Hyperlithemia correction and persistent delirium

Extracorporeal Removal of Poisons and Toxins

Extracorporeal therapies have been used to remove toxins from the body for over 50 years and have a greater role than ever before in the treatment of poisonings. Improvements in technology have resulted in increased efficacy of removing drugs and other toxins with hemodialysis, and newer extracorporeal therapy modalities have expanded the role of extracorporeal supportive care of poisoned patients. However, despite these changes, for at least the past three decades the most frequently dialyzed poisons remain salicylates, toxic alcohols, and lithium; in addition, the extracorporeal treatment of choice for therapeutic removal of nearly all poisonings remains intermittent hemodialysis. For the clinician, consideration of extracorporeal therapy in the treatment of a poisoning depends upon the characteristics of toxins amenable to extracorporeal removal (e.g., molecular mass, volume of distribution, protein binding), choice of extracorporeal treatment modality for a given poisoning, and when the benefit of the procedure justifies additive risk. Given the relative rarity of poisonings treated with extracorporeal therapies, the level of evidence for extracorporeal treatment of poisoning is not robust; however, extracorporeal treatment of a number of individual toxins have been systematically reviewed within the current decade by the Extracorporeal Treatment in Poisoning workgroup, which has published treatment recommendations with an improved evidence base. Some of these recommendations are discussed, as well as management of a small number of relevant poisonings where extracorporeal therapy use may be considered.

Hemodialysis for lithium poisoning

BACKGROUND

Lithium salts, particularly lithium carbonate, are frequently used to treat bipolar disorder and mania. Lithium poisoning, which can occur as a result of reduced renal elimination, prescribing error, drug-drug interactions, or deliberate overdosage, produces neurologic injury that can be permanent. Hemodialysis is often recommended to treat lithium poisoning. Although hemodialysis clearly enhances the elimination of lithium, it is unclear whether this translates into improved patient outcomes. Evidence from observational studies, generally of low methodological quality, shows similar outcomes in patients managed with or without the use of hemodialysis.

OBJECTIVES

To determine whether hemodialysis, applied in addition to standard therapy, reduces the likelihood, severity, or duration of neurological sequelae following lithium poisoning.

SEARCH METHODS

We ran the search on 15 May 2015. We searched the Cochrane Injuries Group's Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE (OvidSP), Embase Classic+Embase (OvidSP), CINAHL Plus, clinical trials registers and four other databases. We screened the reference lists of relevant studies, textbook chapters, and review articles, and performed a Google search to identify grey literature.

SELECTION CRITERIA

In the context of this review, hemodialysis was defined as any extracorporeal technique to filter and extract toxicants from the serum, including all forms of hemodialysis, hemofiltration, and continuous renal replacement techniques, but not peritoneal dialysis. We included any clinical trials in which patients were randomly allocated to receive, or not receive, hemodialysis in addition to standard care for lithium poisoning.

DATA COLLECTION AND ANALYSIS

Two authors reviewed the abstracts of all identified articles. If either author identified an article as potentially meeting the inclusion criteria, both authors reviewed the full text of the article.

MAIN RESULTS

No randomized controlled trials of hemodialysis therapy for lithium poisoning were identified.

AUTHORS' CONCLUSIONS

Although the use of hemodialysis to enhance the elimination of lithium in patients with lithium poisoning appears logical, there is no evidence from randomized controlled trials to support nor refute the use of hemodialysis in the management of patients with lithium poisoning.

Extracorporeal Treatment for Lithium Poisoning: Systematic Review and Recommendations from the EXTRIP Workgroup

The Extracorporeal Treatments in Poisoning Workgroup was created to provide evidence-based recommendations on the use of extracorporeal treatments in poisoning. Here, the EXTRIP workgroup presents its recommendations for lithium poisoning. After a systematic literature search, clinical and toxicokinetic data were extracted and summarized following a predetermined format. The entire workgroup voted through a two-round modified Delphi method to reach a consensus on voting statements. A RAND/UCLA Appropriateness Method was used to quantify disagreement, and anonymous votes were compiled and discussed in person. A second vote was conducted to determine the final workgroup recommendations. In total, 166 articles met inclusion criteria, which were mostly case reports, yielding a very low quality of evidence for all recommendations. A total of 418 patients were reviewed, 228 of which allowed extraction of patient-level data. The workgroup concluded that lithium is dialyzable (Level of evidence=A) and made the following recommendations: Extracorporeal treatment is recommended in severe lithium poisoning (1D). Extracorporeal treatment is recommended if kidney function is impaired and the [Li(+)] is >4.0 mEq/L, or in the presence of a decreased level of consciousness, seizures, or life-threatening dysrhythmias irrespective of the [Li(+)] (1D). Extracorporeal treatment is suggested if the [Li(+)] is >5.0 mEq/L, significant confusion is present, or the expected time to reduce the [Li(+)] to <1.0 mEq/L is >36 hours (2D). Extracorporeal treatment should be continued until clinical improvement is apparent or [Li(+)] is <1.0 mEq/L (1D). Extracorporeal treatments should be continued for a minimum of 6 hours if the [Li(+)] is not readily measurable (1D). Hemodialysis is the preferred extracorporeal treatment (1D), but continuous RRT is an acceptable alternative (1D). The workgroup supported the use of extracorporeal treatment in severe lithium poisoning. Clinical decisions on when to use extracorporeal treatment should take into account the [Li(+)], kidney function, pattern of lithium toxicity, patient's clinical status, and availability of extracorporeal treatments.

Management of Lithium Toxicity

Lithium salts have been used in the prophylaxis and treatment of depression and bipolar disorder for >50 years. Lithium has a narrow therapeutic range, and several well characterised adverse effects limit the potential usefulness of higher doses. Acute ingestion in lithium-naive patients is generally associated with only short-lived exposure to high concentrations, due to extensive distribution of lithium throughout the total body water compartment. Conversely, chronic toxicity and acute-on-therapeutic ingestion are associated with prolonged exposure to higher tissue concentrations and, therefore, greater toxicity. Lithium toxicity may be life threatening, or result in persistent cognitive and neurological impairment. Therefore, enhanced lithium clearance has been explored as a means of minimising exposure to high tissue concentrations. Although haemodialysis is highly effective in removing circulating lithium, serum concentrations often rebound so repeated or prolonged treatment may be required. Continuous arteriovenous haemodiafiltration and continuous venovenous haemodiafiltration increase lithium clearance, albeit to a lesser extent than haemodialysis, and are more widely accessible. Haemodiafiltration sustained for >16 hours allows effective removal of total body lithium, thereby avoiding rebound effects. Enhanced elimination should be considered in patients at greatest risk of severe poisoning: namely those with chronic or acute-on-therapeutic toxicity, those with clinically significant features, and those with chronic toxicity whose serum lithium concentration is >2.5 mmol/L. The choice between haemodialysis and continuous haemodiafiltration techniques will depend on local accessibility and urgency of enhancing lithium elimination. Further research is required to establish the potential benefits of assisted elimination on clinical outcome in patients with lithium poisoning.

The Syndrome of Irreversible Lithium-Effectuated Neurotoxicity

OBJECTIVES

Persistent sequelae of lithium intoxication gained clinical attention in the 1980s and were named Syndrome of Irreversible Lithium-Effectuated Neurotoxicity (SILENT). The authors review the published cases of SILENT reported in the literature and discuss various clinical manifestations.

METHODS

The authors' inclusion criteria included persistence of sequelae for at least 2 months after the cessation of lithium administration. They conducted a MEDLINE and Pub Med search for journal articles from the year 1965 to 2004. They also cross-referenced available papers.

RESULTS

The authors identified 90 cases of SILENT in peer-reviewed publications. Persistent cerebellar dysfunction was the most commonly reported sequela. Other atypical presentations have also been reported.

CONCLUSION

Although the biologic mechanism remains unclear, the authors hypothesize that the putative cause of SILENT is demyelination caused by lithium at multiple sites in the nervous system, including the cerebellum. Recent advances in the understanding of the molecular basis of lithium-induced neurotoxicity may be able to provide a means of defining a pathway associated with the long-term prophylactic properties of lithium, distinct from its toxicity profile. This identification of differential gene expression patterns that distinguish between therapeutic and toxic actions of lithium may help in the discovery of new drugs for mood stabilization. Clinically and heuristically, it is important to raise the awareness of this syndrome so that clinicians are able to avoid it. A precise definition, operational diagnostic criteria, and a descriptive name will aid in the early identification and prevention of SILENT.

[Neurologic sequelae secondary to acute lithium poisoning]

OBJECTIVE

To review the literature on the permanent neurological sequelae resulting from acute lithium poisoning.

METHOD

Sixty-six articles were reviewed in English and in French. They were accessed through Medline and cover the period from 1968 to 1997.

RESULTS

Fifty-nine case studies were broken down into 3 groups: lithium intoxications without a neuroleptic that has provoked a cerebellar syndrome; those in which there was a neuroleptic; and those with diverse neurological consequences, with or without a neuroleptic.

CONCLUSIONS

Lithium has an intrinsic toxicity for the central nervous system and provokes a tropism specific to the cerebellum. The association with neuroleptics appears to increase toxicity as well as some associated factors, including infections and the rapid correction of the lithium level in the blood. We discuss the psychopathological mechanisms invoked to explain lithium's neurotoxicity.

Capillary ion analysis of lithium concentrations in biological fluids and tissues of Poecilia (teleost)

Capillary ion analysis (CIA) is a form of capillary electrophoresis that uses the differential electrophoretic mobility of ions to perform a separation of an ionic mixture. Application of this technique for detection of lithium concentrations in plasma and tissues of Poecilia was the purpose of this investigation. CIA was performed using a 75 microm ID x 60 cm length fused-silica capillary and a run electrolyte of 67.7 mg hydroxyisobutyric acid (HIBA), 52.8 mg 18-crown-6-ether and 64 microL UV-CAT-1 reagent (4-methylbenzylamine) in a volume of 100 mL water (18 (M)omega) with a voltage of 20 kV using ultraviolet absorption detection at 214 nm. Migration times were: potassium, 2.98 min; calcium, 3.48 min; sodium, 3.60 min; barium (internal standard), 4.15 min and lithium, 4.26 min. Lithium and barium migration times were stable and reproducible. Correlation coefficients (r) between peak area ratios of lithium/barium for concentrations ranging from 0.1 to 2.0 mM were from 0.976 to 0.996. Coefficients of variation (CV) for lithium concentrations ranged from 4.07 to 15.71% between days and 4.38 to 7.76% within-day. Application of this methodology for determination of lithium concentrations in the plasma, brains and livers of fish dosed with lithium for 23 days are presented. CIA is applicable to analysis of lithium concentrations in biological fluids and tissues of fish.

Methods used to decrease lithium absorption or enhance elimination

OBJECTIVE

To review current methods, well documented and investigational, being used to decrease lithium absorption or enhance lithium elimination.

METHODS

The basic science and clinical literature on lithium were reviewed by a comprehensive Medline search from 1984 to 1996. Additional references were identified by reviewing the reference citations from the results of the Medline search.

RESULTS

Prevention of Absorption: Whole bowel irrigation has been demonstrated to be an effective means of enhancing lithium removal from the gastrointestinal tract. Sodium polystyrene sulfonate resin administration has been shown to be effective in binding lithium elimination in animal and human models. However, the lower limits of effective sodium polystyrene sulfonate dosing and the extent of potassium lowering in humans are questions that need to be answered before sodium polystyrene sulfonate resin can be recommended for routine, use. Enhancement of Elimination: Saline or forced diuresis is not effective in enhancing lithium elimination unless the patient is volume or sodium depleted. The use of continuous arteriovenous hemodiafiltration or low dose dopamine to enhance lithium elimination has only been documented in case reports. Intravenous aminophylline (theophylline) is not consistently effective and its risks outweigh possible benefits. The literature supports hemodialysis as a well documented and effective means of enhancing lithium elimination. Controversy exists over the appropriate indications for its initiation.

DISCUSSION

Given the wide interpatient variability in lithium pharmacokinetics, single case reports do not provide sufficient evidence of the effectiveness of a given method to enhance