(098) The role of lithium in the management of altered mental status in Phelan-McDermid Syndrome: a case report

Abstract: Introduction

Phelan-McDermid syndrome (PMS) (22q13 microdeletion syndrome) is a rare neurodevelopmental disorder that manifests with intellectual disability and ASD. We present a case of 18-year-old male with this syndrome who presented with neuropsychiatric regression and prominent agitation.

Case

Our patient developed constipation, urinary incontinence, sleep disturbances, decreased eye contact and worsening agitation with lower extremity jerking. He was noted to regress in activities of daily living and would get frozen in select positions, associated with episodes of tachycardia and sweating in the absence of clear environmental changes. Workup at the time included a CT abdomen (normal), chest Xray (normal), CT head (normal), MRI brain (incidental Rathke’s cleft cyst), EEG (without epileptiform discharges), lumbar puncture (normal), blood/urine/CSF cultures (negative), TSH (normal).

In view of the above non-specific signs and symptoms of catatonia, the patient was treated with a course of high dose benzodiazepines at an outside hospital. He was also maintained on Olanzapine, Clonidine, Propofol, and Dexmedetomidine for agitation.

The patient arrived to our institution on 24mg of lorazepam daily, with no observable catatonic symptoms confounded by the fact that he was on propofol and dexmedetomidine. He was switched to a slow clonazepam taper with the aim of observing for any catatonia re-emergence as the sedative medications were tapered in parallel.

The patient continued to exhibit no symptoms of catatonia on lower doses of benzodiazepines, but his mental status continued to be altered with prominent tachycardia possibly pointing to a benzodiazepine withdrawal process. We treated him with valproate (up to 3g daily), memantine (20mg daily), and olanzapine (up to 30mg daily) with some improvement in his attention and level of consciousness. Ultimately, the patient was switched to Lithium (up to 600mg daily with a serum lithium level of 0.5 mmol/L) with remarkable improvement in mental status manifesting with responsiveness to external environment, significant decrease in jerky movements, and resolution of tachycardia.

Discussion

A few case reports describe successful treatment of agitation in PMS using Lithium. In our case report, we describe successful improvement in altered mental status using Lithium after failure of olanzapine, valproate, and benzodiazepines to do so. There is a strong association between bipolar disorder and PMS and our patient’s agitation and regression may have been indicative of an underlying initial manic episode that was masked by the high doses of benzodiazepines and sedatives upon arrival to our institution.

Conclusion

Regardless of underlying etiology (catatonia, encephalopathy, mania), there is a growing body of evidence in the literature pointing to the effectiveness of lithium in treating regression, agitation, and catatonia in PMS.

Serret S, Thümmler S, Dor E. et al. Lithium as rescue therapy for regression and catatonia features in two SHANK3 patients with ASD. BMC Psychiatry 15, 107 (2015).

Presenting Author(s)

Raghid Charara, MD (he/him/his)

CL fellow
Cleveland Clinic Foundatiion
Cleveland, OH, United States

Co-Author(s)

Anna P. Shapiro-Krew, MD

Associate Staff
Cleveland Clinic
CLEVELAND, Ohio, United States