Pott's Puffy Tumour

Clinical History

The patient presented with a 36-hour history of a right-sided forehead swelling and puffy eyes. She was known to suffer from sinusitis and had had a purulent nasal discharge for 2 days.

Imaging Findings

The patient was referred to the ENT department by her GP with a 36-hour history of a right-sided forehead swelling and puffy eyes. She had been suffering from a purulent nasal discharge for 2 days and intermittent headaches for the previous month. There was no fever or vomiting. She was known to suffer from sinusitis and had been seen twice within the last 2 months and received oral antibiotics. The patient was not on any medication and had no allergies.
Examination revealed a fluctuant swelling over the right frontal region, which was slightly tender. She was afebrile and there was some erythema of the skin. Pupils were equal and reactive and there was no ocular palsy or proptosis. Haematological and biochemical parameters were within the normal range.
Intravenous cefuroxime and metronidazole were commenced. A CT scan revealed mucosal disease of the maxillary and frontal air sinuses, free air overlying the soft tissues of the right frontal bone (Fig. 1), and frontal osteomyelitis (Fig. 3), with a ring-enhancing lesion in the right frontal lobe representing an epidural abscess (Fig. 2).
A bicoronal craniotomy was performed by the neurosurgeons, and 20ml of pus was evacuated via a burr hole. Washout of the frontal sinuses was also performed. Culture results showed a growth of Staphylococcus aureus and Streptococcus mellerri.
The patient was commenced on intravenous cefotaxime and metronidazole. Serial CT scans showed the frontal oedema and abscess to be decreasing. She was discharged home fit and continued her antibiotics for a total of 12 weeks. She made a gradual recovery and remains well.

Discussion

Pott's puffy tumour, defined as subperiosteal abscess formation associated with frontal bone osteomyelitis, was first described by Sir Percivall Pott in 1768 as a result of trauma and in 1775 as a complication of sinusitis. This complication is rare in the post-antibiotic era. The disease usually affects males in the second or third decades of life. Although the overall incidence of intracranial complications of other conditions has decreased since penicillin was introduced, 10% of all patients hospitalised for treatment of frontal sinusitis develop intracranial complications. 13% of all brain abscesses are secondary to sinusitis, usually frontal.
The typical symptoms are usually headache, fever, periorbital swelling, rhinorrhea, vomiting and lethargy. Focal neurological symptoms, with or without signs of meningism, may also occur. The organisms responsible are usually streptococci, staphylococci and anaerobes. Infection spreads from the paranasal frontal sinuses intracranially either by direct erosion of the thin anterior wall of the frontal bone or via the valveless diploic veins of the skull.
Intracranial complications of frontal sinusitis include extradural, subdural and brain abscesses, sinus thrombophlebitis and meningitis.The diagnosis of Pott's puffy tumour is usually made by a contrast enhanced CT scan, and some centres advocate the use of a gallium scan.
Treatment includes surgical drainage of the abscess, debridement of the affected bone and appropriate antibiotic therapy. A broad spectrum antibiotic with good CNS penetration is recommended.
In this era of antibiotics, complications such as Pott's puffy tumour are rare, but partially treated frontal sinusitis can result in this potentially fatal condition. A high index of suspicion, early diagnosis and aggressive medical or surgical management will improve the outcome in these patients.

Differential Diagnosis List

Final Diagnosis

Pott's puffy tumour

URL:	https://eurorad.org/case/1521
DOI:	10.1594/EURORAD/CASE.1521
ISSN:	1563-4086