Acute and chronic rhinosinusitis — branching viva

Opening question

Examiner: Take me through this child. What is your diagnosis, and what is your frame for managing it? [1]

Candidate: The first stage is acute bacterial rhinosinusitis, and then an orbital complication. The twelve days of thick nasal discharge and daytime cough without improvement, with the return of fever and the biphasic worsening, meet the AAP criteria for acute bacterial rhinosinusitis. The periorbital swelling, redness and painful eye that have followed mark the orbital complication — post-septal orbital cellulitis with, given the eye is displaced and vision is affected, a likely subperiosteal or orbital abscess. My frame is layered: make the clinical diagnosis, give the right antibiotic, and then recognise that this child has crossed into a sight- and potentially life-threatening complication that needs admission, intravenous antibiotics, urgent contrast CT, and ENT and ophthalmology review. [1] [9]

Examiner: How do you distinguish bacterial rhinosinusitis from a simple viral cold? [1]

Candidate: The nasal and sinus mucosa are one continuous lining, so almost every viral cold briefly involves the sinuses — acute viral and early bacterial rhinosinusitis are clinically indistinguishable for the first ten days. The AAP criteria separate them: persistent symptoms beyond ten days without improvement; a double-worsening course after initial improvement; or a severe onset with fever and purulent discharge for three or more consecutive days. Any one pattern supports the bacterial diagnosis. This child has the persistent and the double-worsening patterns. [1] [2]

Branch 1 — pathophysiology and classification

Examiner: Walk me through how a cold becomes a bacterial sinusitis, and why it reaches the orbit. [3]

Candidate: The paranasal sinuses drain through narrow ostia at the ostiomeatal complex, and continuous mucociliary clearance keeps them sterile. A viral cold inflames the mucosa, the swelling obstructs the ostium, oxygen is resorbed, cilia fail, and secretions stagnate. The warm, static environment lets the colonising bacteria — Streptococcus pneumoniae, nontypeable Haemophilus influenzae and Moraxella catarrhalis — multiply, producing acute bacterial rhinosinusitis. The ethmoid sinuses are present at birth and their lateral wall, the lamina papyracea, is paper-thin, so ethmoid infection erodes or traverses it to reach the orbit. [3] [9]

Examiner: How is the orbital complication classified? [3]

Candidate: By the Chandler classification, ascending through five stages. Stage 1 is preseptal cellulitis — lid swelling only, orbit normal. Stage 2 is orbital cellulitis — oedema of the orbital fat with mild proptosis but no abscess. Stage 3 is a subperiosteal abscess — pus between the periorbita and the bone, displacing the eye down and out, with vision typically still normal. Stage 4 is an orbital abscess — pus within the orbital fat, with marked proptosis, ophthalmoplegia and threatened vision. Stage 5 is cavernous sinus thrombosis — bilateral eye signs, cranial nerve palsies and a toxic, rapidly deteriorating child. [3] [9]

Branch 2 — investigations and imaging

Examiner: What investigations will you do, and when will you image? [9]

Candidate: For the uncomplicated acute bacterial rhinosinusitis, no routine investigation is needed — it is a clinical diagnosis, and plain films and nasal cultures do not help. For this child, who has orbital signs, the key investigation is contrast-enhanced CT of the sinuses and orbits, which I would obtain urgently. CT shows the rim-enhancing subperiosteal or orbital collection, the sinus opacification and any bony erosion. I would reserve MRI with venography for suspected intracranial extension, cavernous sinus thrombosis or brain abscess. Imaging must never delay intravenous antibiotics. [9] [11]

Examiner: What organisms are you covering? [2]

Candidate: The dominant organisms in acute bacterial disease are Streptococcus pneumoniae, nontypeable Haemophilus influenzae and Moraxella catarrhalis. In a complicated case with orbital extension, and certainly in chronic disease or in a child with cystic fibrosis or immunodeficiency, Staphylococcus aureus, Pseudomonas aeruginosa and anaerobes become important. I would send blood cultures and any pus from a drained collection for Gram stain, culture and susceptibility, and de-escalate when results return. [2] [9]

Branch 3 — treatment and the surgical decision

Examiner: If this child had presented before the eye signs — as uncomplicated acute bacterial rhinosinusitis — what would your antibiotic regimen have been? [1]

Candidate: First-line would be high-dose oral amoxicillin-clavulanate 90 mg per kilogram per day of the amoxicillin component in two divided doses, maximum amoxicillin 4 g per day, for ten to fourteen days. The high dose covers penicillin-resistant pneumococci and the clavulanate covers the beta-lactamase-producing Haemophilus and Moraxella. I would add saline irrigation and an intranasal corticosteroid as adjuncts, and for a penicillin allergy I would use cefdinir or cefuroxime, or clindamycin with a third-generation cephalosporin in a severe beta-lactam allergy. [1] [2]

Examiner: Now, with the orbital signs, what is your intravenous regimen, and what about the subperiosteal abscess? [9]

Candidate: With the complication, I would admit and start intravenous ceftriaxone 50 mg per kilogram (maximum 2 g) once daily plus metronidazole 7.5 mg per kilogram (maximum 500 mg) every eight hours, adding vancomycin for suspected MRSA or critical illness. The CT shows a subperiosteal abscess, which classically needs surgical drainage, but a carefully selected small medial abscess in a young child with normal vision and an unambiguous response to antibiotics may be managed medically with close observation, with a low threshold to operate. This child, with reduced vision and the eye displaced, is past that window and needs drainage. [9] [12]

Branch 4 — complications and a sick child

Examiner: What are the intracranial complications, and how would you recognise them? [4]

Candidate: The intracranial complications are meningitis — the commonest; epidural and subdural empyema and brain abscess — the highest mortality; cavernous sinus thrombosis; and Pott puffy tumour, osteomyelitis of the frontal bone with a subperiosteal abscess in the older child. I would recognise them through systemic and neurological deterioration — a severe headache, fever, vomiting, photophobia, neck stiffness, focal neurology, seizures or a depressed conscious state, bilateral eye signs with cranial nerve palsies for cavernous sinus thrombosis, and a boggy forehead swelling for Pott puffy tumour. Any of these needs urgent brain imaging, neurosurgery and prolonged intravenous antibiotics that cross the blood-brain barrier. The valveless diploic and emissary veins explain spread to the brain without a bony defect. [4] [11]

Examiner: The child's vision is now normalising on intravenous antibiotics after drainage. Summarise the sinusitis stance in one sentence. [1]

Candidate: A child who meets an AAP pattern — persistent symptoms beyond ten days, double worsening, or severe onset — has acute bacterial rhinosinusitis and needs high-dose amoxicillin-clavulanate with saline irrigation and an intranasal corticosteroid; the moment a swollen eye, a visual change, a severe headache or any neurological sign appears, the illness has crossed into the orbit or the brain, and needs admission, intravenous antibiotics, contrast CT and the ENT, ophthalmology and neurosurgery teams — because the one child you treat late is the one who loses vision or dies of a brain abscess. [1] [9]