Lamotrigine and hemophagocytic lymphohistiocytosis

Current and emerging pharmacotherapy for the treatment of Lennox-Gastaut syndrome

INTRODUCTION

Lennox-Gastaut syndrome (LGS) is a severe childhood-onset epileptic encephalopathy, characterized by multiple seizure types, generalized slow spike-and-wave complexes in the EEG, and cognitive impairment. Seizures in LGS are typically resistant to treatment with antiseizure medications (ASMs). Tonic/atonic ('drop') seizures are of particular concern, due to their liability to cause physical injury.

AREAS COVERED

We summarize evidence for current and emerging ASMs for the treatment of seizures in LGS. The review focuses on findings from randomized, double-blind, placebo-controlled trials (RDBCTs). For ASMs for which no double-blind trials were identified, lower quality evidence was considered. Novel pharmacological agents currently undergoing investigation for the treatment of LGS are also briefly discussed.

EXPERT OPINION

Evidence from RDBCTs supports the use of cannabidiol, clobazam, felbamate, fenfluramine, lamotrigine, rufinamide, and topiramate as adjunct treatments for drop seizures. Percentage decreases in drop seizure frequency ranged from 68.3% with high-dose clobazam to 14.8% with topiramate. Valproate continues to be considered the first-line treatment, despite the absence of RDBCTs specifically in LGS. Most individuals with LGS will require treatment with multiple ASMs. Treatment decisions should be individualized and take into account adverse effects, comorbidities, general quality of life, and drug interactions, as well as individual efficacy.

Lamotrigine-associated haemophagocytic lymphohistiocytosis (HLH) confounded with underlying rheumatoid arthritis

Haemophagocytic lymphohistiocytosis (HLH) is one of the rare haematological syndromes more commonly reported in infants/children than adults. This disease is known for its aggressive dysregulated immune response affecting the host rapidly, causing multiorgan dysfunction and thus carries a high mortality. The disease still remains cryptic in this current decade despite all the developments in the ever-evolving field of haematology. Due to its rare occurrence and being more frequent in infants and the paediatric population, the literature lacks enough data to standardise therapies. Such events in adults and the elderly are invariably related to an underlying insult such as infections, other autoimmune or rheumatological diseases or drugs. We describe an interesting case of a middle-aged Caucasian woman who presented with fever, pancytopenia and hepatitis, who was eventually diagnosed with HLH just in time to receive the life-saving specific treatment as per available guidelines.

Lamotrigine-associated hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening disorder of excessive immune activation. It is mostly seen in the paediatric population and is rarely observed in adults. HLH can be inherited or acquired and is commonly triggered by activation of the immune system by an underlying viral infection or in immune system deficiency such as malignancy or underlying rheumatological disease. HLH is a difficult entity to diagnose due to the rarity of this disorder, variable clinical presentation and non-specific clinical and laboratory findings. HLH carries a high mortality if left untreated, and therefore prompt diagnosis and initiation of immunosuppressive, immunomodulatory and cytostatic medications are critical to improve survival in affected patients. Here, we present a case of lamotrigine-associated HLH. To our knowledge, only eight other cases of lamotrigine-associated HLH have been reported in adult patients.

Adult macrophage activation syndrome-haemophagocytic lymphohistiocytosis: 'of plasma exchange and immunosuppressive escalation strategies' - a single centre reflection

OBJECTIVE

In the context of systemic autoimmunity, that is systemic lupus erythematosus (SLE) or adult-onset Still's disease (AOSD), secondary haemophagocytic lymphohistiocytosis (HLH; also referred to as macrophage activation syndrome (MAS) or more recently MAS-HLH) is a rare and potentially life-threatening complication. Pathophysiological hallmarks are aberrant macrophage and T cell hyperactivation and a systemic cytokine flare, which generate a sepsis-like, tissue-damaging, cytopenic phenotype. Unfortunately, for adult MAS-HLH we lack standardized treatment protocols that go beyond high-dose corticosteroids. Consequently, outcome data are scarce on steroid refractory cases. Aside from protocols based on treatment with calcineurin inhibitors, etoposide, cyclophosphamide and anti-IL-1, favourable outcomes have been reported with the use of intravenous immunoglobulin (IvIG) and plasma exchange (PE).

METHODS

Here we report a retrospective series of steroid refractory MAS-HLH, the associated therapeutic regimes and outcomes.

RESULTS

In this single-centre experience, 6/8 steroid refractory patients survived (median follow-up: 54.4 (interquartile range: 23.3-113.3) weeks). All were initially treated with PE, which induced partial response in 5/8 patients. Yet, all patients required escalation of immunosuppressive therapies. One case of MAS-HLH in new-onset AOSD had to be escalated to etoposide, whereas most SLE-associated MAS-HLH patients responded well to cyclophosphamide. Relapses occurred in 2/8 cases.

CONCLUSION

Together, early use of PE is at most a supportive measure, not a promising monotherapy of adult MAS-HLH. In refractory cases, conventional cytoreductive therapies (i.e. cyclophosphamide and etoposide) constitute potent and reliable rescue approaches, whereas IvIG, anti-thymoglobulin, and biologic agents appear to be less effective.