Postgrad Med J (1994) 70, 203 - 206 i) The Fellowship of Postgraduate Medicine, 1994

Delayed Diagnosis

Serious unexpected sinus infection discovered by CTscanning for presumed neurological disease

Andrew C. Swift and Geoffrey V. Gill

Aintree Hospitals, Walton, Liverpool, UK

Summary: Serious infection in the paranasal sinuses may present with symptoms suggestive ofneurological disease and thus lead to delay in the diagnosis and subsequent treatment. We present threesuch cases inwhom the initial diagnoses had been acute optic neuritis, a posterior communicating aneurysmand an intracranial space occupying lesion. The fourth patient had meningitis but the paranasal sinuses hadnot initially been considered as a possible source of infection. The current methods of diagnosing sinusitisare discussed.

Introduction

Infection of the paranasal sinuses is common andmay, on occasions, be severe. Acute sinusitis isusually preceded by a viral infection of the upperrespiratory tract with subsequent bacterial secon-dary infection.' The most common bacterialpathogens are Streptococcus pneumoniae, Haemo-philus influenza and, in children, Moraxella catar-rhalis. Anaerobic bacteria are common if thesinusitis is due to dental infection and they are notinfrequent in chronically infected sinuses. Sinusitisis likely to arise from anything that disturbs themucociliary clearance mechanism in the nose.Mucus stasis allows bacteria to proliferate whichinhibits ciliary beat and induces local inflam-mation, thus worsening the degree of stasis. It hasrecently been shown that the normal coordinatedciliary beat can be totally disrupted by compoundsreleased by Streptococcus pneumoniae,2 Haemo-philus influenzae3 and Pseudomonas aeruginosa.4Though symptoms and signs of sinusitis are

usually straightforward, in some cases they may bemisleading and other diagnoses may be made,particularly if the possibility of sinusitis is notconsidered.We present four cases in which serious sinus

infection was not considered, until it was found bychance during computerized tomography (CT) ofthe brain. In three patients, primary neurologicaldiagnoses were made clinically but were not subs-tantiated. In the fourth patient, a neurological

Correspondence: A.C. Swift, Ch.M., F.R.C.S.,F.R.C.S.Ed., Walton Hospital, Rice Lane, Liverpool L91AE, UK.Accepted: 15 September 1993

disorder was present (meningitis) but sinus infec-tion had not been considered as a possible focus ofinfection.

Case histories

Case 1: Unilateral headache/retro-orbitalpain

A 31 year old lady was admitted urgently with a leftparietal headache of sudden onset and severeretro-orbital pain. She was also vomiting and hadparaesthesia of the left side of her face. Onexamination she was distressed and photophobic,but there were no other neurological signs. She wasthought to have acute optic neuritis but a subse-quent CT scan showed a completely opaque leftmaxillary antrum. She underwent irrigation of themaxillary antrum and Staphylococcus aureus wasisolated from the pus. She was treated with appro-priate antibiotics and made a rapid and completerecovery.

Case 2: Orbitalpain/abnormalpupil

A 34 year old man was referred with a 4 day historyof pain around the right eye. On examination theright pupil did not react to light and he had painfulinternal ophthalmoplegia and ptosis. A presump-tive diagnosis of a posterior communicatinganeurysm was made. However, a CT scan showedan opaque right ethmoid, frontal and maxillarysinus (see Figure 1), and on further examination hehad a severe right-sided rhinitis and a purulentdischarge. The right frontal sinus was trephinedand the maxillary sinus drained by an inferior

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204 A.C. SWIFT & G.V. GILL

Figure 1 Coronal CT sinus scan from case 2. The images show an opaque right ethmoid and maxillary sinus due toinfected polyposis (a) and a fluid level in the right frontal sinus (b).

meatal antrostomy. Foul-smelling pus was releasedfrom both sinuses and culture subsequently grew

P-haemolytic streptococci (Lancefield C). The fron-tal sinus was irrigated daily via an indwelling tubewhich was removed 4 days later. He receivedintravenous cefuroxime and metronidazole, andmade a rapid recovery. His right pupil remainedunreactive to light but did respond to accomoda-tion and this was later diagnosed as an Adie's pupil.He remained well for a further 2 months, but his

pain recurred and a coronal CT scan of sinusesshowed an opaque ethmoid, fluid in the rightfrontal sinus, and gross mucosal thickening in theright maxillary antrum. He underwent functionalendoscopic sinus surgery to the right ethmoid andhas since remained well.

Case 3: Headache and nausea

A 21 year old girl presented with a 3 week history ofheadache associated with nausea. The pains were

suggestive of raised intra-cranial pressure and were

worst in the early morning, and increased on

coughing and bending forward. A space-occupyinglesion was considered likely but a CT scan of thehead displayed extensive sinus infection but no

intra-cranial abnormality. The maxillary sinuseswere irrigated and culture of the purulent contents

grew Streptococcus pneumoniae. She was treatedwith co-amoxiclav and made a complete and rapidrecovery.

Case 4: Meningitis

A 28 year old man was admitted with bacterialmeningitis and treated with intravenous penicillinand chloramphenicol. Pneumococci were isolatedfrom the cerebrospinal fluid and he was subse-quently treated with high-dose penicillin alone. Heimproved a little but after 5 days he still had apersistent headache and pyrexia. Although his neckstiffness had improved a CT scan was performed toexclude an intracranial abscess. The scan revealedbilateral frontal sinusitis and subsequent trephina-tion drained pus which grew Streptococcuspneumoniae. Following this he went on to make agood recovery.

Discussion

Sinusitis usually causes pain or discomfort in theface, around or behind the eyes and across theforehead. Sinus sensation is derived from thetrigeminal nerve: the ophthalmic division suppliesthe frontal sinus; the ethmoids and sphenoid sinus

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SINUS INFECTION DISCOVERED ON CT SCAN 205

have a dual supply from the ophthalmic andmaxillary divisions; the maxillary sinus is suppliedby the maxillary branch. The afferent fibres fromthe nasal and sinus mucosa terminate in the sensorynucleus of the fifth cranial nerve alongside theafferent sensory fibres from the skin and mayexplain why pain is often referred.5 Sometimes,pain is very poorly localized and this is typicallyseen in acute sphenoiditis in which pain may beexperienced over the vertex, occiput or mastoid. Incontrast to chronic sinusitis, acute sinusitis isusually accompanied by severe facial pain and/orheadache. Most cases of acute sinusitis do not posea diagnostic problem, the nature and site of thepain is characteristic, and there is usually a historyof an acute respiratory tract infection, nasal dis-charge and obstruction. However, if the presentingsymptoms are unusual or masked by antibiotics,ophthalmological or neurological disease mayseem more likely and acute sinusitis is not initiallyconsidered. A classical problem is seen in patientswho develop recurrent pyrexia whilst being treatedin an intensive care unit: an underlying sinusitis isoften responsible and is predisposed to by indwell-ing nasogastric and/or nasotracheal tubes.6

Neurological signs or symptoms can be partic-ularly misleading. Paraesthesia or numbness of thecheek may be the result of an exposed infraorbitalnerve in the roof of the maxillary antrum in thepresence of purulent infection. Persistent headachewhich is worse on straining or coughing may bemore suggestive of raised intracranial pressurerather than sinusitis. The pupillary abnormalitydescribed above (Case 2) was an Adie's pupilsecondary to ciliary ganglion dysfunction andunrelated to sinusitis.

Purulent sinusitis may extend beyond theconfines of the sinuses to affect either the orbit orintracranial structures. Orbital cellulitis is mostlikely with acute ethmoiditis and is seen mainly inchildren, although all age groups can be affected.7Infection usually spreads through a dehiscence inthe thin lamina papyracea. Initial cellulitis mayprogress rapidly to swelling and inflammation,ptosis, ophthalmoplegia and visual impairment.Rarely, infection may spread posteriorly to lead tocavernous sinus thrombosis, in which case therewould be bilateral orbital swelling in a desperatelyill patient. Other unusual causes of visual impair-ment in sinusitis include optic neuritis and com-pressive optic neuropathy.8'9 A patient with opticneuritis due to purulent maxillary sinusitis wasdescribed by Awerbuch et al.8 The CT scan did notinclude views of the sinuses and maxillary sinusitiswas subsequently identified by a coronal magneticresonance imaging scan of the head.

Intracranial infection usually follows purulentfronto-ethmoiditis. This may lead to meningitis, anepidural or subdural empyema or an intra-cerebral

abscess. Although very unusual, acute sphenoiditismay lead to intracranial complications such ascavernous sinus thrombosis.'0 '1 The most commonorganisms of sinus-related intracranial infectionare anaerobes. Early diagnosis is essential since themortality is high, particularly with a subduralabscess, even with modern treatment.'2 Sometimesan intracranial abscess may be silent or have fewsigns. One of us (ACS) has treated a 60 year oldman with a huge subdural empyema which grosslydisplaced the frontal lobes but caused only mildheadaches and lack of affect. The patient hadpurulent pan-sinusitis, advanced dental caries andhad been treated for recurrent chest infection.The diagnosis of sinusitis and its complications

has recently been greatly enhanced by com-puterized tomography. Patients presenting withatypical symptoms or complications may have anaxial CT scan before a sinus infection is considered,the latter being detected retrospectively. However,there is a danger that sinusitis may be missed ormisinterpreted because the slice thickness beyondthe skull base is often large and the main emphasisis likely to be on intracranial structures. Excellentviews ofthe anatomy and disease within the sinusescan be displayed by a series of fine slices, 4-5 mmwide, taken in the coronal plane.'3 The scans can beset to detect primarily bone or soft tissue byadjusting the window width: the latter being moreuseful in determining the extent of sinus disease.Magnetic resonance imaging is now becomingmore generally available and this also givesvaluable information. It is particularly good atdistinguishing nasal tumours and fungal infections,and has the distinct advantage of being unaffectedby dental artefacts which can seriously interferewith the quality of CT scans."The detection of sinus disease has also been

greatly enhanced by the development of rigidHopkins rod telescopes.'5 The combination ofendoscopy and coronal CT scanning will detectand localize most disease within the paranasalsinuses.'6 This is particularly true for disease in theostiomeatal complex region of the anterior eth-moids which may be quite localized, but may causeobstruction ofthe maxillary and frontal sinus ostia.Once severe purulent sinusitis has been diag-

nosed, treatment should commence with the appro-priate antibiotics and pus should be drained. Theantibiotic ofchoice should be broad-spectrum untilthe bacteriology is known and, ideally, should beresistant to beta-lactamase, particularly if there is ahistory of chronic sinus disease with previousantibiotic administration.' Drainage ofpus is mosteasily attained by irrigation of the maxillary ant-rum, with or without an antrostomy, and trephina-tion and irrigation of the frontal sinus wherenecessary. Although the natural ostia of the maxil-lary and frontal sinuses may be opened with

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206 A.C. SWIFT & G.V. GILL

functional endoscopic sinus surgery (FESS), thiswill be technically difficult due to acute inflam-mation, and bleeding will be easily induced. Theendoscopic approach is also unsuitable in thepresence of orbital or intracranial complications,and open drainage is recommended.'5

In conclusion, a high index of suspicion must bemaintained for the possibility of an underylingsinusitis in all patients presenting with acute symp-

toms related to the face, orbit and head.Neurological or orbital features may representspread ofinfection beyond the adjacent sinuses andlead to diagnostic delay. Plain X-rays ofthe sinuseshave limitations and underestimate sinus disease.Rigid endoscopy and coronal CT scanning of thesinuses will enable a rapid and precise diagnosis ofany underlying pathology.

References

1. Swift, A.C. Infection in ENT surgery. In: Taylor, E. (ed.)Infection in Surgical Practice. Oxford Medical Publications,Oxford University Press, Oxford. 1992, pp. 233-241.

2. Feldman, C., Mitchell, T.J., Andrew, P.W. et al. The effect ofStreptococcus pneumoniae pneumolysin on human respir-atory epithelium in vitro. Microbial Pathogenesis 1990, 9:275-284.

3. Wilson, R. & Cole, P.J. The effect of bacterial products onciliary function. Am Rev Respir Dis 1988, 138: 549-553.

4. Wilson, R., Pitt, T., Taylor, G. et al. Pyocyanin and1-hydroxyphenazine produced by Pseudomonas aeruginosainhibits the beating of human respiratory cilia in vitro. J ClinInvest 1987, 79: 221-229.

5. Friedman, W.H. & Rosenblum, B.N. Paranasal sinusetiology of headaches and facial pain (headache and facialpain). Otolaryngol Clin N Am 1989, 22: 1217-1228.

6. Bos, A.P., Tibboel, D., Hazebroek, F.W.J., Hoeve, H.,Meradjii, M. & Molenaar, J.C. Sinusitis: hidden source ofsepsis in postoperative paediatric intensive care patients. CritCare Med 1989, 17: 886-888.

7. Swift, A.C. & Charlton, G. Sinusitis and the acute orbit inchildren. J Laryngol Otol 1990, 104: 213-216.

8. Awerbuch, G., Labadie, E.L. & Vanalen, J.W.T. Reversibleoptic neuritis secondary to paranasal sinusitis. Eur Neurol1989, 29: 189-193.

9. Simpson, D.E. & Moser, L.A. Compressive optic neuropathysecondary to chronic sinusitis. Am J Optometry PhysiolOptics 1988, 65, 757-762.

10. Macdonald, R.L., Findlay, J.M. & Tator, C.H. Spheno-ethmoidal sinusitis complicated by cavernous sinus throm-bosis and pontocerebellar infarction. Can J Neurol Sci 1988,15: 310-313.

11. Urquhart, A.C., Fung, G. & McIntosh, W.A. Isolatedsphenoiditis: a diagnostic problem. J Laryngol Otol 1989,103: 526-527.

12. Maniglia, A.J., Goodwin, W.J., Arnold, J.E. & Ganz, E.Intracranial abscess secondary to nasal, sinus and orbitalinfections in adults and children. Arch Otolaryngol HeadNeck Surg 1989, 115: 1424- 1429.

13. Zinreich, S.J., Kennedy, D.W., Rosenbaum, A.E., Gayler,B.W., Kumar, A.J. & Stammberger, H. CT ofthe nasal cavityand paranasal sinuses: imagining requirements for functionalendoscopic sinus surgery. J Radiol 1987, 163: 769-775.

14. Zinreich, S.J., Kennedy, D.W., Malat, J. et al. Fungalsinusitis: diagnosis with CT and MR imaging. Radiology1988, 169: 439-444.

15. Stammberger, H. Functional Endoscopic Sinus Surgery. TheMesserklinger Technique. BC Decker, Philadelphia, 1991,p. 275.

16. Nass, R.L., Holliday, R.A. & Reede, D.L. Diagnosis ofsurgical sinusitis using nasal endoscopy and computerizedtomography. Laryngoscope 1989, 99: 1158-1160.

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