In rhinosinusitis, spread of infection beyond the walls of the sinus is uncommon, but complications can be life changing and life threatening. Complications are most commonly caused by acute rhinosinusitis but may also be seen with an acute exacerbation of chronic rhinosinusitis.
• Periorbital and orbital complications.
• Osteomyelitis (maxilla or frontal bone).
• Intracranial complications (meningitis, intracranial abscess and cavernous sinus thrombosis).
• Locoregional complications (pharyngitis, laryngitis and otitis media).
90.2 Periorbital and Orbital Complications
These can occur at any age, but are more common in children, particularly under the age of 6 years. There is usually a history of a viral upper respiratory tract infection (URTI) preceding a periorbital/orbital complication. A secondary suppurative acute rhinosinusitis occurs, which then rapidly involves the orbit and periorbital tissues. In adults, there may be pre-existing chronic rhinosinusitis. The usual bacteria causing such a complication are therefore the bacteria that cause acute and chronic rhinosinusitis without polyps (CRSsNP), particularly Streptococcus pneumoniae and Haemophilus influenzae.
Periorbital cellulitis and orbital abscess may occur from direct spread of suppurative organisms from the ethmoid sinuses, particularly in children. It can also spread from thrombophlebitis of mucosal vessels in the ethmoid and rarely the frontal sinuses. In teenagers and adults, it is occasionally secondary to frontal sinusitis. In children, areas of lamina papyracea are variably deficient and here, only a thin fibrous layer fills the deficiency to separate the orbit from the ethmoid sinuses. By early teens, the lamina papyracea is fully developed, and there is then a complete bony barrier between the ethmoid sinuses and orbit.
Complications are still classified according to Chandler et al. This classification provides a reminder of the usual order of disease progression as well as providing a treatment plan. The orbital septum forms a natural barrier. This is a fibrous framework of the eyelids which is thickened towards the lid margin to form the tarsal plates. Infection may localise in front of the septum as a pre-septal (or periorbital) cellulitis or posterior to the septum as orbital or intracranial infection.
90.2.1 Chandler’s Classification of Orbital Complications of Sinusitis
Stage 1 Pre-septal or periorbital cellulitis. There is lid oedema, which can be marked and usually lid erythema. There is no proptosis, usually no conjunctival chemosis, normal and painless eye movements and normal colour vision. The C-reactive protein (CRP) is raised, but often not markedly in the first 24 hours, and there is usually only a low-grade pyrexia (< 38°C) in the early stages. An urticarial reaction can mimic pre-septal cellulitis. In this situation, there may be conjunctival chemosis, but there is no pyrexia, the white cell count (WCC) is normal and the CRP is normal.
Stage 2 Post-septal or orbital cellulitis. There is orbital inflammation but no abscess formation. The eye is proptosed, conjunctival chemosis is usually present, and there is pain with ocular movements. Colour vision is usually normal. There is usually no diplopia. The WCC is raised and there is a neutrophil leukocytosis. The CRP is significantly raised. It may only be possible to distinguish stage 2 from stage 3 by performing a sinus and orbit computed tomography (CT) scan with gadolinium.
Stage 3 Sub-periosteal abscess. Symptoms and signs may be similar to stage 2, but there is more marked proptosis, greater pain on ocular movement, and there may be diplopia and a progressive deterioration of colour vision, particularly red and green.
Stage 4 Orbital abscess. Severe and often rapidly progressive proptosis, ophthalmoplegia, chemosis and diplopia. Vision may be rapidly lost.