A Layman's Guide to the Health and Nursing Care of Rats
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The inflammation, swelling, congestion or consolidation of the airways and lungs contributed to by these organisms and irritants decreases the ability to breathe effectively.
There are several classifications or types of pneumonia, such as focal, lobar, or Bronchopneumonia. Determination of the type is based on the area and pattern of distribution found in the lobes of the lungs or bronchi. It can be further described based on the pathophysiology of the various organisms that cause infection and or inflammation.
In bacterial infections, pneumonia is believed to be initiated when there is a change, alteration, or increase in the number of organisms normally residing in the nasopharynx that results in the overwhelming of the host’s immune system, or where normal defenses fail to protect the respiratory tree from filtering the organisms from the lungs.
In rats, where severe respiratory disease or pneumonia is present, more than one organism or infection is involved. The most prevalent and naturally occurring organism in the rat that contributes to the development of pneumonia is the bacterium, Mycoplasma pulmonis.
Other bacteria that contribute to the development of pneumonia in association with Mycoplasma pulmonis are Ciliated-Associated Respiratory (CAR) Bacillus, Corynebacterium kutscheri, Streptococcus pneumoniae, Pasturella pneumotropica, Bordetella bronchiseptica, and Klebsiella pnuemoniae (klebsiella is a part of normal gut flora that under certain conditions result in an opportunistic infection).
Viruses such as SDA (sialodacryadenitis) and Sendai can also act in conjunction with Mycoplasma overwhelming the immune system and leading to the development of pneumonia.
In rats that are severely immunosuppressed, pneumonia may be further complicated by the presence of a fungal or protozoan organism such as Pneumocystis carinii, an opportunistic species specific organism.
In aspiration pneumonia where food or liquids have entered the lungs, atelectasis (an airless lung) or pulmonary edema and hemorrhage can occur, especially if the substance aspirated is very acidic.
Lastly, some of the complications occurring in severe cases of pneumonia can be:
Abscesses and empyema (pus filled fluid), or pus filled lumina in pneumonias with mixed organisms such as klebsiella, CAR bacillus, and Mycoplasma. Empyema in Pneumocystis carinii.
Bacteremia, where the infection has spread via blood, particularly in those pneumonias caused by Gram-negative organisms.
Pleural effusion, when the small amount of fluid normally present that lubricates the pleural membranes starts to build up.
Complete blood count with low WBC may indicate mycoplasma or viral illness.
Gram stain.
Blood cultures to rule out bacteremia.
Preferred and alternate antimicrobrial therapy in humans as recommended by CURRENT Medical Diagnosis & Treatment 2002, 41st Edition, Edited by: Lawrence M. Tierney,Jr.,MD ; Stephen J. McPhee,MD. ; Maxine A. Papadakis,MD. , for the following listed identified organisms. These antimicrobials are also helpful in rats:
The choice of treatment in Pneumocystis carinii pneumonia is TMP/SMX (trimethoprim/sulfamethoxazole), along with a corticosteroid such as prednisone.
The following treatment regimen for use in rats with advanced lung infection or more serious respiratory illness with Mycoplasma as the suspected agent , is recommended by Dr. Michael Hutchinson, DVM; Animal General, Cranberry Township, PA., and is based on his experience treating rats and current literature:
Nebulization for 15 minutes, 2 to 3 times a day, for 14 days, with the following mixture:
8 mL sterile saline
0.5mL
Gentocin injectable 100 mg/mL
0.5mL Albuterol 0.083% Inhalation
*Note: excess mixture for nebulization can be refrigerated for up to 3 days.
Dexamethasone 1 mg/lb BID, then weaned down as follows:
1 mg/lb BID injectable or PO (oral) for 3 days
1 mg/lb SID for 3 days
0.5 mg/lb SID for 3 days
0.5 mg/lb orally every other day, three doses
Other veterinary recommended dosing and reduction schedules for dexamethasone may also be used.
Cefadroxil (for secondary infections - best used in combination with Gentocin)
Enrofloxacin (Baytril) and Doxycycline simultaneously.
An aminoglycoside: (such as amikacin or gentamicin) in combination with Cefadroxil.
*Note: Combination of drugs given simultaneously like enrofloxacin (Baytril) + doxycycline, azithromycin + doxycycline, clarithromycin + doxycycline, have been found to be very effective in rats.
The choice of an antibiotic/antimicrobial or combination can be more effective when selected based on culture and sensitivity of organism.
For the nebulization formula using Gentocin and Albuterol in a treatment regimen, recommended by Dr. Michael Hutchinson, see above in the section: A treatment regimen for serious and advanced respiratory illness. See Nursing Care below for more information on nebulizers.
In addition, a corticosteroid such as prednisone or dexamethasone may be added to the treatment regimen to help reduce inflammation of the bronchi and bronchioles in order to help the rat breath easier.
For dexamethasone therapy , in a treatment regimen, for serious and advanced respiratory illness, see doses suggested above by Dr. Michael Hutchinson, listed under: A treatment regimen for serious and advanced respiratory illness.
*Note*
Dexamethasone has been shown, in the controlled studies cited below, to reduce plasma leakage, resolve Mycoplasma induced inflammation, and also reduce the number of Mycoplasma organisms even when used as the only therapy.
It should be noted that based on dexamethasone’s long biologic activity of action it is advised to use the lowest dose for condition being treated which achieves the desired effect.
Due to the belief that Mycoplasma is probably never eliminated entirely from the airways in rats, and because it is a contributor to the development of pneumonia, it often becomes necessary to use pulse antibiotic therapy (long term, intermittent, dosing), or a continuing maintenance schedule of antibiotics for rats with chronic Mycoplasmosis.
Dr. Hutchinson has had some success with the long term, maintenance dosing of enrofloxacin 15 mg/kg BID PO (or in the presence of renal disease 8 mg/kg to 10 mg/kg BID PO) in conjunction with doxycycline 5 mg/kg BID, and based on his experience no discernable side effects have been noted.
For appropriate dosing in pulse antibiotic therapy for chronic illness, discuss with veterinarian.
Remember, it is important to give all doses of a prescribed medication even if clinical signs seem to lessen or disappear. If clinical signs seem to worsen or no improvement is seen, do not stop medication. Contact the veterinarian to discuss changes in medication.
If respiratory distress is present (gasping, or laboring to breathe), and/or gums, ears, feet, or tail appear to be cyanotic (blue-tinge) or are very pale, Oxygen therapy should be initiated.
Nebulized treatment may take from 10 to 30 minutes depending on the volume to be given, and how well the rat tolerates the treatment. Observe for any signs of increased agitation or intolerance. If noted stop treatment and contact vet.
Provide additional nutritional supplement, such as soy baby formula, Ensure, Boost, NutriCal paste (for dogs and cats found in pet store), mashed avocado, and baby foods. If the rat is not willing to eat on its own, provide feeding in an oral syringe every 2 hours being careful to prevent aspiration. Providing small amounts of food in this fashion will help to promote intestinal motility during illness. Also because so much energy is being expended to breathe in pneumonia, the added dietary supplements will keep up the rat’s strength.
It is also helpful to include a multi-vitamin supplement (can be found in pet store) if food intake is poor.
Place food and water close and on same level with the rat to prevent from exerting itself. Over exertion in a rat who already has difficulty breathing will prevent the rat from wanting to eat.
Provide fluids to prevent dehydration. If the rat is willing to drink on its own or by syringe (using needleless syringe), the following are suggested: fresh water, or a glucose mixture of 3 teaspoons of honey in 1 pint of warm water (be sure water is warm enough to dissolve honey and then cooled just enough so as not to burn rat’s mouth), or Jello water , or electrolyte replacement drinks such as Pedialyte or Gatorade which can be found in local grocery stores. Please note that Pedialyte is only good refrigerated for 24 hours after opened, but can be frozen as ice cubes and thawed as needed. Care should be taken to prevent aspiration when giving fluids with an oral syringe. If the rat is not drinking discuss providing warmed SQ fluids with your vet.
Posted on June 25, 2003, 12:19,
Last updated on July 7, 2010, 10:16
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