The neuroleptic malignant syndrome: a review

Fluorouracil-induced leukoencephalopathy mimicking neuroleptic malignant syndrome: a case report

BACKGROUND

Fluorouracil-induced leukoencephalopathy is a rare complication and has been reported to present as confusion, oculomotor abnormality, ataxia, and parkinsonism; however, there is no previous report of a presentation mimicking neuroleptic malignant syndrome. Acute cerebellar syndrome may occur, which can be explained by the extremely high accumulation of the drug in the cerebellum. However, presentation mimicking neuroleptic malignant syndrome similar to our case has never been reported.

CASE PRESENTATION

Here, we describe a 68-year-old Thai male presenting with advanced-stage cecal adenocarcinoma, as well as symptoms and signs indicative of neuroleptic malignant syndrome. He received two doses of intravenous metoclopramide 10 mg 6 hours before his symptoms occurred. Magnetic resonance imaging scan revealed signal hyperintensity within the bilateral white matter. Further evaluation showed that his thiamine level was extremely low. Thus, he was diagnosed with fluorouracil-induced leukoencephalopathy mimicking neuroleptic malignant syndrome. The concomitant fluorouracil-induced thiamine deficiency eventually leads to rapid depletion of thiamine and was considered a risk factor for fluorouracil-induced leukoencephalopathy.

CONCLUSION

Fluorouracil-induced leukoencephalopathy is believed to be caused by insult causing mitochondrial dysfunction. However, the exact mechanism remains unknown, but our finding suggests that thiamine deficiency plays a crucial role in fluorouracil-induced leukoencephalopathy. Diagnosis is usually delayed due to a lack of clinical suspicion and results in significant morbidity requiring unnecessary investigations.

Suspected Neuroleptic Malignant Syndrome During Quetiapine-Clozapine Cross-Titration

Neuroleptic malignant syndrome (NMS) is a physiologic phenomenon that has been associated with the use of both first- and second-generation antipsychotics resultant to their ability to block dopamine blockade in the basal ganglia and hypothalamic regions of the brain. The typical reaction involves the presentation of muscle rigidity, changes in mental status, temperature elevation, labile blood pressure, and elevations in creatinine kinase and white blood cell counts. The reaction is most often reported early in the course of therapy but is well documented to have the potential to occur at any point in time. Untreated NMS can be fatal, often from secondary causes such as deep venous thrombosis and pulmonary embolism. Treatment involves immediate discontinuation of the offending agent, supportive therapy of clinical symptoms, and may include the use of the skeletal muscle relaxant, dantrolene sodium, or the dopaminergic agents bromocriptine or amantadine. In this case, we present a patient who developed symptoms of NMS during the cross-taper and conversion from quetiapine to clozapine. The patient was treated for NMS; however, his clinical diagnosis was never able to be definitively determined as he was initially evaluated for septicemia and later treated for suspected bacterial infection with antibiotics, and clozapine-associated side effects cannot be ruled-out as a contributing source to the clinical presentation. The estimated Naranjo Scale score for this case report is 3.

The treatment and management of neuroleptic malignant syndrome

1. The neuroleptic malignant syndrome was initially described as a disorder specifically related to neuroleptic usage with frequent fatal outcome. The observations of variant or mild cases of this syndrome as well as case reports on neuroleptic-malignant-like syndromes in the absence of neuroleptics raises the issue of the usefulness of this terminology and highlights the potential for inappropriate management of this "malignant" syndrome. It has been suggested that hypothalamic thermoregulatory responses may involve an interplay among noradrenergic, cholinergic and serotonergic pathways. Out treatment strategy is based on the pharmacology of neuroleptics and empirical data, verified in our own clinical practice and considers that it is often difficult to determine whether certain physiologic states are a consequence to or specific triggering factors. 2. If a patient's temperature is less than 101, we emphasize vigorous treatment with anticholinergic agents, while simultaneously assessing the psychiatric need for neuroleptics versus medical risks. Given that the severe rigidity of NMS represents severe extrapyramidal effects of dopamine blockade, there is no reason to withhold anticholinergics in the absence of higher temperatures. Neuroleptics can be stopped at the discretion of the clinician even during circumstances when there is fever below 101. 3. In cases of severe EPS with fever greater than or equal to 101, we recommend stopping neuroleptics, treating with anticholinergics and starting with dopamine agonists. In the event of a poor response to dopamine agonists, a brief trial of dantrolene and/or benzodiazepines is recommended. Dantrolene should not be introduced for prolonged periods, since abnormal liver function studies have been observed in approximately 1.8% of patients. 4. In cases of extreme hyperpyrexia (fever greater than 103), clinicians should consider transfer to an ICU or another medical support. Extreme temperatures have been associated with potentially irreversible cerebellar or other brain damage, if not aggressively treated. If neuroleptics are later indicated, a 2 week interval after resolution of symptoms should be maintained before reinstituting neuroleptics. 5. In patients with severe EPS without fever, we emphasize aggressive use of anticholinergic therapy, while simultaneously considering the psychiatric need for neuroleptics versus medical risks. In all cases where a patient's swallowing, respirations or physical mobility is severely compromised, we suggest stopping neuroleptics. Anticholinergic agents should be continued for 7 days after neuroleptics are stopped. If anticholinergic agents are unsuccessful after 2-3 dosages, dopamine agonists may be added, while simultaneously monitoring vital signs. It should be emphasized that severe EPS sometimes takes days to improve even after neuroleptic cessation and the addition of anticholinergics.(ABSTRACT TRUNCATED AT 400 WORDS)

Incipient neuroleptic malignant syndrome?

Recognising confusion as an antecedent to NMS may help abort the full-blown syndrome. Two such cases are reported, along with a third.

Use of neuroleptics after an episode of neuroleptic malignant syndrome

The authors report a case of unequivocal Neuroleptic Malignant Syndrome, in which the patient was successfully rechallenged with a different potent neuroleptic in substantial dosage during the recovery phase. The Neuroleptic Malignant Syndrome did not recur and the patient's psychosis cleared. Reference is made to the relevant world literature.