This is an acute infection of the soft tissues of the orbit behind the orbital septum.

Etiology

1) exogenous- from penetrating injuries especially when associated with a foreign body lodgement.

2) extensions of infection from neighbouring structures like nose, paranasal sinuses, teeth, face, lids, intracranial cavity and intraorbital structures.

3) endogenous- as in metastatic infection from breast abcess, puerperal sepsis, thrombophlebitis of legs and septicemia

Causative organisms - streptococcus pneumoniae, staphylococcus aureus, streptococcus pyogenes and haemophillus influenzae

PATHOLOGY

Features here are similar to suppurative inflammations except for a few point of difference:

1> due to the absence of lymphatic system the protective agents are limited to local phagocytic elements provided by the orbital reticular tissue

2> due to tight compartments, the intra-orbital pressure is raised which augments the virulence of infection causing early and extensive necrotic sloughing of the tissues.

3> in most cases it spreads as thrombophlebitis..

CLINICAL FEATURES

Symptoms

- swelling

- severe pain

both of which increase by movements of the eye or pressure.

- other associated symptoms are fever, nausea, vomiting, prostrations and sometimes loss of vision.

Signs

- lids : marked swelling, woody hardness and redness

-conjunctiva: chemosis; it may protrude and become desiccated or necrotic

-eyeball : slightly proptosed

-restriction of ocular movements

-fundus shows congestion of retinal veins and signs of papillitis or papilloedema.

COMPLICATIONS

-ocular : blindness, exposure keratitis, optic neuritis, and central retinal artery occlusion.

- orbital : subperiosteal and orbital abscess

- temporal or parotid abscesses

- intracranial complications like cavernous sinus thrombosis, meningitis and brain abscess

-general septecemia or pyaemia

INVESTIGATIONS

1) bacterial cultures from nasal and conjunctival swabs and blood samples

2) complete haemogram may reveal leucocytosis

3)X-rays or para nasal sinuses to identify sinusitis

4) CT and MRI

TREATMENT

- intensive antibiotic therapy to overcome infection

- analgesics and anti-inflammatory drugs for pain and fever

- surgical intervention