Agnes - Otitis Media and Malocclusion

[puffin]

Hello fellow pig slaves! We lost our last pig last summer and after some grieving time, have adopted a new herd of four in February, and as things go, one pig is going to be my little special medical pig!

Agnes (~4 years) was surrendered to a rescue last July with severe tooth overgrowth, weighing in at ~450g. She had some tooth trimmings and was nursed by the staff there until we adopted her. Her weight is now up to ~820g. She has a very slight head tilt, but has otherwise shown no signs of pain or neurological symptoms etc.

She has always been a slower eater, but was eating even slower than normal about three weeks ago, so I figured it was a tooth issue. We were able to get a sedated dental trim and head x-ray. It appears she either has a jaw misalignment or is preferentially chewing on side, because there was uneven tooth wear on her back teeth (one side needed trimming) and her front teeth were at a 45 angle. More concerning were the x-rays that showed thickening in the tympanic bullae on both ears, indicating a possible middle/inner ear infection.

We were referred the exotic specialist hospital for a head CT, which she had Wednesday. That vet agreed with the suspected diagnosis and recommended we do a procedure called a myringotomy to drain the inner ear and hopefully tackle the infection by properly identifying the bacteria so we can chose the right AB to treat. In the interim, we have put her on Chloramphenicol. She is also on meloxicam and has tramadol for additional pain relief (I have not yet used that).

I have a couple of questions I would be grateful for input on!

Question 1
In my cursory research on the myringotomy, it doesn't seem like this is a common procedure on guinea pigs, although my reading of a few references seems to show it has been used successfully and is less invasive than other "inner ear flushing" procedures. My vet is a Diplomate ABVP -Exotic Companion Mammal at a regional specialty hospital that only sees exotics, and indicated she had performed about six of these surgeries in guinea pigs and rabbits. All recovered from the surgery successfully and had various degrees of relief from the ear infection. It seems like the biggest risk would be from the anesthesia, if I understand correctly.

Is anyone familiar with this procedure and outcomes? The alternative was to try her on an AB course and redo the CT scan to see if there was any improvement, but as I understand the nature of these infections and the pus situation in the inner ear, this would be more of a "hopefully maintain the status quo" situation.

We had a prior pig (Louise) who was seen at this same vet practice by a different vet and had to have a splenectomy (as the result of an incidental finding while trying to diagnose persistent bladder stone issues), which I rationally know is a much different and more risky procedure. She made it through the surgery but after several days of hospitalization, was just never able to recover and we had to say goodbye. She was a happy lively pig before she went in, and the emotional side of me is still stuck on the "what ifs". I am having a hard time decoupling that experience from this one, since Agnes also seems lively and happy.

https://www.sciencedirect.com/science/a ... 6319301661
https://www.primescholars.com/articles/ ... 94200.html

Question 2
I started the Chloramphenicol yesterday morning, so she has had three doses now and we are at the ~27 hour mark. I am doing the poop soup about 1.5 hours after the AB, and supplementing with a little critical care for good measure. Her weight is down to about 790g, although it's possible she is still a little messed up from the sedated CT she had on Wed.

Her droppings are good so far and she has a good appetite. She will willingly take about 7 mls of critical care per feeding, and I am not forcing her since she is eating on her own. I have been doing 2 am feedings out of an abundance of caution for leaving her too long without food, although this isn't sustainable for an indefinite amount of time!

If she was going to have a negative reaction to the AB, when might that show up typically? My only data point is another pig (Marmot) who developed stasis about 36 hours after being given marbofloxicin, but at the time, I wasn't doing poop soup, or critical care feedings. Her appetite seemed to abruptly go away.

Since the course of AB is indefinite right now until we decide about the surgery, I assume I would also continue the poop soup (and potentially critical care) with each dose? I'm less experienced with these "big gun" ABs and whether or not there is a certain threshold you can declare that the pig is tolerating it well? I am going out of town for two days next Wed/Thurs (so in about a week) and Agnes' grandmother is looking after her. She is a little anxious (but willing) to do all the steps as best she can, but we are both unsure on how militant one needs to be on the AB routine.

[ItsaZoo]

It sounds like your vet is very knowledgeable and qualified to handle the problems that little Agnes is having. Your case is reminiscent of a situation I had with Gidget. She did not have the dental issues, but had recurring ear infections. She was seen by a certified exotic vet who treated her with antibiotics several times. The vet apparently did not realize the severity of the ear infections and the antibiotics never really eliminated the infection.

What I learned at a different clinic was that Gidget’s ear canals were malformed.Smaller guinea pigs have more issues with dental, sinus, ear, and upper respiratory infections. In this case, the ear infection can set in behind the bone, or bullea, and antibiotics don’t penetrate that area very well due to limited circulation. Kind of like when we have an abscessed tooth.

The ear canal needs to be flushed or drained to clear out the infected material. Then a course of Chloramphenicol would give her the best chance of recovery.

Your vet seems to understand the situation and if it were me, I would trust her advice. The ear infections are serious and need to be treated aggressively or they never clear up completely.

Good luck to you and Agnes.

[Lynx]

Excellent advice from ItsaZoo. You do indeed seem to have a great vet and much personal experience. I believe antibiotic intolerance may vary so I don't know that we could supply you with more info. Your regular weighing and observational skills will likely tell you if this is an issue.
https://www.guinealynx.info/antibiotic_advice.html

I have recently been introduced to Gemini AI which also cited your first article. I don't know if the AI answer asking about the success rate of this procedure will help, but I will copy it here, because it looks reasonable:

The success rate of a myringotomy (surgical drainage of the middle ear) in guinea pigs is difficult to quantify with a single, definitive percentage based on currently available information. Here's a breakdown of why and what the available evidence suggests:

Factors Affecting Success Rate:

• Underlying Cause: The success of a myringotomy often depends on the underlying cause of the middle ear issue. If it's a simple fluid buildup due to a mild infection, drainage can provide significant relief. However, if the infection is severe, chronic, or associated with dental disease, the long-term success might be lower without addressing the primary problem.
• Severity of Infection: More severe or long-standing infections may have a less favorable outcome.
• Concurrent Conditions: The presence of other health issues, such as dental disease (which is often linked to ear infections in guinea pigs), can impact the overall success.
• Post-operative Care: Appropriate medication (antibiotics, anti-inflammatories), hygiene, and follow-up care are crucial for a successful outcome.
• Individual Guinea Pig Factors: Age, overall health, and immune system strength can play a role.
• Surgical Technique and Timing: The skill of the veterinarian performing the procedure and how early in the course of the disease it's performed can influence the result.

What the Limited Evidence Suggests:

• Case Studies Show Promise: Some case reports describe successful use of myringotomy, often combined with video otoscopy and direct antibiotic administration into the middle ear, leading to significant improvement or resolution of clinical signs like head tilt.
• Not Always a Guaranteed Cure: Even with myringotomy, some guinea pigs may not have a complete resolution of signs, and in some cases, neurological signs like head tilt can be permanent.
• Potential Complications Exist: While myringotomy is generally considered a useful procedure, potential complications in guinea pigs can include transient to permanent Horner's syndrome, facial nerve paralysis, vestibular disease, and deafness.
• Mortality Risk: One study on cystotomies in guinea pigs (a different surgical procedure) noted a high mortality rate associated with surgery in this species, highlighting the general risks involved with anesthesia and surgery in guinea pigs. While this isn't specific to myringotomy, it underscores the need for careful consideration.

In conclusion, while myringotomy can be a valuable tool for diagnosing and treating middle ear infections in guinea pigs by providing drainage and allowing for direct medication, the "success rate" isn't a simple number. It's influenced by various factors. Consulting with a veterinarian experienced in treating exotic animals, particularly guinea pigs, is crucial for understanding the prognosis in your specific situation. They can assess your guinea pig's condition, discuss the potential benefits and risks of myringotomy, and provide a more informed outlook.

[puffin]

Thank you both! We have decided to proceed with the myringotomy, which we have scheduled for June 11. Agnes did not tolerate the Chlor, so we stopped for now. The vet will do the culture and then we will proceed from there. We got the CT results back from the radiologist and it seems the infection is quite advanced in her right ear, and will be challenging to fully flush and treat, so will likely be doing a course of ABs for up to 6 months! She recommended Cerenia I believe to help with nausea associated with the ABs, so hopefully we can come up with some strategy over the long term to allow her to tolerate the AB and have quality of life. I will update after the procedure!

[ItsaZoo]

I hope you have success with this procedure. Cerenia treats nausea and motion sickness. I’ve used it for my dog and it works well.