QUESTION: My bun is a 4 year old female netherland dwarf and has a retrobulbar abscess. I woke up one morning and her right eye was bulging. I immediately took her to the nearest "rabbit savvy" vet and after x-rays/blood work the vet was unsure as to what was causing the eye to protrude, but assumed it was a retrobulbar abscess. My bun was prescribe Baytril twice a day for two weeks, but about a week later the eye was looking worse so I took her back to the vet. I was told to continue the Baytril and began giving her Penicillin G injections once a day. About 4 days later the eye was back to normal size! She has been on Penicillin G for a little over a week now and I have about 3 weeks worth of Penicillin G left. My vet is unsure as to how long I should be giving my rabbit the Penicillin injections since the abscess is behind the eye and does not show up on x-rays, what do you recommend?
ANSWER: Dear Lukas,
Head abscesses like this can be extensive, and just because the eye is back to normal doesn't mean the abscess is gone. The purpose of the antibiotics is not to completely kill all the bacteria, but to "knock them back" to levels that the bunny's immune system can handle. Three weeks is probably a good enough time to make sure the bacteria are controlled.
Is there a possibility that your vet could get you some dual-acting penicillin? This is a combination of Penicillin-G Procaine (short-acting) and Benzathine (longer-acting salt of penicillin). This is usually given (subcutaneously only!) every 48 hours, and provides constant, therapeutic levels of antibiotic in the tissues, unlike Pen-G alone. It might be something to consider to really blast the pathogens.
Unfortunately, Netherland Dwarf bunnies are susceptible to abscesses like this because of their short faces: the source of the infection was likely a tooth. Very common in short-faced rabbits. I hope the problem won't recur, but it might. That's why it's a good idea to knock it back as hard as you can the first time, and then hope for the best.
---------- FOLLOW-UP ----------
Thank you for responding so quickly. I had a scare the other night while holding my bun/reading. Her eyes, ears, and mouth began to twitch, but as soon as I called her name she stopped and looked at me. Her eyes weren't darting back and forth, more like blinking. Is this REM sleep? I've been watching her closely lately so perhaps this is the first time I've ever seen it happen.
Also, do you recommend any places to inject the Penicillin? I've been alternating which leg I inject but I'm worried her legs may become sore from being injected too many times.
Yes, you probably were witnessing REM sleep, which rabbits often do with their eyes open. Kind of disconcerting, but cute once you know what it is.
If you are using dual-acting penicillin, you must NEVER inject into a muscle. I can't imagine where you are injecting in the leg, but this is not the best location for subQ injections in a rabbit. Rather, the skin just behind the neck, over the shoulder blades, is best, in my opinion.
You gently tent the skin so there is a little "hollow" under the skin, between it and the underlying tissues. Insert the needle into the hollow, and draw back on the plunger of the syringe to be sure you have not hit a blood vessel. If it's all clear, you can go ahead and inject.
If you are using dual-acting Pen and injecting into a muscle, you have been lucky so far. But if you hit a blood vessel (which is easy to do with IM injections), the results could be fatal.
I hope this helps.