◊ 1-Wounds ◊

SKIN AFFECTIONS

I-WOUNDS

Definition: -

It is any disruption or break down of the skin, mucous membrane, or soft tissues continuity, and when it involves the superficial covering layers (skin or mucous membrane) it predisposes to contamination of the underlying tissue.

Causes: -

Trauma or surgery

Components Of The Traumatic Wound

I-WALL

1-Central Zone of Dead Tissue

It varies in thickness from thin layer that doesn’t interfere with primary healing of open wound to thick one that extend to deeper tissues and terminates as gangrene

2-Ischemic Zone

The tissue of this zone has reduced vitality and threatened with death

3-Outer Zone of Reaction

It is characterized by acute inflammation and actively employed in healing process

II-CONTENT

It varies according to the nature of injury, and usually it involves tissue debris, clotted blood, lymph, and mud or foreign matter

 Classification Of Traumatic Wounds…

I-CLOSED WOUNDS (internal, subcutaneous, or interstitial)

Definition: -

A wound with no break in continuity of skin or mucous membrane but it has various degrees of damage involve the underlying tissues (contusion) or the superficial layer of epithelium (abrasion).

Types: -

1-Contusions

Causes: -

Trauma by blunt objects leading to damage of subcutaneous tissues without breaking the continuity of the skin and according to the degree of injury it can be classified into;

A-1^st degree contusions (Bruises): -

Symptoms: -

1-Slight inflammation and pain

2-Ecchymosis, as a result of ruptured capillaries in the skin and subcutaneous tissues and dissemination of blood through the intercellular spaces without formation of gross collection of blood, leading to reddish blue or purplish coloration of non-pigmented skin

Treatment: -

1-When it left untreated it may undergo resolution

2-Cold or astringent applications, and light bandage to arrest hemorrhage

3-Anodyne ointment over painful surface

B-2^nd degree contusions (Hematoma): -

Definition: -

Accumulation of blood in abnormal cavity, due to injury of superficial vein, that frequently seen subcutaneously, submucously, or subcapsular in large parenchymatous organs

Common seats in various species: -

Species	Seat
Cow	1.The mammary vein region due to rubbing against hard object or butting by the calf 2.The vaginal mucous membrane due to trauma during copulation
Bull	The penis due to injury during copulation
Horse	The external thoracic vein due to injury by the rider
Dog	1.Ear flap 2.Vaginal mucous membrane

Symptoms: -

1-Sudden onset of varied size swelling, at the affected region, and it is usually non-painful

2-Pulsation that indicates rupture of an artery

3-Recent hematoma is fluctuating while elder ones crepitating (due to the formation of fibrin trabeculae, and presence of liquid and coagulated blood). On the other hand long standing hematoma undergo fibrosis and calcification (the wall becomes thicker, and the contents become encapsulated and organized and may be replaced by fibrous tissues even with calcification with formation of bone like structure).

4-Suppuration and abscess formation may occur as a result of infection through tiny undetected wound or indirectly by metastasis

5-Locomotors disturbance may ensue due to intra-articular hematoma (hemarthrosis)

Diagnosis: -

1-Case history                                

2-Symptoms

3-Differential diagnosis from hernia, abscess, cyst, bursitis, and tumor

4-Exploratory puncturing

Treatment: -

1-Recent hematoma can be treated by cold astringent application to minimize hemorrhage

2-Small sized elder hematoma can be treated by hot fomentation or topical irritant (iodine ointment), and firm bandage to stimulate absorption of the fluid and disappearance of the hematoma

3-Large sized old hematoma (10-14 day old) can be treated by evacuation of the clotted blood, by incising it at its lowest point, then the lining is touched with an antiseptic solution (Tr. Iodine 2%) and packed with sterile gauze (drain), and dressing should be repeated daily for 3-4 days till complete obliteration of the cavity

C-3^rd degree contusions: -

Definition: -

It is a severe contusion that causes considerable destruction of deep tissues (bone, tendon, nerve, .. etc.) and may cause gangrene

Symptoms: -

Depending on the affected region

1-Evidence of shock          

2-Injury to internal organs                 

3-Muscular paralysis if motor nerve is involved

Treatment: -

1-Complete rest of the animal and affected organ

2-Moist warm antiseptic applications to restore circulation in the severely damaged tissue and to prevent gangrene

3-Local antiseptic to prevent infection of injured tissue

4-Treatment of gangrene or shock if they exist

2-Abrasion

Definition: -

It is a superficial wound, produced by friction of the skin or mucous membrane against hard or rough surfaces, and it is characterized by removal of small area of epithelium with exposure of the small blood vessels in that area.

Symptoms: -

1-Pain due to exposure of superficial nerve endings

2-Seepage of blood due to injury of superficial capillaries with the formation of blood clot (crusts)

3-Local or general disturbances due to infection under the scab

4-Repeated bleeding if the abrasion is situated over a joint, due to repeated cracking

Treatment: -

1-Cleaning and application of antiseptics or antibiotics ointment, and healing ensues under scab (crust); or removal of the crust, to allow dressing and removing the infected material if there is infection under the crust

2-Immobilization of the joint (if the lesion is over a joint) to prevent cracking and repeated bleeding

3-Sprain and Strain

A-Sprain:  -

Definition: -

It is a damage of ligamentous fibers or its attachment to bone as a result of overstress

Classification: -

i-Mild sprain: -

It is characterized by injury of few fibers, mild hemorrhage, and no actual functional loss

Treatment: -

Treatment is not important and it aims at;

1-Rest

2-Control of pain

ii-Moderate sprain:

Some fibers have been torn (varies from small tear to complete avulsion), no wide retraction of the two ends, some hemorrhage, and some degree of functional loss.

Treatment: -

The same as mild sprain with protection to permit healing

iii-Severe sprain: -

Complete loss of function, hemorrhage, and wide separation of the ends

iv-Sprain fracture: -

Avulsion of a portion of a bone to which the ligament is attached

Treatment: -

Severe or fracture sprain can be treated by apposition of the injured ligament to assure alignment of normal length and strength, with application of cast for 6 weeks.

B-Strain: -

Definition: -

It is damage to a tendon or muscle as a result of overstress or overuse

Classification: -

i-Simple strain: -

Low-grade inflammatory reaction with swelling and edema, but there is no appreciable hemorrhage, and it can incapacitate animal from work.

Treatment: -

1-Relieve of the acute condition by local analgesics and corticoids

2-Ultrasound, local heat and protection

ii-Violent strain or musculo-tendinous injury: -

Definition: -

It is an injury to the muscle and tendon as a result of one violent injury, and it may be associated with tendonitis, tenosynovitis, or tendosynovitis. The tendon may be torn from bone, and the musculo-tendinous junction may be rupture or undergo tearing.

Treatment: -

Surgical repair of ruptured musculo-tendinous junction or severed tendon (wound), followed by application of cast with corrective showing. Sprain is a tearing (partial) of ligaments, tendons, muscular tissues or joints leaving hemorrhage and edema in the area. The loss of function resulting depends on the laceration and the degree of rupture of the fibers. The swelling may become injurious to the overlying tissues, and therefore, rest, elevation and compression should be utilized until healing has occurred. Sprain of the joint results from its movement beyond its physiological limits in the direction of extension, flexion, abduction and adduction. As a consequence the articular and periarticular tissues suffer a certain amount of bruising or laceration. The ligaments in particular are subjected to distortion.

II-OPEN WOUND (External or exposed wound)

Definition: -

It is a disruption or break in the continuity of the skin or mucous membrane to a variable degree with exposure of the underlying soft tissues to contamination, and sometimes it is associated with loss of tissue

Cause: -

External violence

Classification: -

1-Incised Wound

Causes: -

Sharp cutting instruments, such as knives, scalpels, fragments of glass, wire, or a sharp piece of metal

Symptoms: -

1-Gap formation and the extent of gaping depending upon the nature of the causative object, the elasticity of the affected tissue and tension of the surrounding tissues

2-Regular edges and there is comparatively less injury to cells

3-It bleeds freely and may be painful

4-Its length is greater than depth

5-If the edges are in apposition and the wound is protected from infection, it heals by 1^st intention

2-Lacerated Wounds

Causes: -

A lacerated wound is caused by blunt objects such as wheels, stones, barbed wire, or sticks ... etc.

Symptoms: -

1-The edges of the wound are irregular or uneven

2-The skin is more or less extensively injured and it may be lifted over a wide area from underlying tissues

3-Hemorrhage is relatively insignificant or absent due to crushing of blood vessels during trauma, and blood clot easily seen in the wound mixed with dirt or foreign bodies

3-Punctured or Stab Wounds

Causes: -

Punctured wounds are caused by sharp long pointed objects like nails, pins, needles, hooks or fragments of glass.... etc, and an example is picked up nail

Symptoms: -

1-It has a relatively small single orifice of entrance but there is no exit orifice

2-Its depth is longer than its length

3-The orifice is inadequate for drainage

4-Infection or foreign particles might have been carried deep into the wound

4-Penetrating wounds

These are wounds communicating body cavities like abdomen, thorax, joints, trachea ... etc, it has orifice of entrance but there is no exit orifice

Symptoms: -

1-The wound has an entrance but no exit

2-Infection or foreign particles might have been carried deep into the wound

3-The orifice is deep and inadequate for drainage

5-Perforating wounds

A perforating wound has two openings (entrance and exit). However, the term perforating wounds and penetrating wounds are sometimes used synonymously.

6-Gunshot Wounds

Causes: -

These wounds are produced by various types of fire arms

Symptoms

The wound is a combination of lacerated, punctured, penetrating, or perforating wounds, and the point of entrance of the bullet is marked by a small opening on the skin but the course of the bullet in deeper tissues exhibits more extensive damage.

7-Poisoned Wounds

These wounds are characterized by the deposition of acids, alkalis, or mineral or vegetable poison

8-Envenomed Wounds

These wounds are characterized by deposition of venom. These comprise snake, scorpion, bee bites, or bites of other insects

9-Virulent Wounds

These wounds are characterized by the deposition of virulent microorganisms as in case of rabies, anthrax or tuberculosis. The bite of rabid animal may be considered as a punctured wound that contains the virulent saliva of the infected animal (with rabies virus) and thus termed virulent wound

10-Granulating Wounds

These are long-standing wounds that develop an overgrowth, abnormal granulation tissue (exuberant or proud flesh). This tissue is unhealthy and should be removed to permit healing. It can be noticed on movable parts of the body as joints or associating purulent fistulae.

11-Ulcerative Wounds

These comprise wounds or lesions that fail to undergo the natural process of healing, or wounds have no tendency to healing

12-Avulsion Wounds

They are wounds that are associated with loss of tissue as in case of avulsion of hoof or horn

13-Contused Wounds

They are contusions caused by blunt objects but associated with open wound of the skin. They have the same symptoms mentioned before in contusions in closed wounds except for presence of open wound of the skin.

CLINICAL SIGNS OF WOUNDS

I-LOCAL SYMPTOMS

1-Hemorrhage

It varies according to;

1-The vascularity of injured tissue

2-The size of divided vessel

3-The nature of the wound

2-Pain

It varies according to the amount of innervations of injured area, but generally skin is more sensitive than muscles and tendons, and pain is intensified by infection.

3-Gaping of the Wound Lips

It means separation of wound lips and it affects duration of healing and amount of cicatrix, and it depends up on

1-The causative agent

2-The nature of severed tissue (the skin is highly elastic and retracts when incised)

3-The direction of wound as gaping can be observed when the tendons or muscles are severed transversely, more than when they severed on the direction of their long fibers. Generally transverse wounds associated with clearer gaping than longitudinal ones.

4-The location of the wound as gaping can be observed on extension side of joint more than flexion side

4-Phenomena of Repair or Inflammation

Inflammation ensues after wound as a result of injury of cells and destruction of the phospholipids wall and formation of arachidonic acid. The process aims at repair of the wound and indicates that the tissue is healthy.

II-GENERAL SYMPTOMS

General symptoms comprise febrile condition and it varies according to the virulence of infecting micro-organism, degree of injury, and toxemia

III-REMOTE SYMPTOMS

They occur far from the wound region and they include;

1-Ischemia or Gangrene

They ensue when thrombus is formed in an artery involved in the area of the wound

2-Abscess in LN

It occurs when the suppurating micro-organism pass to the LN via lymphatic vessel

3-Neuritis

It ensues along the course of a nerve involved in the wound due to trauma or infection

4-Paralysis

Due to injury of motor nerve

5-Loss of sensation

Due to injury of sensory nerve

Prognosis: -

1-Aseptic wound heals rapidly

2-Open non-infected wound heals rapidly

3-Healing of infected wound depends up on;

a-The virulence of micro organism

b-The location of the wound

c-The general health condition of the patient

General Principles Of Wound Treatment

Generally, open wounds are classified into;

1-Recent accidental wound (up to 8-12 hours)

a-Aseptic wounds (6-8 hours)

b-Suspicious wounds (8-12 hours)

2-Septic or complicated old wounds (over 12 hours)

I-RECENT ACCIDENTAL WOUND (up to 6 or 8 hours)

1-Clean Aseptic Recent Wound

This includes surgical wounds and treated by suturing for promotion of healing by 1^st intention.

2-Contaminated Recent Wound

Generally, every wound except that inflicted by the surgeon is potentially infected. The safe period is 6 hours, probably 8 hours and in some cases 12 hours, before the end of this period the wound can be considered recent and can be treated as follows;

Arresting of hemorrhage by different methods (crushing, ligature, etc…..). Fixing of sterile gauze above the small wound and disinfecting of the skin in its vicinity. Large wounds must be covered with a piece of clean lint and a pad of cotton is applied around the wound and fixed by bandage. It is contraindicated to use any antiseptic or water above the bandage. Clipping and shaving the hair without the use of water or soap and the periphery is disinfected with tincture of iodine. The piece of gauze above the wound is then removed and the foreign bodies, necrotic tissues, bone fragment and clots in the wound must be removed by sterile surgical instruments. If any foreign bodies are adhered in the depth of the wound, it is possible to use a piece of gauze immersed in sterile normal saline, several times, until the wound becomes completely clean. Freshening of the edges of the wound can be performed by excision of small strips of the edges and depth, and removal of lacerated muscles and all necrotic tissues. Control the bleeding either by ligatures, crushing, or cauterization. Insufflate every part of the wound with sulfonamide or antibiotic powder. Suture the wound without tension, using the suitable material for each layer, and if there is loss of tissues that the apposition of the edges is impossible, the wound should be left to heal by second intension and later on the skin be grafted. Put a drain with antibiotics at the lowest point of the wound if there is suspicion of collection of discharge. Inject broad spectrum antibiotic and multivitamins. Put   the   affected    part   in   complete   rest   and    if   possible immobilize it. General treatment involves paying attention to the patient's diet, bowel and bladder.

Every patient with a potentially infected wound must be injected by a prophylactic dose of tetanus antitoxin as well as dose of antibiotics for three successive days

Contraindications: -

1-Application of cotton directly on the wound to prevent fibers from sticking inside the wound and retarding healing process

2-Washing the periphery of the wound by water or antiseptics, to avoid transmission of microorganisms from the skin to inside the wound, and if it is important to wash the wound, it can be washed from its interior by sterile saline.

3-Using strong antiseptics, curettes, and probes because they cause retardation of healing

II-OLD SEPTIC WOUND (over 12 hours)

Clip and shaving the hair at the vicinity of the wound, wash this area by soap and water, and then touch it with tincture iodine. Flush the wound itself with an antiseptic solution and remove the foreign matters as well as the destroyed tissues. When there is a pocket in the wound, in which septic discharge may be accumulated, it will be necessary to provide for good drainage. Paint the interior of the wound by stimulant antiseptic as tincture iodine or phenol   camphor solution   to stimulate growth of granulation tissue. Immobilize the injured area. Repeat the above dressing every 2-3 days till the wound becomes built up to the surface. The line of intended discharge should be protected by emollient ointment or vaseline after every dressing. When the wound cavity is built up to the surface, avoid the use of the stimulant antiseptic and paint the wound by mercuri ointment or solution and initiate the growth of epithelium at the periphery of the wound by using zinc oxide ointment or cod liver oil.

III-TREATMENT OF SOME SPECIFIC WOUNDS

1-Punctured Wounds

1-Cleaning the field as mentioned before

2-Exploration of the depth of the wound under strict hygienic measures, and when it is narrow enough to block exploration, it is advised to widen the orifice to permit exploration and to facilitate drainage

3-The wound is treated locally according to the elapsed time and presence of contamination, but it is contraindicated to suture it.

4-Establishment of drainage is an important step of treatment  

2-Envenomed Wounds

These wounds are usually encountered in the limbs, tail or sometimes the head and lips, and they are either neurotoxin or hemolysin

Treatment: -

1-Recent case is treated by application of an elastic bandage above the site of wound and ice over affected area to induce vasoconstriction and subsequent prevention of toxin spreading. The puncture wound is enlarged and aspiration of toxin, by massage from periphery to center or even suction of venom by mouth (provided that there is no wound the oral mucosa), can be applied

2-Firing the wound with mineral acids or by hot red iron

3-Washing the wounds with agents to neutralize the venom as 1% chloride of gold or 2% calcium chloride

4-Injection of stimulants as caffeine

5-Anti-venom vaccine must be given to the animal within 4 hours after biting

6-Anti-inflammatory and anti-histaminic can be used to reduce inflammation and allergy

3-Wounds Caused by Bee and Wasp Sting

This wound induces severe pain and severe excitation to the animals and even death occurs in small and occasionally large animals.

Treatment: -

1-Spraying the animal with water under pressure for repulsion of bees or wasps

2-The site of biting is washed with alkaline solution (ammonia solution) in case of bee and hornet sting; or weak acidic solution in case of wasp sting, and stings can be removed when it is possible.

3-If inflammatory swelling of nasal passage is large enough to cause dyspnea, tracheotomy is indicated.

4-Injection of stimulants as caffeine, anti-inflammatory

4-Surgical Debridement (Excision of the wound)

It is a method of wound treatment especially when the wound has large amount of damaged tissue or foreign bodies or highly lacerated. It is performed via surgical removal of the superficial portion of the contused or devitalized tissue.

The wound gap is filled with sterile gauze moisten with sterile saline, the hair around the wound is removed, then the skin around the wound is excised carefully including dead zone. The wound should be sutured, even if suturing is impossible, healing will ensue much more rapid than before excision.

Complications of Wounds

I-COMPLICATIONS OF NON-INFECTED WOUNDS

1-Hemorrhage

Hemorrhage is usually arrested via clotting of blood unless the injured vessel is large; the animal suffers from deficiency of coagulation factors like vitamin K or calcium; or the animal suffers from certain diseases like hemophilia, leukemia, liver disease. Continuous bleeding may predispose to anemia and the animal shows collapse, gasping respiration, tachycardia, and pale mucous membranes, and even death may ensue as a result of cerebral ischemia. On the other hand, repeated slight bleeding causes chronic anemia with characteristic pale mucous membranes, tachycardia, and general debility. Generally hemorrhage causes syncope or shock

Treatment: -

See hemorrhage

2-Syncope (Fainting)

Definition: -

It is a state of unconsciousness due to cerebral ischemia due to sudden fall in blood pressure and characterized by a sudden arrest of heart

Etiology: -

1-Severe hemorrhage

2-Reflex action or depression of vasomotor action

Symptoms: -

1-Pale mucous membrane

2-Subnormal body temperature

3-Loss of consciousness

4-Dilated pupils

5-Relaxation of the voluntary muscles

6-Cardiac and respiratory inhibition

Treatment: -

1-Keep the head at a level lower than the body

2-Flicking (striking lightly) the body with towels

3-Performing artificial respiration

4-Subcutaneous injection of caffeine or coramine

5-Cases of severe blood loss should be treated by fluid therapy and blood transfusion

3-Shock (Collapse)

Definition: -

It is profound depression of vital functions of the body as a result of reduced delivery of tissue oxygen and it is either primary (of neurogenic origin) or secondary (of traumatic origin) state of collapse

A-Primary neurogenic shock: -

It may be caused by a variety of conditions associated with noxious sensory stimulation of the medullary centers (transmitted from either the peripheral sensory nerve ending or the sympathetic nerves of an injured part); or it may occur due to prolonged post severe surgical manipulation. This type of shock is associated by generalized reduction in vascular tone and reflex vagal inhibition of the heart, causing fall of blood pressure leading to diminished venous return to the heart.

Example: -

A blow on the testicle may be immediately fatal.

Symptoms: -

1-The animal appears to be in a prolonged fainting fits

2-Pale mucous membranes with warm extremities due to peripheral dilatation

3-Slow poor volume pulse rate

4-Respiration is shallow and slow

Treatment: -

1-In mild cases, rest together with simple stimulant is sufficient.

2-In severe cases, eliminate all noxious stimuli, protect every injured part, and control hemorrhage. Sedatives may be used in small but never in large doses.

B-Secondary traumatic shock: -

It develops few hours or days post-injury sometimes due to internal bleeding

Symptoms: -

1-The animal appears in apathetic condition with signs of thirst and hem-concentration

2-Rapid thready pulse

3-Rapid respiration

4-Subnormal body temperature

5-Low blood pressure

Treatment: -

1-Preventive treatment: -

1-Maintenance of   body   fluid balance during operations

2-Avoid rough handling during operations, especially for the internal organs

3-Reduction of dryness of the internal organs and hemorrhage

2-Active treatment: -

1-Control of hemorrhage if present

2-Vasoconstrictors drugs (only if shock is characterized by vasodilatation and those animals that require treatment for shock should be monitored after recovery to avoid serious relapses)

3-Lower the head, apply firm bandages to the limbs, and keep body temperature near to the normal

4-Fluid therapy; and blood, plasma, or plasma substitute transfusion

5-Control of pain and inflammation by corticosteroids (hydrocortisone, prednisolone, or dexamethsone) and ACTH to combat stress

6-Antibiotics

4-Traumatic Neuralgia (hyperesthesia)

A-Primary traumatic neuralgia: -

It is characterized by the persistence of pain since the wound was produced, and the pain either confined to the region of the wound or extends along the nerves in the vicinity.

B-Secondary traumatic neuralgia: -

It appears few days after the injury either due to infection, or pressure of cicatrisation; and it is either confined to the wound or extend into the vicinity.

Treatment: -

1-Treatment of the wound, aseptically by application of anodyne preparation like moist warm antiseptic compression (that has analgesic effect), or iodoform

2-When the pain is due to rheumatic pain, acetyl salicylic acid is indicated

3-If it is due to contraction of scar, the nerve must be exposed an freed from the contracting tissue and displaced to another site

5-Traumatic Emphysema

Definition: -

It is subcutaneous accumulation of air or gas as a result of injury to the respiratory passage or alimentary tract. It also associates wounds of movable areas like axilla, groin or around joints as the air entrapped into subcutaneous tissue during movement of affected part. Generally it is a common complication of punctured and penetrating wounds. Uncomplicated emphysema is usually harmless and resolved spontaneously within few days.

Symptoms: -

1-Presence of soft, circumscribed, painless, crepitating, swelling which fades gradually with the surrounding area

2-When it involves extensive area, general discomfort and dyspnea may ensue   

Treatment: -

The condition is usually harmless and the air get absorbed in few days when it is aseptic

1-Application of pressure from the periphery of the swelling towards the wound

2-If the axilla or groin is wounded, give rest to the patient and prevent movement

3-If emphysema is generalized subcutaneously, originates from respiratory passage, and causing discomfort and dyspnea, enlarge the wound to permit escape of the air

6-Traumatic Fever

A-Simple traumatic fever (primary): -

It occurs directly after injury to the tissues, that have no infection, due to absorption of inflammatory exudates, results in stimulation of the thermogenic or heat regulation center, and it is characterized by slight rise of temperature and acceleration of pulse and respiration. The temperature returns to normal 1-2 days later.

B-Symptomatic traumatic fever (secondary): -

It occurs as a result of absorption of toxins and byproducts from a septic wound.

Treatment: -

1-Antipyretic

2-Application of efficient wound drainage

3-Protection of the wound from infection

4-Antibiotics if the wound is infected

7-Venous thrombosis

Causes: -

It ensues as a result of phlebitis of a vein which has been opened or contused during the accident or improper dressing. The danger is that the thrombus may disintegrate into emboli and the end results depend upon;

1-The size of the emboli

2-The seat of the emboli 

3-The degree of sepsis of the emboli

Fat embolism may ensue as a result of laceration of adipose tissue accompanying a wound of a vein or when the shaft of a long bone is fractured with subsequent destruction of its marrow. On the other hand, air embolism may occur when injury near a vein occur

Treatment: -

1-Avoid rough handling during dressing of any wound

2-Application of antibiotics course if general infection is suspected

8-Adhesion

Adhesions are considered as a sequel to wound process, during the course of wound healing. when the wounded surfaces of the different tissue skin, sc, muscles, tendons … etc form adhesion between these surfaces that are in contact, such adhesions cause difficulty in normal movements and interfering with the normal function of some structures.

9-Myiasis

Myia is a greek word means fly and myiasis means a condition caused by infestation of the animal body by flies or their larvae. Although many authors consider the presence of such larvae in the wound as a good signs indicating periodic removal of dead tissue which is a good media for bacterial growth, in addition to secretion of metabolic products that acts at the same time as inhibitors for bacterial growth; however some authors prefer to remove it daily with application of turpentine or compher as fly repellant.

II-COMPLICATIONS OF INFECTED WOUND

1-Non-specific Infection

A-Pyogenic infection: -

Causes: -

1-Staphylococci

2-Streptococci

3-E. coli

Virulent Staphylococci tends to spread through extensive areas of tissues producing necrosis of the tissues rather than abscess formation, and formed pus is usually start watery then thickened, while E. coli pus is thin and watery, and has offensive fecal odor

Symptoms: -

1-Sutured wound: -

1-Gradual increase of edema, fluctuation and pain due to pus accumulation

2-Enlargement of lymph vessels and glands

3-Fever, increased heart rate, and loss of appetite

2-Granulating (open not sutured wound): -

Granulation becomes blue or blackish red, grayish white; swollen; and bled easily

B-Cellulitis: -

Definition: -

Cellulitis refers to a painful spreading inflammation of the skin, which appears red and swollen with fluid (this is known as oedema) or it is a spreading of inflammation into subcutaneous or loose connective tissue.

Causes: -

1-Irritant substances lodged in body tissues

2-Serious infection

Pathogenesis: -

At first the seat of infection shows signs of inflammation that rapidly changes to diffuse brawny infiltration. The area becomes slightly raised, red intense and tender, and the edges of the inflamed area are indefinite and fade off into the surrounding normal tissue. Slowly the brawny area will soften until it has boggy touch and if untreated the overlying skin will develop vesicles which discharge a thin sero-pus. Sloughing and gangrene may take place over a very considerable area.

Prevention: -

1-Using sterile injecting equipment;

2-Using sterile water where available

3-Avoiding the injection of irritant

Treatment: -

Treatment includes resting, and treatment with antibiotics and anti-inflammatory drugs.

1-Complete removal of infected wound and retreat it as aseptic recent wound or complete rest of the affected part with:

-Topical treatment of the wound

-Improve the circulation of affected part

2-In boggy cases, incisions should be made and then carefully attended.

3-Systemic antibiotics

2-Specific Infections

A-Tetanus: -

Definition: -

Tetanus is an important disease occurs as a result of infection of punctured deep wounds (castration, docking, or accidental punctured wounds as picked up nail) by Clostridium tetani that produces toxins affecting the nerve centers giving rise to tetanic convulsions.

Signs: -

Signs develop few days up to few weeks after infection according the distance of the wounds from the high centers and the amount of produced toxins

Susceptibility: -

1-Equine most susceptible

2-Sheep and goat

3-Bovine less susceptible

Treatment: -

1-Anti-tetanic serum by all routes of injection to neutralize the toxins (90.000-300.000 I.U., 3 injections, 12 hours interval)

2-Prevent further absorption of toxin via; opening the wound, removing all infected tissues, irrigation by strong antiseptic solution, and change the anaerobic condition of the wound by irrigation with oxidizing agents (hydrogen peroxide).

3-Systemic penicillin

4-Tranquilizers, muscle relaxants, or even intravenous magnesium sulfate, are useful for control of muscular stiffness and tetanic convulsion

5-Nursing via stomach tube or intravenous feeding, catheterization of urinary bladder, enema, and keeping animal in quite dark place

Prophylaxis: -

Injection of anti-tetanic serum (1500-3000 I.U.) immediately after injury or open castration

B-Rabies: -

Definition: -

It is a viral disease affecting animals by a bite of an animal infected with rabies especially dogs

Treatment: -

It is chiefly prophylactic and conservative;

1-The suspected wound should be treated as an envenomed wound by scrapping and bleeding of wound, washing with soap and water, application of 70% alcohol and 10% carbolic acid

2-Hyper- immune serum

C-Erysipelas: -

Definition: -

It is a contagious disease caused by Streptococcus erysipelas

Characters of causative agent: -

1-It survives for long periods in decaying flesh and water

2-It resists preservation processes as salting, smoking, and pickling

3-It causes marked cutaneous swelling at the vicinity of the wound that varies in size but always rectangular in shape, sharply demarcated from the adjacent normal skin. At the beginning they are bright red but later they become purplish and eventually a dark bluish color and the discharge is amber colored but suppuration can be seen on sloughing.

i-Cutaneous erysipelas: -

It is characterized by diffuse, hot, painful swelling of the skin that spread rapidly and may be accompanied with lymphangitis. When the lips of the horse are affected, swelling can be observed all over the head. General symptoms of traumatic fever are noticed

ii-Phlegmonous and gangrenous forms: -

Presence of the general symptoms of diffuse suppurating legion and moist gangrene, fever, and death is a common termination

Treatment: -

Same as septic wound including

1-Provide good drainage

2-Apply anodyne dressing

3-Systemic antibiotics or sulphonamides

4-General tonics and vitamins

D-Gas gangrene (gangrenous septicemia, gas phlegmon, or malignant edema): -

Definition: -

It is an affection caused by group of organisms belonging to Clostridium that invade deep tortuous wounds with tissues that severely bruised and have anaerobic condition

Symptoms: -

1-The local symptoms: -

Hot painful edematous swelling around the wound with grayish or reddish foetid discharge, later on the center of the swelling becomes depressed, cold, insensitive, and crepitating; the exudates become brown; and the muscles appears bluish gray as if it is cooked

2-The general symptoms: -

Fever, toxemia, and increased pulse and respiration, deteriorated general health condition and loss of appetite, and death may supervene in 2-4 days after the onset of infection

Treatment: -

The same as septic lesions and moist gangrene, and specific antiserum should be given.

1-Creation of multiple incisions to change the anaerobic condition of the wound

2-Wash with hydrogen peroxide and apply drain

3-Systemic penicillin, general tonics and vitamins

3-Generalized Infections

A-Septicemia: -

Definition: -

It means that both bacteria and toxin are detectable in blood

B-Bacteremia: -

Definition: -

It means that only bacteria can be detected in the blood

C-Pyemia: -

Definition: -

It is the condition in which multiple abscesses develop in various parts of the body due to the presence of septic emboli. Some of metastatic foci may be inaccessible and may lead to the death of the animal if they reach a vital structure.

D-Toxemia (Sapremia): -

Definition: -

It is the case in which only bacterial toxin can be detected in the blood while the causative organisms located at the site of infection and in such cases, the blood culture is free from any bacteria

Treatment of generalized infections: -

1-Complete rest of the patient and affected part

2-Careful antiseptic dressing of the wound

3-Daily I.V. injection of 10% glucose saline and systemic antibiotics or sulphonamides

4-Granulomatous Infections

A-Actinomycosis (Lumpy jaw): -

Definition: -

It is a disease affecting cattle and caused by Actinomyces bovis (anaerobic gram positive organism) that is a normal inhabitant of the mucous membrane of the upper respiratory and digestive tracts. The organism becomes pathogenic when a local injury reduces the vitality of the tissues.

Characteristics:

1-Abscess formation and encapsulation at bones of the mandible

2-Advanced cases have dense and compact swelling with much connective tissue (lumpy jaw)

Treatment: -

1-Penicillin streptomycin of high doses for 3-14 days

2-Oral 10 gm potassium iodide for 7-10 days and repeated after 14 days

3-Local treatment of the abscess

B-Actinobacillosis (Wooden tongue): -

Definition: -

It is a disease caused by Actinobacillus ligniersi (anaerobic gram negative organism) that causes the formation of abscesses in the cervical region particularly in the tongue or sub-maxillary lymph nodes.

Treatment: -

As mentioned for Actinomycosis

C-Botryomycosis (Granuloma pyogenicum): -

Definition: -

It is a low grade inflammation due to invasion of a wound by Staphytococcus aureus that results in Granulomatous growth with variable degree of suppuration. The lesion involves oral mucosa, udder tissue, spermatic cord (after castration), skin, and internal organs. The lesion start as multiple small swellings that gradually increase in size and become hard in manipulation without pain, and later on the abscess open forming multiple fistulae. 

Treatment: -

Treatment is difficult due to the fact that the process involves the tissue below the mucosa and a special effort must be made to remove all of the infected tissue. Radiotherapy may be employed alone or to support the surgery. Total extirpation may be attempted but when the infection reaches the abdominal wall, the condition is considered incurable.

PROCESS OF HEALING

Generally mucous and serous membranes, and connective tissue undergo rapid healing followed by the skin especially if the edges of the later are opposed, on the other hand, muscular tissues, tendon, and hyaline cartilage lack such regeneration capacity and when they are injured they are replaced by fibrous tissue.

Wounds usually heal in a process which varies according to the character and condition of the wound. This process of healing may be ensued by:

I-HEALING BY 1^st INTENTION (primary union)

After the approximation of the edges of the wound with sutures, the small space in between is sealed by clotting of the blood and plasma which exudes from damaged and severed capillaries.

Within 24-48 hours the fibrocytes, which lie at the margins of clean incision, begin to multiply and within 3-4 days from the time of the injury the fibroblasts migrate into the clot material along the fibrin threads. These fibroblasts are accompanied by macrophages as well as capillary buds which unite to form capillary arches. The macrophages dissolve the clot and remove it.

Within 4-5 days the clot will be replaced by vascular connective tissue growing in an organized manner. This process of organization joins the edges of the wound and replaces the previous fibrinous union by a fibrous union and the wound rapidly gains a tensile strength as the fibroblasts assume the characteristics of the fibrocytes. A high level of the tensile strength is attained within 10 days. Essential factors for that healing are;

1-The wound is recent or the lips are freshened

2-The lips of the wound must be regular

3-The wound is aseptic

4-Absence of hemorrhage

5-Presence of good blood supply to the lips of the wound

6-Accurate apposition of lips by sutures

7-Wound immobilization until cicatrisation ensues

8-Presence of no foreign bodies or gaping in the depth of the wound

9-Presence of no dead tissue in the wound

10-Wound protection from infection by topical antibiotics until cicatrisation ensues

11- Proper alignment and apposition of respective anatomical layers edges

II-HEALING BY 2^nd INTENTION (granulation or tissue replacement)

In the exposed surface of the wound, a delicate layer of moist, clot like exudate is formed into which fibroblasts and capillary buds grow while the leucocytes escape in its meshes. At this time, when the wound surface is inspected it will found to be consisted of red, richly vascular moist tissue with a slightly granular surface which is called granulation tissue.

With minor degree of infection this layer of granulation tissue gradually advances till the defect is filled at the same level of the adjacent tissues. At this stage the growth of this granulation tissue should be arrested and epithelization at the edges of the wound should be initiated to cover this granulation tissue. Excessive irritation at this stage may cause an elevated mass of redundant connective tissue to grow at the site of the wound (over growth or proud flesh). Finally the fibrous tissue contracts causing constriction and obliteration of most of the blood capillaries forming the characteristic pale color cicatrix or scar tissue. The overall process may last 14-21 days up to 6 weeks or more.

III- HEALING BY MIXED INTENTION

It happens when sutured wound undergo partial disruption accordingly this wound undergo healing partly by 1^st intension and partly by 2^nd intension

IV- HEALING BY 3^rd INTENTION (secondary suture)

It occurs when the granulating surface of an extensive wound, which undergoes healing by 2^nd intension, is united by sutures to permit quicker healing.

V-HEALING UNDER SCAB

This occurs in small wounds and abrasions. The blood and lymph which appear on the surface coagulate and become dry, producing dark brown crust. Appearance of granulation tissue takes place under this crust in an identical manner with the healing by 2^nd intension and at the same time the marginal epithelium proliferates to cover this granular surface. As the healing progresses, liquefaction of the depth of the scab at its margins ensues forming thin clefts into which the advancing epithelium flows. This is mostly noticed at the margins where the scab becomes thin and curls upwards. Finally, the raw surface is covered by epithelium and the crust becomes detached and drops or cast off.

FACTORS AFFECTING HEALING OF WOUNDS

I-THE LOCAL FACTORS

1-Devitalized and Necrotic Tissues

These tissues are irritant, serve as an excellent medium for bacterial growth, and exhaust energy of the living cells for eliminating foreign materials on expense of repair of the problem.

2-Infection

It is either primary infection (caused by the wounding agent) or secondary infection (from the animal skin, surrounding or during dressing)

3-Foreign bodies

It is either being introduced from the outside or produced in areas of old injuries (calcium deposition)

4-Inadequate blood supply

It ensues by laceration of regional vessels, pressure of old scar, or undue tension of sutures.

5-Edema or Lymphatic Obstruction, and Hemorrhage

This causes reduction of oxygen tension in the tissues with liberation of carbon dioxide and fall in the pH which in turn result in further devitalization of the tissues. Presence of bleeding, hematoma, and serum collection in a wound result in increased tension on the tissues, pain, ischaemia, necrosis, and delayed healing.

6-Improper Apposition and Presence of Dead Space

Dead space predisposes to edema of the wound with subsequent delayed healing

7-Lack of Immobilization

8-Chemical and mechanical trauma:

II-GENERAL FACTORS

1-Malnutrition

It lowers resistance of the patient leading to failure of the body to mobilize the defense mechanisms. Hypoproteinemia inhibits fibroplasias within granulation tissue so the edges of the wound appear soggy with edema and they may give no evidence of fibroplasia as late as the 8. 14 days after injury

2-Avitaminosis

1-Vit. C is essential for the production and maintenance of the intercellular cement, especially in the capillary beds and in the collagenous tissues. Lack of intercellular substance in the granulation tissue and capillary beds results in hemorrhage into the wound space, retards fibroplasia and delays the development of adequate tensile strength.

2-Vit. A is essential for the epithelization following operations or injuries

3-Vit. K is essential for prevention of hemorrhage

3-Abnormal Temperature

The ideal temperature for the healing of a wound is that of the normal body, and effort should be made to maintain it in regard to dressing and atmospheric condition

4-Restlessness

Rest of the wounded part is of considerable importance especially to wounds of the extremities as in the regions of joints. Movement of the wounded area disturbs the medium in which the cells are growing and causes extravasations of blood and lymph.

5-Metabolic Disorders

Metabolic diseases such as diabetes and liver cirrhosis may inhibit wound healing

6-Age

Healing is quicker and better in young animals than in old one

7-Pregnancy

Healing is delayed in pregnant animals than in non-pregnant

8-Uremia

Wound healing in patients with uremia appears to be retarded

9-Species

Healing is quicker in canine, bovine, and equine respectively

COMPLICATIONS OF HEALING

I-COMPLICATIONS OF HEALING BY 1ST INTENTION

1-Opening of the wound Lips

Causes: -

1-Excessive loss of the skin at the operation site that is associated with tension over the skin during suturing (as during removal of large swelling)

2-Improper knots or using threads of bad quality

3-Early removal of sutures before complete healing of the wound

2-Necrosis of the Wound Lips

Causes: -

1-Due to narrowing the spaces between stitches

2-Strong ligature of the sutures, leading to necrosis within 3-5 days

3-Accumulation of Wound Secretions

Causes: -

1-Suturing the skin only without suturing of the underlying tissues, leading to gap formation under the skin (dead space)

2-Incomplete arrest of hemorrhage before suturing the wounds leading to formation of blood clot in the depth of the wound

3-Secondary hemorrhage due to disintegration of the blood clot or thrombus

Treatment: -

Removal of the sutures from the lowest part of the wound and evacuation of wound contents by blunt instruments

4-Swelling

Small swelling is usually observed around the wounds but large swelling is usually associated with sepsis as pyogenic microorganisms predispose to local inflammation and fever

Treatment: -

1-Removal of sutures

2-Evacuation of pus

3-All measures for treatment of open septic wound are performed

II-COMPLICATIONS OF HEALING BY 2nd INTENTION

1-Hypergranulation Tissue Formation

Granulation tissue usually begins from the depth of the wound until it reaches the surface, then the skin is epithelialized and covers the granulation, but in abnormal healing, the granulation tissue is enlarged and protrudes over the skin forming granuloma. The granuloma is usually exposed to trauma and infection with formation of purulent secretions

Causes: -

1-Presence of wounds in vicinity of mobile regions like joints

2-External irritation by licking, scratching or faulty bandages

3-Faults during treatments by frequent using of caustics, curette, or washing of the wound

Treatment: -

1-Removal of the cause

2-Prevention of irritation by using local anesthetic ointments, fly repellants as tar, applying tail bandage, and mouth mask

3-Removal of excessive granulation tissue either by surgical removal or by topical application of copper sulfate or silver nitrate and application of pressure bandage over the wound

4-Skin transplantation or implantation is indicated when the size of the wound is large

2-Hypoplasia of Granulation Tissues

It is a slow formation of granulation tissue with eversion of the wound lips that is gradually transformed to an ulcer

Causes: -

A- Local causes: -

1. Wound infection
2. Faulty in treatment by using unspecific drugs
3. Paralysis of its nerve supply or venous thrombosis
4. Specific infection as tuberculosis or glanders

B-General: -

1-Age factor (old aged animals)

2-General debility and anemia

3-Species factor as it is noticed in small animals than large ones

Treatment: -

1-Use of good ration with addition of vitamins

2-Using ultra violet therapy is of good result

3-Touch the wound by tincture of iodine followed by cod liver oil

4-Surgical excision of the wound and re-suturing

5-It is contraindicated to use penicillin or cortisone locally as they retard healing process

3-Imperfect Epithelization

Causes: -

1-Presence of unhealthy granulation tissues

2-Hypergranulation tissues

3-Enlargement in the size of the wound

4-Repeated severe irritation to the wound

5-Prolonged application of bandage over the wound leading to destruction of epithelium

Treatment: - 

1-Removal of necrotic tissues

2-Using zinc oxide ointment or cod liver oil ointment to enhance epithelization

4-Pathologic Changes in the Scar

A-Ulceration: -

It is best treated by removal of ulcerated scar and application of skin transplantation

B-Atrophy: -

Causes: -

Slow formation of granulation with fast epithelization

C-Protrusion: -

Causes: -

1-Presence of much fascia is present like carpus, tarsus or forearm

2-Internal pressure on the scar as in case of wounds of abdominal wall

D-Hypertrophy: -

Causes:

1-Disturbance in lymphatic drainage

2-Sepsis

E-Calcification: -

It is usually observed after removal of inflamed bursa or after pig castration

F-Keratinization: -

The scar appears as hypergranulation tissue covered with keratinized tissue

Treatment Of All Pathologic Changes In The Scar: -…

It is best treated by removal of scar and application of skin transplantation

5-Ulcer

Ulcer is a wound of skin or mucous membranes that has no tendency to heal. Ulceration is usually accompanied by presence of pus. See ulceration and ulcer.

6-Fistula

This item will be discussed later