Pott Puffy Tumour

Pott puffy tumour is a subperiosteal abscess of the frontal bone with osteomyelitis, usually a complication of frontal sinusitis, and presents as forehead swelling. It is a surgical emergency because of the risk of intracranial spread.

It occurs mostly in adolescents and young adults, who have a developing diploic venous system and a pneumatised frontal sinus, and in about two thirds of cases it is associated with intracranial complications (epidural abscess, subdural empyema, brain abscess, meningitis, sinus thrombosis). Organisms are streptococci (including Streptococcus milleri group), Staphylococcus aureus and anaerobes.

Pathophysiology.

Infection spreads from the frontal sinus through the thin anterior wall or by valveless diploic veins, causing osteomyelitis of the frontal bone and a subperiosteal collection which pushes the periosteum forward.

Fluctuant, tender forehead swelling, frontal headache, fever, purulent nasal discharge, periorbital swelling and, with intracranial extension, vomiting, seizures, confusion and focal neurological deficit.

Red flags.

• Seizures, confusion or focal deficit.
• Severe headache, neck stiffness or vomiting.
• Orbital extension with reduced vision.
• Sepsis.

CT of the sinuses and brain with contrast shows frontal sinus opacification, bone erosion, subperiosteal collection and intracranial collections. Magnetic resonance imaging with contrast and venography is more sensitive for intracranial disease and sinus thrombosis. Send blood cultures, full blood count and C-reactive protein, and culture the pus.

Differential diagnosis.

• Frontal sinusitis with cellulitis.
• Frontal mucocele or pyocoele.
• Sinonasal tumour.
• Scalp abscess or haematoma.
• Tuberculous or fungal osteomyelitis.
• Langerhans cell histiocytosis.

Start broad spectrum intravenous antibiotics at once and drain the collection (endoscopic frontal sinus surgery, or trephine or open drainage with removal of infected bone). Neurosurgery drains intracranial collections.

• Ceftriaxone: 2 g IV every 12 hours; maximum 4 g daily; usually 4 to 6 weeks for bone infection (IV for at least 2 to 4 weeks); monitor renal function, liver tests and blood counts; no routine renal adjustment.
• Metronidazole (with ceftriaxone): 500 mg IV or orally every 8 hours for the same duration; maximum 1.5 g daily; monitor neuropathy and liver tests; reduce to 500 mg every 12 hours in severe hepatic impairment.
• Vancomycin (added for suspected MRSA): load 25 to 30 mg/kg IV, then 15 to 20 mg/kg every 8 to 12 hours; target area under the curve 400 to 600; monitor levels and creatinine; extend the interval in renal impairment.
• Levetiracetam (seizure prophylaxis or treatment with intracranial disease): 500 mg orally or IV twice daily, increased to 1,000 mg twice daily; maximum 3 g daily; monitor mood and renal function; reduce to 250 to 500 mg twice daily when creatinine clearance is under 50 mL/min.

Monitoring. Neurological observation every 2 to 4 hours at first; repeat imaging at 1 to 2 weeks and at the end of treatment; C-reactive protein weekly.

Referral and escalation. ENT and neurosurgery urgently; critical care for neurological deterioration.

Special groups. Children need weight based dosing: ceftriaxone 100 mg/kg daily (maximum 4 g).