<keypoints>
- **Orbital signs** (periorbital oedema/redness, proptosis, diplopia, ophthalmoplegia, reduced visual acuity) warrant urgent referral, as the orbit is the most common site of complicated sinusitis
- **Intracranial signs** (severe headache, meningism/stiff neck, altered mental status, focal neurological deficits, seizures) suggest spread to the CNS and are medical emergencies
- **Systemic signs** (high fever ≥38.3 °C, signs of sepsis) indicate possible severe bacterial infection or complications
- **Forehead swelling** may indicate frontal bone osteomyelitis (Pott's puffy tumour)
- **Rapidly worsening symptoms** despite treatment, or "double worsening" (improvement then deterioration), should prompt reassessment and imaging
</keypoints>
Red Flags Requiring Urgent Assessment
A comprehensive review of sinusitis complications identifies 10 alarming symptoms/signs that mandate urgent hospital referral:
- Swelling or redness in the orbital area
- Globe malposition, protrusion, or strabismus
- Diplopia
- Ophthalmoplegia
- Reduced visual acuity
- Severe headache
- Swelling of the forehead
- Signs or symptoms of sepsis
- Signs or symptoms of meningitis
- Signs or symptoms of neurological impairment
Orbital complications
The orbit is the most common structure involved in complicated sinusitis, usually from ethmoid sinusitis. Periorbital oedema, double vision, ophthalmoplegia, or visual compromise should prompt immediate referral and hospitalisation. Emergent CT with contrast is recommended in the presence of visual symptoms such as diplopia, decreased visual acuity, or disconjugate gaze.
Intracranial complications
These include meningitis, epidural or subdural empyema, and brain abscess. Key warning features are severe headache, neck stiffness, confusion, somnolence, and focal neurological signs. Neurological and neurosurgical consultation is advised.