Continuous venovenous haemofiltration for the treatment of theophylline toxicity

Severe amnestic syndrome due to theophylline toxicity

We report a case of severe amnestic syndrome following theophylline overdose. A woman in her early 30s was admitted to hospital where she developed status epilepticus following an intentional overdose of theophylline and lansoprazole. She developed a profound acidosis and required intubation in the intensive care unit. Following extubation the patient was noted to have a severe amnestic syndrome with poor short-term memory. A work-up to exclude infectious, autoimmune and paraneoplastic causes for encephalitis was undertaken. Cerebrospinal fluid analysis was normal and autoimmune encephalitis titres were negative. Initial MRI brain imaging demonstrated hyperintensities of the mesial temporal lobes bilaterally. Follow-up imaging at 4 months identified further interval reduction but persistent hippocampal hyperintensities. Theophylline toxicity with corresponding amnestic syndrome and hippocampal hyperintensities has been rarely reported. We believe this case with persistent abnormal Montreal Cognitive Assessment Score at 12 months correlates with persistent hippocampal abnormalities seen on imaging.

Extracorporeal treatment for theophylline poisoning: systematic review and recommendations from the EXTRIP workgroup

BACKGROUND

The Extracorporeal Treatments in Poisoning workgroup was created to provide evidence-based recommendations on the use of extracorporeal treatments (ECTRs) in poisoning. Here, the workgroup presents its systematic review and recommendations for theophylline.

METHODS

After a systematic review of the literature, a subgroup reviewed articles, extracted data, summarized findings, and proposed structured voting statements following a pre-determined format. A two-round modified Delphi method was chosen to reach a consensus on voting statements and the RAND/UCLA Appropriateness Method was used to quantify disagreement. Anonymous votes were compiled, returned, and discussed. A second vote determined the final recommendations.

RESULTS

141 articles were included: 6 in vitro studies, 4 animal studies, 101 case reports/case series, 7 descriptive cohorts, 4 observational studies, and 19 pharmacokinetic studies, yielding a low-to-very-low quality of evidence for all recommendations. Data on 143 patients were reviewed, including 10 deaths. The workgroup concluded that theophylline is dialyzable (level of evidence = A) and made the following recommendations: ECTR is recommended in severe theophylline poisoning (1C). Specific recommendations for ECTR include a theophylline concentration [theophylline] > 100 mg/L (555 μmol/L) in acute exposure (1C), the presence of seizures (1D), life-threatening dysrhythmias (1D) or shock (1D), a rising [theophylline] despite optimal therapy (1D), and clinical deterioration despite optimal care (1D). In chronic poisoning, ECTR is suggested if [theophylline] > 60 mg/L (333 μmol/L) (2D) or if the [theophylline] > 50 mg/L (278 μmol/L) and the patient is either less than 6 months of age or older than 60 years of age (2D). ECTR is also suggested if gastrointestinal decontamination cannot be administered (2D). ECTR should be continued until clinical improvement is apparent or the [theophylline] is < 15 mg/L (83 μmol/L) (1D). Following the cessation of ECTR, patients should be closely monitored. Intermittent hemodialysis is the preferred method of ECTR (1C). If intermittent hemodialysis is unavailable, hemoperfusion (1C) or continuous renal replacement therapies may be considered (3D). Exchange transfusion is an adequate alternative to hemodialysis in neonates (2D). Multi-dose activated charcoal should be continued during ECTR (1D).

CONCLUSION

Theophylline poisoning is amenable to ECTRs. The workgroup recommended extracorporeal removal in the case of severe theophylline poisoning.

The role of continuous renal replacement therapy in the treatment of poisoning

Extracorporeal elimination of drugs and toxins is a critical component in the management of poisonings, though specific techniques and indications remain a matter of debate. Conventional hemodialysis is frequently the treatment of choice because of its widespread availability and proven effectiveness for certain drugs and toxins. With the increased availability of continuous renal replacement therapy (CRRT) modalities, there is yet another therapeutic option, but one that has yet to find a definitive role in this field. The continuous nature of these therapies is attractive for the management of acute renal failure, but the relatively slower clearance rates as compared to conventional hemodialysis is a distinct drawback in patients with acute xenobiotic-induced toxicity. There are abundant case reports as well as a few small case series in the medical literature documenting the use of CRRT, but specific techniques and the clinical outcomes vary considerably. Therefore one cannot draw definitive conclusions regarding benefit. Some patients, particularly those who are hemodynamically unstable and are not candidates for conventional hemodialysis, may warrant a trial of CRRT. However, at the present time, routine use for the treatment of poisoning is not supported. Controlled trials to better clarify its role would be beneficial, though such studies would be extremely difficult to conduct in this field. We believe that the intelligent application of extracorporeal modalities requires a thorough knowledge of drug pharmacokinetics, of the techniques utilized, and a skeptical analysis of the available literature.

1H and 13C NMR spectra and solution structures of novel derivatives of 5-substituted creatinines

Five creatinine derivatives were prepared by the treatment of creatinine with activated carbon and appropriate alcohol (1-4), or ammonia solution (5). Product structures were determined by 1H and 13C NMR spectroscopy in solution, including 2D HSQC and HMBC experiments. Then, the proton and carbon chemical shifts for these compounds were calculated using GIAO-DFT [B3LYP/6-311G(2d,p)] method and the Gaussian 03W program and furthermore for 1 and 5 using polarizable continuum model (PCM). The conclusions coming from the comparison of the experimental and theoretical spectra supported the adopted signal assignments and solved the structural problems due to the potential annular tautomerism of the investigated compounds. One can predict that 5-substituted creatinines, just like creatinine, appear in solution in the form of 2-amino-1,5-dihydro-1-methyl-4-imidazolone. Correlations between experimental and calculated substituent-induced chemical shifts for two tautomeric forms of 5-substituted creatinines indicate that the mechanism of the substituent influence in both tautomers for the investigated compounds appears to be analogous. We can predict that in solution this accepting inductive effect of substituent groups does not significantly influence the structure of creatinine molecule in solution. The analysis of coupling constants for 5-substituted creatinines gives information about conformation of the investigated molecules in solution.

Maintenance pharmacotherapy of chronic obstructive pulmonary disease: an evidence-based approach

Chronic obstructive pulmonary disease (COPD) is a major public health problem and its impact is increasing. Only smoking cessation and oxygen for -hypoxaemic patients have been shown to alter mortality, but modern pharmacological therapies can improve symptoms, lung function and quality of life. Treatment guidelines emphasise the use of bronchodilators as first-line treatment for COPD but make few recommendations about choosing a specific agent. In this review, the results of recent studies are examined to provide evidence-based guidance for the selection of appropriate maintenance therapy. Guidelines also support the use of inhaled corticosteroids in patients with more advanced disease, and the role of these agents is discussed.