Parapharyngeal abscess

1. DR SHAFIQ AHMAD PGR ENT

2. PARAPHARYNGEAL ABSCESS
Other Synonyms are:
 Abscess of pharyngomaxillary
 Lateral pharyngeal space.

3. APPLIED ANATOMY
 Pyramidal in shape
Base is at the base of skull
Apex is at the hyoid bone.

4. RELATIONS
Medial.
Buccopharyngeal fascia covering the constrictor
muscles.
Posterior
Prevertebral fascia covering prevertebral muscles and
transverse processes of cervical vertebrae.
Lateral
Medial pterygoid muscle, mandible and deep surface
of parotid gland.
viz. retropharyngeal, submandibular, parotid, carotid
and visceral.

5. Spaces of head and neck seen in coronal section. Mucosa (1), pharyngobasilar fascia (2),
buccopharyngeal fascia (3), superior con- strictor muscle (4), superficial layer of deep cervical
fascia enclosing submandibular gland (5), parotid gland (6), masseter muscle (7), temporalis
muscle (8) and medial pterygoid muscle (9

6. Anterior & Posterior compartment
Styloid process and the muscles attached to it divide the parapharyngeal
space into anterior and posterior compartments.
Anterior compartment :
is related to tonsillar fossa medially and medial pterygoid muscle
laterally.
Posterior compartment:
 is related to posterior part of lateral pharyngeal wall medially and
parotid gland laterally.
 Through the posterior compartment pass the carotid artery, jugular vein,
IXth, Xth, XIth, XIIth cranial nerves and sympathetic trunk.
It also contains upper deep cervical nodes. Parapharyngeal space
communicates with other spaces

7. AETIOLOGY
Infection of parapharyngeal space can occur from:
1. Pharynx. Acute and chronic infections of tonsil and
adenoid, bursting of peritonsillar abscess.
2. Teeth. Dental infection usually comes from the lower
last molar tooth.
3. Ear. Bezold abscess and petrositis.
4. Other spaces. Infections of parotid, retropharyngeal
and submaxillary spaces.
5. External trauma. Penetrating injuries of neck, injec-
tion of local anaesthetic for tonsillectomy or mandibu- lar
nerve block.

8. CLINICAL FEATURES
Depends on the compartment involved.
Anterior compartment:
(i) prolapse of tonsil and tonsillar fossa
(ii) trismus (due to spasm of medial
pterygoid muscle)
(iii) external swelling behind the angle of jaw.
There is marked odynophagia associated with
it.

9. Posterior compartment:
(i)Bulge of pharynx behind the posterior
pillar
(ii) Paralysis of CN IX, X, XI, and XII and
sympathetic chain
(iii) Swelling of parotid region. There is
minimal trismus or tonsillar prolapse.

10. Other Clinical Features common to both
compartments are:
Fever,
 odynophagia,
 sore throat,
 torticollis (due to spasm of prevertebral
muscles)
signs of toxaemia

11. DIAGNOSIS
1.CECT
• Contrast-enhanced CT scan neck
will reveal the extent of a lesion.
2.MRA
•Magnetic resonance arteriography
is useful if thrombosis of the internal jugular
vein or aneurysm of the internal carotid artery
is suspected.

12. COMPLICATIONS
1. Acute oedema of larynx with respiratory obstruction.
2. Thrombophlebitis of jugular vein with septicaemia.
3. Spread of infection to retropharyngeal space.
4. Spread of infection to mediastinum along the carotid
space.
5. Mycotic aneurysm of carotid artery from weakening
of its wall by purulent material. It may involve common
carotid or internal carotid artery.
6. Carotid blow out with massive haemorrhage.

13. TREATMENT
Systemic antibiotics :
Intravenous antibiotics to cover both aerobic and
anaerobic organisms like:
 Amoxicillin–clavulanic acid
 Imipenem or meropenem along with clindamycin
or metronidazole.
 Gentamicin is useful for Gram-negative bacteria.
The sensitivity of an antibiotic should determine
the selection of antibiotic.

14. Drainage of abscess:
This is usually done under general anesthesia.
 If the trismus is marked, preoperative tracheostomy becomes
mandatory.
Abscess is drained by a horizontal incision, made 2–3 cm below
the angle of mandible.
Blunt dissection along the inner surface of medial pterygoid muscle
towards styloid process is carried out and abscess evacuated.
 A drain is inserted.
Transoral drainage should never be done due to danger of injury to
great vessels which pass through this space.