Describe the complications of sinusitis.

Orbital Complications

• Complications of sinusitis arise when infection spreads beyond the sinus, by direct extension through thin or dehiscent bone, by retrograde thrombophlebitis through valveless veins, or through preformed pathways.
• They are classified as orbital, intracranial and osseous.
• Orbital complications are the commonest, and arise chiefly from the ethmoid sinuses through the paper-thin lamina papyracea — which is why they are predominantly a disease of children, in whom the ethmoids are the developed sinus
• Chandler’S classification describes five progressive stages, and the essential division within it is between the first stage and all the rest:

Intracranial and Osseous Complications

• Intracranial complications arise chiefly from the frontal and sphenoid sinuses, and are predominantly a disease of adolescent males — an epidemiological pattern that is characteristic and worth stating, related to the vascularity of the developing frontal sinus
• They spread by retrograde thrombophlebitis through the valveless diploic veins of breschet in the posterior wall of the frontal sinus.
• Meningitis — the commonest, particularly from sphenoid and ethmoid disease
• Extradural, subdural (empyema) and intracerebral abscess — frontal lobe abscess being characteristic of frontal sinusitis, and notoriously silent, presenting with headache, personality change, drowsiness and vomiting rather than focal signs
• Subdural empyema is more often sinogenic than otogenic, spreads rapidly over the convexity, and has a high mortality
• Cavernous sinus thrombosis — from sphenoid or ethmoid disease, with proptosis, chemosis, ophthalmoplegia, a sixth nerve palsy earliest, and spread to the opposite eye.
• Superior sagittal sinus thrombosis
• Osseous complications — osteomyelitis of the frontal bone, giving POTT’S puffy tumour — a doughy, tender, fluctuant swelling of the forehead from a subperiosteal abscess over frontal osteomyelitis
• Pott’s puffy tumour is not a tumour and not a trivial swelling: it indicates osteomyelitis, and is associated with intracranial complications in a high proportion.
• Osteomyelitis of the maxilla occurs in infants
• Mucocele — considered separately, but belongs among the complications
• Investigation — contrast-enhanced CT of the sinuses, orbits and brain; with MRI.
• Lumbar puncture only after imaging, and never where there is a space-occupying collection
• Management — high-dose intravenous antibiotics crossing the blood-brain barrier (a third-generation cephalosporin with metronidazole), for weeks; neurosurgical drainage of any intracranial collection; and surgical drainage of the sinus.
• The organisms are frequently anaerobic or mixed, particularly Streptococcus anginosus (milleri) group, which has a particular tendency to form abscesses — hence the metronidazole
• The reason these complications are still seen is delayed presentation and partially treated infection, in which antibiotics blunt the clinical picture while the disease advances
• Visual acuity, eye movements and proptosis are the three findings that separate preseptal from postseptal disease
• A relative afferent pupillary defect demands surgery now, as does loss of red colour vision.
• Orbital complications come from the ethmoids through the lamina papyracea.
• Intracranial complications come from the frontal sinus and affect adolescent males.
• Infection reaches the brain through intact bone by retrograde thrombophlebitis, so a normal bony wall is no reassurance
• Frontal lobe abscess is notoriously silent, presenting with personality change and drowsiness rather than focal signs
• Pott puffy tumour means osteomyelitis, and the brain must be imaged because intracranial disease accompanies it more often than not
• Admit any child with periorbital swelling and fever, and review the vision hourly rather than daily
• Operate if there is no improvement in forty-eight hours on intravenous antibiotics, or sooner if vision deteriorates
• A small medial abscess in a young child may be observed, which is a recognised exception but demands close monitoring
• Drain the sinus as well as the collection; the sinus is the source and the complication recurs if it is left
• Give metronidazole, since the organisms are frequently anaerobic or mixed and the milleri group forms abscesses
• Image before any lumbar puncture, and never tap where there is a space-occupying collection