Biomedical subjects

T Y Tan

Publications and source records attributed to T Y Tan.

30 records · Page 2Linked to original sources

PubMed2001

Rapid identification of methicillin-resistant Staphylococcus aureus from positive blood cultures by real-time fluorescence PCR.

Methicillin-resistant Staphylococcus aureus septicemia is associated with significant morbidity and mortality and requires treatment with intravenous glycopeptides. For blood cultures positive for gram-positive cocci, 24 to 48 h is required for the detection of S. aureus bacteremia and the provision of antibiotic susceptibility testing results. We describe a molecular biology-based assay that requires 2 h from the time of initial positivity of blood cultures. The assay correctly detected 96% of the S. aureus isolates including all methicillin-resistant S. aureus isolates. Clinical data collected during the study suggest that 28% of patients with S. aureus bacteremia do not receive early and appropriate treatment and that 10% of patients may initially be receiving inappropriate glycopeptide treatment.

Bacteremia↗

PubMed2001

The value of pre-operative high resolution CT scans in cholesteatoma surgery.

INTRODUCTION: Cholesteatoma is traditionally diagnosed by otoscopic examination and treated by explorative surgery. The need for imaging in an uncomplicated case is contentious. This study assesses the usefulness of a pre-operative high-resolution CT scan in depicting the status of the middle ear structures in the presence of cholesteatoma. MATERIALS AND METHODS: The surgical findings of 36 ears with cholesteatoma operated on by the first author were retrospectively compared with the CT findings reported on by the second author. The following were analysed: diagnostic features of cholesteatoma on CT, status of the middle ear structures (ossicles, facial nerve canal, semicircular canals and tegmen tympani), and presence of any anatomical variations and disease complications. RESULTS: All cases had at least 1, and 30 cases (83.3%) had all, of the following radiological features: (a) a non-dependent tissue mass, (b) a location typical for cholesteatoma and (c) bony erosion. The radiosurgical agreement was excellent for the malleus (kappa statistics, k=0.83), stapes (0.94) and semicircular canals (0.8), good for the incus (0.62) and tegmen (0.65), but poor for the facial nerve canal (0.3). Potential surgical hazards detected by the scans included: low lying dura, high jugular bulb, anterior lying sigmoid sinus, facial nerve dehiscence and other situations brought about by the destructive nature of the lesion. CONCLUSION: There is good to excellent radiosurgical correlation in cholesteatoma for most middle ear structures except for the integrity of the facial canal. The scan alerts the surgeon to potential surgical dangers and complications of disease. High-resolution CT scan is an important investigative tool prior to cholesteatoma surgery.

Cholesteatoma, Middle Ear↗

PubMed2000

Treatment of a vancomycin-resistant Enterococcus faecium ventricular drain infection with quinupristin/dalfopristin and review of the literature.

Central nervous system infections involving vancomycin-resistant Enterococcus faecium (VREF) are infrequently described and pose significant therapeutic difficulties, because these organisms are intrinsically resistant to many antibiotics. We describe the use of intrathecal quinupristin/dalfopristin to treat a VREF-associated infection in a neuro--surgical patient.

Acetamides↗

PubMed2000

The value of MRI in the diagnosis and management of neurocysticercosis.

The clinical manifestation of neurocysticercosis is quite protean and variable making it the 'great imitator' of almost any neurological disorder. In the last decade, developments in diagnostic imaging and effective anticysticercus drug therapy have changed the outlook of the disease. Two cases investigated with CT scan and MRI are reported here. One case was treated effectively with antihelminthic therapy. In both cases MRI was found to be much more sensitive than CT scan in picking up the multiple cystic lesions. In addition, 'protoscoleces' and 'differential ring enhancements' not apparent in CT scan were well shown in MRI hence enabling the demonstration of different activity stages. In the treated patient, repeat MRI showed degeneration of the cyst. These illustrate that MRI is superior to CT scan in both the diagnosis and management of the illness.

Adult↗

PubMed2000

Retroperitoneal Castleman's disease in the perinephric space--imaging appearance: a case report and a review of the literature.

INTRODUCTION: Castleman's disease (CD) is a rare lymphoid tumour usually found in the mediastinum. Extrathoracic sites are uncommon. Its radiological findings may be similar to other retroperitoneal tumours, making diagnosis difficult. CLINICAL PICTURE: A 54-year-old female was found to have an incidental hypoechoic mass in the left posterior perinephric space on routine ultrasound. Abdominal computed tomography (CT) scan demonstrated an isodense mass which enhanced brightly with intravenous contrast. Angiogram confirmed a hypervascular mass. TREATMENT: The retroperitoneal mass was excised. OUTCOME: Histology revealed CD of hyaline-vascular type. CONCLUSION: CD should be considered in the differential diagnosis of a retroperitoneal mass, which demonstrates homogeneous and intense enhancement.

Biopsy, Needle↗

PubMed1999

Non-contrast high resolution fast spin echo magnetic resonance imaging of acoustic schwannoma.

AIM OF STUDY: The current gold-standard of examination for the exclusion of acoustic schwannomas is contrast-enhanced magnetic resonance (MR) imaging. Many patients however, still cannot afford to pay for the cost of this examination. As a result, many clinicians still resort to contrast-enhanced computed tomography (CT) scan; an examination which could miss small intracanalicular acoustic schwannomas. The aim of this study was to report on our experience on the usage of the more affordable high-resolution fast spin-echo (FSE) MR imaging for the diagnosis of acoustic schwannoma. METHODOLOGY: A study involving 123 patients with symptoms of sensorineural hearing loss, vertigo and tinnitus was carried out between August 1996 and March 1997. All cases were scanned with a 1.5 T MR unit using a quadrate head coil. The section thickness was 1.5 mm, with TR/TE of 4000/96. Any mass arising from the vestibulocochlear nerve was considered to be an acoustic schwannoma, and most of these positive cases underwent further contrast-enhanced MR imaging to confirm the diagnosis. RESULTS: A total of 7 acoustic schwannomas were detected on high resolution FSE MR imaging and for 5 of these cases, the diagnosis was confirmed with contrast-enhanced MR imaging. Three of the 7 positive patients had contrast-enhanced CT scan done just prior to the MR study and the tumours were not detected on CT scan. The smallest acoustic schwannoma detected on high-resolution FSE MR imaging had a dimension of 0.5 x 0.4 x 0.5 cm. CONCLUSION: High resolution FSE MR imaging is more sensitive than contrast-enhanced CT scan in the diagnosis of acoustic schwannoma. Although the sensitivity is less than that of contrast-enhanced MR imaging, high resolution FSE MR is more affordable and therefore can play a role in the screening for acoustic schwannomas in selected groups of patients.

Adolescent↗

PubMed1999

Large endolymphatic duct and sac syndrome--a case report.

A 17-year-old girl with a history of hearing loss, presented with recurrent episodes of vomiting. CT scan revealed bilateral enlarged vestibular aqueducts and MR scanning confirmed the diagnosis of large endolymphatic duct and sac syndrome. This article looks into the anatomy and physiology of the endolymphatic duct and sac as well as possible explanations for the hearing loss associated with this syndrome.

Adolescent↗

PubMed1999

Cerebral sparganosis: case report.

A 19-year-old man visited our hospital following an attack of general tonic-clonic convulsion. Multiple lesions were noted over bilateral frontal areas on brain computed tomography and magnetic resonance images. The diagnosis was confirmed by positive antibody for sparganum using enzyme-linked immunosorbent assay (ELISA). Praziquantel, 2400 mg/d for one month, was prescribed before the antibody test results came out and the treatment failed. Total removal of the lesion and the enclosed parasite cured the patient. Although the features of cerebral sparganosis on brain computed tomography and magnetic resonance images have been previously described, the findings were not specific and the present case exhibited some different patterns including bilateral multiple calcifications and ventricular compression. The significance of the bilateral involvement is not known but the ventricular compression suggests that the disease was in an active stage. Imaging studies appear to only provide some clues for the diagnosis of sparganosis. Bilateral involvement may be seen as in the present case. The final diagnosis depends on pathologic or immunologic examination results. Surgical intervention either using stereotactic techniques or total removal of the lesion is the treatment of choice while antiparasitic agents are ineffective.

Adult↗

PubMed1999

Antenatal HIV screening--knowledge, attitudes and practices of obstetricians in KKH.

AIM OF STUDY: To determine the knowledge, attitudes and practices of obstetricians with regards to HIV screening in pregnant women. METHOD: This is a cross-sectional study based on a questionnaire survey of all obstetricians in KKH from January to August 1997. MAIN OUTCOME MEASURES: Obstetricians' knowledge and beliefs of HIV epidemiology and HIV perinatal transmission, and attitudes and practices with regards to antenatal HIV screening. RESULTS: Forty-one (77.4%) obstetricians responded to the survey. At the time of the survey, only 43.9% of the respondents had offered the HIV serology test to their patients with only 17.1% and 19.5% providing pre-test and post-test counselling respectively. Seventy-eight percent of them were aware of reports that zidovudine could reduce the vertical HIV transmission rate. All the respondents felt that HIV testing should be performed in pregnant women. The majority (70.7%) felt that antenatal HIV testing should be voluntary rather than mandatory and 56.1% felt that the patients' civil rights and confidentiality could be more assured if HIV testing is voluntary than if it was mandatory. Most respondents (56.1%) felt that antenatal HIV screening should be universally offered rather than targeted to those with risk factors. Most obstetricians did not feel comfortable (58.5%) or competent (80.5%) to manage HIV infection in pregnancy. Those who felt competent were more likely to feel comfortable, more likely to have provided HIV test in the clinic, and less likely to opt out of caring for an HIV-infected patient. CONCLUSION: The majority of the surveyed obstetricians would support a program of voluntary antenatal HIV screening that is universally offered to all pregnant women. The feelings of discomfort and incompetence of the obstetricians towards caring for an HIV-infected pregnant woman need to be addressed further. There is a need for continuing medical education to help obstetricians keep abreast with the advances in HIV screening and its management.

AIDS Serodiagnosis↗

PubMed1998

Distribution patterns of inflammatory sinonasal diseases.

BACKGROUND/AIM OF STUDY: There has been an increase in the demand for coronal sinus CT scan since the introduction of functional endoscopic sinus surgery; as the information provided by the scans assist the surgeon in the pre-operative plannings. Babbel and colleagues had demonstrated five distinctive patterns of recurring inflammatory sinonasal disease on CT scan. The aim of this study was to evaluate the patterns in the local population and to see if there was a difference compared to the Caucasian population. METHODS AND MATERIALS: A retrospective review of 302 scans done between March 1993 and September 1995 was carried out. All scans were carried out using a 5 mm thickness to cover the posterior sinuses and a 3 mm thickness to cover the anterior sinuses. The scans were then grouped into the various patterns and an analysis was carried out comparing the differences in the patterns between the Chinese and the non-Chinese, and between the local population and the Caucasian population in Babbel's series. RESULTS: There was no significant difference between the Chinese and the non-Chinese in the distribution of the various disease patterns. When compared to the Caucasian population, the local population had more sinonasal polyposis and sphenoethmoidal recess obstruction. CONCLUSION: The smaller nasal passages of the Asians, particularly in the Chinese, could be the reason for the more prevalence of Type III and Type IV disease compared to the Caucasian population. The more constant and frequent exposure to allergens might also contribute to the increased prevalence of Type IV disease.

Adolescent↗

PubMed1998

Contrast-enhanced magnetic resonance imaging of the internal auditory canals and posterior fossa.

A retrospective review of 314 cases of contrast-enhanced magnetic resonance imaging (MRI) of the posterior fossa and internal auditory canals was carried out correlating the presenting symptoms with the scan findings. 7.2% of the cases showed findings on the MRI which could account for the patients' symptoms. Patients with sensorineural hearing loss were more likely to have a positive scan than those presenting with vertigo and/or tinnitus without hearing loss. Acoustic schwannoma was the most common lesion detected. Labyrinthine lesions e.g. cochlear schwannoma, labyrinthitis, congenital labyrinthine abnormality, and central lesions e.g. multiple sclerosis, brainstem glioma were some of the other lesions detected.

Adolescent↗

PubMed1994

High resolution computed tomography of the temporal bone: preliminary experience.

High Resolution Computed Tomography (HRCT) can demonstrate the detailed anatomy and pathology of the temporal bone and is fast becoming an important imaging modality in the diagnosis and preoperative management of our local patients with temporal bone diseases. We present our experience in the usage of HRCT in temporal bone lesions in Tan Tock Seng Hospital, using 8 cases as illustration. The protocol that we used to obtain the images is described. We also give an overview of those clinical conditions whereby HRCT can provide information which will help surgeons in the management of their patients. These clinical conditions are hearing loss, external auditory canal atresia, middle ear inflammation/cholesteatoma, temporal bone trauma, pulsatile tinnitus and vascular tympanic membrane.

Adult↗