November 2001

A 13-year-old male presented with a 2-day history of low-grade fever, congestion and headache. This was associated with a bump over the right eye, which was the focus for the pain, and seemed to be getting worse. He had just returned with his family from a weekend trip to a local lake. He was seen in the emergency department where he had a temperature of 102.2° F, and diagnosed with a viral syndrome and treated symptomatically. His past medical history is significant for having had Haemophilus influenzae meningitis at age 22 months. This left him with a severe seizure disorder that is very difficult to control and some decreased function of his left upper extremity. As part of his seizure management, he underwent neurosurgery about 1 year earlier for a mapping procedure at a different facility. Details of this were not available on admission. His review of systems is otherwise unremarkable and his immunizations are up to date.

Examination was positive for a temperature of 101° F. He was alert and oriented. His head was noted to have several scars from the previous surgery. There also was a soft, painful boggy mass over the right eye (figures 1 & 2) with slight erythema. The eye exam is normal. A CT scan is shown in figures 3-7.

What’s Your Diagnosis?

1. Pott’s puffy tumor
2. Amebic meningoencephalitis
3. Unrecognized head injury during a seizure
4. Preseptal cellulitis

Answer

This patient had Pott’s puffy tumor, which is a swelling of the soft tissue overlying an area of osteomyelitis of the frontal bone. This occurs as a result of frontal and/or ethmoid sinusitis that has spread beyond the sinus space to involve the overlying bone. This condition was first described by the English surgeon, Sir Percival Pott in 1760 (Observations on the Nature and Consequences of Wounds and Contusions of the Head. London, Hitch and Howes, 1760; pp 38, 53-58), in which he noted there was a “puffy circumscribed indolent tumor of the scalp, and spontaneous separation of the pericranium (periosteum) from the skull under such tumor.”

In the preantibiotic era, suppurative complications of sinus disease were much more common than today. However, they still occur, especially in patients with chronic sinus disease and/or damaged sinuses from trauma or previous surgery. This patient’s history was complicated by having had a mapping procedure done about a year earlier. In the process, the right frontal sinus was apparently entered with one of the probes. The resultant, unavoidable damage to the sinus may have contributed to the ultimate spread of the infection beyond the sinus.

Likewise, Pott’s puffy tumor is also more likely to occur in those patients who have sustained frontal sinus trauma from any other cause. The infection can also extend inward, producing a variety of suppurative intracranial complications, such as epidural abscess, subdural empyema, frontal lobe abscess, septic thrombosis of dural sinuses, etc. When cranial osteomyelitis complicates frontal sinusitis, the cause is usually Staphylococcus aureus, but numerous other organisms have also been found. Streptococcus pneumoniae, Haemophilus influenzae (nontypable), Moraxella catarrhalis, Streptococcus pyogenes make up the majority of aerobic pathogens found in sinus disease. It is often a mixed infection, and through the work of Itzhak Brook, MD, we know anaerobes are usually in the mix. This is true of virtually all sinopulmonary infections. In fact, I recently presented a child with a lung abscess in this column, and failed to mention the important role of anaerobes in that condition. Dr. Brook published a very nice paper on this subject that is worth placing in your pneumonia file (“Anaerobic Lower Respiratory Tract Infections in Children, Clinical Pulmonary Medicine, 4(1):1-7, January, 1997).

The fact that anaerobes are not recovered in a case like this usually means there was a break in proper collection and/or handling of the specimen. Also, because these patients are often already on antimicrobial therapy at the time of diagnosis, the cultures are often negative or difficult to grow. Antimicrobial therapy is essential, but is no substitute for prompt and aggressive surgery to debride infected bone and drain the pus (figure 8, courtesy of Dr. Lewis Hutchinson, Otolaryngologist at Scott & White), especially with intracranial involvement. The antibiotics chosen should cover the above organisms until a specific cause can be identified in the lab. Most experts recommend that antibiotics be continued for 4-6 weeks. This probably should be done in consultation with an infectious disease specialist, especially if shorter course therapy is being considered, as relapse of these infections can occur years later.

This patient went to surgery to have the abscess drained. It grew non-typable H. influenzae a few days later. Anaerobic cultures were negative. He had an uneventful recovery.

Amebic meningoencephalitis was thrown in because of the recent trip to an area lake. There actually have been cases in past summers during droughts from some of the local lakes. There are different clinical presentations of this condition, depending on the cause. Naegleria fowleri causes a typical, rapidly progressive meningoencephalitis that unless treated very early and aggressively, is usually fatal. This means treating even before confirmation of the cause. Amphotericin B is the drug of choice. Some experts recommend adding rifampin and miconazole to the regimen. Intrathecal miconazole at 10 mg/day may also be helpful (John D. Nelson’s 1998-1999 Pocket Book of Pediatric Antimicrobial Therapy. 13th Edition, Williams & Wilkins). Acanthamoeba and Balamuthia species usually result in a more insidious disease referred to as granulomatous amebic encephalitis, and are more common in immunocompromised patients. Months may go by after exposure before symptoms appear. There can be a variety of neurologic symptoms, and in a patient like the one presented who has a seizure disorder and some neurologic deficit, it could be difficult to pick up on the cause.

Naegleria is sometimes diagnosed with a wet mount of the cerebrospinal fluid (CSF). There is a special culture technique as well for Naegleria and Acanthamoeba, using a 1.5% nonnutrient agar overlaid with enteric bacteria in Page saline (figures 9 & 10 showing the trophozoites and cyst forms). Acanthamoeba and Balamuthia are not as likely to be found in the CSF on wet mount, but Acanthamoeba may be cultured. A brain biopsy may be required for diagnosis. Acanthamoeba may be treated with a variety of drugs with in vitro sensitivities such as ketoconazole, pentamidine, and flucytosine (Ancobon, ICN).

Unrecognized injury is always possible in seizure patients, and was considered a possibility in this patient. However, he also had a fever and congestion with worsening pain rather than improvement, as one would expect with an injury. The CT scan then confirmed the diagnosis.

Preseptal cellulitis is an infection of the soft tissues about the eye, anterior to the orbital septum. There could be enough swelling associated with Pott’s puffy tumor to appear similar to preseptal cellulitis (figure 11). The findings on exam of this patient, however, clearly pointed to this boggy mass above the eye as being the focus of the problem.

Acknowledgement: Special thanks go to Lewis R. Hutchinson, MD, Chief, Section of Pediatric Otolaryngology, Scott & White Hospital, Temple, Texas, for his assistance with this case.

For Your Information:

• James H. Brien, DO, Pediatric Infectious Disease, Scott and White's Children's Health Center and Texas A&M University, College of Medicine, Temple, Texas. E-mail: jhbriend@aol.com