Neonatal-onset brainstem reticular reflex myoclonus following a prenatal brain insult: generalized myoclonic jerk and a brainstem lesion.
Brainstem reticular reflex myoclonus (BRRM) is characterized by sudden, generalized, shock-like movements that can be elicited by sensory stimulation. We present a boy, born after 35 weeks gestation, who was diagnosed with neonatal-onset BRRM. Within 1 hr of birth, the patient showed spasticity and generalized clonic movements of all limbs elicited with tactile stimulation anywhere on the body. Surface electromyography showed co-contraction of agonistic and antagonistic muscles, revealing that his generalized clonic movements were tremulous myoclonus in nature. Brain magnetic resonance imaging (MRI) at 21 hrs after birth disclosed high-intensity lesions in the Rolandic area, thalamus, basal ganglia, and brainstem, including the dorsal pons and medulla, the center of BRRM, in T1-weighted images. Follow-up MRI at 1 month revealed dramatic improvement in the pontine lesion. The patient showed gradual remission of the characteristic movements, which disappeared at 1 year of age, but the patient died unexpectedly at 1 year and 3 months. In conclusion, neonatal BRRM arises as a result of severe brainstem injury, and the associated lesions may only be seen temporarily on MRI taken soon after birth.
Kakisaka
Yosuke
Y
Department of Pediatrics, Tohoku University Graduate School of Medicine, and Tohoku Kosei Nenkin Hospital, Sendai, Japan. kakisuke@mui.biglobe.ne.jp
Haginoya
Kazuhiro
K
Togashi
Noriko
N
Kitamiura
Taro
T
Uematsu
Mitsugu
M
Hino-Fukuyo
Naomi
N
Kure
Shigeo
S
Saito
Junko
J
Kitaoka
Setsuko
S
Watanabe
Shuei
S
Yoshikawa
Hideto
H
Nara
Takahiro
T
Suzuki
Yoichi
Y
Tsuchiya
Shigeru
S
D004576:Electromyography; D017809:Fatal Outcome; D006801:Humans; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D008297:Male; D009207:Myoclonus / Q000209:etiology* / Q000473:pathology*; D049188:Prenatal Injuries / Q000473:pathology*; D012021:Reflex, Abnormal; D012154:Reticular Formation / Q000293:injuries*