Chaturaka Rodrigo

Primaquine in vivax malaria: an update and review on management issues

Primaquine was officially licensed as an anti-malarial drug by the FDA in 1952. It has remained the only FDA licensed drug capable of clearing the intra-hepatic schizonts and hypnozoites of Plasmodium vivax. This update and review focuses on five major aspects of primaquine use in treatment of vivax malaria, namely: a) evidence of efficacy of primaquine for its current indications; b) potential hazards of its widespread use, c) critical analysis of reported resistance against primaquine containing regimens; d) evidence for combining primaquine with artemisinins in areas of chloroquine resistance; and e) the potential for replacement of primaquine with newer drugs.

Learning styles and approaches to learning among medical undergraduates and postgraduates

BackgroundThe challenge of imparting a large amount of knowledge within a limited time period in a way it is retained, remembered and effectively interpreted by a student is considerable. This has resulted in crucial changes in the field of medical education, with a shift from didactic teacher centered and subject based teaching to the use of interactive, problem based, student centered learning. This study tested the hypothesis that learning styles (visual, auditory, read/write and kinesthetic) and approaches to learning (deep, strategic and superficial) differ among first and final year undergraduate medical students, and postgraduates medical trainees.MethodsWe used self administered VARK and ASSIST questionnaires to assess the differences in learning styles and approaches to learning among medical undergraduates of the University of Colombo and postgraduate trainees of the Postgraduate Institute of Medicine, Colombo.ResultsA total of 147 participated: 73 (49.7%) first year students, 40 (27.2%) final year students and 34(23.1%) postgraduate students. The majority (69.9%) of first year students had multimodal learning styles. Among final year students, the majority (67.5%) had multimodal learning styles, and among postgraduates, the majority were unimodal (52.9%) learners.Among all three groups, the predominant approach to learning was strategic. Postgraduates had significant higher mean scores for deep and strategic approaches than first years or final years (p < 0.05). Mean scores for the superficial approach did not differ significantly between groups.ConclusionsThe learning approaches suggest a positive shift towards deep and strategic learning in postgraduate students. However a similar difference was not observed in undergraduate students from first year to final year, suggesting that their curriculum may not have influenced learning methodology over a five year period.

Scrub typhus: pathophysiology, clinical manifestations and prognosis

Scrub typhus is a zoonosis caused by the pathogen Orientia tsutsugamushi (O. tsutsugamushi). The disease has significant prevalence in eastern and Southeast Asia. Usually presenting as an acute febrile illness, the diagnosis is often missed because of similarities with other tropical febrile infections. Many unusual manifestations are present, and these are described in this review, together with an outline of current knowledge of pathophysiology. Awareness of these unusual clinical manifestations will help the clinician to arrive at an early diagnosis, resulting in early administration of appropriate antibiotics. Prognostic indicators for severe disease have not yet been clearly established.

Leukotriene receptor antagonists for chronic urticaria: a systematic review

A significant proportion of patients with chronic urticaria respond inadequately to first line treatment with antihistamines. Leukotreine receptor antagonists (LTRA) are also used for chronic urticaria, although firm recommendations on their use are lacking. We performed a systematic review of randomised trials to determine the role of LTRA in treatment of chronic urticaria. A search of PUBMED, EMBASE, SCOPUS, LILACS, the Cochrane Central Register of Controlled Trials, and the Web of Science for relevant randomized control trials or cross over studies yielded 10 eligible studies. The heterogeneity of trials were high, preventing valid meta-analysis of data. Most trials indicated that LTRA are not superior to placebo or antihistamine therapy, while combination therapy of LTRA and antihistamines appear to be more efficacious compared to antihistamine alone. The side effect profile and tolerability of this group of drugs is acceptable. The use of LTRA as monotherapy cannot be recommended. LTRA are effective add-on therapy to anti-histamines, and their use in patients responding poorly to antihistamines is justifiable. Further well designed randomized controlled trials with clear and standardized outcome measures are needed to determine the role of LTRA in chronic urticaria.

Current status of HIV/AIDS in South Asia

Background: According to the United Nations Joint Program on HIV/AIDS, 33.2 million adults and children are living with the infection worldwide. Of these, two to three million are estimated to be in South Asia. All countries of the region have a low prevalence of human immunodeficiency virus (HIV). However, it is important to review the current epidemiological data to identify the trends of infection as it would have implications on prevention. Materials and Methods: We performed a MEDLINE search using phrases ‘South Asia’ plus ‘HIV’, ‘AIDS’, and names of individual countries in South Asia (limits: articles published in last 10 years, in English language). Clinical trials, reviews, meta-analyses, letters, editorials, and practice guidelines were all considered. The following countries were included as belonging to South Asia; Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan and Sri Lanka. Recent estimates and data on country status, and details of national control programs were obtained from websites of international agencies such as the World Bank and United Nations Joint Program on HIV/AIDS (UNAIDS). Results and Discussion: This review looks into many aspects of HIV infection in South Asia including country profiles with regard to infection, economic and psychological burden of illness and treatment issues in the South Asian context.

Drug treatment of scrub typhus

Scrub typhus is a vector-borne disease caused by the pathogen Orientia tsutsugamushi. We review the published literature for evidence on drug treatment in scrub typhus. Doxycycline has a proven efficacy in several trials and a meta-analysis, although resistance has been documented in parts of northern Thailand. Macrolides are equally efficacious and have less adverse effects, but they are expensive. Azithromycin is the recommended drug in pregnancy and for children. Rifampicin is effective in areas where doxycycline resistance is present. Quinolones have shown some degree of efficacy but the evidence is scant. Most clinical evidence on drug treatment is from cases of mild-to-moderate scrub typhus. Further study is needed on the efficacy of different antibiotics in the treatment of severe, life-threatening scrub typhus.

Antibiotics for human toxoplasmosis: a systematic review of randomized trials

Abstract The efficacy of different treatment regimens in clinical syndromes of toxoplasmosis were assessed by conducting a systematic review of published randomized clinical trials through extensive searches in MEDLINE, EMBASE, and SCOPUS with no date limits, as well as manual review of journals. Outcome measures varied depending on the clinical entity of toxoplasmosis. Risk of bias was evaluated and quality of evidence was graded. Fourteen randomized trials were included of which one was a non-comparative study. One well-designed trial showed that trimethoprim-sulphamethoxazole was more effective than placebo for clinical recovery of toxoplasmic lymphadenopathy in immunocompetent hosts. For toxoplasmic encephalopathy, efficacy of pyrimethamine+sulphadiazine and trimethoprim+sulphamethoxazole were similar, whereas pyrimethamine+sulphadiazine versus pyrimathamine+clindamycin showed no difference, irrespective of the outcome. Intravitreal clindamycin+dexamethasone and conventional treatment with oral pyrimethamine+sulphadiazine had similar efficacy with regard to all outcome measures in ocular toxoplasmosis, and intravitreal therapy was found to be safe. Adverse effects seemed more common with pyrimethamine+sulphadiazine. Most trials for encephalitis and ocular manifestations had a high risk of bias and were of poor methodological quality. There were no trials evaluating drugs for toxoplasmosis in pregnancy, or for congenital toxoplasmosis. Pyrimethamine+sulphadiazine is an effective therapy for treatment of toxoplasmic encephalitis; trimethoprim+sulphamethoxazole and pyrimethamine+clindamycin are possible alternatives. Treatment with either oral or intravitreal antibiotics seems reasonable for ocular toxoplasmosis. Overall, trial evidence for the efficacy of these drugs for toxoplasmosis is poor, and further well-designed trials are needed.

Pharmacological management of tetanus: an evidence-based review

Tetanus is becoming rarer in both industrialized and developing nations due to an effective vaccination program. In 2010, the World Health Organization estimated there was a 93% reduction in newborns dying from tetanus worldwide, compared to the situation in the late 1980s. Due to its rarity, many diagnostic delays occur as physicians may not consider the diagnosis until the manifestations become overt. Without timely diagnosis and proper treatment, severe tetanus is fatal (mortality is also influenced by the comorbidities of the patient). The principles of treating tetanus are: reducing muscle spasms, rigidity and autonomic instability (with ventilatory support when necessary); neutralization of tetanus toxin with human antitetanus immunoglobulin or equine antitetanus sera; wound debridement; and administration of antibiotics to eradicate locally proliferating bacteria at the wound site. It is difficult to conduct trials on different treatment modalities in tetanus due to both logistical and ethical reasons. However, it is imperative that physicians are aware of the best evidence-based treatment strategies currently available to improve the outcome of patients. This review concentrates on analyzing the current evidence on the pharmacological management of tetanus.

A meta-analysis of magnesium for tetanus.

Uncontrolled studies suggest that magnesium sulphate controls spasms in patients with established tetanus. We performed a meta‐analysis of controlled trials that compared magnesium sulphate with placebo or diazepam for the treatment of patients with tetanus. We searched PubMed, Scopus, Embase and the Cochrane clinical trials registry. Three studies met the inclusion criteria, containing 275 participants (199 male patients, 72.4%). Magnesium sulphate did not reduce mortality, relative risk (95% CI): vs placebo, 0.80 (0.41–1.58); vs diazepam, 1.11 (0.70–1.75). The data on duration of total intensive care unit stay, total hospital stay and the need for ventilatory support were conflicting and pooling of results could not be done due to methodological differences of individual trials. More controlled trials are needed to assess the effect of magnesium sulphate on reducing autonomic instability, spasms, duration of intensive care and hospital stays and the need for mechanical ventilation.

Developing a clinically relevant classification to predict mortality in severe leptospirosis

Background: Severe leptospirosis requires critical care and has a high mortality. We reviewed the literature to identify factors predicting mortality, and such predictors were classified according to the predisposition, infection, response, organ dysfunction (PIRO) concept, which is a risk stratification model used in severe sepsis. Material and Methods: PUBMED was searched for all articles (English), with the key word leptospirosis in any field, within the last 20 years. Data were collected from 45 relevant papers and grouped into each component of the PIRO model. Results: The following correlated with increased mortality: predisposition – increasing age and chronic alcoholism; infection - leptospiraemic burden; response - hemodynamic disturbances, leukocytosis; organ dysfunction – multiple organ dysfunction syndrome, pulmonary involvement and acute renal failure. Conclusions: Further research is needed to identify the role of infecting serovars, clinical signs, inflammatory markers, cytokines and evidence of hepatic dysfunction as prognostic indicators. It is hoped that this paper will be an initiative to create a staging system for severity of leptospirosis based on the PIRO model with an added component for treatment-related predictors.