Download orbital complications of rhinosinusitis

ORBITAL COMPLICATIONS OF
RHINOSINUSITIS
By
Dr. Firas M. Hassan
F.I.B.M.S
Otolaryngologist
Introduction
Complication of rhinosinusitis may be defined as any adverse progression of
chronic or acute bacterial infection beyond the paranasal sinuses.
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The incidence of rhinosinusitis-related complications has fortunately
decreased since the introduction of antibiotics, but they result in devastating
consequences if they are not promptly recognized and treated. They are often
categorized based on orbital, intracranial, or osseous involvement. In general,
computed tomography (CT) is considered ideal for radiographical evaluation of the
orbit while magnetic resonance imaging (MRI) is better utilized for the
intracranium.
Its close proximity to the paranasal sinuses makes the orbit the most
commonly involved structure in rhinosinusitis-related complications,
encompassing between 60-75% of such events. This is usually attributed to the
ethmoid sinuses although the frontal and maxillary sinuses may occasionally
contribute to these conditions. The orbit is often the first to experience sequelae of
rhinosinusitis in light that the bony lamina papyracea and the fibrous periorbita and
orbital septum are the only major anatomic barriers protecting the orbit from direct
extension of the inflammatory and infectious changes occurring in the neighboring
sinuses. Furthermore, the valveless superior and inferior ophthalmic veins
facilitate a relatively unimpeded route for infectious thrombophlebitis to travel past
the periorbita and affect the orbital contents.
Children tend to experience orbital complications more than the adult
population, but they do not always exhibit typical clinical findings suggestive of
acute infection such as complaints of pain or a general deterioration, and
leukocytosis is found only in approximately half of cases. Individuals younger
than seven years of age are usually afflicted solely with orbital manifestations
while older children often experience both orbital and intracranial complications.
This difference is thought to be related to the age-related sinus development of the
frontal sinus.
Streptococcus and Staphylococcus species are the more commonly
responsible microbial agents involved in pediatric orbital complications, while
Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis
usually affect adult patients.
Chandler devised a classification scheme that categorizes the various forms
of rhinosinusitis-related orbital complications in to:
1. Preseptal cellulitis
Inflammation does not extend beyond the orbital septum (the site at which
the medial orbital periosteal reflection attaches to the medial eyelid at the
tarsal plate).
2. Postseptal cellulitis or orbital cellulitis without abscess
Inflammation extends into the tissues of the orbit.
3. Subperiosteal abscess
There is abscess formation deep to the periosteum of the orbital
bones, usually the lamina papyracea.
4. Orbital abscess
There is abscess formation within the orbit which has breached the
periosteum.
5. Cavernous sinus thrombosis/abscess
The inflammatory process has extended through the optic foramen into the
cavernous sinus which thromboses and possibly progresses to abscess
formation.
Despite five distinct processes described with this classification scheme, it is
important to appreciate that they are not mutually exclusive and may occur
concurrently.
Management of Orbital Complications
Clinical presentation
 history of a mild upper respiratory tract infection accompanied or followed
by swelling around the eye.
 It is far more common in children (50 percent under six years) and young
adults (76–85 percent under 20).
 Visual problems may be present if the problem is stage three (subperiosteal
abscess) or beyond, and specific enquiries should be made regarding visual
acuity and colour vision, problems which might indicate a compromise of
optic nerve function.
 At stage five (cavernous sinus thrombosis), as well as chemosis, periorbital
oedema and proptosis, there will be a progressive opthalmoplegia (lateral
gaze may be affected first) and visual impairment (possibly resulting in total
blindness) due to direct cranial nerve involvement, together with other
symptoms including headache and trigeminal parasthesia. These are often
bilateral, especially proptosis.
Physical examination
 Clinical endoscopic examination of the nose should be performed to help
determine the site and extent of disease.
 Formal ophthalmological assessment of:
o full range of eye movements,
o degree of proptosis,
o relative afferent pupillary defect,
o visual acuity (using a Snellen chart),
o colour vision,
o inspection of the optic disc should be made.
 This assessment should be repeated daily where clinically appropriate.
Where there is increasing concern, six-hourly monitoring of the full range of
eye movements, visual acuity and colour vision should be undertaken in
conjunction with regular temperature and pulse measurements.
 For ongoing monitoring of treatment, the simple regular measurement of
temperature should not be forgotten, as any persisting infection may
manifest itself as sustained or ‘spiking’ pyrexia. Such a situation would
indicate further radiological investigation.
Investigations
Radiological investigation
 The main aim of radiological investigation will be to define the extent and
site of the disease.
 If there is full ocular movement and normal vision (including colour vision),
no immediate radiological investigation is indicated, unless there are
concerns about an intracranial problem also being present.
 Appropriate investigations should be undertaken to confirm the presence,
and site of, a suspected surgically treatable abscess prior to drainage.
 The investigation of choice is a high definition computed tomography (CT)
scan taken in both coronal and axial planes.
Haematological investigations
The place of haematological investigations is:
1. to help ensure there is no serious underlying disease process such as a
leukaemia;
2. to act as an assessment of fitness for surgery;
3. to monitor the patient's response to treatment.
Other investigations
 It will often be helpful to set up blood cultures as soon as possible,
preferably prior to, but not at the expense of, antibiotic treatment.
 Similarly, the culture of any purulent material found in the nose on clinical
examination at the time of surgery in the sinuses or from an abscess is
important.
 In patients with a diagnosed complication of rhinosinusitis, urinalysis should
be undertaken to detect diabetes mellitus, which might have led to
immunocompromise.
Treatment
Medical tratment
Unless an abscess is demonstrated by radiological or other investigation,
nonsurgical management of rhinosinusitis complications would usually be the first
choice. The exception to this would be when vision was affected by pressure on the
optic nerve resulting from surrounding inflammation without abscess formation.
The aim of medical management is two-fold:
(1) to control and eliminate the disease process directly relating to the
complication;
(2) to control and eliminate the primary rhinosinusitis.
Although antimicrobials will form the mainstay of medical treatment, many
clinicians would advocate specific treatment for nasal decongestion with the aim of
facilitating resolution of the underlying rhinosinusitis. A typical decongestant
regime would be the intranasal administration of ephedrine 0.5 percent drops, two
drops six-hourly to the affected side of the nose. However, there is little evidence
to support this as an addition to treatment.
The selection of antibiotics will usually be made before any information regarding
the infecting organism or its sensitivity to antimicrobials is available. The choice of
antibiotics, therefore, needs to be of a broad enough spectrum to cover the likely
infecting organisms, but at the same time be reasonably selective in order to
minimize the development of microbe resistance.
Accordingly, a regime of intravenous cephalosporin with metronidazole would be
an appropriate first choice.
Initially, medical management should be planned for 24 hours, with
frequent monitoring of the patient over this period as described above. If there is
not a significant clinical improvement in the first 24 hours of medical treatment,
surgical intervention should be considered. Additionally, if there is clinical
deterioration, then emergency surgical intervention is likely to be appropriate.
For orbital complications, intravenous antibiotic administration should continue
until clinical improvement is well established and only then should oral treatment
be substituted. A good indication of established improvement is the absence of
pyrexia for a period of 24 hours combined with a general clinical improvement.
There is little good evidence as to how long oral antibiotics should be continued,
but a period of 7–14 days would usually be effective.
In the case of cavernous sinus thrombosis, the addition of anticoagulation to
antibiotic therapy and appropriate surgical drainage of any collection may be
beneficial in preventing mortality, but not morbidity. In all instances, the
importance of working with and consulting other clinical colleagues should not be
overlooked. An appropriate combination of ear, nose and throat (ENT) surgeons,
paediatricians, ophthalmologists and neurologists should be involved in the
management from the time the patient is admitted to hospital.
Surgical treatment
The surgical treatment of patients with complications of rhinosinusitis can
be conveniently divided into that necessary for the treatment of the rhinosinusitis
and that necessary for the treatment of the complication. These are likely to be
carried out at the same time, but may involve more than one team of surgeons.
Infections with cellulitis alone are likely to settle with conservative treatment,
whereas patients with proptosis but normal eye movements and visual acuity are
likely to require surgery.
Orbital cellulitis is almost always secondary to ethmoid rhinosinusitis, but may
occur with frontal rhinosinusitis.
Some surgeons suggest that endoscopic ethmoidectomy together with removal of
the lamina papyracea and perinasal drainage of the orbital abscess is sufficient
treatment. However, unless the surgeon is extremely familiar with endoscopic
nasal surgery, it is probably easier and wiser to use an external approach. This has
the advantage of allowing an assistant to help keep the operative field clear. If an
external approach is used, the conventional Lynch–Howarth approach for an
external ethmoidectomy will allow the surgeon to drain the subperiosteal abscess
‘on the way’ to carrying out the definitive ethmoidectomy.
Drainage of the abscess can be established using drainage tubes placed to drain
either into the nasal cavity (fixing to the septum) or externally through the medial
canthal incision.
The former, endonasal, siting is likely to result in less cosmetic deformity than
leaving an external drain. Although simple drainage of an orbital abscess without
any ethmoid surgery (relying on medical treatment to deal with the rhinosinusitis)
may be effective, it is probably better to perform both definitive surgery for the
rhinosinusitis, as well as surgery for the orbital abscess at the same time.
Treatment of specific types of Orbital Complication
Preseptal Cellulitis
Eyelid edema and erythema is quite noticeable with preseptal cellulitis, but a
small eyelid abscess may occasionally be encountered. A key characteristic is the
integrity of both extraocular muscle movment and inherent vision. CT images will
only reveal diffuse thickening of the eyelids and conjunctiva, all of which should
occur superficial to the orbital septum. As such, medical therapy is typically
sufficient to adequately treat cases of preseptal cellulitis with the initiation of
intravenous antibiotics, application of warm compresses, and elevating the head of
the bed. Additionally, facilitating sinus drainage with nasal saline irrigations,
decongestants, and mucolytics may provide some benefit.
Orbital Cellulitis
Progression of the inflammatory changes deep to the orbital septum
constitutes orbital cellulitis. While eyelid edema and erythema will also be
present, the eye may demonstrate proptosis and chemosis. Some patients may
complain of pain or diplopia due to impaired extraocular muscle movement, but
the vision itself remains unaffected. Low-attenuation adjacent to the lamina
papyracea is often noticed on CT, but a discrete abscess should not be encountered.
As with preseptal cellulitis, medical management with antibiotics and nasal
drainage is often successful. Clinical reassessment and surgical drainage should be
considered if visual acuity is at 20/60 or worse or if there is no improvement or
even symptomatic progression within 24 hours.
Subperiosteal Abscess
This subperiosteal collection typically displaces orbital contents inferiorlylaterally with subsequent exophthalmos. While some may exhibit normal
extraocular muscle movement early on, patients will present with proptosis,
chemosis, and ophthalmoplegia leading to complaints of orbital pain, diplopia, and
reduced visual acuity. Some abscesses may extrude through the eyelid. CT
imaging is diagnostically accurate in 86-91%, revealing a rim-enhancing
hypodensity adjacent to the lamina papyracea with mass-effect.
Acquiring the assistance from the ophthalmologist and pursuing prompt
surgical intervention is clearly warranted since drastic visual sequelae may result if
this condition is not addressed, especially in the face of progressively worsening
vision or extraocular muscle movement or if there is a lack of improvement after
24 hours. There is a small contingent that advocates medical therapy alone may be
sufficient in 50-67%, but this notion is usually reserved for children less than four
years of age with small abscesses. Ultimately, a combined surgical and medical
treatment plan should achieve complete resolution in 95-100% of cases.
The chosen surgical approach varies by surgeon but is often set with the goal
of removing the lamina papyracea and opening the ethmoid cells to remove the
abscess and facilitate sinus drainage. Most prefer an external incision, such as the
Lynch incision, along the medial-superior aspect of the orbital rim to provide
access to the subperiosteal plane. Antral wash-out can be used as an adjuvant for
the external approach. An endoscopic approach may be ideal for more medially
located collections, allowing the removal of the lamina papyracea while sparing
the patient an external facial incision.
Orbital Abscess
An abscess formation within the orbital tissues themselves will present with
a similar clinical picture as a subperiosteal abscess. Ophthalmoplegia and reduced
visual acuity is also present, but the degree of exophthalmos and chemosis is felt to
be more severe compared to that experienced with subperiosteal abscesses. A
similar rim-enhancing hypodensity is noted on CT, but it is not relegated solely to
near the lamina papyracea. In conjunction with draining the responsible paranasal
sinuses, incising the periorbita and draining the intraconal abscess with the
assistance with ophthalmology is paramount to avoid the significant risk of
irreversible blindness.
Cavernous Sinus Thrombosis
Cavernous sinus thrombosis often manifests with similar signs as an orbital
abscess as the inflammatory and infectious process traverses posteriorly from the
orbit toward the intracranium. Orbital pain, proptosis, chemosis, ophthalmoplegia,
and impaired vision are also present, but the key distinguishing feature is that there
is also contralateral involvement. Poor venous enhancement may be noted on CT,
but the presence of heterogeneity and increased size of the cavernous sinus on MRI
is considered a more confirmatory radiographical finding.
Cavernous sinus thrombosis is often associated with meningismus and
sepsis, and not surprisingly carries a mortality rate up to 30%. High-dose
intravenous antibiotics that can cross the blood-brain barrier and surgical drainage
of the paranasal sinuses are clearly warranted, but the use of anticoagulation to
prevent thrombus propagation has been highly controversial.
Algorithm showing the management of orbital
complications
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