Pott's puffy tumor

Definition:

Pott's puffy tumor is defined as osteomyelitis of frontal bone. It was first described by Sir Percivall Pott in 1775. It is infact a subperiosteal abscess of frontal bone which appears as a localized swelling of the frontal region associated with frontal osteomyelitis.

Etiology:

It can be caused by acute / chronic frontal sinusitis. This entity is getting uncommon these days due to the advent of powerful excellent antibiotics.

This condition is also associated with epidural purulent collection, subdural empyema and intracerebral abscess.

Applied anatomy:

The mucosal lining of frontal sinus, marrow cavity and frontal bone share common venous drainage through valveless diploeic veins. This venous drainage permits spread of infection from frontal sinuses into the frontal bone. Local suppuration of frontal bone propagates to the Haversian system of inner and outer tables of skull causing local demineralisation and necrosis. This leads to perforation of the anterior table of frontal sinus, resulting in subperiosteal collection of pus and granulation tissue formation causing Pott's puffy tumor.

Microbiology:

Causative agents include: staph aureus, non enterococcal streptococci, and oral anaerobes. In cases of intracranial complications anaerobes like Fusobacterium, Bacteroids have been implicated. It has been postulated that relatively low oxygen concentration in frontal sinuses could predispose to this problem.

Diagnosis:

1. Head ache

2. Photophobia

3. Swelling / deformity of forehead - Fluctuant and tender erythematous swelling of scalp at the mid forehead region is pathognomonic

4. Fever

5. Purulent rhinorrhoea

6. Signs of raised intracranial tension in complicated cases due to intracranial abscess

Investigation:

CT scan is diagnostic. MRI should be considered as gold standard for diagnosis of intracranial complication.

In CT scan picture taken with contrast hypodense collection of fluid external to the frontal bone with an enhancing rim suggests Pott's puffy tumor.

Treatment:

1. Intravenous administration of broad spectrum antibiotics

2. Surgery - Endoscopic frontal sinusotomy / Frontal sinus trephining

Frontal trephination is a simple and effective procedure, and still remains the main stay of treatment of complicated frontal sinusitis.

Picture showing a patient with Pott's puffy tumor