Life-threatening sodium valproate overdose: a comparison of two approaches to treatment

Valproate overdose leading to hyperammonaemic encephalopathy

Sodium valproate is a commonly prescribed anticonvulsant medication; however, it can cause uncommon side effects such as hyperammonaemia and encephalopathy. We present the case of a male in his early 50s brought to the emergency department after being found collapsed by his wife, with an empty bottle of sodium valproate tablets. The patient developed hyperammonaemic encephalopathy due to sodium valproate overdose and was treated with supportive care and renal replacement therapy. This case highlights the importance of recognising the potential complications of sodium valproate and its prompt treatment.

Undifferentiated non-hepatic hyperammonemia in the ICU: Diagnosis and management

Hyperammonemia occurs frequently in the critically ill but is largely confined to patients with hepatic dysfunction or failure. Non-hepatic hyperammonemia (NHHA) is far less common but can be a harbinger of life-threatening diagnoses that warrant timely identification and, sometimes, empiric therapy to prevent seizures, status epilepticus, cerebral edema, coma and death; in children, permanent cognitive impairment can result. Subsets of patients are at particular risk for developing NHHA, including the organ transplant recipient. Unique etiologies include rare infections, such as with Ureaplasma species, and unmasked inborn errors of metabolism, like urea cycle disorders, must be considered in the critically ill. Early recognition and empiric therapy, including directed therapies towards these rare etiologies, is crucial to prevent catastrophic demise. We review the etiologies of NHHA and highlight the first presentation of it associated with a concurrent Ureaplasma urealyticum and Mycoplasma hominis infection in a previously healthy individual with polytrauma. Based on this clinical review, a diagnostic and treatment algorithm to identify and manage NHHA is proposed.

Continuous renal replacement therapy and its impact on hyperammonaemia in acute liver failure

OBJECTIVE

Hyperammonaemia contributes to complications in acute liver failure (ALF) and may be treated with continuous renal replacement therapy (CRRT), but current practice is poorly understood.

DESIGN

We retrospectively analysed data for baseline characteristics, ammonia concentration, CRRT use, and outcomes in a cohort of Australian and New Zealand patients with ALF.

SETTING

All liver transplant ICUs across Australia and New Zealand.

PARTICIPANTS

Sixty-two patients with ALF.

MAIN OUTCOME MEASURES

Impact of CRRT on hyperammonaemia and patient outcomes.

RESULTS

We studied 62 patients with ALF. The median initial (first 24 h) peak ammonia was 132 μmol/L (interquartile range [IQR], 91-172), median creatinine was 165 μmol/L (IQR, 92-263) and median urea was 6.9 mmol/L (IQR, 3.1-12.0). Most patients (43/62, 69%) received CRRT within a median of 6 hours (IQR, 2-12) of ICU admission. At CRRT commencement, three-quarters of such patients did not have Stage 3 acute kidney injury (AKI): ten patients (23%) had no KDIGO creatinine criteria for AKI, 12 (28%) only had Stage 1, and ten patients (23%) had Stage 2 AKI. Compared with non-CRRT patients, those treated with CRRT had higher ammonia concentrations (median, 141 μmol/L [IQR, 102-198] v 91 μmol/L [IQR, 54-115]; P = 0.02), but a nadir Day 1 pH of only 7.25 (standard deviation, 0.16). Prevention of extreme hyperammonaemia (> 140 μmol/L) after Day 1 was achieved in 36 of CRRT-treated patients (84%) and was associated with transplant-free survival (55% v 13%; P = 0.05).

CONCLUSION

In Australian and New Zealand patients with ALF, CRRT is typically started early, before Stage 3 AKI or severe acidaemia, and in the presence hyperammonaemia. In these more severely ill patients, CRRT use was associated with prevention of extreme hyperammonaemia, which in turn, was associated with increased transplant-free survival.

Correction and Control of Hyperammonemia in Acute Liver Failure: The Impact of Continuous Renal Replacement Timing, Intensity, and Duration

OBJECTIVES

Hyperammonemia is a key contributing factor for cerebral edema in acute liver failure. Continuous renal replacement therapy may help reduce ammonia levels. However, the optimal timing, mode, intensity, and duration of continuous renal replacement therapy in this setting are unknown. We aimed to study continuous renal replacement therapy use in acute liver failure patients and to assess its impact on hyperammonemia.

DESIGN

Retrospective observational study.

SETTING

ICU within a specialized liver transplant hospital.

PATIENTS

Fifty-four patients with acute liver failure.

INTERVENTIONS

Data were obtained from medical records and analyzed for patient characteristics, continuous renal replacement therapy use, ammonia dynamics, and outcomes.

MAIN RESULTS

Forty-five patients (83%) had high grade encephalopathy. Median time to continuous renal replacement therapy commencement was 4 hours (interquartile range, 2-4.5) with 35 (78%) treated with continuous venovenous hemodiafiltration and 10 (22%) with continuous venovenous hemofiltration. Median hourly effluent flow rate was 43 mL/kg (interquartile range, 37-62). The median ammonia concentration decreased every day during treatment from 151 µmol/L (interquartile range, 110-204) to 107 µmol/L (interquartile range, 84-133) on day 2, 75 µmol/L (interquartile range, 63-95) on day 3, and 52 µmol/L (interquartile range, 42-70) (p < 0.0001) on day 5. The number of patients with an ammonia level greater than 150 µmol/L decreased on the same days from 26, to nine, then two, and finally none. Reductions in ammonia levels correlated best with the cumulative duration of therapy hours (p = 0.03), rather than hourly treatment intensity.

CONCLUSIONS

Continuous renal replacement therapy is associated with reduced ammonia concentrations in acute liver failure patients. This effect is related to greater cumulative dose. These findings suggest that continuous renal replacement therapy initiated early and continued or longer may represent a useful approach to hyperammonemia control in acute liver failure patients.

[Valproic acid-induced hyperammonemic encephalopathy in a patient receiving valproic acid monotherapy]

A 79-year-old female was diagnosed with epilepsy because she experienced loss of consciousness twice in January and February and then had a seizure in June 2016. She was treated with 800 mg sodium valproate (sustained release). After 3 days, she experienced loss of appetite, and more than 3 days later, disturbance of consciousness. Serum valproic acid (VPA) concentration was 128.3 μg/ml and serum ammonia was 404 μmol/l. Cerebral edema and status epilepticus occurred. Severe neurological dysfunction remained, even after treatment with continuous hemodiafiltration and levocarnitine. VPA is widely used for the treatment of generalized epilepsy. VPA-induced hyperammonemic encephalopathy is a rare but serious adverse event of VPA. Thus, we must pay attention to serum ammonia levels when using VPA, even VPA monotherapy.

All guns blazing: management and survival of massive valproic acid overdose - case report and literature review

A 51-year-old woman, who intentionally ingested a massive dose of ~60 g of valproic acid which she was using as a mood stabilizer for bipolar affective disorder, presented within 30 minutes of ingestion to the emergency department. The patient was asymptomatic and was immediately started on decontamination therapy with activated charcoal (AC). Drug serum levels, liver functions, and ammonia levels were tested and followed up during treatment. Due to the massive ingestion and continuous rise in serum drug levels, the patient received regular multiple doses of AC, as well as l-carnitine for liver protection. The patient was started on extracorporeal therapy in the form of renal replacement therapy in the intensive care unit (ICU), followed by intermittent hemodialysis. Drug serum levels dropped significantly. Ammonia levels showed improvement with treatment. The patient was discharged from the ICU after 14 days of treatment. She was stable and in good condition with no residual hepatic or central nervous system (CNS) manifestations.

Valproic Acid Overdose Review of a Case With Electrocardiographic Changes

BACKGROUND

Valproic acid (VPA) is increasingly used to treat a variety of medical disorders, such as seizures, psychiatric disorders, and headaches. Therefore, accidental and intentional ingestions with valproic acid are increasing.

OBJECTIVES

A case is presented in an adolescent with ischemic electrocardiographic changes after an acute overdose with VPA.

DISCUSSION

Major features of a valproic acid overdose include respiratory depression, progressive coma, hepatotoxicity, thrombocytopenia, and hemodynamic instability. Electrocardiographic abnormalities usually consist of tachycardia and nonspecific changes. Supportive care is indicated in most overdoses and involves the monitoring and correction of electrolyte abnormalities, coagulopathies, and acid-base imbalances. Treatment may include activated charcoal, naloxone, l-carnitine, and extracorporeal detoxification.

CONCLUSIONS

Valproic acid overdose is a relatively rare and electrocardiographic changes usually consist of tachycardia and nonspecific changes, but ischemic changes may occur and usually transient and require only recognition.

Evaluation of efficacy of resin hemoperfusion in patients with acute 2,4-dinitrophenol poisoning by dynamic monitoring of plasma toxin concentration

OBJECTIVE

The intoxications caused by 2,4-dinitrophenol (2,4-DNP), even death, have been frequently reported in recent years. This study aims to investigate the dynamic changes of plasma toxin concentration and explore the clinical value of resin hemoperfusion (HP) in the treatment of patients with acute 2,4-DNP poisoning.

METHODS

We reported 16 cases of acute 2,4-DNP poisoning through occupational exposure due to ignoring the risk of poisoning. The blood samples were collected from the 14 survivors. According to the different treatments of resin HP, the survivors were divided into routine HP (n=5) and intensive HP (n=9) groups. Ultra high performance liquid chromatography/ tandem mass spectroscopy (UPLC-MS/MS) was used to detect the 2,4-DNP concentration in plasma in this study.

RESULTS

The 14 survivors recovered very well after treatment. The initial plasma 2,4-DNP concentrations (C1) of survivors ranged from 0.25 to 41.88 µg/ml (mean (12.56±13.93) µg/ml). A positive correlation existed between initial plasma 2,4-DNP concentration (C1) and temperature. The elimination of 2,4-DNP was slow and persistent, and the total clearance rates of plasma toxin from the 1st to 3rd day (R3), the 3rd to 7th day (R3-7), and the 1st to 7th day (R7), were only (53.03±14.04)%, (55.25±10.50)%, and (78.29±10.22)%, respectively. The plasma toxin was cleared up to 25 d after poisoning in most of the patients. The R3, R3-7, and R7 in the intensive HP group were all apparently higher than those in the routine HP group, with statistical significance (P<0.05). Simultaneously, the elimination half-life (t1/2) of 2,4-DNP in the intensive HP group was apparently shorter than that in the routine HP group, with statistical significance (P<0.05).

CONCLUSIONS

The clinicians should be aware of this slow and persistent process in the elimination of plasma 2,4-DNP. Higher initial plasma toxin concentration resulted in a more severe fever for the patient. According to the limited data, longer and more frequent resin HP may accelerate to eliminate the poison.

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

BACKGROUND

The EXtracorporeal TReatments In Poisoning (EXTRIP) workgroup presents its systematic review and clinical recommendations on the use of extracorporeal treatment (ECTR) in valproic acid (VPA) poisoning.

METHODS

The lead authors reviewed all of the articles from a systematic literature search, extracted the data, summarized the key findings, and proposed structured voting statements following a predetermined 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 in person. A second vote was conducted to determine the final workgroup recommendations.

RESULTS

The latest literature search conducted in November 2014 retrieved a total of 79 articles for final qualitative analysis, including one observational study, one uncontrolled cohort study with aggregate analysis, 70 case reports and case series, and 7 pharmacokinetic studies, yielding a very low quality of evidence for all recommendations. Clinical data were reported for 82 overdose patients while pharmaco/toxicokinetic grading was performed in 55 patients. The workgroup concluded that VPA is moderately dialyzable (level of evidence = B) and made the following recommendations: ECTR is recommended in severe VPA poisoning (1D); recommendations for ECTR include a VPA concentration > 1300 mg/L (9000 μmol/L)(1D), the presence of cerebral edema (1D) or shock (1D); suggestions for ECTR include a VPA concentration > 900 mg/L (6250 μmol/L)(2D), coma or respiratory depression requiring mechanical ventilation (2D), acute hyperammonemia (2D), or pH ≤ 7.10 (2D). Cessation of ECTR is indicated when clinical improvement is apparent (1D) or the serum VPA concentration is between 50 and 100 mg/L (350-700 μmol/L)(2D). Intermittent hemodialysis is the preferred ECTR in VPA poisoning (1D). If hemodialysis is not available, then intermittent hemoperfusion (1D) or continuous renal replacement therapy (2D) is an acceptable alternative.

CONCLUSIONS

VPA is moderately dialyzable in the setting of overdose. ECTR is indicated for VPA poisoning if at least one of the above criteria is present. Intermittent hemodialysis is the preferred ECTR modality in VPA poisoning.

A stepwise approach for the management of poisoning with extracorporeal treatments

The use of an extracorporeal treatment (ECTR) in a poisoned patient may be life-saving in a limited number of scenarios. The decision-processes surrounding the use of ECTR in poisoning is complex: most nephrologists are not trained to assess a poisoned patient while clinical toxicologists rarely prescribe ECTRs. Deciding on which ECTR is most appropriate for a poison requires a good understanding of the poison's physicochemical and pharmacokinetic properties. Further, a detailed understanding of the capabilities and limitations of the different ECTRs can be useful to select the most appropriate ECTR for a given clinical situation. This manuscript provides a stepwise approach to assess the usefulness of ECTRs in poisoning.

Preventing cerebral oedema in acute liver failure: the case for quadruple-H therapy

Severe cerebral oedema is a life-threatening complication of acute liver failure. Hyperammonaemia and cerebral hyperaemia are major contributing factors. A multimodal approach, which incorporates hyperventilation, haemodiafiltration, hypernatraemia and hypothermia (quadruple-H therapy), may prevent or attenuate severe cerebral oedema. This approach is readily administered by critical care clinicians and is likely to be more effective than the use of single therapies. Targeting of PaCO2 in the mild hyperventilation range, as seen in acute liver failure patients before intubation, aims to minimise hyperaemic cerebral oedema. Haemodiafiltration aims to achieve the rapid control of elevated blood ammonia concentrations by its removal and to reduce production via the lowering of core temperature. The administration of concentrated saline increases serum tonicity and further reduces cerebral swelling. In addition, the pathologically increased cerebral blood-flow is further attenuated by therapeutic hypothermia. The combination of all four treatments in a multimodal approach may be a safe and effective means of attenuating or treating the cerebral oedema of acute liver failure and preventing death from neurological complications.

Miscellaneous central nervous system intoxicants

The topic of central nervous system intoxicants encompasses a multitude of agents. This article focuses on three classes of therapeutic drugs, with specific examples in which overdoses require admission to the intensive care unit. Included are some of the newer antidepressants, the atypical neuroleptic agents, and selected anticonvulsant drugs. The importance of understanding pertinent physiology and applicable supportive care is emphasized.

2, 4-dinitrophenol poisoning caused by non-oral exposure

2, 4-Dinitrophenol (2, 4-DNP) is widely used in industry, but recently, poisoning through consumption for weight control has been frequently reported. We report the cases of two patients whose deaths were attributed to occupational and non-oral exposure of 2, 4-DNP. They were all poisoned through skin absorption and respiratory tract inhalation; common features were excessive sweating, hyperthermia, tachycardia, clouded consciousness and asystole. Because of the lack of specific early symptoms, effective antidotes and the means of washing the contamination from the skin, their arrival in hospital was delayed and the supportive therapy was ineffectual. Cardiac arrest occurred quickly and unexpected after admission.