Olfactory taste disorder as a presenting symptom of COVID-19: a large single-center Singapore study.

PURPOSE: To investigate the prevalence and epidemiological risk factors of olfactory and/or taste disorder (OTD), in particular isolated OTD, in patients with laboratory-confirmed COVID-19 infection. METHODS: We conducted a retrospective and cross-sectional study. Patients with laboratory-confirmed COVID-19 infection were recruited from the National Centre for Infectious Diseases (NCID) Singapore between 24 March 2020 and 16 April 2020. The electronic health records of these patients were accessed, and demographic data and symptoms reported (respiratory, self-reported OTD and other symptoms such as headache, myalgia and lethargy) were collected. RESULTS: A total of 1065 patients with laboratory-confirmed COVID-19 were recruited. Overall, the prevalence of OTD was 12.6%. Twelve patients (1.1%) had isolated OTD. The top three symptoms associated with OTD were cough, fever and sore throat. The symptoms of runny nose and blocked nose were experienced by only 29.8 and 19.3% of patients, respectively. Multivariate analysis demonstrated that the female gender, presence of blocked nose and absence of fever were significantly associated with OTD (adjusted relative risks 1.77, 3.31, 0.42, respectively). All these factors were statistically significant. CONCLUSION: Patients with COVID-19 infection can present with OTD, either in isolation or in combination with other general symptoms. Certain demographic profile, such as being female, and symptomatology such as the presence of blocked nose and absence of fever, were more likely to have OTD when infected by COVID-19. Further studies to elucidate the pathophysiology of OTD in these patients will be beneficial.

Food allergy and allergic rhinitis in 435 asian patients - A descriptive review.

OBJECTIVE: To describe the prevalence of food allergy in Asian patients with allergic rhinitis. STUDY DESIGN: A non-randomized prospectively collected patients over a three year period, with complaints of nose congestion, rhinorrhea and/or nasal discharge. RESULTS: There were 435 patients enrolled, 213 children and 222 adults. The children group had a high prevalence of allergen specific IgE to Dermatophagoides pteryonysinus (70%), Dermatophagoides farina (69%), and Blomia tropicalis (55%); followed by dogs (32%), cats (19%) and cockroaches (19%). In the children food allergy category, the top three allergens were egg white (54%), milk (31%) and soya bean (13%). The adult group had results of Dermatophagoides pteryonysinus (71%), Dermatophagoides farina (72%), and Blomia tropicalis (59%); the adult food allergy category, the top 3 allergens were egg white (13%), milk (6%) and soya bean (5%). There was a statistically significant difference in the child and adult group for Dust, D. pteryonysinus, D. farina, B.tropicalis, egg white, wheat, gluten and soya bean. In the age specific child groups, there was an increased in egg food allergy levels, with a peak at the age of five-nine years old and decreasing thereafter (p=0.04). In the children group, the mean Total Nasal Symptom Score (TNSS) was 10.3 (range of 7 to 13); the adult group was similar, with a mean TNSS of 9.8 (range 5 to 12). CONCLUSION: The prevalence of food allergy in paediatric patients with allergic rhinitis is fairly high and should be considered when treating these children.

Next-Gen phylogeography of rainforest trees: exploring landscape-level cpDNA variation from whole-genome sequencing.

Standardized phylogeographic studies across codistributed taxa can identify important refugia and biogeographic barriers, and potentially uncover how changes in adaptive constraints through space and time impact on the distribution of genetic diversity. The combination of next-generation sequencing and methodologies that enable uncomplicated analysis of the full chloroplast genome may provide an invaluable resource for such studies. Here, we assess the potential of a shotgun-based method across twelve nonmodel rainforest trees sampled from two evolutionary distinct regions. Whole genomic shotgun sequencing libraries consisting of pooled individuals were used to assemble species-specific chloroplast references (in silicio). For each species, the pooled libraries allowed for the detection of variation within and between data sets (each representing a geographic region). The potential use of nuclear rDNA as an additional marker from the NGS libraries was investigated by mapping reads against available references. We successfully obtained phylogeographically informative sequence data from a range of previously unstudied rainforest trees. Greater levels of diversity were found in northern refugial rainforests than in southern expansion areas. The genetic signatures of varying evolutionary histories were detected, and interesting associative patterns between functional characteristics and genetic diversity were identified. This approach can suit a wide range of landscape-level studies. As the key laboratory-based steps do not require prior species-specific knowledge and can be easily outsourced, the techniques described here are even suitable for researchers without access to wet-laboratory facilities, making evolutionary ecology questions increasingly accessible to the research community.

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.

Sutter bipolar radiofrequency volumetric tissue reduction of palate for snoring and mild obstructive sleep apnoea: is one treatment adequate?

OBJECTIVE: To evaluate the efficacy of bipolar radiofrequency volumetric tissue reduction, using Sutter technology, in the treatment of snoring and mild obstructive sleep apnoea. DESIGN: Prospective, non-randomised trial. METHODS: Fifty-two patients with simple snoring and mild obstructive sleep apnoea underwent bipolar radiofrequency palate reduction under local anaesthesia. RESULTS: All patients were Friedman stage II and III, with tonsil sizes graded as zero, one or two, a mean body mass index of 22.6, and a mean age of 36.2 years. Seventy-seven per cent of patients reported improvement in their snoring; patients' mean snoring level (assessed by visual analogue scale) improved from 8.9 to 3.4 (p < 0.05). Eighty-three per cent of patients reported an improvement in their Epworth sleepiness scale score, from a mean of 14.6 to 9.5. Seven out of the 17 patients (41.2 per cent) met the surgical success criteria (i.e. at least a 50 per cent reduction of the pre-procedure apnoea-hypopnoea index, and a post-procedure apnoea-hypopnoea index of below 15). Patients' mean apnoea-hypopnoea index improved from 13.6 to 9.8, and their mean lowest oxygen saturation improved from 88.3 to 92.5 per cent. Eighty-two per cent of patients reported an improvement in their quality of life as a result of the procedure. CONCLUSION: One session of Sutter bipolar radiofrequency tissue volume reduction represents a viable method of treating snoring and mild obstructive sleep apnoea, with good results.

Haemangioma of the uvula causing loud habitual snoring--a rare entity.

Mucosal haemangiomas are unusual and typically involve frequently traumatised areas such as the lip, buccal mucosa and lateral borders of the tongue. Uvular haemangioma is rare and to our knowledge, has never been reported to cause obstructive sleep apnoea (OSA). We report an unusual case of uvular haemangioma causing loud habitual snoring and symptoms suggestive of OSA. This case report illustrates a rare cause of OSA and demonstrates the efficacy of surgery for obvious obstructive lesions of the pharynx.

MR spectroscopy in sinus mucocele: N-acetyl mimics of brain N-acetylaspartate.

We describe MR spectroscopy in 2 patients with frontal sinus mucoceles that showed a dominant metabolite peak at 2.0-ppm chemical shift, simulating N-acetylaspartate (NAA) of normal neuronal tissue. In vitro analysis of postsurgical mucocele samples confirmed that the signal at 2.0 ppm was arising from the methyl moiety of an N-acetyl compound. This is probably caused by N-acetylgalactosamine or N-acetylglucosamine, which are glycoproteins found in normal respiratory mucus produced by the paranasal sinus epithelium.

Migration of a foreign body in the maxillary sinus illustrating natural mucociliary action.

We present a case of a foreign body which migrated to the maxillary ostia by mucociliary action from its initial location on the floor of the maxillary sinus where it was traumatically introduced. This report illustrates that a powerful mechanism of mucociliary action can cause relatively heavy objects within the maxillary sinus to migrate naturally to the sinus ostia against gravitational force.

Why generic and disease-specific quality-of-life instruments should be used together for the evaluation of patients with persistent allergic rhinitis.

BACKGROUND: The importance of assessing health-related quality of life (HRQL) of patients with allergic rhinitis (AR) has been well established, but the specific roles of rhinitis-specific or general health instruments have not been delineated. OBJECTIVE: We analysed the psychometric properties of a disease-specific instrument, the Rhinoconjunctivitis Quality-of-Life Questionnaire (RQLQ) and the general health instrument, the Medical Outcome Short-Form 36 (SF-36) as they are employed in combination in patients with persistent AR in clinical practice. METHOD: We analysed the data collected from a prospective study of 43 newly diagnosed patients with persistent AR and 44 controls. We interviewed the patients four times, at baseline, weeks 4, 8 and 10. RESULTS: The RQLQ and SF-36 have good discriminative property, internal consistency, and test-retest reliability. The RQLQ is superior to the SF-36 as an evaluative instrument because more of its domains respond to change, the magnitude of change was greater, and the response was faster. The SF-36 is more susceptible to floor and ceiling effects. Both instruments are unsuitable for mildly symptomatic patients based on Rasch model analysis. Each questionnaire assesses a distinct and significant portion of the total HRQL of persistent AR. CONCLUSION: The SF-36 and RQLQ are good for discriminating rhinitis patients from controls, but the former is poor for detecting changes in QOL. Both are inappropriate for mildly symptomatic patients. Each instrument measures non-overlapping halves of the measurable HRQL. For an assessment of the HRQL in persistent AR that is complete and responsive both instruments should be employed together.

Migration of a foreign body in the maxillary sinus illustrating natural mucociliary action.

We present a case of a foreign body which migrated to the maxillary ostia by mucociliary action from its initial location on the floor of the maxillary sinus where it was traumatically introduced. This report illustrates that a powerful mechanism of mucociliary action can cause relatively heavy objects within the maxillary sinus to migrate naturally to the sinus ostia against gravitational force.

Thyroid surgery--the Tan Tock Seng Hospital otolaryngology experience.

INTRODUCTION: Central to the management of a patient with a thyroid nodule is the evaluation of the risk of malignancy. Postoperative morbidity, though rare, remains a concern because of its impact on the quality of the life of the patient. MATERIALS AND METHODS: A retrospective audit of 91 consecutive patients who underwent thyroid surgery for thyroid nodules, at the Department of Otolaryngology, Tan Tock Seng Hospital, between January 1995 and December 2000. RESULTS: The sensitivity and specificity of fine-needle aspiration cytology (FNAC) were 60% and 100%, respectively. The sensitivity and specificity of intraoperative frozen section examination was 82% and 100%, respectively. Sixty-four patients experienced no postoperative morbidity. Of the 27 patients with postoperative morbidity, only 1 was permanent. The incidence of transient and permanent biochemical hypocalcaemia was 44% and 0%, respectively. Nodal dissection performed together with total thyroidectomy increased the incidence of postoperative hypocalcaemia (P < 0.05). The number of parathyroid glands preserved in situ did not predict for postoperative hypocalcaemia. The incidence of transient and permanent recurrent laryngeal nerve (RLN) palsy was 10.3% and 1.1% (8.2% and 0.9% of nerves at risk), respectively. Tracheo-oesophageal groove clearance performed together with thyroid lobectomy did not increase the incidence of postoperative RLN palsy (P > 0.05). The median hospital stay was 3 days for benign thyroid disease, 4.5 and 16 days for malignant disease with tracheo-oesophageal groove clearance only and with neck dissection, respectively. CONCLUSION: The combination of clinical examination and FNAC remains the mainstay in selecting patients for surgery. Frozen section examination is an important intraoperative diagnostic adjunct to decide the extent of surgery. With proper surgical training and experience, thyroid surgery for malignancy can be undertaken with minimum postoperative morbidity and a short hospital stay.

Resurfacing of the nasopharynx after nasopharyngectomy using a free radial forearm flap.

BACKGROUND: Nasopharyngectomy is emerging as an important treatment option for salvaging locally recurrent nasopharyngeal carcinoma (NPC). After nasopharyngectomy, resurfacing the nasopharynx and covering the internal carotid artery is important to minimize the risk of infection, osteoradionecrosis, and carotid rupture. Previous authors have advocated the use of free grafts of skin and mucosa for this purpose but have also described significant rates of partial and total graft failure. METHODS: We believe that the best and most reliable way to resurface the nasopharynx is with vascularized tissue, and our preference is for the use of a free radial forearm flap. To illustrate our approach, we present two patients who underwent nasopharyngectomy by means of a maxillary swing approach and who had resurfacing of the surgical defect with a free radial forearm flap. RESULTS: Both patients had complete en bloc resection of tumor followed by the insetting of a free radial forearm flap to reline the surgical defect. Both flaps remained completely viable, and both patients achieved successful resurfacing of the entire nasopharynx. The morbidity of surgery was minimal, and there were no perioperative complications. On assessment 1 year later, the free radial forearm flap continues to reline the entire neonasopharynx, and the long-term functional recovery after surgery is excellent. CONCLUSION: Resurfacing the nasopharynx after nasopharyngectomy with a free radial forearm flap aids healing and minimizes the risk of complications. The morbidity of surgery is minimal and the functional recovery is excellent.

Swallowing problems in post irradiated NPC patients.

We present three patients with Nasopharyngeal Carcinoma (NPC) developing swallowing problems after radiotherapy as the primary modality of treatment. All patients had advanced stage NPC presenting with enlarged neck nodes and underwent radical external beam radiotherapy. All three patients had both CN X and CN XII palsies and had difficulty in both the oral and pharyngeal phases of swallowing. None of them has any clinical or radiological evidence of local recurrence in the post nasal space and neck or metastasis to the skull base. One patient underwent cricopharyngeal myotomy with epiglottopexy and hyoid suspension which failed and subsequently underwent laryngectomy. Another patient had medialisation thyroplasty and the third underwent a percutaneous endoscopic gastrostomy (PEG).

Tracheoesophageal puncture outcomes and predictors of success in laryngectomised patients.

INTRODUCTION: Prosthetic voice restoration has been widely used for vocal rehabilitation in laryngectomised patients. The objectives of this study were to examine success rates, predictors of success and complications for our patients who had undergone tracheoesophageal punctures (TEPs) and voice prosthesis placement after laryngectomy. To our knowledge, this is the first analysis of the use and complications of TEPs in Singapore. PATIENTS AND METHODS: Thirty-eight patients seen in our centre were analysed in this retrospective case review. Factors analysed included voice quality with age, timing of insertion, type of closure, use of radiotherapy, regular maintenance and attendance at our clinic. Twenty-eight had undergone primary TEP surgery and 10 had undergone secondary TEP surgery for voice restoration after laryngectomy for cancer. Thirty-five patients had primary closure of the pharynx with 13 vertical, 19 horizontal and 3 T-shaped closures. The other 3 patients required reconstructive surgery. Thirty-five patients had radiotherapy. A numerical assessment of voice production was made of patients immediately and at 6 months post-insertion. A review of the complications was also done. RESULTS: TEPs provided a fair to good voice in 74% of our laryngectomees. Patients who attended the voice restoration clinics and who regularly cleaned their prostheses were found to have statistically better voices (P = 0.044 and P = 0.002, respectively). Patients less than 60 years old had better results, as did patients with horizontal or T-shaped closures; however, these were not statistically significant. Secondary TEPs provided fair/good voices in 90% of cases compared to 68% of primary TEPs. Voice quality during radiotherapy was diminished but recovered at 6 months postradiotherapy. The commonest complications noted included crusting (seen in 40% of cohort), candida infections and leaks which were seen in 16% of our patients. There was no mortality attributable to the use of TEPs in our study.

Pharyngocutaneous fistula after laryngectomy--incidence, predisposing factors and outcome.

AIMS: The occurrence of pharyngocutaneous fistula in a totally laryngectomised patient is a serious complication as it increases patient morbidity and mortality. This paper aims to determine the incidence of the problem in our patients, to identify factors which may contribute to fistula formation and to analyse our results in managing this complication. METHODS: The case records of 69 patients who underwent total laryngectomy between April 1990 and July 1997 were assessed. RESULTS: There were 11 cases of pharyngocutaneous fistula out of 69 patients with total laryngectomy, giving an incidence of 15.9%. Our findings showed that fistula formation was significantly more common in patients who had received pre-operative radiotherapy (p = 0.001) or who had tumour involved surgical resection margins (p = 0.018). The development of fistula delayed hospital discharge, and in 1 patient, contributed to sepsis and death. Of the 11 patients with fistula, 4 required surgical intervention for closure. There was a trend towards surgical repair when the size of the fistula was large (> 2 cm). CONCLUSION: This paper identifies the patients at high risks for developing pharyngocutaneous fistula and also discusses our experience with managing this complication.

An audit of endoscopic sinus surgery.

AIM OF STUDY: A prospective study was carried out to evaluate the results of endoscopic sinus surgery based on symptom score and endoscopic findings and to evaluate the prognostic factors using an audit form designed by IS Mackay of London. METHODS: Consecutive cases undergoing endoscopic sinus surgery were entered into the study. Pre-operative symptom, computer tomographic and endoscopic scores were recorded. Operations were also evaluated objectively; post-operative symptom and endoscopic scores were recorded at 3, 6 and 12 months. Cases lost to follow-up were interviewed over the telephone and offered free endoscopic assessments. Those who required revision surgery were considered failures and re-entered into the study. RESULTS: The study comprised 113 cases (108 patients, 60 males and 48 females) with ages ranging from 14 to 80 years (mean 40.4). There were 52 with chronic rhinosinusitis, 46 with nasal polyps, 7 with tumours/inverted papillomata, 5 with acute complicated sinusitis and 3 with fungal sinusitis. Of these, 81.9% of patients with chronic rhinosinusitis or polyps showed an overall improvement of symptoms. Nasal obstruction showed the greatest improvement, followed by rhinorrhoea, loss of smell and headaches and facial pain. Endoscopic improvement was greatest in polyps (83.3%) and oedema (87.0%) but less for discharge (59.4%). CONCLUSIONS: Our results compared well with international series. Computer tomography scoring and the number of revision operations emerged as potential prognostic indicators requiring further evaluation.

Quality of life of patients with perennial allergic rhinitis: preliminary validation of the Rhinoconjunctivitis Quality of Life Questionnaire in Singapore.

Though sufferers of perennial allergic rhinitis do not die from their ailment, they endure years of chronic nose disease that Interferes with many important aspects of their lives. A rhinitis-specific instrument to gauge the quality of life of patients with this disease was published in 1991. Here, we validated the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) for use in English-speaking patients with perennial allergic rhinitis. We established that the RQLQ distinguishes between patients and control, demonstrates internal consistency and is sensitive to change. This study suggests that the RQLQ can be used to assess the quality of life of patients with perennial allergic rhinitis in Singapore.

Spontaneous retropharyngeal emphysema--case report.

Retropharyngeal emphysema is a radiological finding with a cause for concern. When associated with oesophageal perforation due to an impacted foreign body or recent oesophageal instrumentation, it heralds potentially fatal complications such as mediastinitis. Early diagnosis leading to prompt surgical intervention is essential. Spontaneous retropharyngeal emphysema is an uncommon disease entity. Its clinical course is relatively benign and recovery usually uneventful. Two cases are presented. The anatomy etiology and pathophysiology of the disease are reviewed. Barium swallow studies are recommended for all cases of retropharyngeal emphysema to exclude oesophageal perforation due to foreign body impaction and Boerhaave's syndrome.