Frontal bone osteomyelitis

Synonyms: Pott's puffy tumour (PPT), osteomyelitis of the calvarium ¹

Description

• Frontal bone osteomyelitis is rare. It is osteomyelitis with a subperiosteal (extradural) abscess in the frontal bone.

• It usually represents an anterior extension of a frontal sinus infection or as a complication of a compound skull fracture.

• It can also be a complication of mastoiditis and has been reported following an insect bite.²

• Streptococcus milleri group is the most common pathogen.

• Mucormycotic (fungal infection caused by a group of moulds called mucormycetes) osteomyelitis of the frontal bone has been reported in several patients with rhinocerebral mucormycosis, secondary to COVID infection.³

Frontal bone osteomyelitis symptoms (presentation)

• Headaches.

• There may be localised swelling.

• Fever.

• Nuchal rigidity.

• Altered mental state (from subtle changes, confusion or complete coma)

• Focal neurological signs, eg, seizures.⁴

Pott's puffy tumour is a potential complication of acute frontal sinusitis, characterised by subperiosteal abscess and osteomyelitis of the frontal bone. It can be managed with a combination of open and endoscopic sinus surgery, and intravenous antibiotic therapy.⁵

Since the advent of antibiotics, Pott's puffy tumour (PPT) has been only rarely reported (mostly in children and adolescents) but more recently has been described following intranasal and inhaled cocaine or methamphetamine abuse,⁶ and as a complication of dental sepsis.⁷

Diagnosis

CT scan (with and without contrast) or MRI scan.⁸ CT scan may reveal bone erosion and evidence of rim enhancing abscess formation. There may be intracranial involvement, eg, fluid collection and CT/MRI may also help in this.

Frontal bone osteomyelitis treatment and management

Admission with removal of the infected bone and prolonged intravenous antibiotics (eg, for six weeks or longer). All cases should be discussed with the local microbiologist and antibiotics should be altered once sensitivities are known.⁵

Complications

• Extension of infection, eg, brain abscess.⁹

• Meningitis.

• Epidural empyema.

• Subdural empyema.

History

Percivall Pott (1714-1788) was a London surgeon (St. Bartholomew's Hospital) who also gives his name to Pott's disease of the spine (spinal tuberculosis - scrofula), and to Pott's fracture (fracture dislocation of the ankle). He was first to describe an industrially acquired disease: cancer of the scrotum in chimney sweeps.¹⁰