Respiratory Diseases Found in Animals

List of fifteen major diseases of the respiratory system found in animals:- 1. Nasal Catarrh 2. Epistaxis 3. Laryngitis 4. Chronic Laryngitis or Chronic Cough 5. Bronchitis 6. Chronic Bronchitis 7. Bronchial Asthma 8. Roaring 9. Lesions 10. Pulmonary Hyperemia 11. Pulmonary Emphysema or Broken Wind and Others.

Respiratory System: Disease # 1. Nasal Catarrh:

It is a catarrhal inflammation of the nasal mucosa. The disease may be simple or only symptomative of some contagious disease such as Distemper, Strangles, Influenza. It is commonly due to some infection and the organisms respon­sible may be common. Saprophytes only take on pathogenic powers when resistance is broken down by a chill, defective ventilation or some other debilitating circumstance. Catarrh may also be due to dust or polyp such as hay fever or dust fever.

Symptoms:

There appears a nasal discharge which is, at first, watery later is opaque and yellowish white. This is accompanied by sneezing in cats and dogs and snorting in horses. Some­times, the affection is up to Ductus and Nasus which become swollen and causes an overflow of tears and even eyelids may be swollen. Fever or rise of temperature only occurs when these ca­tarrhal symptoms are associated with some conta­gious general disease.

Mucous membrane is usu­ally red and sometimes ducts of mucosa are swol­len and prominent. A common catarrh is a mild affection and runs its course in 4 or 5 days with complete recovery. Sometimes, it extends to air sinuses or pharynx or to other parts of respiratory tract and may become chronic.

Treatment:

Keep the animal warm and com­fortable but allow plenty of fresh air. Nasal drops may be used and antihistaminic drugs may be of some use.

Respiratory System: Disease # 2. Epistaxis:

Bleeding from nose – In epistaxis, haemorrhage is usually slight and drops in small streams. Blood is bright red, occasionally in clots and is unmixed with air and the animal fre­quently snorts.

Etiology:

(1) Some ulceration of nose in glanders or purpura haemorrhagica.

(2) Mechanical irritants like straw or foreign bodies such as bites of insects or ulcerating new growth. In the horse of the present day, epistaxis is commonly due to some defects in the walls of nasal vessels which rupture when the animal is subjected to severe exercise such as racing or hunting or unusual excitement. It is very common in race horses and is hereditary and the animals are called Bleeders or Blood vessel breakers. The bleeding occurs suddenly and is usually one-­sided. It is usually bright red in colour and un­mixed with air.

Treatment:

The natural tendency is sponta­neous recovery. Keep the animal quiet. Apply cold scrab or ice over poll and give adrenaline subcutaneously. Camphorated oil may be used. Tie up head short. Rarely it is necessary to plug the nose and both nostrils require plugging, Tra­cheotomy must first be performed.

Respiratory System: Disease # 3. Laryngitis:

Involves the mucous membrane of the larynx. It may be acute or chronic. The most common form is catarrhal, but it may be phlegomonous or oedematous, Croupous or Diphtheria, Ulcerative or Necrotic— such as in glanders. Calf-diphtheria.

Etiology:

(1) Pathogenic microorganisms — many non-contagious forms of laryngitis are also due to pathogenic bacteria, some of which may be saprophytic on the surface and only invade the mucous membrane when the resistance is broken down by chills, sudden change of temperature and exposure’ to cold and wet.

(2) Inhalation of irritant gases in concentra­tion or irritant fumes.

(3) Drenches which may go in the wrong way.

Cough and the severity of the cough varies in proportion to the difficulty experienced by the larynx in removing foreign body such as dis­charge or dry mucous. In the dry stage of inflam­mation, the cough is loud and harsh, later when an exudate appears, it becomes moister and softer. It is frequent after feeding or during sudden change of temperature. Soon a nasal discharge appears which comes from both nostrils.

It is similar to that of catarrh. In the dog, the cough is often associated with shaking of head and even attempts of retching and vomiting. It is some­times thought that there is some foreign body in the throat.

Squeezing over the larynx causes flinching and pain and induces coughing. There may be some difficulty in swallowing but that symptom is more closely associated with pharyngitis. In oedema of the larynx, the symp­toms — which have been previously there of a simple laryngitis — become very severe.

Dyspnoea sets in owing to the narrowing of the opening from the accumulation of exudate in the mucosa and submucosa causing swelling of the mucous membrane. This dyspnoea may ap­pear very rapidly and be very severe. A roaring sound is often produced and there is great diffi­culty in swallowing food or fluids. The great danger here is asphyxia. Ulceration of larynx is occasionally noted in glanders and there roaring sometimes appear as a symptom. The course of the disease varies from a week to 10 days or more. Recovery is usual.

Respiratory System: Disease # 4. Chronic Laryngitis or Chronic Cough:

It appears as a sequel to the acute form but some­times appears independently. The chief symptom is a persistent dry cough appearing in spasms. Sometimes there is a nasal discharge which is often white and scanty. The animal may make noise. This may give rise to pulmonary emphy­sema.

Treatment:

Begin with the same treatment as in the acute form of Laryngitis. Various other agents may be used.

Respiratory System: Disease # 5. Bronchitis:

When the very small bronchioles become involved, the condition is called Capillary bronchitis. The great danger in bronchitis is that the inflammation extends to the alveoli of lungs and sets up Broncho-pneumonia. All the domestic animals are subject to this affection.

Etiology:

The chief causes are:

(1) Associated with contagious disease as Influenza, Distemper etc.

(2) Pathogenic bacteria and virus.

(3) Chemical irritants such as irritant gases.

(4) Various worm parasites – the most com­mon cause of bronchitis in young cattle, sheep and pig.

The common forms are acute and chronic, catarrhal chiefly, occasionally croupous.

Symptoms:

Acute:

Usually very marked and consists of constant blowing and coughing. The cough is very much like that in Laryngitis and is harsh and dry. When the mucous membrane is dry, it is very distressive and appears in paroxysms. The cough results from irritation of bronchial mucosa. Later, the cough becomes softer and moist when the discharge appears.

The dyspnoea is more se­vere in the early stage and the animal is not inclined to move very much. Visible mucous membrane has a slight bluish tinge but the tem­perature is not much disturbed, nor is there inter­ference with the appetite. In the later stage, there is discharge from both nostrils similar to that in Laryngitis. On auscultation over the lungs, one hears rough sounds, dry rales; while in the later stages, they become moist.

There is no marked change on percussion. As a rule, recovery takes place in a comparatively short time and the ani­mal seldom dies of bronchitis, unless it is in a very debilitating condition. The most serious com­plication is Bronchopneumonia. In that case, tem­perature rises, appetite diminishes. There is fever and in auscultation and percussion over chest consolidated areas can be determined in the lungs.

Other sequences are:

(1) The condition becomes chronic

(2) Asthma

(3) Emphysema of lungs.

Treatment:

Apart from parasitic bronchitis is on the same lines as for Laryngitis. Give plenty of fresh air and keep animal warm. Stimulating lini­ments may be applied. Sulfonamides or Antibiot­ics may be administered.

Respiratory System: Disease # 6. Chronic Bronchitis:

Is sometimes seen as a sequel to the acute form but not uncommonly it develops insidiously. It is sometimes seen in all old fat pet dogs where it may be mistaken for Asthma. The chief symptoms shown – a chronic cough which may be wheezing and distressing and appears in spasms.

On auscultation over chest, dry or moist rales may be heard. In dogs, the condition is very chronic and may persist for long periods. Although, temporary improvement may be noticed from time to time. Unlike Asthma, symptoms do not disappear. In this condition, there may be a Chronic Bronchiectasis.

Treatment:

Same as Acute Bronchitis. To relieve spasms, antispasmodic drugs such as Aminophyllin, Deriphyllin etc. may be adminis­tered.

Respiratory System: Disease # 7. Bronchial Asthma:

Is brought about by spasm of the bronchial muscles. In the later stages of the attack, the mucosa may be swollen and mucous falls. Among the domestic animals, the condition is not very common and is chiefly ob­served in the horse and dog. In the dog, it is more common in old fat animals. The actual cause of asthma has only definitely been made out in human medicine in some cases where it has been shown to be anaphylactic in origin.

The asthmatic patient may be hypersensitive to a great many different forms of foreign protein, e.g., pollen, the epidermal scales of different animals, different foodstuffs such as eggs, fish or potatoes.

The evidence of such factors being responsible for asthma in lower animals has not yet been defi­nitely established. In asthmatic subjects, the at­tacks are sometimes ascribed to peripheral irrita­tion, some digestive disturbances which may act reflexly through the vagus nerve or due to vari­ous climatic condition.

Symptoms:

One of the prominent features of asthma is that the disease appears intermittently and between the attacks, the animal is perfectly normal. The attacks come on very suddenly and pass off quite as suddenly. There is dyspnoea, the patient stands with elbows abducted, neck stretched and respiratory movements are pro­longed and exaggerated. This may be accompa­nied by a wheezing cough.

The cough is very distressive and the patient keeps mouth open or protrudes the tongue. The mucosa are slightly cyanotic, pulse becomes more frequent. The inter­nal and external temperatures are undisturbed. Bronchial sounds are dry and intensified and can be heard without auscultation.

Owing to distress the animal may not feed well. When the attack passes off, the animal appear perfectly normal. In the horse, the condition may be mistaken for “Broken wind” but as distinguished from “Bro­ken wind”, the animal appears perfectly normal at times.

Treatment:

Keep the animal on restricted diet in order to prevent pressure on lungs. Laxa­tives are sometimes useful. Allow animal plenty of fresh air and keep in a dry place – various agents are used to relieve the spasms during an attack: – Ether given by mouth is said to be nearly specific in horse. Aminophyllin or Deriphyllin may be given either orally or by injection to relieve spasms. Asthalin is a good drug. Amyl Nitrite inhalation is of some use. There are no lesions in this disease but emphysema may arise as a sequel.

Respiratory System: Disease # 8. Roaring:

It is also called Hemiplegia Laryngis or Laryngismus paralyticus – this is a chronic disease due to paralysis, usually affecting the left side of the larynx in which an abnormal sound is produced during forced inspiration. This disease in entirely confined to horses. Rarely, it has been noticed in dogs and cattle. It is seen in all breeds, most commonly in larger animals while cobs (short-legged strong horse) and ponies are only occasionally affected. This disease is associ­ated with long necks and narrow throat.

Etiology:

The most important factors in the production of roaring are strangles and heredity. Strangles is the most exciting cause. Roaring may also follow Laryngitis, Bronchitis, Pneumonia, In­fluenza and Pleurisy. Probably, these diseases act through the toxins of the pathogenic organisms upon the nerve endings of the Left Recurrent Laryngeal Nerve causing degenerative changes and paralysis.

Since the Left Inferior Laryngeal Nerve is most commonly affected attempts have been made to explain the reason. The explana­tions offered are unsatisfactory, e.g. The long course of nerve, aneurysm of Aorta and pressure on the nerve by enlarged glands or thickened pleura.

Roaring may also result from lead poison­ing and from feeding with paw. Heredity acts as a predisposing cause. Roarers beget roarers. But young animals show no symptoms until they are 3 or 4 years old, then they are put to work for exercise. Sometimes, roaring does not appear un­til late in life. Mitchell is of opinion that the condition may be due to imbalance or deficiency of minerals in the diet.

Respiratory System: Disease # 9. Lesions:

When an affected larynx is exam­ined postmortem, it would be noted that left arytenoid cartilage is depressed or has fallen into the lumen of the larynx. The intrinsic muscles on the left side and occasionally on the right side with the exception of Crico-thyroid will be found to be atrophied and undergoing fatty changes, that is posterior and later Crico-arytenoid, Arytenoideus, Thyro-arytenoid.

The posterior Crico-arytenoid is the most important and most powerful. The Crico-thyroid is the only intrinsic muscle not affected. The Inferior Laryngeal nerve is also undergoing degeneration beginning at the larynx. A horse may be sound one day and roar on the next day and one cannot state with cer­tainty how long it takes the disease to develop after an attack of strangles.

Symptoms:

Unless the horse is badly af­fected, no abnormality is noted during rest.

Evi­dence of the presence of disease is obtained in one of two chief tests:

(1) The most important by exercise. Exercise may be given by galloping preferably in a circle or in the case of heavy horses by harnessing to a heavy load. The amount of exercise required var­ies with the condition of the horse and is contin­ued until the horse shows some respiratory dis­tress. The sound or noise is produced during inspiration and can be heard particularly when turning or when the horse is pulled up suddenly, but it disappears rapidly on standing.

The noise is essentially an inspiratory one. That noise is due to the stationary condition of the vocal chord and arytenoid cartilage which impinge on the open­ing. The sound is similar to that produced by blowing through the neck of a bottle. In doubtful cases, it is advisable to rest the animal, feed and then give a second trial.

(2) Grunting:

By placing the animal against the wall and threatening it with a stick or some object. This is. the only method of determining in some cases. Grunting is not constant in Roarers but it occurs sometimes in animals which after­wards become affected. A grunt is prolong. A horse may grunt from other causes, e.g., nervous­ness or jumping or from attachment of lungs to the chest wall but in these cases, grunt is short and sharp.

The importance of roaring arises from several causes:

(i) Noise itself

(ii) Respiratory distress and

(iii) The chronic nature and hereditary ten­dency of the condition.

The respiratory distress may be so great as to prevent the animal from taking moderate exercise or doing light work. This may be due to want of aeration of the blood or some defect in circulation. The loudness of the sound is not always an index to the distress caused. The condition is also chronic and the animal seldom recovers. The disease may remain static or become worse. As a rule, the distress is greater where an animal is out of condition.

Some­times, attempts are made to modulate the symp­toms, so that the disease may not be recognised. Partial occlusion of nostrial before exercise, with­drawal of water or bulky food before exercise. Sometime, 150 gms of butter or glycerine is given 15 minutes before exercise. 95% of the horses which make a noise during exercise are Roarers. Other conditions liable to cause an abnormal sound are Altherma of false nostrils, fracture of bones or cartilages in the respiratory passages from various causes.

Treatment:

Is palliative, no cure.

(1) Tracheotomy will relieve the distress.

(2) Ventricle stripping – is the most popular method of treatment and the noise is often re­moved and sometimes the distress, but grunting remains.

Preventive Measures:

Avoid breeding from affected horses and mares (Thoroughbreds are excluded officially). Rest after Strangles and a course of tonics and antibiotic or Sulfonamide treatment.

Respiratory System: Disease # 10. Pulmonary Hyperemia:

It is more common in horses than any other animal. It is really a heart affection which has its repercussion upon lungs. In its most acute form, it is observed in horses (Race horses and Hunters) — specially not in hard condition — that are given very fast work or exercise. It is also observed in Cart-horses or horses in low condition which are given excessive exercise and then placed in a badly ventilated box. A similar condition noted in goats and sheep due to defective ventilation or Heat Stroke. The affection of the lungs are due to the inability of the heart to force the blood through the pulmo­nary vessels.

Symptoms:

Very alarming. There is great respiratory distress. When condition occurs at exercise, the animal has been run to a standstill. It stands with its legs abducted, neck stretched out, nostril dilated, flanks heaving heavily and the respiration not only exaggerated but very fre­quent. Eyes are blood shot, the superficial vessels are distended. Sometimes, Jugular pulse may be noted. The pulse is small and is very frequent.

The mucous membranes are of a dull slaty colour. The internal temperature varies. In hunting field or Race course, temperature is not raised but when it occurs on board of a ship, the tempera­ture is raised. Extremities are cold. In very acute cases, there may be a blood stained discharge from the nose.

Heart is tumultous and, on auscul­tation, the vesicular murmur is subdued. Course varies very greatly. Sometimes, death occurs within a few minutes or hours while, in other cases, recovery is just as rapid. The important indication of improvement is the character of the pulse which becomes more distinct and fuller.

Complications:

(1) Pneumonia or Pleurisy

(2) Edema of lungs.

(3) Laminitis.

Morbid Anatomy:

In the acute stage, both lungs will be found to be nearly black but not solid but easily broken down and the heart will be found to be dilated and filled with black blood.

Treatment:

Allow plenty of fresh air. If the animal is in the open, remove any pressure over the chest. Turn the animal head to wind. Keep animal warm. Venisection is very useful in early stages. Give stimulants either in bolus or hypodermically. If these are not at hand, give Whisky or Brandy by stomach tube.

Apply stimulating liniments to chest walls as in pneumonia. Keep animal warm and in a well-ventilated stall. Venous congestion may arise in dogs and other animals in a much less acute form. From incom­petence of bicuspid valve, e.g. in Endocarditis and symptoms shown are coughing and dyspnoea.

Respiratory System: Disease # 11. Pulmonary Emphysema or Broken Wind:

A chronic condition noted in horses. Emphy­sema is the appearance of gas or air in sides in which it does not normally occur or in excess in situations in which it is normally found. Subcuta­neous emphysema or Emphysema of muscle. Emphysema of lungs has also been noted.

Etiology:

(1) May be due to the feeding, e.g., Dusty food which brings about coughing or bulky food, specially if the animal is worked hard immedi­ately after feeding.

(2) It may follow upon chronic cough, Bron­chitis, Pneumonia or Asthma. Probably, its devel­opment is due to congenital weakness of the lung tissue. In emphysema, the elastic tissue of the lungs is ruptured and the normal recoil during expiration is lost or impaired. Hence, the abdomi­nal muscles are called in to play in an exagger­ated fashion to complete the expiratory effort.

Symptoms:

The condition is more common in cobs with rounded barrels than in other breeds. But it is found in all types of horses. Animals are usually good feeder and are often in good_! Condi­tion, the two characteristic symptoms of “Broken Wind” are

(1) Double expiratory effort and short abrupt inspiration.

(2) Cough – The cough is barely frequent and can readily be brought on by pressure over the larynx. It is short and hard and may appear in spasms. Respiratory distress may be noted in severe cases but it is only brought on by exercise in the moderate cases. The movements are exag­gerated during expiration. There is first a short normal contraction of the abdominal muscles and after a slight pause, a second more prolonged contraction.

There may be a slight or moderate discharge from the nose. On auscultation on chest, slight crackling sound may be heard. In extreme cases, there are in and out movements of anus. Such horses are unable to do more than slight or moderate exercise or work and may be useless to owners. There is no likelihood of recovery. But in affected mares, symptoms are somewhat relieved during pregnancy.

Treatment:

Is at best palliative. Keep bowels open and on laxative diet. Bulky food should only be given in moderate quantities and dusty food avoided.

Preventive Measures:

Attend to feed, avoid bulky or dusty food before exercise. Do not give forced exercise to horse in soft condition after feeding.

Respiratory System: Disease # 12. Hemoptysis or Pulmonary Hemorrhage:

Etiology:

Overexertion may cause hemoptysis. Early stages of acute pneumonia in Purpura hemorrhagica, fracture of ribs and punc­ture of lung when tapping.

Symptoms:

Appears suddenly and hemor­rhage takes place from both nostrils, respiration become frequent and blowing and the passage of blood is accompanied with coughing and the blood is bright red and frothy. It is brought about during coughing. On auscultation, fluid rales may be heard. When bleeding is profuse, the symp­toms of hemorrhage are noted viz. – anemia, decreasing strength, increase in frequency of heart beats, weakness. Condition is always grave.

Treatment:

Rest and treat as for internal hemorrhage. Keep the animal warm. Give fluid diet or normal saline injection when hemorrhage is profuse. Various hemostatics may be used.

Respiratory System: Disease # 13. Pneumonia:

1. Broncho or Catarrhal pneumonia:

Which involves the alveoli, as well as the small bronchial tubes and is catarrhal in form. This form is lobular in character though many areas may be involved.

2. Acute lobar or Croupous pneumonia:

A very common form in horses, occasionally noted in cattle, seldom in pigs or other animals. This involves considerable areas of the lungs and the exudate is fibrinous and may contain blood. This form of pneumonia is very liable to be followed by gangrene – Septic pneumonia is that form associated with gangrene or with symptoms of Toxemia.

3. Interstitial pneumonia:

Is that in which fibrous tissue forms around the lung tissue.

Etiology:

(1) Pathogenic bacteria:

It appears com­monly in a great variety of contagious diseases, e.g. contagious pneumonia of horse, strangles, glanders, contagious Bovine pleuro-pneumonia, Hemorrhagic septicaemia, Infectious pneumonia of calves and lambs, calf diptheria, Swine fever and Swine plague and Distemper in dogs and cats.

Whether the disease is contagious or not, pneumonia in the large proportion of cases al­most invariably due to bacterial invasion, some of which may be commonly saprophytic on respira­tory mucosa. The resistance of the tissue being broken down by predisposing causes- e.g. chills, debility, pulmonary congestion or by an exten­sion from Bronchitis.

(2) Irritant gases – Inhaled in concentration.

(3) Drenches which go the wrong way, occa­sionally in cattle, a foreign body such as a piece of wire which has entered the lung from the Reticu­lum.

(4) Helminthic parasites in bronchial tubes and lungs.

(5) The disease may be metastatic or embolic and follow upon various fistula, sinuses, ulcers, abscesses, metritis or Endocarditis.

Symptoms (Acute in horse):

Those for Infec­tions pneumonia. In early stages, rise of tempera­ture, loss of appetite and dullness. The animal is not inclined to move. Later, the symptoms of fever are pronounced. The animal may show mus­cular weakness and staggering gait. Respirations are accelerated and exaggerated. Nostrils dilated, elbows abducted.

The horse usually stands per­sistently and even if he lies down, he lies on the affected side. There is a short soft cough which only appears at times. Usually, a nasal discharge is seen which is scanty and rusty coloured and forms a crust inside the nostrils. In the later stages, the discharge becomes greyish and more abundant. The pulse is frequent and full and it is a good guide as to the progress. The mucous membranes are congested and may be slightly yellow.

Physical signs:

On percussion of the chest, dull sounds can be heard over the consolidated areas. On auscultation; there is an absence of vesicular murmur in the affected area while fine crepitating sounds appear at the borders. The heart sounds are more distinct over the consoli­dated areas.

Course:

In acute cases, the disease is at its height in 5 or 6 days in horse and in favourable cases declines in about 7 to 8 days. Then the temperature falls gradually. Animal appears bet­ter, brighter and feels better. The nasal discharge becomes more profuse and respiration declines in urgency and frequency. On auscultation, second­ary crepitation sounds could be heard in the pre­viously consolidated areas. Complete recovery will effect in one or two weeks. Relapses are not uncommon, especially if the animal is put to work or exercise too soon.

Complications:

(1) Gangrene of the lung in acute pneumo­nia of horse, then there is a very offensive odour from breath, great weakness and dark coloured putrid discharge from nose with temperature. It is very fatal.

(2) Abscess formation: Is more liable to occur in Broncho-pneumonia and only distin­guished from gangrene by the absence of foetid odour.

(3) Pleurisy and

(4) Laminitis: specially in heavy cart horses.

Death may occur of asphyxia, toxemia or heart failure. The disease is most serious when a large proportion of both lungs are involved. In unfavourable cases, the respirations are rapid and laboured. Pulse — small, irregular and weak. Heart’s action tumultuous, extremities cold and mucous membrane cyanotic.

Respiratory System: Disease # 14. Broncho-Pneumonia:

In Broncho-pneumonia, the course is somewhat more irregular. There is a catarrhal discharge from the nose which be­comes profuse. The temperature is usually not so high and on auscultation — the areas of consoli­dation are not so extensive, although they may be multiple.

Treatment:

Isolate the animal. Keep it in a well-ventilated comfortable room, allow plenty of fresh air. Keep the animal warn. Give plenty of water, keep excretions active. In high fever, febri­fuges may be used attend to condition of heart and give heart and general tonics. Neo-Salvarson given intravenously from 2 to 3 gms. in 100 ml. of water freshly prepared and given twice at an interval of 2 to 3 days is said to be specific for acute pneumonia in horse—Sulfapyridine, Sulfathiazole, Sulfadiazene, Sulfameragine etc. drugs are very effective in the treatment of pneu­monia. Sulfathiazole may cause renal complica­tions.

Trimethoprim combined with Sulfadiazene is very effective. In order to produce an effective concentration of the active drug in the blood as rapidly as possible, the initial doses of Sulfapyridine should be large, thereafter smaller doses should be used to maintain the blood level. It is desirable to repeat the administration every 8 hours to 12 hours.

Antibiotic treatment such as Penicillin, Ampicillin, Amoxycillin etc. is very effective and safe and is atleast possesses certain advantages over the Sulfonamide therapy. When the progno­sis is grave in older patients, in kidney diseases and liver damage and blood disorder, when the administration of Sulfonamide would place an undue burden upon the patient and certainly in presence of bacterimea, Penicillin is the chemo- therapeutic drug of choice.

Penicillin and other similar drugs produce favourable responses in Sulfonamide resistant bacteria and has resulted in recovery in many cases of such severity which could not have been possible with Sulfonamide therapy. The dosage should be determined from the body weight of the animal and according to severity of the disease.

Respiratory System: Disease # 15. Pleurisy:

May be acute or chronic, as usually being distinguished according to the nature of the exudate when present as serous, sero-fibrinous, purulent and often gangrenous. It is usually sec­ondary condition, being secondary to pneumonia, but the extent of pneumonia present varies a great deal. Traumatic forms may occur—such as pleurisy may follow upon an injury on the chest wall, from rupture of an abscess or from rupture of esophagus or tubercular in origin.

Symptoms:

In acute cases in horses, animals may show colicky symptoms, uneasiness and rig­ors in early stages but those symptoms usually last only for a short time during the dry stage of pleurisy. The animal appears very stiff, is not inclined to move and groans when move. Respi­rations are accelerated and difficult.

They are abdominal in the early stages. There is a distinct pleuritic groove. The nostrils are dilated, head is stretched out. There is an occasional short painful or suppressed cough and the usual symptoms of fever. Pulse is very frequent and wiry at feel.

Physical signs:

On percussion in the dry stage, the animal flinches and grunts and on aus­cultation—rustling sounds or friction sounds (crepitation) will be heard which are synchronous with respirations. When effusion occurs, the ani­mal becomes easier and feels better, but the respi­rations become more urgent and frequent.

On percussion, there is dullness in lower portion of the chest and absence of lung sounds on auscul­tation up to the upper level of the fluid which may be marked by a horizontal line. Tinkling and splashing sounds may also be heard at the up­ward border of the fluid. Heart sounds are muffled.

Course:

It varies. Resolution takes place in light cases and the fluid becomes absorbed. There may be left some chronic thickening or adhesion of pleura, as a result of which the animal becomes a grunter. In the later stages edematous swellings adhere under abdomen and limps. In the horse, the hair of the mane and tail is easily pulled out. In tapping, unfavourable signs are purulent con­dition of the exudate and a foetid odour. Death results from asphyxia, heart failure or toxemia.

Diagnosis:

It is made from the symptoms, and sometimes also from the puncture of the chest.

Treatment:

When colicky symptoms appear, give antispasmodics or sedatives. Treat as for pneumonia but in addition the chest should be tapped as early as possible. In the horse the pleurisy is always bilateral. If tapping is delayed, the animal may not recover but may be kept alive by repeated tapping for several weeks. In the dry stage, calcium may be of some use and be given intravenously.