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A 13 year-old girl with right eye swelling
Digital Journal of Ophthalmology 2004
Volume 10, Number 7
May 14, 2004
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 Vittal Nayak | K.S. Hedge Medical Academy Jayram Shetty | K.S. Hedge Medical Academy Vijay Pai | K.S. Hedge Medical Academy Vasanthi Bangera | K.S. Hedge Medical Academy Namitha Manohar | K.S. Hedge Medical Academy Ajith Adyanthaya | K.S. Hedge Medical Academy Harish Shetty | K.S. Hedge Medical Academy
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| Diagnosis and Discussion | Orbital abscess is a well delineated form of orbital cellulitis or a complication thereof characterized by collection of pus within the orbital tissues [1]. Orbital abscesses are potentially blinding/lethal diseases in patients of all ages [2 ,3]. Adjacent sinus disease accounts for most of orbital cellulitis in children [2,3,4]. Ethmoidal sinusitis is the most common etiological factor, others being trauma, skin infections, dental infections, otitis media, intraorbital foreign bodies, endophthalmitis, dacryoadenitis, squint surgery, retinal buckling procedures, bacteremia & HIV [6,7, 8, 9]. Orbital abscesses are more common on the leftside though no reason has been determined [1].
The mean age at presentation is 20-31 years [5 ,10]. They commonly present as an acute febrile illness, with proptosis, lid swelling, chemosis, impaired ocular motility, visual defects, pupillary abnormalities,colour vision deficits, and field defects [2,9] .Orbital infections are classified as [7]:
Group I Preseptal cellulitis, inflammatory edema, congestion
Group II Orbital infiltration& Mass effects & Functional deficits
Group III Subperiosteal abscess
Group IV Orbital abscesses & Mass effects
Group V Intracranial extension of inflammation into cavernous sinus.
Differential diagnosis of orbital cellulitis includes leukaemia [11], rhabdomyosarcoma [2], metastatic tumors [2], retinoblastoma [12], hemangiomata [13], lymphangiomata [14], dermoid cysts [15], neurofibromas with associated with bony defects and meningoencepahloceles [16], hydatid cysts of the orbit [17], and orbital varices [18].
Complications include intracranial spread leading to meningitis, intracranial abscess, cavernous sinus thrombosis, blindness [19,20,21], and death.
Etiological agents implicated include Staphylococcus aureus, Streptococcus pneumoniae, Hemophilus influenzae, anaerobes, Propionibacterium acnes, Pseudomonas, Pneumocystis, mixed infections and rarely parasites, fungi & mollicutes [1, 10,22,23,24,25] . Leukocytosis and blood cultures are unreliable. CT scans with coronal sections are useful [26]. It is important to note that computerized scans cannot predict whether the mass represents a haematoma, an exudate or a transudate [20]. MRI is frequently necessary for patients with intracranial infections [27, 28]. Ultrasonography is a useful adjunct [28]. Fine needle aspiration biopsy has been used to diagnose orbital metastatses [29].
Aggressive parenteral antibiotics with judicious surgical intervention constitute the mainstay of treatment [30]. Empirical treatment of proptosis with systemic steriods should be avoided as infections will be aggravated [24]. Cephalosporins every 12hrs for 7-10 days, followed by oral cephalosporins for 7 days are most commonly used drugs. B-lactamase resitant penicillins are also useful. Chloramphenicol, clindamycin, vancomycin are alternatives if initial treatment is not successful due to resistance. It is important not to overlook the possibility of the abscess being tuberculous. Anti-inflammtory medications, such as NSAIDs, may help reduce inflammation.
Criteria for nonsurgical treatment of subperiosteal abscess include: age < 9 yrs, normal visual acuity, normal visual fields, normal motility, no cranial nerve palsy, and no afferent pupillary defect [30,31].
Indications for surgical treatment include worsening of clinical parameters, such as decreasing visual acuity [5]. Abscess drainage becomes necessary in 50% to 70% of cases [5]. Standard technique of drainage involves making a skin incision closest to the abscess site, deepening it to the periosteum, and then inserting an instrument into the subperiosteal space of the orbit to break the abscess wall. Aspiration of the contents to avoid intra-orbital spread is essential.
In this context, CT guided orbital abscess drainage can be performed via CT guidance, as is performed for biopsies of optic nerve tumors [21,32]. It is important to note the maximum length of the needle for drainage of orbital abscesses is 3.75 cm [21]. A Venflon 22 gauge cannula is 3.5 cm long and is incapable of reaching the intracranial space through the superior orbital fissure. The Venflon cannula (22 gauge) is inserted in one of the oblique quadrants rather than directly above or below the globe to avoid accidental perforation. The cannula is closely watched to see if blood / pus are noted as the Venflon is introduced. Once pus is seen the inner needle is removed and a syringe with negative pressure is attached to the Venflon facilitating quick drainage into the syringe. The material obtained is subjected to microbiological examination (Gram stain, Ziehl Neilsen & Fungal Stains, aerobic and anaeorbic culture), and cytopathological examination [21,31] .
In spite of CT Scan guidance, adequate anesthesia, and guarded insertion of the Venflon cannula, complications can occur. The most common complication reported is hematoma formation which resolves spontaneously. Loss of extra ocular movements, ptosis, blindness, death are other complications [21,32].
Failure to drain may suggest a mass lesion, orbital pseudotumor or tumor, and indicate the need for an open biopsy, or may suggest that the cannula is not within the abscess and requires re-positioning. Microbiological and cytopathological examination of aspirates from the orbit is essential and may provide a clue to the diagnosis
The procedure of draining orbital/subperiosteal abscesses using a Venflon cannula may be tried on a large scale. We recommend a larger trial by the ophthalmic fraternity.
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