Orbital abscess as a complication of Pott’s puffy tumour in an adolescent male

Abstract

Pott’s puffy tumour (PPT) is a known complication of frontal sinusitis. It is defined as subperiosteal abscess formation due to osteomyelitis of the frontal bone presenting as a forehead swelling. It is a life-threatening condition that can lead to intracranial and intraorbital complications. Gadolinium-enhanced MRI and contrast CT scan are the best modalities to localise and define the collection, in addition to confirming disease extension. Once confirmed by imaging and depending on disease extension, management of PPT requires a multidisciplinary team approach and depends on the local provision of surgical care. Following surgical drainage of the abscess cavity, a prolonged course of antibiotics is required postoperatively to treat the underlying osteomyelitis.

Background

First described by Sir Percivall Pott in 1768, this rare condition is still seen today in the era of antibiotic advancements.¹ It is characterised by progressive frontal oedema due to an underlying periosteal abscess and osteomyelitis of the frontal bone. Cases usually arise from untreated frontal sinusitis or trauma. Symptoms include frontal scalp swelling, headache, seizures, fever, purulent nasal drainage, photophobia and frontal sinus tenderness.^{2 3} Neurological complications such as epidural abscesses have been extensively recorded in the literature. However, less is known of orbital complications from this entity. In this study, we present a case of Pott’s puffy tumour (PPT) with an intraorbital abscess in a 16-year-old adolescent male secondary to trauma.

Case presentation

A 16-year-old adolescent male presented to otolaryngology with a 3-day history of progressive right frontal swelling and headaches. He was pyrexic at 37.8°C and appeared unwell. He admitted to sustaining a nasal bridge laceration from a fall 2 weeks prior to presentation (figure 1). This wound had been closed using tissue glue by an emergency physician at a different hospital. There was no past medical or surgical history.

Figure 1.

The patient with progressive frontal and periorbital oedema.

Prior to his referral to otolaryngology from ophthalmology, he had a non-contrast CT head done. This was requested by the accident and emergency department to rule out facial fractures, as the patient admitted coincidentally falling off his bed earlier that morning.

On examination, the patient had significant oedema over the right frontal sinus and upper eyelid with severe pain along the distribution of the supraorbital and supratrochlear nerves. There was evidence of right orbital proptosis, chemosis, decreased extraocular movement and double vision. The unaided visual acuity score on the right side measured 6/7.5 compared with 6/6 on the contralateral side. Flexible nasendoscopy showed mucopus in the nasopharynx.

Investigations

His blood results on admission showed raised inflammatory markers, with a white cell count (WCC) of 14.8x10⁹/L and a C reactive protein (CRP) of 86. The non-contrast CT of head ruled out facial fractures but identified a right periorbital collection and frontal sinusitis. This scan did not clearly rule out intraorbital extension of the subperiosteal abscess. Therefore, a repeat CT scan with contrast was ordered to exclude orbital involvement. This orbital contrast CT scan revealed right frontal sinusitis with bony erosion, subperiosteal collection extension into the lateral wall of the orbit (figure 2A). There was no evidence of intracranial extension (figure 2B).

Figure 2.

Pott’s puffy tumour. (A) Right subperiosteal abscess with extension into lateral wall of orbit. (B) CT of bone window showing frontal sinusitis and osteomyelitis of the frontal bone.

Treatment

The patient was started on intravenous coamoxiclav 1.2 g three times a day, metronidazole 350 mg three times a day and otrivine nasal decongestant two drops three times a day. Due to the patient’s clinical findings that suggested impending visual loss (decreased visual acuity, chemosis and ophthalmoplegia), immediate surgical intervention was deemed necessary. In the operating theatre, he underwent exploration and drainage of the right subperiosteal frontal and superotemporal orbital abscess combined with endoscopic sinus surgery. This procedure was carried out jointly with the oculoplastics team. A supraorbital incision through the brow line was chosen (rather than an upper-eyelid approach) as the best access at the time of operation. This incision provided (1) adequate access to the orbit (for abscess drainage) and frontal sinus (for trephination) and (2) optimal cosmetic scar appearance. After draining the orbital collection, a yates drain was left in situ to facilitate frontal sinus irrigation postoperatively. The endonasal aspect of the procedure involved a right partial uncinectomy, middle meatal antrostomy and frontal recessotomy (figure 3). Pus swabs were sent for microbiology analysis and culture.

Figure 3.

Well-demarcated osteomyelitis of frontal bone with inferior retractor exposing roof of orbit.

Outcome and follow-up

Postoperatively, the visual acuity had improved to 6/4.8 (unaided) in both eyes. His proptosis and extraocular movements also showed significant improvement with resolution of his diplopia. Additionally, there was marked reduction of his inflammatory markers (WCC 6.3×10⁹/L, platelets 310×10⁹/L, CRP 47 mg/L). Frontal sinus irrigation using 10 mL of 0.9% saline was carried out daily, on morning rounds. The drain itself was removed after 48 hours. All pus swabs taken intraoperatively came back sterile. The patient received 7 days of intravenous antibiotics. Discharge medications included 3 weeks of oral coamoxiclav, paediatric otrivine (two doses three times a day for 1 week), Nasonex nasal spray (twice a day for 4 weeks) and NeilMed saltwater nasal douches (three times a day for 2 weeks). At his 1-week ophthalmology follow-up appointment, his visual acuity remained at 6/4.8 unaided bilaterally with normal extraocular movements. This remained unchanged at his 7-week appointment. Otolaryngology review in clinic at 2 weeks postdischarge revealed a healing sinus cavity. The patient failed to attend further otolaryngology appointments.

Discussion

PPT is a rare life-threatening condition that is still seen in today’s advanced antibiotic era. It occurs predominately in children and adolescence and rarely in adults.^{3 4} The frontal sinus pneumatises by age 2 years and is not fully developed till late teens. Diploic veins are distributed between the external and internal tables of the calvaria. In adolescences, these veins have a loose connection between the frontal sinuses with bone marrow space compared with adults. This results in a higher infection rates in young people than adults.⁵

PPT is known to result from untreated frontal sinusitis and head trauma. However, it has been documented arising from insect bites, mastoid surgery and even a wrestling injury.^{6 7}

Akiyama et al found in their review of PPT cases that immune compromised states such as those seen in diabetes, HIV and chronic renal failure may contribute to frontal sinusitis activation.⁵ In our patient, we believe his previous nasal trauma may have been the initial source of infection and not underlying sinusitis.

Differential diagnosis for PPT includes dermoid cyst, lipoma, haematoma, soft tissue infections, frontal sinus mucocele, malignant tumours and metastasis.^{2 5} Causative bacteria include streptococcus, staphylococcus and Haemophilus influenza. Anaerobes such as enterococci, Fusobacterium and Bacteriodes have also been discovered in culture. However, infections are often polymicrobial in origin.^{2 8} In this case, the cultures were negative likely owing to the use of intravenous antibiotics given before surgery.

Signs and symptoms of PPT typically occur over a matter of days to weeks. These include frontal scalp swelling, headache, seizures, fever, purulent nasal drainage, photophobia and frontal sinus tenderness.^{2 3} This is not always the case, as there have been recorded cases of patients presenting with remitting forehead swelling for several years and even as a subcutaneous draining fistula.⁵

Imaging of the abscess is imperative to confirm the diagnosis and rule out any intracranial or intraorbital collection. Non-contrast imaging is not ideal, as it will not reveal the extent of abscess extension and could lead to delay in presentation as this case exemplifies. Contrast-enhanced CT scan can reveal sinusitis, bone erosion, subperiosteal collection and intracranial extension. Gadolinium-enhanced MRI scan can reveal intraparenchymal pathology, dural sinus thrombosis and dura mater involvement. Though ultrasound has limited use in PTT, it can assist with initial investigation and guide needle aspiration.²

Orbital involvement in PPT is not well documented in the literature. Most case studies/series focus on intracranial complications. Nisa et al carried out a systemic review of orbital involvement in PPT. They reviewed 139 articles over a 60-year period (1950–2010) obtaining 42 cases. Of these cases, only one case recorded an orbital collection. The most common orbital manifestation of PPT was periorbital or preseptal cellulitis.⁹ These findings highlight the uniqueness of our case study.

Definitive treatment of PPT is prolonged intravenous antibiotics combined with surgical drainage. Antibiotic therapy should be directed by microbiological identification and continued for 4–6 weeks.⁵

Conclusion

PPT is a rare life-threatening complication of frontal sinusitis. High suspicion and prompt diagnosis with contrast CT scan or gadolinium-enhanced MRI imaging is required to forgo catastrophic outcomes. Intracranial and intraorbital collections require urgent surgical drainage along with combined sinus trephination. This should be followed by a 4-week to 6-week course of broad-spectrum antibiotics.

Learning points.

• Pott’s puffy tumour (PPT) should be considered in the differential diagnosis of a forehead swelling.

• Urgent imaging with contrast CT or gadolinium-enhanced MRI scan is of utmost importance to confirm diagnosis and disease extensions.

• Intraorbital abscess, though an uncommon occurrence in PPT, should not be missed.

• Urgent surgical drainage followed by prolonged intravenous antibiotics is the mainstay of treatment in PPT. A multidisciplinary surgical approach should be sought when managing these patients, which will depend on the local provision of surgical care.