Allergic rhinitis: evidence-based practice.

Allergic rhinitis is a common condition in Singapore, with a considerable disease burden. This article reviews the latest evidence-based concepts and current understanding of the disease, including its aetiology, pathogenesis, signs and symptoms, investigations as well as management. Particular attention is given to reviewing principles that will aid the management of this disease from a practical point of view, and the latest evidence for the various pharmacological options as well as immunotherapy is discussed. The article should be of interest to otolaryngologists as well as allergists, respiratory physicians and family practitioners.

Ministry of Health clinical practice guidelines: Management of Rhinosinusitis and Allergic Rhinitis.

The Ministry of Health publishes national clinical practice guidelines to provide doctors and patients in Singapore with evidence-based guidance on managing important medical conditions. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the Ministry of Health clinical practice guidelines on Management of Rhinosinusitis and Allergic Rhinitis, for the information of readers of the Singapore Medical Journal. Chapters, page and figure numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website (http://www.moh.gov.sg/mohcorp/publications.aspx?id=24046). The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Comparison of eye lens dose on neuroimaging protocols between 16- and 64-section multidetector CT: achieving the lowest possible dose.

BACKGROUND AND PURPOSE: To our knowledge, there has been no study that compares the radiation dose delivered to the eye lens by 16- and 64-section multidetector CT (MDCT) for standard clinical neuroimaging protocols. Our aim was to assess radiation-dose differences between 16- and 64-section MDCT from the same manufacturer, by using near-identical neuroimaging protocols. MATERIALS AND METHODS: Three cadaveric heads were scanned on 16- and 64-section MDCT by using standard neuroimaging CT protocols. Eye lens dose was measured by using thermoluminescent dosimeters (TLD), and each scanning was repeated to reduce random error. The dose-length product, volume CT dose index (CTDI(vol)), and TLD readings for each imaging protocol were averaged and compared between scanners and protocols, by using the paired Student t test. Statistical significance was defined at P < .05. RESULTS: The radiation dose delivered and eye lens doses were lower by 28.1%-45.7% (P < .000) on the 64-section MDCT for near-identical imaging protocols. On the 16-section MDCT, lens dose reduction was greatest (81.1%) on a tilted axial mode, compared with a nontilted helical mode for CT brain scans. Among the protocols studied, CT of the temporal bone delivered the greatest radiation dose to the eye lens. CONCLUSIONS: Eye lens radiation doses delivered by the 64-section MDCT are significantly lower, partly due to improvements in automatic tube current modulation technology. However, where applicable, protection of the eyes from the radiation beam by either repositioning the head or tilting the gantry remains the best way to reduce eye lens dose.

Long-term results of endoscopic resection of nasopharyngeal tumours.

Traditional open approaches to the nasopharynx either provide limited access and risk significant morbidity. Here we describe our experience with endoscopic resection of nasopharyngeal tumours. Retrospective chart review was performed for all patients who underwent endoscopic nasopharyngeal resection from September 1993 to January 2007 at a tertiary rhinology centre. Six patients underwent endoscopic nasopharyngectomy for tumours arising from or involving the nasopharynx. The mean age was 49.8 years (range 23 - 70). The sex distribution was five males and one female. Four tumours were malignant and two were benign. The mean disease-free and overall survival for malignant tumors was 90.75 months (range 66 - 120 months). None of the benign tumors recurred. The endoscopic nasopharyngectomy technique may be successfully used for resection of tumors arising from or involving the nasopharynx with good efficacy and a decrease in morbidity when compared to open approaches.

Paediatric acute epiglottitis re-visited.

INTRODUCTION: Paediatric acute epiglottitis is rare in Asia. The National University Hospital in Singapore has seen only two cases of paediatric acute epiglottitis in the last 10 years. The topic is re-visited here to remind physicians of its acutely dramatic progression. CLINICAL PICTURE: Both boys presented with a viral prodrome which progressed within hours to life-threatening upper airway obstruction. Examination revealed an inflamed epiglottitis. TREATMENT: They were successfully intubated and treated with intravenous antibiotics. OUTCOME: Both recovered uneventfully. CONCLUSION: Paediatric acute epiglottitis has declined markedly in the West with widespread vaccination against HiB. In contrast, the incidence of invasive HiB disease in Asia has always been low despite limited vaccination. Clinicians must remain vigilant of the possibility of acute epiglottitis in a child with "flu".

Diagnostic value of Epstein-Barr viral serology in nasopharyngeal carcinoma.

Although Epstein-Barr virus (EBV) IgA serology has been established as an effective marker for nasopharyngeal carcinoma (NPC), it remains unclear how useful or cost-effective it is as a screening test. This article is aimed at establishing how these tests could be used most effectively in the diagnosis of NPC in an otolaryngology outpatient clinic. A total of 111 consecutive patients with NPC and an equal number of control subjects were studied. Forty-seven patients with NPC had early (AJCC stages 1 and 2) and 64 had advanced (stages 3 and 4) disease. A positive early antigen (EA) serology result was found in 81.2% of NPC patients and in none of the controls. Negative EA and viral capsid antigen (VCA) serology results were present in 2.7% of NPC patients and in 46.8% of controls. Negative EA and positive VCA serology results were found in 30.0% of NPC patients with early disease, 7.8% of NPC patients with advanced disease, and 53.2% of controls. Given its high specificity, serology for EA is recommended as a clinically useful screening test. Serology for VCA, although highly sensitive, has an unacceptably high false-positive rate, and its cost-effectiveness as a universal screening test is questionable.

Correlating clinical appearance of nasopharyngeal carcinoma with tumour staging.

Since there is a tendency for nasopharyngeal carcinoma (NPC) to exhibit sub-mucosal spread and endophytic growth, it would be useful to know if NPC remained inconspicuous in the post-nasal space (PNS) even in advanced stages of disease. The aim of this study was to find out if there was a correlation between tumour appearance in the PNS and tumour stage. One hundred and twenty-two consecutive patients with NPC were studied. The appearance of a tumour in the PNS was classified as to whether or not it was obviously malignant-looking (via naso-endoscopy). Tumour stagings were undertaken according to computerised tomography (CT) scan findings. Of the patients studied, 67 (54.9%) had obvious malignant-looking lesions. Tumour appearance was found to correlate with tumour-staging (p = 0.023, chi-squared test). There was, therefore, a tendency for early tumours to present as inconspicuous or innocuous-looking lesions, whereas advanced tumours tended to appear as obvious malignant-looking lesions in the PNS. The clinical significance of these findings is discussed.

Otogenic lateral sinus thrombosis--a case report.

INTRODUCTION: We portray and discuss a case of lateral sinus thrombosis following acute otitis media and mastoiditis. CLINICAL PICTURE: The patient presented with otorrhoea, otalgia, neck pain, fever and chills. TREATMENT: Cortical mastoidectomy was performed. Intravenous antibiotics and heparin were administered. OUTCOME: The patient had a complete recovery with no sequelae. CONCLUSIONS: Neurotologic complications of suppurative otitis media like meningitis, cerebral abscess, extradural abscess and dural sinus thrombosis are rare in the antibiotic era. Hence, doctors today have to maintain extra vigilance and a high index of suspicion for such complications.

Factors contributing to delayed diagnosis in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) can be difficult to diagnose. Not only is the post-nasal space (PNS) inaccessible to examination, it is frequently occupied by normal lympho-epithelium which can make differentiation from NPC difficult. Together with its frequent atypical presentation, it is not surprising that the diagnosis is missed or delayed. This is undesirable as the treatment of early NPC carries an excellent prognosis. The aim of this study is to ascertain the extent of the problem of missed or delayed diagnosis and to study the factors responsible. This was a retrospective study of all newly diagnosed patients with NPC from the Singapore General Hospital and treated in the Department of Therapeutic Radiology in the year 1996 (1 January-31 December). A total of 126 patients were studied. Eighteen patients (14.3 per cent) were found to have delayed diagnosis of more than a month. The delay ranged from 1.2 to 25 months (mean 7.2 months). Factors identified which contributed to delayed diagnosis included i) Clinicians not considering a diagnosis of NPC ii) Clinicians suspecting NPC but misled by the results of investigations iii) Patients refusing investigation or defaulting follow-up. Nearly a fifth of patients with NPC had delayed diagnosis. Many of the factors responsible for the delays appear to be preventable by better patient education and counselling, doctors having sharper clinical acumen and skills in NPC diagnosis and the hospital administration having a system of tracking down high risk patients who default.