Sudden Infant Death Syndrome – Role of Trigeminocardiac Reflex: A Review

Abstract

Sudden infant death syndrome (SIDS) is an unexplained death in infants, which usually occurs during sleep. The cause of SIDS remains unknown and multifactorial. In this regard, the diving reflex (DR), a peripheral subtype of trigeminocardiac reflex (TCR), is also hypothesized as one of the possible mechanisms for this condition. The TCR is a well-established neurogenic reflex that manifests as bradycardia, hypotension, apnea, and gastric hypermotility. The TCR shares many similarities with the DR, which is a significant physiological adaptation to withstand hypoxia during apnea in many animal species including humans in clinical manifestation and mechanism of action. The DR is characterized by breath holding (apnea), bradycardia, and vasoconstriction, leading to increase in blood pressure. Several studies have described congenital anomalies of autonomic nervous system in the pathogenesis of SIDS such as hypoplasia, delayed neuronal maturation, or decreased neuronal density of arcuate nucleus, hypoplasia, and neuronal immaturity of the hypoglossal nucleus. The abnormalities of autonomic nervous system in SIDS may explain the role of TCR in this syndrome involving sympathetic and parasympathetic nervous system. We reviewed the available literature to identify the role of TCR in the etiopathogenesis of SIDS and the pathways and cellular mechanism involved in it. This synthesis will help to update our knowledge and improve our understanding about this mysterious, yet common condition and will open the door for further research in this field.

Trigeminocardiac Reflex: Beyond a skull base Reflex

“…Sometimes, it can be fatal. Our group demonstrated that the TCR phenomenon is not only limited to the clinical neurosurgical domain, it also has a possible influence on many conditions including bruxism, sudden death infant syndrome, obstructive sleep apnea, sudden death in adults, acute nonsurgical conditions (epistaxis) and forensic medicine [20,21]. Future investigations should reveal many more associations of TCR in various other neurological conditions.…”

“…We do not yet know the answer. But from examinations in sudden infant death [20], it seems that changes in the brainstem make the patients prone to the TCR and SCR.…”

“…The role of the TCR is not only limited to certain neurosurgical conditions and recently, it is also linked with various other surgical conditions, sleep disorders, sudden infant death syndrome and other interventions [20,21]. Similar to the TCR, recently Chowdhury and Schaller described the spinal cardiac reflex (SCR) [22] in spine surgeries that has also some similarities to the TCR; however, its mechanism is not yet fully elucidated.…”

Brain and heart connections: The trigeminocardiac reflex!

“…[70] In addition, the role of the TCR in various sleep disorders was also highlighted recently. [71,72]…”

Sleep Disorders: Is the Trigemino-Cardiac Reflex a Missing Link?

“…Various manifestations of the TCR include the naso-cardiac reflex, peripheral TCR, the diving reflex (DR), and the central TCR ( 6 – 10 ). Interestingly, DR, a subtype of TCR, has been hypothesized to have a role in sudden infant death syndrome (SIDS) ( 11 ) and the TCR is also linked to sleep disorders like sleep-related bruxism (SB) ( 12 ). It is reported that sudden microarousals (MA) occurring in the brain due to airway obstruction during sleep cause tachycardia, which stimulates RMMA and teeth grinding that activate the TCR resulting in bradycardia.…”