Otitis media is inflammation behind the eardrum, in a bulla that holds about 1 mL of air and sits under the eye, and it hides behind a normal-looking ear canal in roughly 30% of cats. Three nerve signs separate it from a simple outer-ear problem: facial nerve weakness, Horner syndrome, and vestibular ataxia. A CT in 1 of 2 modes confirms it, 4 to 6 weeks of prescription medication treats it, and 3 fixed rechecks close it out.
Why the middle ear is not the outer ear
The cat ear canal runs about 1 mm wide at the horizontal part and turns almost 90 degrees before the eardrum, so neither a swab nor a drop sitting in the vertical canal reaches the bulla. That bulla is a thin-walled cavity, 1–2 mm thick in a healthy cat, with only a few millimeters of bone between it and the brain. Infection gets in 3 ways: a ruptured eardrum after weeks of otitis externa, a nasopharyngeal polyp growing backward, or the bloodstream.
Age points at the cause. A cat under 2 years with a head tilt and a history of snoring or a voice change more likely has a polyp. A cat over 8 years with chronic smelly discharge more likely has bacterial otitis media on top of years of externa, and a hard neck lump found on the same exam is a separate workup (thyroid nodule). Both need imaging, and the plans differ by weeks.
The 3 nerve signs that change the plan
1. Facial nerve palsy. Look for a lip that droops on 1 side, an ear that sits lower, and a blink that is slower on that side. Test the blink by touching the inner eye corner: a cat that does not close within 1 second can ulcerate in 24–48 hours, so this sign alone justifies same-day care.
2. Horner syndrome. A pupil 1–2 mm smaller than the other, a third eyelid that slides up 2–3 mm, and an eye that looks sunken. In cats this is often the only visible sign of middle ear disease, and it is easy to miss in a dark room.
3. Vestibular signs. A head tilt of 10–45 degrees, nystagmus that beats 2–3 times per second, and ataxia with a wide stance. A cat that rolls or circles is compensating for a balance organ that is being pushed by fluid or a polyp.
CT in 2 modes, and what each one shows
| Mode | Scan time | Report in | Shows best | Limits |
|---|---|---|---|---|
| Non-contrast, bone window | 10–15 min | 1–2 days | Bulla wall thicker than 1 mm, septal lysis, fluid, polyp stalk | Cannot separate mucus from soft tissue |
| Contrast, soft tissue window | 20–30 min | 1–3 days | Extension into the nasopharynx, bone erosion, abscess rim | Needs IV contrast, 1 blood test first |
| MRI (if brain signs) | 45–60 min | 2–3 days | Brainstem, meninges, nerve swelling | 3–4 times the cost, longer anesthesia |
| Skull x-ray | 10 min | same day | Bulla opacity | Misses 50% of early cases |
Most clinics start with a non-contrast bone-window CT because it answers the surgical question: is the bulla wall intact, and is there a soft-tissue mass inside? Contrast adds value when the scan shows lysis, when the cat has facial paralysis, or when surgery is planned. Contrast medium is given intravenously by the hospital at a weight-based dose under veterinary prescription, after a creatinine check.
Sampling method and reference intervals
Otoscopy under sedation comes first, and a sterile swab from the canal gives cytology in 5–10 minutes and culture in 3–5 days. Cytology has no numeric reference interval in the usual sense: a normal ear shows squames and no neutrophils, while more than 5 neutrophils per field with bacteria inside them points to infection, not wax. If the drum is ruptured, a bulla sample is taken by lavage under anesthesia, never through an intact drum in an awake cat.
Bloodwork before anesthesia is standard: packed cell volume 30–45%, total protein 6.0–8.0 g/dL, creatinine 1.0–2.0 mg/dL, and a T4 in any cat over 8 years. A raised T4 changes anesthesia risk and belongs in the same workup.
4 to 6 weeks of treatment, by prescription only
Bacterial otitis media needs 4–6 weeks of an antibiotic chosen from culture, not 7 days of drops left over from another cat. The drug, dose and route are by veterinary prescription only; the owner's job is the schedule. A cat that improves in 10 days and stops at day 12 relapses in 3–4 weeks, because the bulla lining turns over slowly and fluid sits in a space that drops cannot drain.
Ear cleaning continues through the course: 1 flush per day for the first 7 days if the drum is open, then every 2–3 days. Never push a cotton swab past the first 5 mm. Never use a dog ear product containing permethrin on a cat; it causes tremors within hours, so check every label against the poisoning list first.
3 rechecks, and what each one decides
| Recheck | When | Test | Decision |
|---|---|---|---|
| Baseline | day 0 | Otoscopy, cytology, CT | Sets drug, course and recheck dates |
| 1st | day 14 | Otoscopy plus cytology | Change drug if neutrophils are still above 5 per field |
| 2nd | week 4–6, last day of course | Otoscopy, ± repeat CT | Extend 2 weeks or stop |
| 3rd | 3 months after the last dose | Otoscopy plus owner log | Discharge, or refer for surgery |
The 3-month recheck exists because 15–20% of cases look cured at week 6 and relapse by week 12. A cat that relapses twice, or has a polyp, is a surgery case: ventral bulla osteotomy, 60–90 minutes under anesthesia, 3–5 days in hospital, and a 2-week recovery with a drain that comes out at day 3–5.
Cost and realistic timelines
A CT scan runs $300–800, anesthesia $150–350, culture $80–150, and each recheck $60–120. Total medical management lands at $900–1,800 over 6 weeks; surgery adds $2,000–3,500. The head tilt usually improves in 7–14 days; the Horner pupil lags 4–8 weeks, sometimes permanently.
When to see a vet
Same-day care for a head tilt with nystagmus that does not settle in 48 hours, a drooping lip or an eye that no longer blinks, a pupil difference of 1 mm or more, discharge that smells foul, pain when the mouth is opened, or a cat that stops eating for 24 hours. Emergency care for convulsions, a cat that cannot stand, or breathing that becomes noisy and fast. A cat with facial palsy and no blink can lose the eye to an ulcer in 2 days, so do not wait for an appointment.
5 steps after the diagnosis
- Get a CT report in writing, with the bulla wall thickness and any lysis noted.
- Insist on a culture before the first antibiotic, and read it at day 3–5.
- Set the 3 rechecks on the calendar the day treatment starts.
- Flush as directed, never with a swab, and check every product for permethrin.
- Photograph the ear and the eye weekly; a 1 mm pupil change is easier to see in a photo.
Terms mentioned in this article
Frequently asked
Can ear drops alone cure otitis media?
Rarely. Drops sit in the canal and reach the bulla only if the eardrum is open and the fluid can drain, which is why bacterial media gets 4 to 6 weeks of systemic antibiotics chosen by culture. The drug and dose are set by your vet by prescription only. A cat that stops at day 12 after looking better usually relapses within 3 to 4 weeks.
Is a CT scan always necessary?
No, but it changes the plan in most cats with nerve signs. A non-contrast bone-window CT takes 10 to 15 minutes and shows whether the bulla wall is thicker than 1 mm or eaten away, and whether a polyp is present. Contrast or MRI is added when there is facial paralysis, bone lysis, or a surgical plan, and MRI when brain signs appear.
How long until the head tilt goes away?
Most cats improve within 7 to 14 days and are steady by 4 weeks. The Horner pupil lags 4 to 8 weeks and may keep a 1 mm difference permanently, which is cosmetic. A tilt that is unchanged at the 3-month recheck, or a cat that relapses twice, is referred for a ventral bulla osteotomy rather than another course of drops.