Clinical Reasoning: A 72-year-old man with rapid cognitive decline and unilateral muscle jerks

Abstract

A 72-year-old man presented with cognitive decline and unilateral muscle jerks. Three months prior to presentation, the patient suddenly developed violent muscle jerks involving the right side of his body and face that impaired his gait and balance. Approximately 1 week later, he acutely developed confusion and memory loss. Over the following weeks, he experienced fluctuating symptoms of confusion, memory impairment, insomnia, and paranoid delusions. His muscle jerks and unstable gait were intermittent with return to baseline in between attacks, but they increased in frequency and occurred many times throughout the day. He was found to be mildly hyponatremic and was eventually admitted to a psychiatric ward for treatment of acute psychosis.The patient's medical history was significant for hypertension, well-controlled diabetes, and a myocardial infarction 22 years previously. He was a retired mechanical engineer and was physically active prior to the onset of symptoms.On neurologic examination, the patient was alert and oriented to person only. He registered 3 items but was unable to recall them at 5 minutes and was unable to complete serial 7s. He had no language deficits and could follow 3-step commands without difficulty. His cranial nerve, motor, and sensory examination results were normal. He had a wide-based gait with prominent right lateral pulsion and retropulsion, without any observed muscle jerks during gait examination. Occasional myoclonus involving the right side of his face and right upper extremity were observed, which were associated with loss of awareness and dystonic posturing of the right arm.The patient was admitted to the general neurology ward and an MRI of the brain was performed (figure).

Basal ganglia T1 hyperintensity in LGI1-autoantibody faciobrachial dystonic seizures

“…In contrast, BG MRI abnormalities were exclusive to LGI1-Ab encephalopathy patients with FBDS and were typically contralateral to episodes (e.g., figure 2 ), suggesting a BG origin, which is consistent with the conclusions of prior publications on FBDS. 2 , 3 , 16 This is further supported by the characteristic semiology and the few previously reported cases of T2 hyperintensities, 2 , 3 , 17 , 18 FDG-PET hypermetabolism, 2 , 3 and T1 hyperintensity in the BG (only 2 other cases to our knowledge) 19 , 20 ; furthermore, LGI1 mutant mice develop dystonia. 13 Our study demonstrated that BG T1 hyperintensity can be reliably detected by neuroradiologists.…”

Faciobrachial motor seizures: A more apt description?

“…tonic-dystonic or myoclonic-dystonic) is not unique to our patient and is reported in more than one-third of all the cases published in the literature ( Table 1 ). Of these mixed phenotypes, tonic-dystonic was the commonest phenotype [13] , [14] , [17] , [18] , [19] , followed by myoclonic-dystonic subtype [20] , [21] .…”

Long-term Outcome of LGI-1 Encephalitis in Chinese: a 2-year follow-up

“…LGI-1 encephalitis is a rare neurological disorder with sub-acute course of progressive encephalopathy and FBDS [1,2] and which is the autoantigen associated with limbic encephalitis previously attributed to voltagegated potassium channels [3] . In addition to clinical manifestation of classic limbic encephalitis, some patients may develop hyponatremia and have preceding or concomitant myoclonic-like jerks described as FBDS [4,5] . and its incidence is rising.…”