Otitis 2 Flashcards
When is MRI used in otitis cases?
MRI reserved for animals presenting with neurological signs (where more detailed assessment of inner ear and brain required) or where soft tissue surgical planning required (assess for para-aural abscessation)
Describe the uses of radiography for otitis
Most widely available
Potential to ID
- mineralisation of EEC cartilages
- Fluid lines, osteolysis & bony proliferation in bullae
Cant be used to confirm otitis media
Describe the uses of CT for otitis cases
Imaging modality of choice for chronic otitis cases without neurological signs
Good assessment of
- EEC: thickening and stenosis, mineralisation
- Bony structures: bony change affecting tympanic bulla
- Middle ear: sensitive for diagnosis OM
- Inner ear: OI may be ID but less info on soft tissue (brain) involvement
- Bullae should be completely black (air filled)
Quicker and cheaper than MRI (may be quicker than radiography)
Describe the uses of MRI for otitis cases
Far better appreciation of soft tissue structures
- Meningeal involvement with OI
- Para-aural abscess with severe, chronic OE
Expensive: will take significant part of client’s budget!
What if I don’t have CT/MRI or my client can’t afford it??
Assessment for OM: myringotomy
Which techniques provide the most accurate way of assessing otitis media?
Myringotomy plus cytology - requires skill and experience
What is myringotomy?
A myringotomy is a procedure to create a hole in the ear drum to allow fluid that is trapped in the middle ear to drain out. The fluid may be blood, pus and/or water. In many cases, a small tube is inserted into the hole in the ear drum to help maintain drainage.
List the indications for a myringotomy
- Bulging eardrum on otoscopy with pain or neurological signs (Horner’s syndrome, vestibular disease, facial paresis)
- Radiographic/CT/MRI bulla changes and intact eardrum
- Evidence of fluid/tissue behind eardrum (requires experience of assessing eardrum)
- Medically unresponsive vestibular disease with an intact eardrum
- Chronic OE cases > 6 months failing to respond to treatment (requires judgement)
Why is it important to clean ears in otitis cases?
Majority of otitis cases benefit from cleaning
- Removal of infectious debris & disruption of microbial biofilms
- Visualisation of TM
- Assess epithelium: hyperplasia, ulceration, defects
- Expose and/or sample otic polyps/tumours
- Enhance action of topical therapy
The method of ear cleaning depends on which factors?
Severity of otitis (stenosis, pain)
Type and volume of discharge
Client factors e.g. finances
Patient factors e.g. TM rupture
How is ear cleaning done in cases of acute otitis with no pain and minimal debris?
Conscious animal
Proprietary cleaner (check TM)
How is ear cleaning done in cases of chronic otitis with copious discharge?
- General anaesthesia, intubation
- Handheld vs video otoscope
- Lavage with sterile water/saline until TM seen to be intact
- Post cleaning analgesia (paracetamol 10mg/kg q8hrs 3 days)
- Pre-treatment with prednisolone
Name some available ear cleaners
Otodine
Otoact
Otoprof
TrizChlor
TrizAural
What are biofilms? How do they affect otitis?
Microbes stuck together in extracellular matrix
Protected environment, infection difficult to treat
How are biofilms in otitis treated?
- N-acetylcysteine (Tris-NAC®), Betaine/polyhexanide (Prontosan® Wound Irrigation Solution)
- Disrupt biofilm and reduce viability of Staphylococcus spp. and Pseudomonas spp.
- Sterile water/saline lavage, instill product, massage (< 5 mins)
- Remove by suction, thoroughly lavage with sterile saline