Pneumonia

Pneumonia is commonly classified by its original cause:

Bacterial Pneumonia (often secondary to severe kennel cough particularly in young puppies that have been shipped long distances, aspiration as from megaesophagus, or secondary to either of the above causes.)

Viral Pneumonia (usually the result of canine distemper virus infection, parainfluenza or a complicated feline upper respiratory infection)

Fungal Pneumonia (caused by a fungus, typically Coccidioidomycosis immitis, Cryptococcus neoformans or other fungi that are particularly difficult to treat).

Parasitic Pneumonia (from lungworms directly or from the migration of other worms through the lung.)

Allergic Pneumonia (the result of extreme infiltration of the lung by inflammatory cells in the absence of infection.)

In most cases of pneumonia there is a bacterial component. This means that no matter what started the pneumonia, bacteria have joined in adding their own special pus, fever, and potential for disaster; in most cases, management of the bacteria is vital. This article centers on the management of bacterial pneumonia.

When to Suspect Pneumonia:
Coughing is hallmark symptom, though certainly not all coughing pets (or even most coughing pets) have pneumonia.

Coughing puppies from the pet store or shelter may have a simple kennel cough (a minor bronchitis) but they are high risk for distemper infection. Sometimes, kennel cough can lead to a bacterial pneumonia as well.

Coughing dogs or cats with a fever, listlessness, or appetite loss should be radiographed for pneumonia; though many patients with pneumonia will not have fevers and some will still be deceptively active.

Coughing dogs with a history of megaesophagus (malfunctioning esophagus) or with a history of symptoms typical of megaesophagus should be radiographed for pneumonia.

Kittens with severe upper respiratory infections who do not respond to the usual management should be radiographed for pneumonia.

Diagnosis of Pneumonia:
The diagnosis of pneumonia is based on listening to the lungs with a stethoscope (auscultation), observing the breathing pattern and radiographs (X-rays). Frequently we will obtain sputum samples from the lungs for further definition of the pneumonia by performing a procedure known as a trans-tracheal wash. During this procedure the pet is briefly anesthetized and a sterile catheter is introduced into the lungs. Sterile saline is infused into the lungs and then sucked back out. The resulting liquid is sent to the laboratory for culture and cellular analysis. The results help us choose the correct antibiotics and help determine the cause of the pneumonia.

This xray shows a pet with pneumonia

Notice the fluid filled lung lobe


Notice the white fluid filled lung

Treatment:
The pneumonia patient may be in one of three states:

• Stable (eating well and active despite a nasty cough). These patients can often be treated at home.
• Unstable (poor appetite, inactive) in need of hospitalization.
  Critical (unable to get enough oxygen into their systems.) These patients require oxygen therapy and possibly 24 hour care.
• The goal is to get the patient stable enough for home treatment as several weeks are needed to fully clear pneumonia. When the patient is eating well, he or she may be discharged with oral antibiotics, a regimen of physical therapy, and a schedule for re-check radiographs (usually weekly).

The hospitalized patient has the following needs:
Intravenous fluid therapy

Coughing may be annoying but it is therapeutic and, when it comes to pneumonia, we want to encourage it, not suppress it. Coughing brings up the pus, mucus, and inflammatory cell products that make our patient sick. If the secretions of the lung are allowed to dry up, the patient will never be able to cough them up. For this reason, IV fluids must be maintained to keep our patient hydrated and keep the respiratory secretions wet.

Antibiotic therapy

Antibiotics are given to kill the bacteria, but which antibiotics should be chosen? We need something that will penetrate into the pus and mucus (which many antibiotics cannot do). Often a four quadrant approach is used that covers bacteria classified as Gram negative and Gram positive as well as those classified as aerobic and anaerobic. This typically involves two antibiotics used in combination to synergize one another.

Alternatively, the lungs may be cultured via a procedure called a tracheal wash. This process involves light sedation which the patient must be stable enough to withstand. Sample fluid from deep in the lung can be retrieved for culture. A culture identifies the organism and provides a list of antibiotics that can kill it.

If the patient is sick enough for hospitalization, antibiotics are typically given as injections so as to maximize absorption into the body.

Nebulization
This technique is becoming more and more available to small hospitals. It involves a piece of equipment called a nebulizer, which creates a mist of fine saline droplets. These droplets are far smaller than those produced by commercial vaporizers that many people have in their homes. The droplet size determines how far into the respiratory tract the moisture can be inhaled. Vaporizer droplets are typically halted in the nasal passages and throat while nebulized droplets can travel all the way into the lung. Nebulized saline may carry antibiotics with it thus providing an additional source of moisture and antibiotic for the sick lung.

Physical Therapy
A technique called coupage is helpful at mobilizing respiratory secretions. The therapist’s hand is cupped and gently but rapidly taps the patient’s chest wall repeatedly. This loosens some of the deeper secretions and helps them move into airways. Material in the airway generates coughing which removes these materials from the body. Coupage should be performed at least four times daily and should be continued at home as long as the patient has a cough.

Light exercise is also helpful in mobilizing the respiratory secretions. The patient should not be over-exerted as he/she does not have normal lung capacity but one can use one’s judgment as to what level of exercise is tolerated by the patient.

Oxygen Therapy
In most cases, oxygen therapy is not necessary but when a pneumonia patient simply cannot move enough air, there is no substitute for oxygen. Room air is 20% oxygen. An oxygen cage typically is set to deliver 40% oxygen (higher percentages over long term are actually toxic to lung cells), and special oxygen-delivery hoods are also popular. A patient who requires this level of support is extremely sick.

Home Care:

Once the patient has a good appetite, he or she may be discharged for home care. The following tips are recommended as long as the patient is coughing:

• Do not allow prolonged exposure to extreme cold or wet weather. Keep your pet primarily indoors.
• Consider use of a vaporizer for 15 to 20 minute intervals a couple of times daily. If you do not have a vaporizer, leave the pet in the bathroom with the shower on to create a misty vapor.
• Perform coupage at least 4 times daily and allow light exercise to promote the cough.
  Cough suppressants may be dispensed to help improve your pet’s ability to rest, it is still important to do the coupage to encourage movement of the sputum.
• Use the antibiotics as directed. Several weeks of antibiotic therapy may be needed.
• Return for re-check radiographs as indicated by your doctor

If you pet appears to be worsening, especially if he/she has a bluish color to the tongue or gums, call us or seek emergency attention.