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H S Lam

Publications and source records attributed to H S Lam.

At least 19 recordsLinked to original sources
PubMed2006

Cough frequency in children with mild asthma correlates with sputum neutrophil count.

BACKGROUND: A study was undertaken to measure cough frequency in children with stable asthma using a validated monitoring device, and to assess the correlation between cough frequency and the degree and type of airway inflammation. METHODS: Thirty six children of median age 11.5 years (interquartile range (IQR) 9-14) with stable asthma were recruited. They underwent spirometric testing, exhaled nitric oxide (eNO) measurement, sputum induction for differential cell count, and ambulatory cough monitoring for 24 hours. Coughing episodes were counted both as individual spikes and as clusters. RESULTS: All children had mild intermittent asthma and their median forced expiratory volume in 1 second and eNO were 83.3% (IQR 81.1-97.6) and 56.1 ppb (IQR 37.4-105), respectively. The median number of cough episodes per day was 25.5 (IQR 16-42.8). Sputum induction was successful in 69% of the subjects and cough frequency was found to have a significant positive correlation with sputum neutrophil count (r = 0.833, p = 0.0001). CONCLUSIONS: Children with stable mild asthma have increased cough frequency that might be driven by a neutrophilic inflammatory pathway.

Asthma↗
PubMed2005

Mal-positioned umbilical venous catheter causing liver abscess in a preterm infant.

Neonatal liver abscess is uncommon, carries a high mortality and is difficult to diagnose. We report an unusual case of liver abscess in a preterm infant presenting with abdominal distension and suspected gastrointestinal perforation, rather than the more usual features of fever, hepatomegaly, abdominal tenderness, right-sided pleural effusion, and leukocytosis. We discuss current treatments for neonatal liver abscess and argue that in view of the high mortality and difficulty in diagnosis, prevention should be the primary objective. We believe that mal-positioning the umbilical venous catheter in the liver substantially increases the life-threatening risk of this complication, and advocate extreme care in the placement and use of these catheters.

Catheterization, Peripheral↗
PubMed2005

Wire-guided excision of mammographic abnormalities.

OBJECTIVE: A review of wire-guided excision of abnormal lesions viewed on screening mammography. DESIGN. Retrospective review. SETTING: Regional hospital, Hong Kong. PATIENTS: Patients who underwent wire-guided excision of abnormalities visualised on screening mammography between 1999 and 2002. INTERVENTION: Wire-guided excision. MAIN OUTCOME MEASURES: Biopsy rate and positive biopsy rate. RESULTS: A total of 65 patients underwent wire-guided excision of an abnormal lesion previously identified by screening mammography. Twenty-one were benign, two were lobular carcinoma in situ, and 42 were malignant. Of the latter, 30 were identified as ductal carcinoma in situ, and 12 as invasive breast cancer. Thirty-eight of the 42 malignant cases required further treatment, and 24 of them underwent further operation. Radiological assessment of the 65 patients suggested that nine lesions were probably benign, 31 indeterminate, 20 suspicious, and five malignant. Malignancy was subsequently confirmed by histological examination in 6, 20, 13, and 3 cases of the respective group of radiological assessment. CONCLUSION: The biopsy rate was approximately 3.7 per 1000 screened women, with results benign in 1.19 per 1000. The positive biopsy rate was 64.6%, and invasion was evident in 28.6%.

Biopsy↗
PubMed2004

Imaging of gastrointestinal stromal tumour (GIST).

Gastrointestinal stromal tumour (GIST) represents the most common kind of mesenchymal tumour that arises from the alimentary tract. GIST is currently defined as a gastrointestinal tract mesenchymal tumour containing spindle cells (or less commonly epithelioid cells or rarely both) and showing CD117 (c-kit protein) positivity. Targeted molecular therapy of non-resectable GIST using imatinib, a specific tyrosine kinase receptor inhibitor, represents a real milestone in the management of solid malignancy. Imaging studies, both anatomical and functional, are playing an increasingly important role in management of patients with GIST. This review illustrates the radiological appearance of GISTs and the site-specific roles of each imaging tool. Clinical features and radiological differential diagnosis of GIST are also discussed.

Angiography↗
PubMed2002

Scattered radiation level during videofluoroscopy for swallowing study.

AIM: To evaluate the scattered radiation exposure to the surroundings during videofluoroscopy for swallowing study (VFSS). MATERIALS AND METHODS: Scattered radiation exposure was measured using an ion chamber survey meter for 17 adult patients undergoing videofluoroscopy for swallowing study. The cumulative dose area product of each case was also recorded. Data were presented as mean +/- standard deviation. RESULTS: The scattered radiation exposure at a distance of 150 cm from the patient and the dose area product recorded were 149 +/- 78 microR (range 42-308 microR) and 842 +/- 544 cGy.cm(2) (range 258-2151 cGy.cm(2)), respectively, for a single study of 18 +/- 6 minutes. A formula was then derived for estimating the scattered radiation dose to muscle tissue at an arbitrary distance based on the accumulated dose area product. With this formula, the mean scattered radiation dose to naked muscle tissue of the surrounding people at a distance of 30-100 cm from the patient were estimated to be 33.68-3.03 microSv respectively. CONCLUSION: The scattered radiation detriment associated with videofluoroscopy for swallowing study was well within acceptable levels.

Adult↗
PubMed2002

Prone table stereotactic breast biopsy.

The prone table machine is a mammographic X-ray system specially designed for use in the stereotactic localisation of breast abnormality. In this study, its clinical usefulness was investigated in terms of duration, success rate, complications, and patients' acceptance of the procedure. During a 5-month period, 79 patients attended the Kwong Wah Hospital for stereotactic-guided biopsy on the prone table. Eighty-one lesions were assessed-seven by fine needle aspirations, 67 by large-core needle biopsies, and seven by vacuum-assisted biopsies. Most of the biopsies were done because of clustered microcalcifications (77.8%) and the majority were of mammographically indeterminate nature (58.0%). The mean duration of the procedure was 49 minutes. A high degree of acceptance was experienced by patients. Only one patient had persistent haemorrhage after the biopsy. In conclusion, the prone table machine was considered to be useful and efficient, and had a high degree of acceptance among patients.

Adult↗
PubMed2001

Diagnostic accuracy of vacuum-assisted biopsy device for image-detected breast lesions.

BACKGROUND: Non-palpable breast lesions present diagnostic difficulties. Ultrasound-guided fine-needle aspiration cytology (FNAC) is a common method used to obtain a diagnosis, but FNAC is frequently inconclusive or insufficiently accurate. Recently a vacuum-assisted biopsy device (Mammotome, Ethicon, Endo-surgery, USA) has been introduced. The diagnostic accuracy of this biopsy device was assessed for lesions that were visible on ultrasound. METHODS: Fifty ultrasound-guided mammotome biopsies were performed. All were small breast lesions primarily detected by ultrasound. All received FNAC as initial assessment. Mammotome biopsy was performed whenever the breast lesion was considered indeterminate or if it was considered benign and there were associated risk factors such as a family history of breast cancer. RESULTS: Of 50 mammotome biopsies 45 had benign histology. Three of 45 lesions were excised at the patients' request and were confirmed to be benign. The remaining 42 patients received an ultrasound follow up at 6 months. The lesion size remained static in 39 patients. In three patients the lesion size increased and they were excised and histology was benign. For the four malignancies diagnosed with mammotome biopsy, three patients received definitive treatment and one patient defaulted. There was one failed mammotome biopsy in the present series. CONCLUSIONS: Mammotome biopsy is an acceptable diagnostic method for small breast lesions seen on ultrasound. It reduces the need for open biopsy without compromising diagnostic accuracy.

Adult↗
PubMed2001

Validation of the Ottawa ankle rules in a Hong Kong ED.

The Ottawa ankle rules (OAR) have been validated in many Western countries. However, a recent study performed in an accident and emergency department in Singapore failed to validate the OAR. Therefore, the implementation of the use of OAR in accident and emergency departments in Hong Kong may be treated with skepticism. This prospective study was performed to validate the ordering of radiographs using OAR in Chinese patients with foot and ankle injuries in Hong Kong. Emergency physicians trained in the use of the OAR assessed 773 eligible patients and one hundred thirty-one fractures were identified. The sensitivity and specificity of the OAR for ankle injuries was 98% and 40.8%. For midfoot injuries, the sensitivity and specificity of the OAR was 100% and 43.8%. We concluded that the OAR are applicable in our population with potential advantages for reducing the number of unnecessary investigations and shortening the patients' length of stay in accident and emergency departments.

Adolescent↗
PubMed2001

Migrainous spasm simulating carotid dissection: a pitfall in MR arteriographic findings.

An MR arteriogram obtained in a patient with migraine headaches during prodrome showed features of carotid dissection. A repeated study conducted within minutes demonstrated complete patency. Vascular spasm was proposed to be the cause. Migraine occurs in more than 10% of the population. The possibility of misdiagnosing a vascular spasm as carotid dissection is real and should be guarded against since there are great prognostic and treatment implications.

Adult↗
PubMed2000

Clinical and radiological features of biliary papillomatosis.

Biliary papillomatosis is a rare disease with strong potential for malignant degeneration. Diagnosis is often not easy and most are made intraoperatively. In the present study, five patients with biliary papillomatosis admitted between 1990 and 1997 were reviewed. Their clinical presentation, radiological and biochemical findings were analysed. The aim of the study was to discern a set of characteristic features that would enable an early diagnosis. All of the five patients presented with recurrent episodes of acute cholangitis and epigastric pain with raised serum alkaline phosphatase. Imaging modalities including ultrasound, CT, endoscopic retrograde cholangio-pancreatogram, MRI and magnetic resonance cholangio-pancreatogram were reviewed. Salient imaging features included a dilated biliary tree with multiple ill-defined and fuzzy filling defects or endoluminal frond-like mass lesions. In conclusion, biliary papillomatosis is a rare but important cause of biliary obstruction with relapsing cholangitis and obstructive jaundice. With a healthy index of suspicion, the diagnosis can be reached when the above features are available.

Adenoma, Bile Duct↗
PubMed2000

Unilateral right-sided internal jugular phlebectasia in asthmatic children.

The most common cause of a neck mass that increases in size on straining is laryngocele. Internal jugular phlebectasia, which is of unknown cause, may present similarly. We present three cases of internal jugular phlebectasia, all of whom were asthmatic children. This association of asthma and internal jugular phlebectasia has not been reported previously.

Asthma↗
PubMed2000

Clinics in diagnostic imaging (45). Osmotic myelinolysis ( central potine myelinolysis).

A 65-year-old woman developed progressive neurological deterioration following rapid correction of hyponatremia. Magnetic resonance imaging showed T2 hyperintense areas in the central pons, basal ganglia and deep white matter, typical of osmotic myelinolysis (OM). Previously thought to be uniformly fatal, there are increasing reports of non-fatal cases of OM. The recognition and understanding of this entity is important to prevent or reduce the incidence of its occurrence, as there is no specific treatment once it develops. The clinical and radiological features of OM are reviewed.

Aged↗
PubMed2000

Clinics in diagnostic imaging (51). Multiloculated cerebral abscesses due to paradoxical cardiac emboli.

A 19-year-old woman with congenital cyanotic heart disease (Epstein anomaly and ventricular septal defect) had persistent headaches and intermittent fever for five weeks. Physical examination revealed central cyanosis, finger clubbing and fever. The leucocyte count was elevated. Cerebral MR imaging showed the characteristic features of brain abscesses in the right frontal lobe, including multiloculation with adjacent satellite lesions, ring enhancement, T1-hyperintense and T2-hypointense signal areas within the abscess rim, as well as hypointense internal concentric rings on T2-weighted images. The diagnosis of brain abscesses was confirmed by craniotomy and pus drainage. She made a good recovery with a combination of antibiotics and surgery. Follow-up CT scans showed only changes of encephalomalacia at the healed abscess site. The aetiology, clinical features, and the role of CT and MR imaging in the diagnosis and management of brain abscess are discussed.

Adult↗
PubMed2000

Clinics in diagnostic imaging (47). Huntington's disease.

A 38-year-old man presented with progressive worsening of choreiform movements. Serum biochemistry analysis did not reveal any abnormality. Magnetic resonance imaging demonstrated symmetrical caudate nucleus atrophy and generalised cerebral strophy. Huntington's disease was diagnosed in view of the clinical presentation and the characteristic imaging findings. The clinical, pathological and imaging features of this disease process are discussed.

Adult↗
PubMed1998

Mammogram screening of Chinese women in Kwong Wah Hospital, Hong Kong.

The incidence of primary carcinoma of the breast in Hong Kong has been rising. A screening team including radiologists, breast surgeons, cytopathologists, a full-time gynaecologist and mammographers was set up at Kwong Wah Hospital. The screening method includes a clinical breast examination (CBE) and two-view mammography. The target age group is 40-70. A total of 13,033 women were screened from March 1993 to March 1995 and 8504 mammograms were performed. A double reading system was used, with an experienced mammographer as the first reader. The films were then read by radiologists and were reported. All abnormal films and normal films with palpable masses or clinical symptoms were reviewed in a weekly meeting. A total of 113 biopsies were performed including 86 stereotactic-guided fine needle aspirations (FNA) and 27 stereotactic-guided hook-wire biopsies. Four FNA showed malignant cells and another five showed suspicious cells. Eleven hook-wire biopsies showed carcinoma. The benign to malignant ratio of the hook-wire biopsies was 16:11 (< 1.5). The total number of carcinomas disclosed was 42, and 16 of these were not palpable. Four palpable tumours were not detected by mammography. The overall carcinoma of the breast detection rate was 4.94/1000, with a rate of 4.61/1000 for the 40-49-year age group and a rate of 6.46/1000 for the over 50 years of age group. The incidence of ductal carcinoma in situ plus T1 tumours was 2.82/1000.

Adult↗
PubMed1996

Stereotactic fine needle aspiration in the management of mammographic abnormalities detected in breast screening.

BACKGROUND: Fine needle aspiration (FNA) is used routinely in the management of palpable breast lumps; with the implementation of the stereotactic technique its use has been extended to the investigation of mammographic abnormalities. The advent of breast screening means that many mammographic abnormalities will be detected; because routine open biopsy is impractical and undesirable, stereotactic fine needle aspiration becomes the method of choice for investigation. METHOD: Within a 28 month interval, 81 Chinese women underwent stereotactic FNA in Kwong Wah Hospital, Hong Kong. RESULTS: Fifty-one women (62.9%) had a benign cytology result and no further investigations were required. Inconclusive results were obtained in 18.6% of the aspirates. Open biopsy was required in 16 women (19.8%). CONCLUSION: Stereotactic FNA is very useful in the exclusion of malignancy and the avoidance of open biopsy in asymptomatic women who have mammographic abnormalities.

Adult↗
PubMed1996

Early experience with surgically inaccessible wide-necked intracranial aneurysm embolised with Guglielmi Electrically Detachable coils and electrothrombosis.

We describe our early successful experience with Guglielmi Electrically Detachable Coils (GDC) and electrothrombosis in treating a surgically inaccessible wide-necked intracranial aneurysm in a Chinese patient. The precautions taken to prevent unnecessary complications while performing this technique was also described. It provides a serious alternative to other less ideal types of embolising agents and direct surgery in treating patients with these difficult-to-treat aneurysms.

Cerebral Angiography↗