Bronchiectasis in Dogs

 

The trachea, or wind pipe, divides into two main bronchi, which further divide several more times into smaller bronchioles, forming the bronchial tree that feeds air into the lungs.

 

In bronchiectasis, bronchi are irreversibly dilated due to destruction of elastic and muscular components of airway walls, with or without accompanying accumulation of lung secretions. Dilatation and accumulation of secretions perpetuates lung damage, invite infections to settle, and compromise the lung functions in patient. American cocker spaniels, West Highland white terriers, miniature poodles, Siberian huskies, and English springer spaniels are predisposed to this condition. Bronchiectasis can occur at any age but commonly seen middle-aged or older dogs which chronic lung disease.

 

Symptoms and Types

 

• Chronic cough (moist and productive)
• Hemoptysis (coughing up blood) in some dogs
• Intermittent fever
• Lethargy
• Exercise or work intolerance
• Rapid breathing
• Difficulty in breathing normally, especially after exercise
• Chronic nasal discharge

 

Causes

 

• Primary ciliary dyskinesia (malfunction of the mucous clearing cilia in the lungs)
• Long-standing infections
• Inadequately treated infections or inflammations in the lungs
• Smoke or chemical inhalation
• Aspiration pneumonia (pneumonia caused by food, vomit, or other content being breathed into lungs)
• Radiation exposure
• Inhalation of environmental toxins followed by infections
• Obstruction of bronchi due to a foreign body
• Neoplasia of the lungs

 

Diagnosis

 

There are variable causes which may lead to bronchial inflammation in your dog. Therefore, a detailed history and a complete physical examination are essential for diagnosis. You will need to give your veterinarian a thorough history of your dog’s health, the onset of symptoms, and possible incidents that might have led to this condition. Standard laboratory testing will include complete blood count (CBC), biochemistry profiling, and urinalysis. Blood gas analysis will reveal information about the functional aspects of the lungs.

 

These tests will be helpful in looking for infections or other changes related to the underlying disease. Your veterinarian will also take x-ray images of the chest, respiratory tract, and bronchial tubes, which may or may not show abnormalities in the architecture of the lungs, including dilatation of the bronchi.

 

It is hoped that x-rays will reveal characteristic abnormalities in the bronchi that are related to this disease, but that is not always the case. Other changes in the lungs pertaining to chronic infections typically can be visualized using x-rays. Long term inflammation will leave evidence that can be visually examined. More sensitive testing, like computed tomography (CT) scanning, can be used for some patients, and this test may reveal more detailed information about structural changes within lungs. Your veterinarian will also take samples of tissue and fluid from the bronchi for laboratory evaluation.

 

Carbon Monoxide Toxicosis in Dogs

 

Carbon monoxide is an odorless, colorless, non-irritating gas produced by the incomplete combustion of carbon fuels. It is potentially toxic for dogs as well as humans. Common sources of carbon monoxide are unventilated kerosene or propane heaters, gasoline engines, automobile exhaust, or fumes from carbon-based fuel heating systems.

 

When inhaled, this gas is readily absorbed into the blood, combining with hemoglobin to form carboxyhemoglobin, reducing oxygen delivery to the body, and thereby leading to decreased utilization of oxygen in the brain and heart. Most cases of carbon monoxide toxicity in dogs occur as a result of human error, such as when a dog has been left in an enclosed area where carbon monoxide is being released. A dog left in an enclosed garage with a running automobile can be exposed to toxic levels of carbon monoxide in about ten minutes. Animals are also exposed to toxic levels of carbon monoxide when they are trapped in a building that is on fire. Prolonged exposure to carbon monoxide will lead to hypoxemia and eventually death.

 

Symptoms and Types

 

Depending upon the concentration and duration of exposure of carbon monoxide, the symptoms may be acute or chronic in nature.

 

• Sleepiness
• Cherry red skin and mucous membranes (e.g., nostrils, lips, ears, genitals), but this side-effect is usually not visible in most animals
• Weakness
• Lethargy
• Difficulty in breathing
• Seizures
• Abortion in pregnant animals especially those in late gestation period
• Depression
• Deafness
• Uncoordinated movements
• Coma
• Death

 

Symptoms with chronic exposure to carbon monoxide include:

 

• Nausea
• Abnormally high levels of acids in blood (acidosis)
• Vomiting
• Cough
• Flu like symptoms
• Loss of exercise stamina
• Disturbances in gait

 

Causes

 

Exposure to any source of carbon monoxide, like:

 

• Incomplete combustion of carbon fuels
• Accidental enclosure of dog in garage with automobile engine turned on
• Poorly ventilated areas with any source of carbon monoxide (e.g., fireplace, oven, barbecue grill)
• Unventilated furnaces
• Gas water heaters
• Gas or kerosene heaters
• House fires

 

Diagnosis

 

The foremost step in carbon monoxide toxicity is to get your dog away from the source of the carbon monoxide. Carbon monoxide toxicity is a life-threatening condition requiring immediate veterinary intervention. Your veterinarian will start immediate oxygen therapy to remove the carbon monoxide from the blood and bring your dog’s oxygen levels back to normal. While your dog is receiving oxygen your veterinarian will collect samples of blood for diagnostic testing. A complete blood count, biochemistry profile, urinalysis and other applicable body fluid tests will be performed. Your veterinarian will also collect samples for determination of carboxyhemoglobin levels in the blood. Establishing the levels of carbon monoxide in the blood is the most useful test for basing the initial treatment plan.

 

Carboxyhemoglobin levels rise in acute cases and drop within a few hours once exposure to the source of the carbon monoxide has been removed. Levels of acids in the blood will also be determined during blood testing, as acid concentrations tend to rise in response to this condition and their values will determine the appropriate diagnosis and medical response. Other diagnostic tools your veterinarian may use include an electrocardiogram (ECG) to determine whether the heart has also been affected.

 

 

Nasopharyngeal Stenosis in Dogs

 

Nasopharyngeal stenosis is a narrowing of one of the four portions of the nasal cavity on either side of nasal septum. Any of the four portions can be affected, which include the common, inferior, middle, and superior portions. The nasal septum is the part of nose that separates the two airways in the nostrils.

 

The narrowing may occur due to the formation of a thin but tough membrane in the passage of the nasal cavity. Chronic inflammation and subsequent fibrosis (formation of excess fibrous tissue) after an infection is one of the probable causes. Also, inflammation after chronic regurgitation, or vomiting of acidic material may be suspected as a causative factor. This problem is not common in dogs.

 

Symptoms and Types

 

• Whistling or snoring noise
• Difficulty when breathing
• Breathing with open mouth
• Nasal discharge in some patients
• Aggravation of symptoms during eating
• Failure to respond to conventional therapy, including antibiotics

 

Causes

 

• Upper respiratory infections and diseases
• Foreign body or any irritant contacting affected area

 

Diagnosis

 

You will need to give a thorough history of your dog’s health, including a background medical history and onset of symptoms. After taking a complete history, your veterinarian will conduct a complete physical examination, with standard laboratory tests including a complete blood count (CBC), biochemistry profile, and urinalysis. The results of these routine laboratory tests usually return within normal ranges. Outward symptoms will suggest a need for radiographic studies, including X-rays and computed tomography (CT-scan) to diagnose the narrowing of the nasal passage. Your veterinarian may also pass a catheter through nasal passage or use a bronchoscope for further confirmation.

 

 

 

Infectious Canine Tracheobronchitis

 

Kennel cough, the common name given to infectious canine tracheobronchitis, is a highly contagious respiratory disease among dogs. As the name suggests, it is typified by inflammation of the trachea and bronchi. This disease is found throughout the world and is known to infect a high percentage of dogs at least once during their lifetime. It is also sometimes referred to as bordetellosis.

 

Young puppies often suffer the most severe complications that can result from this disease since they have immature immune systems. Also at increased risk are older dogs, who may have decreased immune capabilities, pregnant bitches, who also have lowered immunity, and dogs with preexisting respiratory diseases.

 

SYMPTOMS

 

• A persistent cough is the most common symptom

• In mild cases, dogs are often active and eating normally

• In severe cases, symptoms progress and can include pneumonia, inappetence, fever, lethargy and even death

 

CAUSES

 

Some of the most common microorganisms that contribute to infectious canine tracheobronchitis are Bordetella bronchiseptica bacteria, canine adenovirus, parainfluenza virus, and mycoplasma. Any of these organisms can cause the symptoms of this disease, alone or in combination. Infections with multiple organisms tend to cause the most severe symptoms. 

 

Dogs often develop clinical signs associated with kennel cough 3-4 days after exposure to a large number of other dogs (e.g., at a boarding facility or show).

 

DIAGNOSIS

 

The diagnosis of this disease is largely based upon the type of symptoms that are present and a dog’s history with regards to exposure to other dogs. You will need to give a thorough history of your dog’s health and onset of clinical signs. Your veterinarian may order some combination of blood chemistry tests, a complete blood cell count, a urinalysis, fecal examinations, and chest X-rays. If a dog does not respond to treatment as expected, additional testing (e.g.,  bacterial cultures) may be necessary to identify the microorganisms that are causing kennel cough.

 

TREATMENT

 

Treatment depends on the severity of the infection. If your dog is alert, active, eating well, and has only minor symptoms, your veterinarian may only prescribe general supportive care like rest and good hydration and nutrition. More severely affected dogs benefit from medications that reduce inflammation and coughing. If a bacterial infection is present, antibiotics may help shorten the course of the disease. Dogs with pneumonia often need to be hospitalized for more aggressive treatment.

 

LIVING AND MANAGEMENT

 

In order to prevent the spread of this disease, dogs with kennel cough should be isolated until they are better and no longer contagious. Dogs who are at high risk for infection (e.g., those who attend shows or spend time in boarding or day care facilities) should be vaccinated against Bordetella bronchiseptica and canine parainfluenza virus. All dogs should be vaccinated against canine adenovirus.

 

Even after being vaccinated, dogs may still acquire kennel cough (although usually a less severe form than they would have otherwise). It is best to be observant and prepared.

 

Although this infection usually does not cross over to humans, there are instances where young children and adults with compromised immune systems may be at risk. In these instances, it is best to talk to your veterinarian and human health care provider about your options.

 

Hypoxemia Due to Aspiration of Water in Dogs

 

Near-drowning is determined by an event that involves prolonged submersion in water, followed by survival for at least 24 hours afterward. Following submersion, typical symptoms include elevated carbon dioxide levels in the bloodstream, stimulated respiration, and subsequent aspiration of water into the lungs. In rare cases, hyperventilation prior to submersion, or laryngospasm (spasmodic closing of the larynx) may prevent aspiration of water, an involuntary reaction that can lead to a condition called dry drowning.

 

There are four phases in a typical drowning: breath-holding and swimming motion; water aspiration, choking, and struggling for air; vomiting; and cessation of movement followed by death. The mammalian diving reflex may occur, leading to a slowed heart rate, a halt in breathing, and blood circulation limited only to the essential organs of the body. Large volumes of water are not typically aspirated at this stage.

 

Fresh water aspiration leads to a collapse of respiratory cells with possible infectious pneumonia. Hypertonic seawater aspiration leads to a diffusion of water entering the lungs and into the alveoli (the air cells of the lungs). Since the dog cannot obtain enough oxygen, oxygen levels in the blood drop and the blood becomes acidotic (abnormal increase in acidity).

 

Submersion time, temperature of the water, and the type of water the dog is submerged in (whether the water is fresh, salt, or chemical) will significantly affect the development of organ damage.

 

Symptoms and Types

 

• Bluish skin and gums
• Coughing with clear to frothy red sputum (spit-up)
• Cessation of breathing
• Difficulty breathing
• Crackling sound from the chest
• Vomiting
• Semi-conscious and dazed to comatose
• Increased or decreased heart rate
• The heart may cease to beat

 

Causes

 

• Owner negligence
• Inadequate safety precautions
• Young, inexperienced dog (less than four months of age)
• Dog was in or near water at the time of a seizure
• Following head trauma
• Rapid drop in blood sugar, abnormal heart beat rhythm, or fainting episode while in body of water place dogs at higher risk of drowning

 

 

Diagnosis

 

Your veterinarian will perform a complete physical exam on your dog. Standard laboratory tests will include a blood chemical profile, a complete blood count, a urinalysis and an electrolyte panel.

 

Chest X-rays may show aspiration pneumonia or fluid in the lungs one to two days after the near-drowning. Foreign body inhalation may produce segmental lung collapse. Pulmonary injury progressing to acute respiratory distress syndrome (ARDS) is possible.

 

An endotracheal or transtracheal wash, followed by a cytologic evaluation and culture with sensitivities is indicated. Electrocardiographic monitoring to examine the electrical currents in the heart muscles may be performed to assess heart damage. Your veterinarian will also want to determine the auditory evoked response (BAER) for hearing loss assessment. Cervical X-rays, computed tomography (CT), or magnetic resonance imaging (MRI) of the brain and brain stem may be helpful in select cases.

 

Tussis in Dogs

 

The act of coughing serves as a protective mechanism for preventing the accumulation of secretions and foreign materials inside of the respiratory tract, but coughing can also serve as an early warning sign for respiratory diseases. Coughing is generally a symptom of an underlying problem, such as a respiratory or cardiovascular system disease.

 

This automatic and involuntary behavior is one of the most powerful reflexes in the body and is essential for keeping the pharynx and airways free of accumulated secretions and foreign material. This is, therefore, a normal response to any invasion, obstruction, or abnormality of the airways. The medical term for coughing is tussis, and this condition can be found in dogs of all ages and breeds.

 

Symptoms and Types

 

• Cough
• Retching
• Vomiting
• Sudden collapse
• Coughing up blood may be seen in certain diseases or with prolonged and violent coughing

 

Causes

 

• Respiratory tract diseases including tumors, infections (viral, bacterial, and parasitic)
• Aspiration pneumonia (pneumonia due to entrance of stomach contents or ingested food particles in the respiratory tract)
• Foreign bodies in the respiratory tract
• Allergies
• Cardiac diseases

 

Diagnosis

 

For your veterinarian to establish an initial diagnosis, you will need to provide a thorough history of your dog’s health, recent activities, and onset of symptoms. Sneezing and coughing can often be confused with each other, so your veterinarian will evaluate your dog’s cough to determine if it is really a cough or a sneeze. The sounds can be very similar, so closer attention will need to be paid. Obvious outward differences may show the mouth staying closed during the reflexive action, indicative of a sneeze, whereas with cough, the mouth is opened.

 

The pattern and frequency of the cough are very important in determining the cause of the cough. Your veterinarian will ask you about the duration, timing, pattern, frequency, and characteristics of your dog’s cough, so it can be helpful to both you and your doctor if you make notes of your dog’s symptoms before you see your veterinarian.

 

Your veterinarian will need to evaluate whether the cough is productive or non-productive, so a cough will need to be artificially initiated by your doctor. In productive coughs, secretions, fluid, and mucous may be expelled from the airway, whereas with non-productive coughing or dry coughing no such material comes out with the cough. As coughing is associated with a number of diseases, a careful diagnostic workup is essential for establishing the diagnosis.

 

After the history and initial physical examination have been done, your veterinarian will take a complete blood count, biochemistry profile, and urinalysis to be analyzed in the lab. A complete blood count may suggest the presence of infections or allergies, based on the amount of white blood cells that are present in the blood, and a blood biochemistry test may show abnormally elevated liver enzymes or other abnormalities that are related to the underlying cause.

 

If your dog is also experiencing nose bleeds or is coughing up blood, tests related to blood clotting will be conducted to determine whether blood clotting mechanisms in the body are working normally. Other diagnostic tools that may be used include radiographic studies, such as X-rays, computed tomography (CT) and magnetic resonance imaging (MRI), all of which can be extremely valuable in determining the cause of the cough.

 

For a closer and more detailed view of the respiratory tract, your veterinarian may also use a laryngoscope, tracheoscope, or bronchoscope for a direct visualization of the various parts of the upper tract. Fecal testing may also be conducted to check for the presence of respiratory parasites in the body and your dog will be tested for heartworm disease, which can also lead to coughing in affected dogs. Your veterinarian can also take fluid samples from the respiratory system for further evaluation, since some types of parasites will remain on the walls of the respiratory tract.

 

 

Stertor and Stridor in Dogs

 

Unusually loud breathing sounds are often the result of air passing through abnormally narrowed passageways, meeting resistance to airflow because of partial blockage of these regions. The origin may be the back of the throat (nasopharynx), the throat (pharynx), the voice box (larynx), or the windpipe (trachea). Abnormal breathing sounds of this type can be heard without using a stethoscope.

 

Stertor is noisy breathing that occurs during inhalation. It is a low-pitched, snoring type of sound that usually arises from the vibration of fluid, or the vibration of tissue that is relaxed or flabby. It usually arises from airway blockage in the throat (pharynx).

 

Stridor is high-pitched, noisy breathing. The higher-pitched sounds result when relatively rigid tissues vibrate with the passage of air. It often occurs as the result of partial or complete blockage of the nasal passages or voice box (larynx), or collapse of the upper part of the windpipe (known as cervical tracheal collapse).

 

The upper respiratory tract or upper airways includes the nose, nasal passages, throat (pharynx), and windpipe (trachea).

 

Noisy breathing is common in short-nosed, flat-faced (brachycephalic) dog breeds. Inherited paralysis of the voice box, known as laryngeal paralysis, has been identified in Bouviers des Flandres, Siberian huskies, bulldogs, and Dalmatians.

 

Acquired paralysis of the voice box (laryngeal paralysis) is more common in certain giant-breed dogs, such as St. Bernards and Newfoundlands, and in large-breed dogs, such as Irish setters, Labrador retrievers, and golden retrievers, than other breeds.

 

Affected short-nosed, flat-faced dogs with inherited paralysis of the voice box typically are younger than one year of age when breathing problems are first detected. Acquired paralysis of the voice box typically occurs in older dogs. Inherited paralysis of the voice box has a 3:1 male-to-female ratio.

 

Symptoms and Types

 

• Change or loss of voice – inability to bark
• Partial blockage of the upper airways produces an increase in airway sounds before producing an obvious change in breathing pattern
• Unusually loud breathing sounds may have existed for as long as several years
• Breathing sounds can be heard from a distance without the use of a stethoscope
• Nature of the sounds range from abnormally loud to obvious fluttering to high-pitched squeaking, depending on the degree of airway narrowing
• May note increased breathing effort; breathing often accompanied by obvious body changes (such as extended head and neck and open-mouth breathing)

 

Causes

 

• Condition of abnormal breathing passages in short-nosed, flat-faced animals (a condition known as brachycephalic airway syndrome), characterized by any combination of the following conditions: narrowed nostrils (stenotic nares); overly long soft palate; turning inside-out of a portion of the voice box or larynx (everted laryngeal saccules), such that the space for air to pass through the larynx is decreased; and collapse of the voice box or larynx (laryngeal collapse), and fluid build up (edema) of the voice box or larynx
• Narrowing of the back of the nose and throat (nasopharyngeal stenosis)
• Paralysis of the voice box or larynx (laryngeal paralysis) – may be inherited or acquired
• Tumors of the voice box or larynx – may be benign or malignant (cancer)
• Nodular, inflammatory lesions of the voice box or larynx (granulomatous laryngitis)
• Reduction in the diameter of the lumen of the windpipe (trachea) during breathing (tracheal collapse)
• Narrowing of the windpipe (trachea; tracheal stenosis)
• Tumors of the windpipe (trachea)
• Foreign bodies in the windpipe (trachea) or other parts of the airway
• Inflammatory masses that develop from the middle ear or eustachian tube (nasopharyngeal polyps)
• Condition caused by excessive levels of growth hormone, leading to enlargement of bone and soft-tissues in the body (acromegaly)
• Nervous system and/or muscular dysfunction
• Anesthesia or sedation – if certain anatomy exists (such as a long soft palate) that increases susceptibility to abnormal, loud breathing sounds
• Abnormalities or tumors of the soft palate (the soft portion of the roof of the mouth, located between the hard palate and the throat)
• Excessive tissue lining the throat (redundant pharyngeal mucosal fold)
• Tumor in the back of the throat (pharynx)
• Fluid build-up (edema) or inflammation of the palate, throat (pharynx), and voice box (larynx) – secondary to coughing, vomiting or regurgitation, turbulent airflow, upper respiratory infection, and bleeding
• Discharges (such as pus, mucus, and blood) in the airway lumen – may occur suddenly (acutely) after surgery; a normal conscious animal would cough out or swallow them

Risk Factors

• High environmental temperature
• Fever
• High metabolic rate – as occurs with increased levels of thyroid hormone (hyperthyroidism) or a generalized bacterial infection (sepsis)
• Exercise
• Anxiety or excitement
• Any breathing or heart disease that increases movement of air into and out of the lungs (ventilation)
• Turbulence caused by the increased airflow may lead to swelling and worsen the airway obstruction
• Eating or drinking

 

 

Diagnosis

 

You will need to provide a thorough history of your pet’s health leading up to the onset of symptoms. Your veterinarian will use a stethoscope to listen to the entire area from the pharynx to the trachea. If the sound persists when your pet opens its mouth, a nasal cause can virtually be ruled out. If the sound occurs only during expiration, it is likely that airway narrowing is the cause. If the abnormal sounds are loudest during inspiration, they are from disease other than in the chest. If you have noticed a change in your dog’s voice, the larynx is the likely abnormal site. Your veterinarian will systematically listen with the stethoscope over the nose, pharynx, larynx, and trachea to identify the point of maximal intensity of any abnormal sound and to identify the phase of respiration when it is most obvious. It is important to identify the location from which the abnormal sound arises and to seek aggravating causes.

 

Internal imaging techniques, such as radiography and fluoroscopy, are important for assessing the cardiorespiratory system and to rule out other or additional causes of respiratory difficulty. Such conditions may add to an underlying upper airway obstruction, causing a subclinical condition to become clinical. X-rays of the head and neck may help to identify abnormal soft tissues of the airway. A computed tomography (CT) scan may also be used to provide additional anatomic detail.

 

In some cases, your dog’s physiological inheritance can make the diagnosis more apparent, such as with dogs that are brachycephalic. In these situations, your veterinarian will determine the location that is being most affected by your dog’s conformation and decide where to go from there.

 

Lung Damage Due to Smoke Inhalation in Dogs

 

In smoke inhalation, injury occurs as a result of direct heat damage to the upper airway and lining of the nose. Injury to the tissue is seen after inhalation of carbon monoxide, which decreases tissue oxygen delivery by binding to red blood cells; inhalation of other toxins that directly irritate the airway (e.g., oxidants and aldehydes); and inhalation of particulate matter that adheres to the airways and small air sacs in the lungs.

 

The extent of damage depends on the degree and duration of exposure to smoke and the material that was burning. Dogs may have serious lung injury with little evidence of burning on their skin. Lung reaction is initially symptomized by constriction of the lungs, airway swelling, and mucus production, followed by an inflammatory response in the trachea and bronchial area, and fluid accumulation in the lungs. Most patients show progression of lung dysfunction in the initial two to three days after exposure. Follow-up bacterial infections are a common cause of death late in the disease due to the wounded tissue being an advantageous receptor for bacteria.

 

Symptoms and Types

 

• Smoky odor
• Soot in the nasal or throat passages
• Rapid breathing and increased depth of respiration
• Breathing effort that suggests upper airway obstruction by swelling
• Postural adaptations to respiratory distress (i.e., positioning the body to make breathing easier)
• Mucous membranes may be cherry red, pale, or cyanotic (blue)
• Reddened eyes
• Hoarse cough
• Confusion, fainting
• Vomiting
• Shock

 

Causes

 

Exposure to smoke/carbon monoxide, usually the result of being trapped in a burning building.

 

Diagnosis

 

You will need to give a thorough history of your dog’s health, onset of symptoms, and possible incidents that might have preceded this condition, such as exposure to burning material. A complete blood profile will be conducted, including a chemical blood profile, a complete blood count, and a urinalysis. The blood count will show the level of red blood cells that are capable of carrying oxygen, and white cells that are capable of fighting infection. The blood profile will also show whether the arterial blood gases are at normal levels and will show the degree of oxygen shortage in the blood. The urinalysis will show how the kidney is functioning. Visual diagnostics, such as X-ray and ultrasound, may also be used to determine if there is fluid buildup in the lungs. A bronchoscopy, which uses a flexible tube with a camera attached and which can be inserted into the airway, may allow your doctor to determine the severity of airway damage.

 

Samples will be taken of the cells inside the mouth and in the airways and cultured to determine whether there are bacteria present. If there is tissue damage to the airways, your veterinarian may prescribe a prophylactic antibiotic to prevent infection.

 

 

Pneumocystosis in Dogs

 

Pneumocystosis is a fungal (Pneumocystis carinii) infection of the respiratory system. Commonly found in the environment, P. carinii only affects dogs (or humans) with compromised immune systems. This is because the weakened body defenses allows the organism to multiply and grow to critical levels in the lungs.

 

Symptoms and Types

 

Generally, the breathing difficulties will progressively worsen over a four-week period. Other signs associated with pneumocystosis include:

 

 

Causes

 

Pneumocystosis is caused by an overabundance of the P. carinii fungus in the respiratory system, typically found in immune-compromised dogs.

 

Diagnosis

 

You will need to give a thorough history of your dog’s health, including the onset and nature of the symptoms, to your veterinarian. He or she will then perform a complete physical examination, as well a biochemistry profile, urinalysis, and complete blood count (CBC) — the results of which are usually non-specific and may show increased number of leukocytes or white blood cells as seen in infections, increased number of eiosinophils, and increased number of red blood cells. Blood gases testing, meanwhile, may reveal decreased partial pressure of oxygen in blood (hypoxemia), and increased pressure in blood pH. Thoracic X-rays are also conducted to see the severity and stage of the infection, as related to the lungs.

 

For definitive diagnosis, however, your veterinarian will take a respiratory fluid sample or tissue sample to a pathologist to test for abnormal levels of P.carinii. Although it is the most reliable method for verifying pneumocystosis, lung biopsies are not without complications. Moreover, few diagnostic kits are available.

 

 

Tracheal Perforation in Dogs

 

Tracheal perforation is a loss of the integrity of the tracheal wall, in the form of a hole or rip, allowing leakage of air into the surrounding tissues and creating air pockets under the skin, air collection in the mediastinum (in between the lungs), and potentially air in the sac around the heart, free air in the chest cavity, and air in the most posterior part of the abdominal cavity (pneumoretroperitoneum). This loss of integrity can be caused by a penetrating trauma, trauma from inside the trachea, or blunt neck or chest trauma.

 

The severity of tracheal perforation ranges from a small perforation to complete tracheal avulsion (tearing away of the trachea). In dogs with complete avulsion, the mediastinal tissues can help to maintain the airways.

 

Symptoms and Types

 

The following signs may occur immediately after injury or up to a week later:

 

• Pockets of air collected under the skin
• Respiratory distress
• Lack of appetite (anorexia)
• Lack of energy
• Gagging
• Excessive salivation (ptyalism)
• Vomiting
• Coughing
• Harsh crowing sound as dog breathes in
• Shock

 

Causes

 

Penetrating cervical (neck) wounds:

 

• Bite wounds
• Missiles (e.g., gunshots, arrows)

 

Perforation by a veterinarian (iatrogenic):

 

• During a transtracheal wash (a saline wash and collection of tissue and fluid through [trans] the trachea when evaluating for respiratory diseases)
• Inadvertent puncture while drawing blood, or during neck surgery
• Anesthesia and intubation procedures (to maintain an airway during anesthesia)

 

Blunt trauma can cause intrathoracic tracheal avulsion:

 

• Motor vehicle accident
• Falling from great heights

 

 

Diagnosis

 

Your veterinarian will perform a thorough physical exam on your dog, taking into account the background history of symptoms and possible incidents that might have led to this condition. A complete blood profile will be conducted, including a chemical blood profile, a complete blood count, a urinalysis and an electrolyte panel. An arterial blood gas analysis may also be done to check oxygenation of blood. A pulse oximetry measurement may show less than normal (or even low) oxygen saturation.

 

Side view X-rays of the neck and chest are essential for diagnosis. Air pockets under the skin, air collection in the mediastinum, free air in the chest cavity, and potentially air in the sac around the heart will be seen with tracheal perforation. In cases of tracheal avulsion, the site of disruption may be visible. Abdominal X-rays may show a pneumoretroperitoneum — air that has escaped into the space behind the lining of the stomach (peritoneum).

 

An examination of the interior walls of the trachea can be done by tracheoscopy to confirm the diagnosis of tracheal perforation and to estimate its severity. False-negative examinations can sometimes occur.