Otitis Externa Aetiology Quiz

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Questions and Answers

What is the recommended dosage for topical medication applied to the ear?

0.1 – 0.3 ml per ear twice daily

0.5 ml per ear three times daily

0.5 – 1 ml per ear usually twice daily (correct)

1 – 1.5 ml per ear once daily

Which of the following is a recommended practice for treating secondary infections in otitis externa?

Only rely on clinical signs for medication selection

Use oral antibiotics as the primary treatment

Conduct in-house cytology to guide drug choice (correct)

Avoid using any topical treatments

What is the primary purpose of ear cleaning in otitis externa treatment?

To introduce new medications into the ear canal

To improve compliance with medication use

To prevent owner involvement in the treatment process

To remove earwax and enhance exposure to topical treatments (correct)

What should be included in the cleaning fluid for manual ear cleaning?

Ceruminolytics, surfactants, and antimicrobial agents Signup and view all the answers

What is the guideline for frequency of ear cleaning in general treatment?

Once or twice weekly Signup and view all the answers

What does the term otitis externa specifically refer to?

Inflammation of the outer ear canal Signup and view all the answers

Which anatomical feature is absent in the lower ear canal of horses?

Hair follicles Signup and view all the answers

What is cerumen commonly known as?

Ear wax Signup and view all the answers

What type of skin is found in the normal ear canal?

Thin stratified keratinizing epidermis Signup and view all the answers

Which of the following is NOT a common aetiological factor for otitis externa?

Ototoxicity Signup and view all the answers

Which procedure is essential for determining the aetiology of otitis externa?

Otoscopy Signup and view all the answers

What role do sebaceous glands play in the ear canal?

Producing cerumen Signup and view all the answers

Which of these statements about otitis externa is incorrect?

It is a rare condition in small animal practice. Signup and view all the answers

What effect does TrizEDTA have on bacterial cells?

Damages bacterial cell walls Signup and view all the answers

What is the primary benefit of ear flushing in initial otitis externa therapy?

Improves visualization of the ear canal Signup and view all the answers

When should TrizEDTA be administered relative to other ear treatment products?

20-30 minutes before other products Signup and view all the answers

What role do porphyrins play in photodynamic therapy?

Sensitize organisms to light exposure Signup and view all the answers

Which medication can be used for treating ear infections in dogs and cats?

Fluralaner (Bravecto®) Signup and view all the answers

What treatment is NOT commonly utilized for primary keratinisation disorders?

Weight management Signup and view all the answers

Which of the following factors is important to address in the treatment of otitis externa?

Addressing underlying systemic disease Signup and view all the answers

Which of the following corticosteroids has the highest potency for treating otitis externa?

Betamethasone Signup and view all the answers

What is a necessary requirement for performing ear flushing?

Use of general anesthesia Signup and view all the answers

In treating secondary infections caused by bacteria or yeasts, which is an appropriate treatment option?

Antibiotics Signup and view all the answers

Why might surgical procedures be considered in the treatment of otitis externa?

To remove primary neoplasia or stenotic canals Signup and view all the answers

For immune-mediated conditions, which of the following medications is commonly used?

Corticosteroids Signup and view all the answers

What is the most common reason for recurrence in treatment failure?

Failure to identify the primary cause Signup and view all the answers

What type of saline solution is recommended for use during ear flushing?

Sterile saline or dilute chlorhexidine solution Signup and view all the answers

Which of the following is considered a primary cause of skin issues?

Food allergies Signup and view all the answers

What is the recommended approach for treating foreign bodies in the ear?

Irrigate and flush the ear Signup and view all the answers

What is the primary function of corticosteroids in treating acute otitis externa?

Reduce inflammation Signup and view all the answers

What type of therapy is preferred for the treatment of secondary diseases?

Topical treatment Signup and view all the answers

Which of the following is a common consideration when choosing topical treatments for infections?

Systemic vs topical application Signup and view all the answers

Which category includes allergens related to skin conditions?

Flea allergies Signup and view all the answers

What should be done when treating infections caused by ear mites?

Systemic treatment Signup and view all the answers

Which of the following is NOT part of the treatment process for allergies?

Immediate surgical intervention Signup and view all the answers

In the management of primary keratinisation disorders, what treatment option is often utilized?

Zinc supplements Signup and view all the answers

Which of the following factors is NOT categorized as a perpetuating factor in skin treatment?

Dietary choices Signup and view all the answers

What is the primary purpose of lateral wall resection (LWR)?

To improve drainage and access lesions Signup and view all the answers

In what scenario is vertical canal ablation (VCA) considered appropriate?

For irreversible disease of the vertical canal Signup and view all the answers

What is a common reason for the recurrence of otitis externa?

Failure to identify the primary cause Signup and view all the answers

What should be done if the ear canal is swollen shut?

Use cortisone to reduce swelling before examining the canal Signup and view all the answers

Why is it important to educate the client about ear cleaning?

To ensure they can help in long-term management Signup and view all the answers

What is TCA and when is it indicated?

Used for chronic end-stage otitis and neoplasia Signup and view all the answers

What is the first step in managing otitis externa?

Find and treat the primary cause Signup and view all the answers

What is the significance of follow-up examinations in treating otitis externa?

They ensure the primary cause has been resolved Signup and view all the answers

Study Notes

Otitis Externa

Otitis externa is the inflammation of the outer ear canal.
It has variable degrees of severity.
Normal ear anatomy includes cartilage and bone covered by skin, hair follicles, sebaceous glands, and apocrine glands.
The skin of the normal ear has a thin keratinising epidermis and a thin dermis containing adnexal structures.
Cerumen, commonly called earwax, is a mixture of secretions from sebaceous and apocrine glands, and dead skin cells.
The density of hair follicles in the ear varies among species.
Otitis externa occurs in species with external auditory components.
Any dermatosis can affect the external ear.
Canine otitis externa is a common presentation in small animals.

Aetiology: PSPP

Primary causes affect healthy ears.
Secondary causes affect abnormal ears, often combined with predisposing factors.
Predisposing factors increase the risk of developing otitis externa.
Perpetuating factors occur as a result of otitis externa.
Primary causes include allergies, parasites, foreign bodies, immune-mediated disease, primary keratinisation disorders, neoplasia, endocrine diseases, and miscellaneous causes (e.g., atopic dermatitis, food allergy).
Secondary causes include bacteria (e.g., Staphylococcus, Streptococcus), yeasts (e.g., Malassezia), and gram-negative bacteria (e.g., Pseudomonas).
Perpetuating factors include ear canal stenosis, ulceration, otitis media, and ear cartilage mineralisation.
Predisposing factors include conformation, humidity, inappropriate cleaning, irritant treatments, and systemic disease.

Diagnosis

History is crucial to identifying primary causes (e.g., dietary history, medication history, environmental factors).
Clinical examination includes general and dermatological examination, evaluation of ear canal (hard, soft, pain), pinna examination (hair loss, erythema, scaling), examination of the ear canal (visual and digital).
Otoscopic examination; evaluation of ear inflammation, ulceration, discharge, foreign bodies, neoplasia, and stenosis.
Cytology involves sampling of the ear canal.
Culture and sensitivity are indicated in chronic recurrent cases where antibiotics are ineffective and when rods are observed on cytology.
The decision for cytology and culture/sensitivity is dependent on the primary cause(s) being revealed from the history or initial examination.

Treatment

Identify and treat primary causes.
Treat secondary causes.
Minimise perpetuating factors.
Correct predisposing causes.
Relieve pain, discomfort, and inflammation.
Educate owner.
May include ongoing treatment, or further investigation if necessary.
Medical treatments for primary disease, secondary disease (topical preferred), antibiotics, antifungals, anti-inflammatories, and cleaning agents.
Surgical options for primary disease, predisposing/perpetuating factors, and possible cases of irreversible disease.

Follow Up Examination

Revisit cases after 3 days of oral cortisone, 7-10 days of topical treatment.
Continue/amend treatment until primary and controlled secondary disease is resolved (on cytology).
Failure to identify primary cause is common reason for recurrence.

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Description

Test your knowledge on otitis externa, the inflammation of the outer ear canal. This quiz covers the anatomy of the ear, the causes and factors involved in the condition, and its prevalence in dogs. Perfect for veterinary students and professionals.