondary
1.Flies with habit of breeding only in wounds of warm blooded animal.	1.Flies complete lifecycle without larva in wound of warm blooded animals.
2.larvae from eggs burrow deep into tissues	2.Donot burrow deep.
3.They feed on living tissue.	3.Feed on necrotic tissue.
Eg: Lucilia Cuprina(Green bottle fly)       L.Sericata       Calliphora Erythrocephala(Blue bottle fly)       C.Vomitora       Phoromia sps.	Eg:Chrysomia Bezziana       C.Chloropya       (Bluish green bottle fly)       Sarcophaga Haemmorhdalis       Musca Domestica(Common house fly)

 

Life Cycle:

Lifecycle of flies causing myiasis takes about 21 days

Egg deposited in wound hatch in one day àLarva 6 day growth phase àDropped on soil àpupa àAdult (8day to 21months)                  

Prognosis:

Primary myiasis: If not treated, death in 2 weeks in fly seasons with repeated infestation àmore dangerous in sheep, goats and horse then in cattle.

-Within 4 days infection gets treated but requires one month for recovery.

Secondary myiasis gets treated easily.

Mixed myiasis is possible.

Treatment:

1.Chloroform, turpentine, camphor in oil for 24 hrs in guage.

2.Open wound treated with fly repellents like neem oil, loraxane(Proflavin), Annona squamosa leaves.

3. Inj.Ivermectin will relieve maggots fastly.

Maggots in greek medicine—Keeps wound in alkaline medium, bacteria in acidic medium so no pus in maggoted wound.

 

Surgical bacteriology of wounds:

Infection through wounds is called surgical infection.

Application of knowledge of bacteriology for diagnosis and treatment of surgical infections called as surgical bacteriology.

Bacteria responsible for wounds are

1.Staphylococcci, 2.Streptococci, 3.Bacillus Coli, 4.Bacillus Pyocyaneus.

1.Staphylococci—S.aureus,S.albus, S.Citras –Produce frank pus, abscess with thick creamy pus.

2.Streptococcus—No frank pus, Inflammation like cellulitis, swelling spreading more extensively, no abscess but thin watery and scanty discharges.

3.B.Coli-G.I tract commensal, thin watery pus with offensive odour.

4.B.Pyacyaneus-In mixed infection with green colour pus.

Animal Bite wounds:

Dog bite	Scorpion sting	Snake bite	Insect bite	Rat bite
Rabid/Not	Severe pain , burning sensation, 4-6 hrs profuse sweating,gasping, anaphylactic shock.	Cobra and krait are neurotoxin. Krait –painless bite. Viper-Cardiotoic or hemotoxic	Wasp,Bees,Spiders-produces local infl and urticaria.	Intermittent fever(Rat bite fever) in humans. By Spirochetes(Spirullinum minus).
Observe for 10 days	In 10 vomiting blood with pulmonary edema.	Treatment: Polyvalent Antivenom	Treat: Wash with alkaline Solun. Sting should be removed. Corticosteroids for urticaria.
Soap water	Death in 2-3 days
	Treatment: Symptomatic Salines, Corticosteroids, Atropine, morphine.