Biomedical subjects

V C C Cheng

Publications and source records attributed to V C C Cheng.

29 records · Page 2Linked to original sources

PubMed2004

Detection of SARS coronavirus in patients with suspected SARS.

Cases of severe acute respiratory syndrome (SARS) were investigated for SARS coronavirus (SARS-CoV) through RNA tests, serologic response, and viral culture. Of 537 specimens from patients in whom SARS was clinically diagnosed, 332 (60%) had SARS-CoV RNA in one or more clinical specimens, compared with 1 (0.3%) of 332 samples from controls. Of 417 patients with clinical SARS from whom paired serum samples were available, 92% had an antibody response. Rates of viral RNA positivity increased progressively and peaked at day 11 after onset of illness. Although viral RNA remained detectable in respiratory secretions and stool and urine specimens for >30 days in some patients, virus could not be cultured after week 3 of illness. Nasopharyngeal aspirates, throat swabs, or sputum samples were the most useful clinical specimens in the first 5 days of illness, but later in the illness viral RNA could be detected more readily in stool specimens.

Antibodies, Viral↗

PubMed2004

Viral loads in clinical specimens and SARS manifestations.

A retrospective viral load study was performed on clinical specimens from 154 patients with laboratory-confirmed severe acute respiratory syndrome (SARS); the specimens were prospectively collected during patients' illness. Viral load in nasopharyngeal aspirates (n = 142) from day 10 to day 15 after onset of symptoms was associated with oxygen desaturation, mechanical ventilation, diarrhea, hepatic dysfunction, and death. Serum viral load (n = 53) was associated with oxygen desaturation, mechanical ventilation, and death. Stool viral load (n = 94) was associated with diarrhea, and urine viral load (n = 111) was associated with abnormal urinalysis results. Viral replications at different sites are important in the pathogenesis of clinical and laboratory abnormalities of SARS.

Adult↗

PubMed2003

Risk factors for development of paradoxical response during antituberculosis therapy in HIV-negative patients.

The risk factors for development of paradoxical response were studied in a cohort of 104 patients with culture-documented Mycobacterium tuberculosis infection. Paradoxical deterioration occurred in 16 (15.4%) patients (case group) during antituberculosis therapy, involving lungs and pleura (n=4), spine and paraspinal tissue (n=5), intracranium (n=3), peritoneum (n=2), bone and joint (n=1), and lymph node (n=1). The median time from commencement of treatment to paradoxical deterioration was 56 days (range, 20-109 days). Compared with 53 patients without clinical deterioration after antituberculosis therapy (control group), patients with paradoxical response were more likely to have extrapulmonary involvement (62.5% vs. 17.0%; P<0.05) at initial diagnosis, to have lower baseline lymphocyte counts (672+/-315 cells/microl vs. 1,328+/-467 cells/microl; P<0.001), and to exhibit a greater surge in lymphocyte counts (627+/-465 cells/microl vs. 225+/-216 cells/microl; P<0.05) during paradoxical response. Further studies on lymphocyte subsets and cytokine levels would be useful in understanding the exact immunological mechanisms involved in immunorestitution.

Adult↗

PubMed2003

Clinical progression and viral load in a community outbreak of coronavirus-associated SARS pneumonia: a prospective study.

BACKGROUND: We investigated the temporal progression of the clinical, radiological, and virological changes in a community outbreak of severe acute respiratory syndrome (SARS). METHODS: We followed up 75 patients for 3 weeks managed with a standard treatment protocol of ribavirin and corticosteroids, and assessed the pattern of clinical disease, viral load, risk factors for poor clinical outcome, and the usefulness of virological diagnostic methods. FINDINGS: Fever and pneumonia initially improved but 64 (85%) patients developed recurrent fever after a mean of 8.9 (SD 3.1) days, 55 (73%) had watery diarrhoea after 7.5 (2.3) days, 60 (80%) had radiological worsening after 7.4 (2.2) days, and respiratory symptoms worsened in 34 (45%) after 8.6 (3.0) days. In 34 (45%) patients, improvement of initial pulmonary lesions was associated with appearance of new radiological lesions at other sites. Nine (12%) patients developed spontaneous pneumomediastinum and 15 (20%) developed acute respiratory distress syndrome (ARDS) in week 3. Quantitative reverse-transcriptase (RT) PCR of nasopharyngeal aspirates in 14 patients (four with ARDS) showed peak viral load at day 10, and at day 15 a load lower than at admission. Age and chronic hepatitis B virus infection treated with lamivudine were independent significant risk factors for progression to ARDS (p=0.001). SARS-associated coronavirus in faeces was seen on RT-PCR in 65 (97%) of 67 patients at day 14. The mean time to seroconversion was 20 days. INTERPRETATION: The consistent clinical progression, shifting radiological infiltrates, and an inverted V viral-load profile suggest that worsening in week 2 is unrelated to uncontrolled viral replication but may be related to immunopathological damage.

Administration, Oral↗

PubMed2003

Peripartum tuberculosis as a form of immunorestitution disease.

The aim of this study was to assess the clinical spectrum of peripartum tuberculosis from the perspective of immunorestitution disease. Of 29 patients with peripartum tuberculosis, 27 (93.1%) had extrapulmonary tuberculosis, 20 (69%) of whom were affected in the central nervous system. Twenty-two (75.9%) patients had no clinical features suggestive of tuberculosis during pregnancy. The median time from delivery to the onset of immunorestitution was 4 days, but treatment with anti-tuberculous therapy was delayed for a median time of 27 days after the onset of symptoms. Despite therapy, 11 (38%) patients died and 4 (13.8%) had residual functional deficits. Peripartum tuberculosis is an important differential diagnosis of postpartum fever (of unknown origin) without localized signs.

Adult↗

PubMed2003

Coronavirus as a possible cause of severe acute respiratory syndrome.

BACKGROUND: An outbreak of severe acute respiratory syndrome (SARS) has been reported in Hong Kong. We investigated the viral cause and clinical presentation among 50 patients. METHODS: We analysed case notes and microbiological findings for 50 patients with SARS, representing more than five separate epidemiologically linked transmission clusters. We defined the clinical presentation and risk factors associated with severe disease and investigated the causal agents by chest radiography and laboratory testing of nasopharyngeal aspirates and sera samples. We compared the laboratory findings with those submitted for microbiological investigation of other diseases from patients whose identity was masked. FINDINGS: Patients' age ranged from 23 to 74 years. Fever, chills, myalgia, and cough were the most frequent complaints. When compared with chest radiographic changes, respiratory symptoms and auscultatory findings were disproportionally mild. Patients who were household contacts of other infected people and had older age, lymphopenia, and liver dysfunction were associated with severe disease. A virus belonging to the family Coronaviridae was isolated from two patients. By use of serological and reverse-transcriptase PCR specific for this virus, 45 of 50 patients with SARS, but no controls, had evidence of infection with this virus. INTERPRETATION: A coronavirus was isolated from patients with SARS that might be the primary agent associated with this disease. Serological and molecular tests specific for the virus permitted a definitive laboratory diagnosis to be made and allowed further investigation to define whether other cofactors play a part in disease progression.

Adult↗

PubMed2003

Nontuberculous mycobacterial infections in Chinese hematopoietic stem cell transplantation recipients.

Between 1995 and 2002, nine cases of nontuberculous mycobacterium (NTM) were isolated from 462 allogeneic stem cell transplant (SCT) recipients (1.9%), and none from 139 autologous cases. They included three cases each of Mycobacterium fortuitum and M. chelonae, and single cases of M. scrofalaceum, M. gordonnae and M. avium complex. Seven cases were respiratory, including five cases requiring treatment, and two involved infected catheters and vascular conduits. Compared with nine cases of mycobacterium tuberculosis (MTB) isolated in the same period, NTM isolation occurred later after HSCT and involved more unrelated donors. Important risk factors for NTM infection included significant aGVHD (P=0.043), leukemia relapse (P=0.022), MUD and mismatch SCT (P<0.001) and existence of BO (P<0.001). Coinfection with aspergillus was common. Invasive NTM disease required prolonged antimicrobial treatment in five cases due to M. fortuitum and M. chelonae. With better MTB prophylaxis, intensive immunosuppression and better awareness, NTM has become an emerging threat in oriental allogeneic HSCT recipients. The cutoff between colonization and infection, and the threshold for starting treatment is unclear. NTM isolation is a marker for severe immunosuppression and poor prognosis. When there is doubt over species identity or extent of infection, broad-spectrum cover may be prudent.

Adult↗

PubMed2003

Disseminated zoster, hyponatraemia, severe abdominal pain and leukaemia relapse: recognition of a new clinical quartet after bone marrow transplantation.

Reactivation of varicella-zoster virus (VZV) is one of the commonest complications after stem cell transplantation, and often presents with atypical manifestations. We describe two unusual cases of occult disseminated zoster in allogeneic stem cell transplant recipients, presenting as severe abdominal pain and syndrome of inappropriate antidiuretic hormone secretion/hyponatraemia, and accompanied by leukaemia relapse. There was complete clinical recovery with high-dose aciclovir and intravenous immunoglobulin. Prompt treatment of leukaemia relapse also resulted in complete remission. A possible immunological link between concurrent breakdown of immune control of VZV and leukaemia is discussed.

Abdominal Pain↗

PubMed2002

Clinical spectrum of paradoxical deterioration during antituberculosis therapy in non-HIV-infected patients.

Paradoxical deterioration during antituberculosis therapy, defined as the clinical or radiological worsening of pre-existing tuberculous lesions or the development of new lesions in a patient who initially improves, remains a diagnostic dilemma. Although different clinical presentations of paradoxical response have been described, a systematic analysis of the entity in non-HIV-infected patients is lacking. Reported here are two cases of paradoxical deterioration in which sequential changes in lymphocyte counts and tuberculin skin test results are emphasized. In addition, 120 episodes of paradoxical response after antituberculosis treatment were reviewed. Of the total 122 episodes, 101 (82.8%) were associated with extrapulmonary tuberculosis. The median time from commencement of treatment to paradoxical deterioration was 60 days. The median time to onset of central nervous system manifestations (63 days) was longer than the time to onset of manifestations at other sites (56 days) ( P=0.02). Development of new lesions in anatomical sites other than those observed at initial presentation was observed in 31 (25.4%) episodes. A surge in the lymphocyte count, accompanied by an exaggerated tuberculin skin reaction, was observed in our patients during the paradoxical deterioration, analogous to the findings in HIV-positive patients. Treatment of the paradoxical response included surgical intervention (60.7%) and administration of steroids (39.3%). The use of steroids appeared to be safe in this series, as 95% of the Mycobacterium tuberculosis isolates were susceptible to first-line antituberculosis therapy.

Abscess↗

PubMed2002

Clinicopathological features and risk factors of clinically overt haemorrhagic cystitis complicating bone marrow transplantation.

Haemorrhagic cystitis (HC) is an important complication after bone marrow transplantation (BMT). Overt HC (grade > or =2, gross haematuria, clot retention and impairment of renal function), clinically more important than mild and occult HC (grade 1, microscopic haematuria), leads to substantial morbidity and occasional mortality. We retrospectively analyzed 32 cases of clinically overt HC from a series of 236 BMT patients. Significant risk factors included the use of busulphan during conditioning, allogeneic BMT and acute GVHD. Logistic regression showed GVHD to be the most important risk factor. According to the time of engraftment, HC could be divided into pre- and post-engraftment subtypes. Pre-engraftment HC was brief, not more severe than grade 2, and subsided with supportive treatment. In contrast, post-engraftment HC was protracted, often of grade > or =3, associated with severe GVHD, and required surgical intervention in many cases. Polyoma BK viruria, but not adenoviruria, could be demonstrated in both types of HC. The increased severity and association with GVHD of post-engraftment HC suggested that attack of urothelium by immunocompetent cells, possibly directed against BK viral antigens, might play a pathogenetic role.

Adenoviridae↗

PubMed2002

Candida tropicalis fungaemia in adult patients with haematological malignancies: clinical features and risk factors.

Candida tropicalis fungaemia is a serious opportunistic infection. Eighteen consecutive patients with C. tropicalis fungaemia diagnosed within a five-year period were studied retrospectively. All patients had haematological malignancies treated by chemotherapy or bone marrow transplantation (BMT). Antifungal prophylaxis included nystatin (20 mg daily) for patients receiving chemotherapy, and fluconazole (200 mg daily) for patients undergoing BMT. Sixteen patients had refractory and advanced haematological malignancies. All patients were neutropenic, had central venous catheters, and were receiving treatment with broad-spectrum antibiotics at the time of fungaemia. Septic shock with skin emboli were the most common presenting features. In seven cases, fungaemia was preceded by a positive culture of C. tropicalis in the urine. Concomitant bacteraemia was found in 11 cases, of which six cases were due to Staphylococcus aureus. The overall mortality rate was 56%. The predominance of chemotherapy-treated patients developing fungaemia in this series might be attributable to the omission of fluconazole prophylaxis. The clinicopathologic features and risk factors identified in this study may help design better treatment strategies for this often-lethal complication.

Adolescent↗