Adenoid

By

Dr. T. Balasubramanian M.S. D.L.O.

Adenoid is a collection of lymphoid tissue in the mucous membrane overlying the basisphenoid area.  It has an oblong shape, similar to that of a truncated pyramid.  It infact virtually hangs from the roof of the naso pharynx.  Its anterior edge of this tissue is vertical and lie in the same plane as the post nasal aperture.  Its posterior edge gradually merges into the posterior pharyngeal wall. and its lateral edges incline towards midline.   It is lined by ciliated columnar epithelium.  The surface of adenoid has furrows.  It feels like a bag of worm to touch.  Laterally adenoid is continuous with lymphoid tissue around the pharyngeal end of eustachean tube.  This lymphoid tissue around the eustachean tube orifice is also known as Gerlat's tonsil.

Blood supply to adenoid is by

1. Ascending pharyngeal artery

2. Ascending palatine artery

3. Pharyngeal branch of internal maxillary artery

4. Artery of pterygoid canal

5. Contributions from tonsillar branch of facial artery

Venous drainage from the adenoid is through the pharyngeal plexus which in turn drain into the internal jugular vein.

The adenoid normally enlarges during childhood between 3 - 4 years.  This is a period during which the child is most prone to respiratory infections.  As the child grows older the adenoid regresses in size, may even disappear during puberty.  The initial reduction in the size of adenoid has been attributed to the rapid enlargement of the nasopharynx when compared to the size of the adenoid.

Adenoids can contribute to recurrent sinusitis and chronic persistent or recurrent ear disease because they can harbor a chronic infection. The type and amount of pathogenic bacteria seem to vary based on the disease present and the age of the child.denoids can contribute to recurrent sinusitis and chronic persistent or recurrent ear disease because they can harbor a chronic infection. The type and amount of pathogenic bacteria seem to vary based on the disease present and the age of the child.

Overall, the most commonly cultured bacteria have been Haemophilus influenzae, group A beta-hemolytic Streptococcus, Staphylococcus aureus, Moraxella catarrhalis, and Streptococcus pneumoniae, usually in that order.  
      
A large adenoid causes nasal obstruction, mouth breathing, snoaring and restless sleep.  It even causes change in voice i.e. rhinolalia clausa.  Enlarged adenoid causes typical changes in the face of young children.  These changes are collectively clubbed under the term adenoid facies.
Enlarged adenoid also causes enlargement of Gerlat's tonsil which in turn obstructs the eustachean tube causing middle ear effusions.

The adenoid normally enlarges during childhood between 3 - 4 years.  This is a period during which the child is most prone to respiratory infections.  As the child grows older the adenoid regresses in size, may even disappear during puberty.  The initial reduction in the size of adenoid has been attributed to the rapid enlargement of the nasopharynx when compared to the size of the adenoid.
      A large adenoid causes nasal obstruction, mouth breathing, snoaring and restless sleep.  It even causes change in voice i.e. rhinolalia clausa.  Enlarged adenoid causes typical changes in the face of young children.  These changes are collectively clubbed under the term adenoid facies.  This is caused due to chronic mouth breathing during active stage of facial skeletal growth.

The features of adenoid facies include elongated face, pinched nostrils, open mouth, high arched palate, shortened upper lip, and vacant expression.
     Adenoid should always be removed along with tonsillectomy irrespective of its size, this is because it has a propensity to undergo compensatory hypertrophy after removal of tonsil.  Adults with enlarged adenoids should always undergo evaluation for chronic sinusitis.  In patients with chronic sinusitis the presence of recurrent post nasal drip is enough to cause enlargement of adenoid.
Investigations:  Xray skull lateral view will show clearly the enlarged adenoid tissue causing narrowing of the naso pharyngeal airway.

Xray lateral view of skull showing enlarged adenoid tissue

Even though the adenoid and tonsils are pathophysiologically united they also show some differences.  The differences between tonsil and adenoid are

Adenoiditis:  Infections involving adenoid is known as adenoiditis.  An excessively enlarged adenoid causes failure to thrive.  In addition to all the symptoms of adenoid enlargement narrated above these children has a propensity to vomit immediatly after feeds.  This occurs because the enlarged adenoid causes total obstruction to the nasal airway, the child is forced to gulp in air along with food.  This gulped in air reaches the stomach and causes bloating.  This bloating in turn leads to vomiting in these patients.

Management of pateints with enlarged adenoid:
These children must undergo a complete course of medical treatment.  The ideal drug of choice is penicllin group.  Ampicillin or Amoxycillin can be administered in doses ranging 40 - 50 mg /kg body weight.  In case of allergy to penicillin group of drugs Erythromycin can be administered in doses of 40 mg /kg body weight.  Recently cephalosporin has found favour with treating physicians.

The question when to operate on a patient with adenoid enlargment is highly controversial.  There has been a continuing clash between the paediatricians and ENT surgeons on the effects of adeno tonsillectomy on the immune profile of the patient.  All said and done surgery has a definite role to play in chronic adeno tonsillitis.  Surgery is preferably done after the child reaches the age of 5.  This is because at this age only the child can withstand the bleeding during adenotonsillectomy.  Infact even in the best of hands the bleeding during surgery would be rougly about 100 ml.  The child must be in a position to withstand this blood loss.

Adenoid is removed during tonsillectomy using St Claire Thompson Adenoid curette.  This instrument is held in the dominant hand during surgery like a dagger.  It comes in two versions 1. with cage and 2. without cage.  In fact the adenoid curette with cage can be dismantled and cage removed and can be used like a uncaged curette.  The basic advantage of having this cage is the adenoid tissue is held within the cage while it is being scooped out thereby minimising the risk of aspiration of adenoid tissue into the airway.   It can also be removed using a micro debrider intranasally under endoscopic control.

Picture showing adenoid curette

1. Dislocation of atlanto occipital joint  (Griesel syndrome)

2. Bleeding due to remnant adenoid

3. Lung infections following aspiration of adenoid remnants

4. Injury to the torus tubaris causing secretory otitis media

5. Nasal regurgitation is common in patients with occult cleft palate following adenoid surgery.  Occult cleft palate can be diagnosed clinically by the presence of bifid uvula.  Hence the presence of bifid uvula is a relative contra indication for adenoidectomy.

6. Rarely injury to eustachean tune may occur.

7. Nasopharyngeal stenosis (more common after adenotonsillectomy than after adenoidectomy alone)

8. Velopharyngeal insufficiency occurs in 0.2 % of patients undergoing adenoid surgery.  It is commonly observed in most patients post operatively.  It is transient, lasting just for a couple of weeks.  In case of persistent velopharyngeal insufficiency speech therapy must be started.  Persistent velopharyngeal insufficiency occurs in children with poor palatal muscle tone, occult cleft palate etc.  Some recommend performing a partial adenoidectomy, leaving the inferior portion of the adenoid pad, in patients at high risk for Velopharyngeal insufficiency. 

9. Torticollis: Because the adenoids are removed from the posterior wall of the nasopharynx over the spine and superior constrictor muscle, children can have a stiff neck or spasm of the neck, occasionally with torticollis. Torticollis is a rare occurrence. Warm compresses, a neck brace, and anti-inflammatory medications may be helpful for relieving the spasm and pain.

Copyright drtbalu 2007