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Biomedical subjects

A Wilder-Smith

Publications and source records attributed to A Wilder-Smith.

14 recordsLinked to original sources
PubMed2005

High prevalence of vasomotor reflex impairment in newly diagnosed leprosy patients.

BACKGROUND: Initial nerve damage in leprosy occurs in small myelinated and unmyelinated nerve fibers. Early detection of leprosy in the peripheral nervous system is challenging as extensive nerve damage may take place before clinical signs of leprosy become apparent. PATIENTS AND METHODS: In order to determine the prevalence of, and factors associated with, peripheral autonomic nerve dysfunction in newly diagnosed leprosy patients, 76 Brazilian patients were evaluated prior to treatment. Skin vasomotor reflex was tested by means of laser Doppler velocimetry. Blood perfusion and reflex vasoconstriction following an inspiratory gasp were registered on the second and fifth fingers. RESULTS: Vasomotor reflex was impaired in at least one finger in 33/76 (43%) patients. The fifth fingers were more frequently impaired and suffered more frequent bilateral alterations than the second fingers. Multivariate regression analysis showed that leprosy reaction (adjusted odds ratio = 8.11, 95% confidence interval: 1.4-48.2) was associated with overall impaired vasomotor reflex (average of the four fingers). In addition, palmar erythrocyanosis and an abnormal upper limb sensory score were associated with vasomotor reflex impairment in the second fingers, whereas anti-phenolic glycolipid-I antibodies, ulnar somatic neuropathy and a low finger skin temperature were associated with impairment in the fifth fingers. CONCLUSIONS: A high prevalence of peripheral autonomic dysfunction as measured by laser Doppler velocimetry was observed in newly diagnosed leprosy patients, which is clinically evident late in the disease. Autonomic nerve lesion was more frequent than somatic lesions and was strongly related to the immune-inflammatory reaction against M. leprae.

Adolescent↗
PubMed2005

Infectious respiratory illnesses and their impact on healthcare workers: a review.

Respiratory illnesses are increasingly recognised as a growing concern for healthcare workers (HCWs) and patients. The recent hospital-based outbreak of Severe Acute Respiratory Syndrome (SARS) has once again highlighted the vulnerability of HCWs. The new epidemic of the 21st century resulted in tremendous economic and psychological impact with its high rates of mortality and nosocomial transmission. Even as the epidemic was brought under control within months, many details about the SARS coronavirus remained a mystery. The threat of another potential global outbreak continues to lurk in the background. Many valuable lessons have been learned through the SARS epidemic. It is, therefore, timely for us to review some of the respiratory pathogens that are well-known to cause nosocomial outbreaks. We need to be better armed to deal with future potential outbreaks and biohazardous situations. The importance of safeguarding the health of our medical staff and the community cannot be over-emphasised. In this paper, we review the incidence, transmission and various preventive strategies of respiratory illnesses in HCWs, in particular, new diagnostic tools, infection control management strategies, personal protective equipments, vaccination programmes and post-exposure prophylaxis.

Cross Infection↗
PubMed2005

Tsunami in South Asia: what is the risk of post-disaster infectious disease outbreaks?

The World Health Organization has warned that in the aftermath of the recent tsunami, infectious disease outbreaks will add to the heavy toll of the disaster itself, possibly even doubling the number of casualties. However, many experts believe the risks of infectious disease outbreaks following natural disasters have been overemphasised and have led to unnecessary and potentially harmful public health activities. This paper discusses the risk and prevention strategies of potential infectious diseases in the aftermath of the tsunami based on a literature review of previous similar disasters and current evidence. Infectious disease outbreaks, if any, will most likely be the consequence of post-tsunami camp situations involving large displaced populations rather than the tidal wave itself. Lessons have been learned from previous large-scale humanitarian crises about the provision of aid and the mitigation of epidemics. This paper examines the risk and preventive strategies of vector- and food/water-borne diseases, measles, acute respiratory infections and meningitis. Alert thresholds at which to trigger outbreak investigations, and standardised guidelines with regard to their control are outlined, based on the Sphere Project.

Communicable Diseases↗
PubMed2002

Adult community acquired bacterial meningitis in a Singaporean teaching hospital. A seven-year overview (1993-2000).

BACKGROUND: The objective of this study is to describe the bacteriological, clinical and laboratory features of community acquired bacterial meningitis in adults admitted to a Singapore tertiary-care hospital. METHODS: Two hundred sixty-nine cases of meningitis or meningoencephalitis admitted between 1993 and 2000 were identified by their discharge diagnosis codes. All case records except for 57 which could not be retrieved were retrospectively reviewed. Patients less than 14 years or with skull fractures, post-neurosurgery or with indwelling intracranial devices were excluded. Inclusion criteria was a clinical picture compatible with a diagnosis of bacterial meningitis with either (1) positive cerebral-spinal fluid (CSF) cultures or latex coagglutination or CSF neutrophilic pleocytosis accompanied by positive blood cultures or (2) in the absence of positive blood cultures, CSF cultures and latex agglutination, presence of CSF pleocytosis of at least 100 neutrophils per microL. RESULTS: Fifteen "culture-positive" and 11 "culture negative" cases were identified. Six (55%) of the "culture-negative" cases received antibiotics prior to admission. Cultures grew Streptococcus pneumoniae in four cases, three cases each of Group B streptococci and Neisseria meningitides. Listeria monocytogenes and Klebsiella pneumoniae were each seen twice and Streptococcus suis once. All cases of Group B streptococci occurred in the year 1998. Mortality was 19% (n = 5), six developed infections in other sites, three epileptic seizures, three developed hydrocephalus, and two hearing loss. CONCLUSIONS: Pathogens are similar to those reported in other studies but for an outbreak of Group B Streptococcus in 1998. There were a high number of "culture-negative" cases which may be due to preceding antibiotic intervention.

Adolescent↗
PubMed2000

Comparison of immunogenicity and safety of a virosome influenza vaccine with those of a subunit influenza vaccine in pediatric patients with cystic fibrosis.

The objective of this study was to compare the immunogenicity and safety of a single-dose regimen and a two-dose regimen of a trivalent virosome influenza vaccine (Inflexal Berna V) with those of a trivalent subunit influenza vaccine (Influvac) in children and adolescents with cystic fibrosis (CF). In an open, randomized, multicenter study with parallel groups, 11 young children with CF (1 to 6 years old) and 53 older children and adolescents with CF (>6 years old) were randomly assigned to one of the following immunization regimens: virosome vaccine at 0.5 ml on study day 0 or 0.25 ml on days 0 and 28 or a standard regimen of subunit vaccine, i. e., 0.5 ml on day 0 for older children and 0.25 ml on days 0 and 28 for younger children. Safety assessments, i.e., recording of systemic and local adverse events (AEs) and vital signs, were made for a 5-day observation period after each immunization. Hemagglutination inhibition (HI) titers were determined at baseline and 4 weeks after the single-dose and the two-dose immunizations, respectively. Immunogenicity was assessed according to the criteria of the European Agency for the Evaluation of Medicinal Products (EMEA). Both vaccines induced comparable HI antibody titers. Seroconversion (> or =4-fold rise in HI antibody titers, reaching a titer of > or =1:40) was achieved in 41 to 100% of the participants. Seroprotection (HI titer, > or =1:40) and a >2.5-fold increase in geometric mean titers were achieved in 100% of the participants. Thus, all three EMEA requirements for influenza vaccine efficacy were met by all treatment groups and for both vaccines. The virosome vaccine, when administered as a single dose, seemed to induce superior immunogenicity compared with the standard pediatric two-dose regimen. Totals of 42 and 57% of vaccinees receiving virosome and subunit vaccines, respectively, reported at least one local AE (predominantly pain). Totals of 84 and 71% of subjects receiving virosome and subunit vaccines, respectively, complained in response to questions of at least one systemic AE (mainly cough, fatigue, coryza, or headache). The majority of events were mild or moderate and lasted 1 or 2 days only. No obvious relationship was found between AE reporting rate and vaccine formulation, age group, or dose regimen. The relatively high AE reporting rate seemed to be partly related to the symptomatology of the underlying CF disease. In summary, the virosome and subunit vaccines induced in both age groups and against all three influenza strains an efficient immune response and were well tolerated by the children and adolescents with CF.

Adolescent↗
PubMed1997

Peripheral autonomic nerve dysfunction in asymptomatic leprosy contacts.

In endemic areas, subclinical autonomic nerve dysfunction may be a manifestation of infection with M. leprae and possibly allow detection before progression to clinical disease. Vasomotor reflex (VMR) testing was performed in 36 asymptomatic leprosy contacts (24 household contacts, 12 hospital contacts) and 47 age- and sex-matched controls in Pokhara, Nepal. Mean age was 30 years, two thirds were male. A Moor instruments DRT4 laser doppler monitor was used for velocimetry of microvascular blood flow. The flow reduction following an inspiratory gasp was recorded from finger and toe tips. Mean percent reduction was 57.8 (standard deviation 14.6) among household contacts, 61.9 (17.5) among hospital contacts and 66.8 (7.8) among controls (p=0.001 by analysis of variance). The prevalence of abnormal test results was 54% among household contacts, 42% among hospital contacts and 15% among controls (p=0.0005 by chi-square test for trend). Subclinical autonomic neuropathy is common among healthy contacts of leprosy patients. Prospective studies are now needed to clarify to what extent abnormal VMR tests predict the risk of progression to clinical disease.

Adult↗
PubMed1997

Effect of steroid therapy on parameters of peripheral autonomic dysfunction in leprosy patients with acute neuritis.

Recent electrophysiological studies on peripheral autonomic dysfunction in leprosy patients show a high prevalence of autonomic dysfunction as measured by abnormal vasomotor reflexes (VMR) and absent sympathetic skin response (SSR). Nothing is known about the reversibility of these autonomic parameters with treatment. Since there is evidence that small fiber function may be the most reversible component in neuropathies, we measured the effect of steroid treatment on autonomic parameters together with motor and sensory functions in leprosy patients with acute neuritis. Control subjects were investigated for repeatability testing of autonomic function. Due to a relatively high variability on repeat VMR testing in the controls, we defined a change in VMR testing as a change of > 30%. With this definition, the VMR of 14.8% of the patients improved, 75% remained unchanged, and 10.2% worsened. Absent SSR became positive in 16.6% and remained unchanged in 83.4%. Improvement in sensory motor functions was seen in 21.2% and 1.3% of the patients, respectively.

Acute Disease↗
PubMed1996

Vasomotor reflex testing in leprosy patients, healthy contacts and controls: a cross-sectional study in western Nepal.

OBJECTIVE: To examine test characteristics of laser Doppler vasomotor reflex testing for leprosy and to determine the prevalence of abnormal responses in leprosy patients, healthy contacts and controls. DESIGN AND PARTICIPANTS: Cross-sectional study including 89 leprosy patients (mean age 35 years, 74% male), 36 healthy contacts (29 years, 64% male) and 47 controls (30 years, 68% male), for a total of 172 participants. SETTING: Leprosy hospital in an endemic region 200 km west of Kathmandu, Nepal. OUTCOME MEASURE: Finger-tip and toe-tip vasomotor reflexes elicited by inspiratory gasp were measured using a laser-doppler flow temperature technique. Results were expressed in per cent as the maximal reduction in bloodflow from baseline. RESULTS: For all 12 measurement sites there were highly significant (p > 0.0001 to < 0.004) differences between the three groups tested. Leprosy patients consistently had the lowest responses and controls the highest, with healthy contacts showing intermediate values. Thresholds defined as mean bloodflow reductions among controls minus 1.64 or minus 1.96 standard deviations provided optimal combinations of sensitivity and specificity. Using these cut-off values around 80% of leprosy patients, 50% of healthy contacts and 20% of controls had two or more abnormal reflexes (p < 0.0001 for differences between groups). CONCLUSIONS: In endemic regions, subclinical autonomic neuropathy may be an early but detectable marker for the risk of subsequent leprosy, making early treatment and prevention of transmission possible. Prospective studies are needed to establish the predictive value of abnormal vasomotor reflexes.

Adult↗
PubMed1996

Electrophysiological evaluation of peripheral autonomic function in leprosy patients, leprosy contacts and controls.

Since there is immunocytochemical evidence that the initial damage in leprosy is directed at distal, small, unmyelinated nerve fibers, we investigated several electrophysiological methods for their potential value in detecting peripheral autonomic dysfunction in leprosy contacts and leprosy patients. Fingertip blood flow velocity and its control by vasomotor reflexes (VMR) with a laser Doppler flowmeter, fingertip skin temperature, and the sympathetic skin response (SSR) to exosomatic stimuli were studied in 89 leprosy patients, 36 leprosy contacts and 47 normal subjects. Whereas there were no significant differences between the groups in fingertip skin temperature and resting blood flow velocity measurements, there were significant differences in the prevalence of impaired fingertip VMR and absent SSR. The prevalence of absent SSR in leprosy patients was 60.9%, in contacts 13.8%, in controls 6.3%. The prevalence of abnormal VMR in leprosy patients was 61.2%, in contacts 34.7% and in controls 10.6%. VMR testing is a more sensitive test method for autonomic dysfunction compared with the SSR. The implication of impairment in vasomotor and sudomotor function in leprosy contacts needs yet to be determined. However, we propose this to be a response to exposure to Mycobacterium leprae, which represents either ongoing nerve damage or nonprogressive residual autonomic nerve damage. We suggest that VMR testing and SSR are valuable methods to evaluate early leprous neuropathy.

Adolescent↗
PubMed1995

[Complex partial seizures as cause of transient cardiac arrhythmia].

The frequency and type of seizure-induced cardiac arrhythmias is presented in light of 36 partial-complex seizures recorded with simultaneous EEG/ECG. An average increase in heart rate of 35% (sinus tachycardia) was observed in 60% of patients (22/36). Bradycardia was demonstrated in 17% (6/36) due to AV-block in 3 cases, once due to sinus bradycardia and once due to bradycardia in the presence of atrial fibrillation. In one patient with a pacemaker spontaneous heart rhythm ceased. The average slowing of heart rate was 29% with a maximum of 62.5%. In the remaining 23% of patients (8/36), no change in heart rate was observed. These results, in conjunction with those of the literature, indicate that a primary epileptic origin needs to be included in the differential diagnosis of cardiac arrhythmias.

Adolescent↗