PBL 7 - Tonsils and Otitis Media with Effusion

Question 1

Draw a diagram that shows all of the tonsils.

Answer 1

See Stewart McDonald’s diagram.

Include:

1. Palatine tonsils
2. Lingual tonsil
3. Adenoid/pharyngeal tonsil
4. Tubal tonsil

Question 2

What is another name for the pharyngeal recess?

Answer 2

Fossa of Rosenmuller

Question 3

Define “tonsil”.

Answer 3

A mass of lymphoid tissue located around the pharynx

Question 4

List the 4 different tonsils, and state how many of each are found.

Where are they located?

Answer 4

Palatine tonsil (x2)
---Location: each side of oropharynx between palatoglossal and palatopharyngeal folds

Adenoid/pharyngeal tonsil (x1)
—Location: midline of the roof of the nasopharynx

Tubal tonsil (x1)
---Location: around the opening of the Eustachian canal in the nasopharynx (i.e. the tubal elevation)

Lingual tonsil (several)
---Location: posterior 1/3 of the tongue

Question 5

Describe the structure and histology of tonsils.

Answer 5

Epithelium: stratified squamous

Structure:

1. Hemicapsule - separates tonsil from underlying tissue
2. Lymphoid follicles - contain germinal centres
3. Tonsillar crypts - invaginations which are infiltrated by lymphocytes

Question 6

What is the blood supply of the tonsils?

Answer 6

1. Palatine tonsils - tonsillar branch of facial artery
2. Upper pharynx - branches of the external carotid artery
   a. Ascending pharyngeal artery
   b. Ascending palatine/tonsillar branches of the facial artery
   c. Branches of the maxillary and lingual arteries
3. Lower pharynx - branches of the thyrocervical trunk of the subclavian artery
   a. Pharyngeal branches from the inferior thyroid artery

Question 7

Outline the function of the tonsils.

Answer 7

Function: protection against infection

Process:

1. Antigens enter the tonsillar crypts
2. Antigens enter the lymphoid follicles via transcytosis
3. Lymphocytes are activated by antigen presentation
4. An immune response is initiated:
   a. Efferent lymphatic vessels drain to the deep cervical chain of lymph nodes
   b. Activated lymphocytes migrate into the lamina propria of the oral/nasopharyngeal mucosa

Question 8

Define otitis media with effusion (or glue ear).

Answer 8

A condition in which viscous fluid accumulates in the middle ear, causing deafness. Most often seen in children due to malfunction of the Eustachian tube

Question 9

Describe the clinical features of OME.

Answer 9

1. Often asymptomatic
2. Mild/intermittent ear pain
3. Sense of fullness in ear
4. Ear “popping”
5. Hearing loss, e.g. shown by:
   a. Inattentiveness
   b. Behavioural changes
   c. Failure to respond to speech
   d. Poor school problems
   e. Balance problems
   f. Delayed speech and language problems
6. Secondary manifestations in children, e.g. ear rubbing

Question 10

List the complications of OME.

Answer 10

1. Permanent hearing loss
2. Acute/chronic mastoiditis (necrosis of the mastoid bone; perforation of tympanic membrane)
3. Cholesteotomas (erosion of ossicles/labyrinth)
4. Intracranial complications (meningitis or facial nerve paralysis)

Question 11

Describe the prognosis of OME.

Answer 11

50% cases resolve spontaneously within 3 months

30-40% cases become recurrent OME

5-10% cases last 1 year or longer

Question 12

What are the causes of OME?

Answer 12

1. Spread of infection from:
   a. Maxillary sinus
   b. Adenoid tonsils
   c. Palatine tonsils
2. Uncomplicated upper respiratory tract infection
3. Residual inflammation
4. Underlying mucosal inflammation resulting in effusion

Question 13

List some of the risk factors for OME.

Answer 13

1. Young age
2. Dysfunction of Eustachian tube
3. Premature birth
4. Male gender
5. Ethnicity
6. Family history
7. Orofacial abnormalities (e.g. cleft palate)
8. Bottle feeding

Question 14

How is OME diagnosed?

Answer 14

1. Recent/acute onset of symptoms
2. Middle ear inflammation
   a. Erythema of tympanic membrane
   b. Bulging of tympanic membrane
   c. Otalgia
3. Otoscopic signs of middle ear effusion
   a. White/yellow/blue discolouration of the ear drum
   b. Opacification of ear drum
   c. Decreased/absent motility of ear drum
   d. Bubbles behind ear drum
4. Culture/sensitivity testing of fluid from middle ear via tympanocentesis

Question 15

Outline the treatment for OME.

Answer 15

1. Wait 3 months for the OME to resolve spontaneously
   a. Observation
   b. Antibiotics
   c. Corticosteroids
2. After 3 months:
   a. Hearing evaluation
   b. Rule out anatomic variations (e.g. enlarged adenoids)
   c. Referral to ENT surgeon
   d. Grommet/ventilation tube placement
   e. Adenoidectomy

Question 16

How do grommets help in OME?

Answer 16

Equalise pressure

Question 17

How do you tell the difference between conductive hearing loss and sensorineural hearing loss?

Answer 17

1. Rinne test - place the tuning fork on their mastoid process, then next to their ear
   a. Normal - airborne conduction is better/louder
   b. Conductive hearing loss: bone conduction is better/louder
2. Weber test - place a tuning form on the centre of their forehead
   a. Detects whether hearing loss is unilateral or bilateral

Question 18

How are children screened for deafness?

Answer 18

1. Automated otoacoustic emission (AOAE) test
   a. Earpiece in baby’s ear plays soft clicking sounds
   b. Screening equipment measures the cochlea’s response to this
2. Automated auditory brainstem response (AABR)
   a. 3 small sensors are placed on the head/neck
   b. Brainstem response to soft clicking sounds is monitored over 5-15 minutes