Should all patients with unexplained anaemia be screened for chronic lead poisoning?

The global prevalence of lead poisoning is declining. However, the prevalence of lead poisoning in patients with either microcytic or normocytic anaemia is unknown. Blood samples from anaemic patients residing in south-east London without an obvious cause for anaemia had their blood lead concentration (BLC) analysed.A batch of 988 samples was analysed for BLC using atomic absorption spectroscopy. Median haemoglobin was 10.3 g/dL (range: 4.2–10.9) in females, 10.6 g/dL (range: 5.2–11.4) in males and 10.7 g/dL (range: 6.7–10.9) in children. Median BLC was 2.63 μg/dL (0.21–24.0 μg/dL; 95th centile 7.54 μg/dL). Fifteen samples (1.5%) had a BLC>10.0 μg/dL, five samples (1%)>15.0 μg/dL and one sample (0.1%)>20.0 μg/L. In the 106 children, median BLC was 2.34 μg/dL (0.5–14.5 μg/dL; 95th centile 6.12 μg/ dL). Only one child (14.5 μg/L) had a BLC>10.0 μg/dL. There was a poor correlation between haemoglobin and BLC (r2=0.08).Routine screening for lead poisoning cannot be justified in all patients with unexplained anaemia, unless there is a history or clinical features to suggest lead toxicity. Additionally, we have shown that in this former high-risk area for lead exposure, there is a low point prevalence of significant lead poisoning, even in an anaemic population.

Peripheral burning sensation: a novel clinical marker of poor prognosis and higher plasma-paraquat concentrations in paraquat poisoning

INTRODUCTION

Self-poisoning with paraquat has a case fatality ratio (CFR) over 65% in Sri Lanka. Plasma-paraquat concentration is the best prognostic indicator for patient outcome but is not readily available. Alternative surrogate clinical markers could be useful in management and determining prognosis. Anecdotal reports by medical and research staff suggested that patients who complained of burning sensation of the body had a poor prognosis and a prospective study was initiated.

METHODS

This was a prospective observational study in three hospitals in Sri Lanka. We collected demographic data, presence or absence of burning sensation, and major outcome, and determined the plasma-paraquat concentration within 24 h post-ingestion.

RESULTS

There were 179 patients with deliberate self-ingestion of paraquat over 30 months. Burning sensation was reported in 84 patients (48%), which was initiated at a median of 1 day (range 1-3 days) post-ingestion. Of the patients who had burning, 61 died [CFR = 72.62%; 95% confidence interval (CI) = 62-81]. Of the 91 patients who had no peripheral burning, 23 died (CFR = 25.27%, 95% CI = 18.15-35.9). Presence of peripheral burning sensation was associated with a significantly higher risk of death (odds ratio = 7.8, 95% CI = 3.9-15, p < 0.0001). Patients who complained of peripheral burning died at a median of 36 h (interquartile range = 30.5-88) following ingestion whereas those who had no peripheral burning died at a median of 50.5 h (interquartile range = 16.75-80). The difference was not significant (p > 0.05). Median admission plasma-paraquat concentration in patients with peripheral burning (2.67 microg/mL, 95% CI = 0.84-14.2) was significantly higher than in the patients with no peripheral burning (0.022 microg/mL, 95% CI = 0.005-0.78; p < 0.001). Peripheral burning has a sensitivity of 0.72 (95% CI = 0.6-8) and specificity of 0.74 (95% CI = 0.64-0.08) and a positive predictive value of 0.73 (95% CI = 0.6-0.8).

DISCUSSION

It is possible that this symptom may help discriminate between patients who have poor chance of survival and those who may potentially benefit from interventions. The mechanism is not clear but could either include a direct concentration-related effect or be a marker of oxidative stress.

CONCLUSION

Presence of burning sensation is associated with high plasma-paraquat concentrations and is strongly predictive of death.

Auditory event-related potential changes in chronic occupational exposure to organophosphate pesticides

OBJECTIVE

To determine whether chronic occupational exposure to organophosphates (OP) pesticides leads to cognitive impairment using event-related potentials (ERPs).

METHODS

ERPs of 38 vegetable farmers applying OP pesticides and 35 controls were recorded using an auditory oddball paradigm. The N1, P2, N2 and P300 ERP components and the number of counting errors were compared between the groups.

RESULTS

The farmers made significantly more counting errors than controls in the oddball task. The mixed model ANOVA of component latencies revealed a significant componentxgroup interaction, suggesting farmers had a greater delay in later ERP components. Intergroup comparisons of individual components showed significant delays in N2 and P300 latencies. Subsequent ANCOVA showed significant P300 delay even after adjusting for the latency of the preceding component, N2. Intergroup differences of P300 amplitudes were not significant, although there was limited evidence of a difference in scalp topography.

CONCLUSION

Our findings indicate that chronic low-level occupational exposure to OP pesticides is associated with progressively increasing delay in successive ERP components, particularly P300.

SIGNIFICANCE

Chronic exposure to OP pesticides may delay the neurophysiological processes underlying early stages of selective attention and late stages of sensory information processing that include stimulus evaluation and updating of working memory.

Emerging epidemic of fatal human self-poisoning with a washing powder in Southern Sri Lanka: a prospective observational study

INTRODUCTION

Self-poisoning is a public health problem in Sri Lanka. A new laundry detergent consisting of a sachet each of 1.2 g of potassium permanganate and 12.5 g of oxalic acid has become a popular agent among the youth for self-poisoning.

METHOD

Prospective clinical data and major outcomes were recorded in all patients admitted to a referring and a referral hospital. Serial biochemistry was performed in 20 patients. Postmortem examinations were performed in some patients.

RESULTS

There were 115 patients. The majority developed symptoms of the gastrointestinal tract within the first 24 h. There were 18 deaths. Ingestion of oxalic acid was associated with a case fatality ratio of 25.4% (95% CI = 14-39), while ingestion of both potassium permanganate and oxalic acid was associated with a case fatality ratio of 9.8% (95% CI = 3.2-21). Ingestion of more than one sachet was associated with a significantly higher risk of death (risk ratio = 13.26, 95% CI = 3.2-54, p < 0.05). Majority of the deaths occurred within an hour since ingestion. Postmortem examinations revealed mucosal ulceration in the majority of deaths.

DISCUSSION

This case series brings to light an emerging epidemic of fatal self-poisoning in Sri Lanka from a compound that is not regulated. As deaths occur soon after ingestion, medical management of these patients is bound to be difficult.

CONCLUSION

This case series highlights a fatal mode of self-poisoning that could be controlled through regulation of the manufacture and sale of the product.

Improvement in the management of acutely poisoned patients using an electronic database, prospective audit and targeted educational intervention

PROBLEM

The need to improve the clinical assessment and management of acutely poisoned patients presenting to an NHS hospital emergency department (ED).

DESIGN

Creation of an electronic clinical toxicology database to prospectively collect all aspects of clinical information on poisoned-patient presentations. Systematic analysis of collated information to identify shortfalls in patient assessment and management. Bimonthly audit meetings, and design and implementation of educational interventions to address identified shortfalls. Ongoing audit to demonstrate continued improvement in patient care.

BACKGROUND AND SETTING

ED in tertiary-level inner-city London teaching hospital. Study conducted by staff from the ED and clinical toxicology service.

KEY MEASURES FOR IMPROVEMENT

Demonstration of overall reduction in the incidence of predefined shortfalls in patient assessment and management during 12-month study period.

STRATEGIES FOR IMPROVEMENT

Targeted educational lectures and case-based clinical scenarios addressing identified deficiencies in the knowledge required to effectively manage poisoned patients. Weekly case-based anonymised feedback report sent electronically to staff involved in caring for poisoned patients.

EFFECTS OF CHANGE

Implementation of targeted teaching of ED staff and regular electronic distribution of teaching cases. Between the first and second 6 months of the study, there was a significant increase in the proportion of presentations for which clinical management was graded as "good" (77.6% to 89.4%, p<0.0001) and a significant reduction in the proportion of "major" (9.9% to 5.8%, p = 0.012) and "minor" (12.6% to 4.8%, p<0.0001) shortfalls.

LESSONS LEARNT

Systematic collection of clinical information, using a dedicated electronic database and subsequent review and audit of collated data by interested clinicians, enabled design and implementation of targeted educational interventions to address shortfalls in patient management. This process has led to significant improvements in the clinical care of acutely poisoned patients presenting to the ED.

Laryngeal edema and metabolic acidosis after Omnicide ingestion

INTRODUCTION

Glutaraldehyde and quaternary ammonium compounds are widely used as disinfectants and sterilizing agents. Glutaraldehyde is irritating to the eyes and upper respiratory tract, and has been associated with occupational asthma. Acute oral ingestion of a concentrated solution has not been previously reported in humans.

CASE REPORT

A 19-year-old woman presented after deliberate ingestion of a biocide containing glutaraldehyde and a quaternary ammonium compound. She developed respiratory distress and severe metabolic acidosis 10 hours after admission. Marked laryngeal edema was noted when she was being intubated. She eventually improved following supportive care and was discharged alive after 9 hospital days.

DISCUSSION

There are no reports of acute ingestions of both glutaraldehyde and quaternary ammonium compounds. As both these substances are known to cause metabolic acidosis, localized edema, erosion and sensitization of both the respiratory and alimentary tract. The clinical effect may be additive or synergistic.

CONCLUSIONS

Omnicide ingestion should be closely monitored for metabolic acidosis and laryngeal edema which may progress to upper airway obstruction requiring urgent airway stabilization.

Severe hypokalaemic metabolic alkalosis following ingestion of gaviscon®

INTRODUCTION

Uncommon metabolic abnormalities in the emergency department could be a result of drug overdose due to uncommon agents.

CASE REPORT

A 35-year-old male presented to the emergency department with a Glasgow Coma Scale (GCS) of 3/15 and a normal pulse rate and blood pressure. Subsequent questioning after recovery revealed he had ingested 2 L of Gaviscon over the preceding 48 hours. He had normal haematology, liver, and renal function during admission. The electrocardiogram showed T wave inversion in the inferior leads on admission. Arterial blood gas on air was: pH 7.54, HCO3 50 mmol/L (50 meq/L), Chloride 66 mmol/L, anion gap was 19, pO2 11 kPa (82.5 mmHg), and pCO2 8 kPa (60 mmHg). Serum sodium was 127 mmol/L and serum potassium was 1.6 mmol/L. His GCS improved within one hour of admission with supportive care, and his serum potassium and bicarbonate improved within 24 hours. He subsequently made a full recovery. Discussion. Bicarbonate ingestion in the form of Gaviscon(R) and vomiting made this patient alkalotic, and simple supportive care provided effective management with a complete recovery.

CONCLUSION

This case illustrates how a severe metabolic alkalosis can result from a significant ingestion of Gaviscon, and that such presentations can give rise to diagnostic dilemma.

Routine antibiotic therapy in the management of the local inflammatory swelling in venomous snakebites: results of a placebo-controlled study

OBJECTIVE

To evaluate the value of routine antibiotic therapy in the management of the local swelling of patients with venomous snakebites.

METHODS

A prospective, placebo-controlled study at the General Hospital, Anuradhapura, Sri Lanka where 144 patients with envenoming and local swelling in the leg were allocated to receive either antibiotics (Group A = test group) or placebo (Group B = controls). Benzyl penicillin 2 mega units intravenously 6 hourly and metronidazole 500 mg by intravenous infusion 8 hourly for 5 days from the first day of the bite were given to Group A. Ethical committee approval was obtained from the Committee of General Hospital, Anuradhapura.

MAIN OUTCOME MEASURES

Circumference difference between the affected limb and the normal limb, length of the swelling measured in centimetres, and the physical characteristics of the local swelling of both groups were compared.

RESULTS

Group A had 69 patients and the Group B 75. The mean circumference difference (MCD) of the leg between the groups showed no significant difference for 4 days (P > 0.05), except at the site of the bite on the third day when the Group B showed a significant improvement (p = 0.02). There was no significant difference in the length of the local swelling or the score of physical characteristics between the two groups (P > 0.05). The proportions of recovery of the local swelling on the fourth and fifth day had no significant difference between the groups (P > 0.05).

CONCLUSION

The routine use of antibiotics (penicillin and metronidazole) does not seem to be of value in reducing the local inflammatory swelling in venomous snakebite.

Epidemiology, clinical features, laboratory investigations and early diagnosis of dengue fever in adults: a descriptive study in Sri Lanka

A descriptive observational study was conducted to identify the epidemiology, clinical features, laboratory investigations and markers for early diagnosis of acute dengue virus infection in adults. We enrolled 404 patients over a period of two years, beginning from 2001, at the Teaching Hospital Peradeniya, Sri Lanka. Based on serology, 239 patients were grouped as: IgM 43 (18%), IgG and IgM 140 (58%), and IgG 28 (12%). The clinically diagnosed group without serology numbered 165 patients. Most of the parameters between groups showed a similar pattern: mean age of 30 years, mean duration of fever 7 days (range 1-19 days). Mean total white blood cell and platelet counts started to fall from the second day of fever, with the lowest counts on the 5th to 7th days. Packed cell volume (PCV) showed minimum fluctuation. One hundred and sixty (88%) patients showed elevated liver enzymes (ALT and AST), with 122 of them having a two-fold increase. Three patients died, and complications such as myocarditis, large effusions, encephalopathy, acute renal failure, acute liver failure and diarrhea were observed. These results suggest that a combination of clinical picture, thrombocytopenia, leukopenia and elevated liver enzymes could be used as markers for early diagnosis of dengue infection. Furthermore, evidence-based guidelines should be developed for managing dengue infection in adults.

Survival Pattern in Patients with Acute Organophosphate Poisoning Receiving Intensive Care

BACKGROUND

Approximately 35% of patients acutely poisoned with organophosphates (OP) in developing countries like Sri Lanka require intensive care and mechanical ventilation. However, death rates remain high.

OBJECTIVE

To study the outcomes and predictors of mortality in patients with acute OP poisoning requiring intensive therapy at a regional center in Sri Lanka over a period of 40 months.

METHODS

Retrospective analysis of all intensive care records of patients with acute OP poisoning admitted to the Intensive Care Unit (ICU) between March 1998 and July 2001.

RESULTS

During the study period, 126 subjects were admitted to the ICU with acute OP poisoning. Records of 10 patients were lost and those of 37 were incomplete and hence were excluded. All the remaining 71 patients (59 male) had required endotracheal intubation and mechanical ventilation for a period of four (median) days (range 1-27) in addition to gastric lavage and standard therapy with atropine and oximes and adequate hydration. Of these 71 patients, 36 (28 male) had died. Life table analysis demonstrated a steep decline in the cumulative survival to 67% during the first three days. Systolic blood pressure of < 100 mmHg and FiO2 of >40% to maintain a SpO2 of >92% within the first 24 h were recognized as poor prognostic indicators among mechanically ventilated patients.

CONCLUSION

Mortality following OP poisoning remains high despite adequate respiratory support, intensive care, and specific therapy with atropine and oximes. One-third of the subjects needing mechanical ventilation and reaching intensive care units die within the first 72 h of poisoning. Systolic blood pressure of less than 100 mmHg and the necessity of a FiO2>40% to maintain adequate oxygenation are predictors of poor outcome in patients mechanically ventilated in the ICU.

Emerging rickettsial infections in Sri Lanka: the pattern in the hilly Central Province

OBJECTIVES

To identify different rickettsial infections using a specific immunofluorescent technique in patients clinically diagnosed as 'typhus fever' in the Central Province of Sri Lanka, and to define the clinical picture, assess the severity of infection and to determine the pattern of geographical distribution of the infections of the hospital-based patients.

METHODS

A specific indirect immunofluorescent antibody technique was used on the sera of two groups of patients in laboratories in Japan and Thailand.

RESULTS

We serodiagnosed infections with Orientia tsutsugamushi, Rickettsia typhi and spotted fever group in 56 of 118 clinically investigated patients. There were eight infections with O. tsutsugamushi, two with R. typhi and 10 spotted fever group patients with IgM antibodies suggestive of acute infection. Nineteen patients had antibodies against these three rickettsial species, suggestive of past exposure, co-infection or cross-reactivity of antigens. Discrete, erythematous maculopapular rash was common to all three types of infection except for five patients who had no rash. Five patients positive for spotted fever antibodies developed fern-leaf type skin necrosis with severe illness. Duration of the febrile period ranged from 4 to 23 days with defervescence occurring after specific antibiotic treatment.

CONCLUSIONS

The study has shown the presence of different types of rickettsial infections in the Central Province of Sri Lanka. The characterization of the clinical picture and the severity of infection provide useful information for the proper management of the patients in the future.