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Diagnosing Shaken Baby Syndrome
Surv Ophthalmol 54 (1) January--February 2009
BOOK REVIEWS
signaling are events that correlate with neuronal plasticity, it remains to be determined whether antidepressants induce long-term functional modifications of neuronal circuitries in the brain. This study investigated whether chronic treatment with fluoxetine, a selective serotonin reuptake inhibitor, restores plasticity in the adult visual system of the rat. This study examined two classical models of plasticity: 1) the ocular dominance shift of visual cortical neurons after monocular deprivation; and 2) the recovery of visual functions in the adult after long-term monocular deprivation leading to amblyopia. These processes are absent in the adult because of a decline in plasticity that is largely attributed to maturation of intracortical inhibition. Visual evoked potentials were performed, extracellular basal levels of g-aminobutyric acid (GABA) were measured in the visual cortex, long-term potentiation of the white matter in layers II--III of the visual cortex (a form of synaptic plasticity that is absent in the adult because of the maturation of intracortical inhibitory circuitries) induced by burst stimulation were examined, and BDNF levels within the visual cortex were measured. Fluoxetine promoted the recovery of vision and reinstated ocular dominance plasticity during patching in adult rats compared to controls. These effects were accompanied by reduced intracortical inhibition and increased expression of BDNF in the visual cortex. These results demonstrate that chronic fluoxetine administration has the potential to reinstate a juvenile-like form of ocular dominance plasticity in this adult animal model. They further suggest that enhanced serotonergic transmission induced by chronic treatment with fluoxetine promotes functional and/or structural mechanisms that shift the intracortical inhibitory--excitatory balance, triggering plasticity in the adult visual cortex. The authors propose that reduced GABAergic inhibition induced by chronic fluoxetine administration and increased BDNF expression open the pathway to the genes that regulate plasticity, thus allowing a functional modification of neuronal circuitries that underlies the sensitivity to monocular deprivation. Fluoxetine may have potential clinical application in the treatment of human adult amblyopia. Michael C. Brodsky, MD Rochester, Minnesota, USA doi:10.1016/j.survophthal.2008.10.009
159
Diagnosing Shaken Baby Syndrome, Forbes BJ, Cox M, Christian CW: Retinal hemorrhages in patients with epidural hematomas. J AAPOS 12(2):177--80, 2008 The management of ‘shaken baby syndrome’ or non-accidental trauma is fraught with difficulties. It is a tragedy that unfolds from many perspectives. The victim is the abused infant whose injuries may be severe and involve life-long neurological disabilities. The cases are not always straightforward. Nonaccidental trauma may not be the diagnosis, despite seemingly suspicious signs. Parents can be wrongly accused of harming their infant. Sometimes, it is difficult to determine whether an infant has been shaken or sustained an accidental trauma. That may be determined by a court of law, based on the evidence provided by doctors, nurses, and allied health care workers. A salient feature that lawyers ask about is the presence of retinal hemorrhages. But how diagnostic of non-accidental trauma are retinal hemorrhages? Is there a feature of retinal hemorrhages that could be diagnostic of nonaccidental trauma? Is their absence helpful in deciding that the trauma was accidental? There are many questions posed. Forbes et al highlight that the presence of retinal hemorrhages, together with epidural hematomas sustained from trauma, does not necessarily indicate that the cause is provable non-accidental trauma. They describe five patients, all under the age of 8 months, with retinal hemorrhages associated with epidural hematomas that required evacuation. The retinal hemorrhages are described as being superficial, sparse, and either unilateral or bilateral. The injuries sustained by the infants were presumably the consequence of falls or drops that were short distances. This paper is important for doctors, allied health workers, and even law courts to consider when weighing the evidence as to whether or not the diagnosis of shaken baby syndrome can be made. Susan M. Carden, MBBS, FRANZCO, FRACS Melbourne, Victoria, Australia doi:10.1016/j.survophthal.2008.10.010
BOOK REVIEWS
signaling are events that correlate with neuronal plasticity, it remains to be determined whether antidepressants induce long-term functional modifications of neuronal circuitries in the brain. This study investigated whether chronic treatment with fluoxetine, a selective serotonin reuptake inhibitor, restores plasticity in the adult visual system of the rat. This study examined two classical models of plasticity: 1) the ocular dominance shift of visual cortical neurons after monocular deprivation; and 2) the recovery of visual functions in the adult after long-term monocular deprivation leading to amblyopia. These processes are absent in the adult because of a decline in plasticity that is largely attributed to maturation of intracortical inhibition. Visual evoked potentials were performed, extracellular basal levels of g-aminobutyric acid (GABA) were measured in the visual cortex, long-term potentiation of the white matter in layers II--III of the visual cortex (a form of synaptic plasticity that is absent in the adult because of the maturation of intracortical inhibitory circuitries) induced by burst stimulation were examined, and BDNF levels within the visual cortex were measured. Fluoxetine promoted the recovery of vision and reinstated ocular dominance plasticity during patching in adult rats compared to controls. These effects were accompanied by reduced intracortical inhibition and increased expression of BDNF in the visual cortex. These results demonstrate that chronic fluoxetine administration has the potential to reinstate a juvenile-like form of ocular dominance plasticity in this adult animal model. They further suggest that enhanced serotonergic transmission induced by chronic treatment with fluoxetine promotes functional and/or structural mechanisms that shift the intracortical inhibitory--excitatory balance, triggering plasticity in the adult visual cortex. The authors propose that reduced GABAergic inhibition induced by chronic fluoxetine administration and increased BDNF expression open the pathway to the genes that regulate plasticity, thus allowing a functional modification of neuronal circuitries that underlies the sensitivity to monocular deprivation. Fluoxetine may have potential clinical application in the treatment of human adult amblyopia. Michael C. Brodsky, MD Rochester, Minnesota, USA doi:10.1016/j.survophthal.2008.10.009
159
Diagnosing Shaken Baby Syndrome, Forbes BJ, Cox M, Christian CW: Retinal hemorrhages in patients with epidural hematomas. J AAPOS 12(2):177--80, 2008 The management of ‘shaken baby syndrome’ or non-accidental trauma is fraught with difficulties. It is a tragedy that unfolds from many perspectives. The victim is the abused infant whose injuries may be severe and involve life-long neurological disabilities. The cases are not always straightforward. Nonaccidental trauma may not be the diagnosis, despite seemingly suspicious signs. Parents can be wrongly accused of harming their infant. Sometimes, it is difficult to determine whether an infant has been shaken or sustained an accidental trauma. That may be determined by a court of law, based on the evidence provided by doctors, nurses, and allied health care workers. A salient feature that lawyers ask about is the presence of retinal hemorrhages. But how diagnostic of non-accidental trauma are retinal hemorrhages? Is there a feature of retinal hemorrhages that could be diagnostic of nonaccidental trauma? Is their absence helpful in deciding that the trauma was accidental? There are many questions posed. Forbes et al highlight that the presence of retinal hemorrhages, together with epidural hematomas sustained from trauma, does not necessarily indicate that the cause is provable non-accidental trauma. They describe five patients, all under the age of 8 months, with retinal hemorrhages associated with epidural hematomas that required evacuation. The retinal hemorrhages are described as being superficial, sparse, and either unilateral or bilateral. The injuries sustained by the infants were presumably the consequence of falls or drops that were short distances. This paper is important for doctors, allied health workers, and even law courts to consider when weighing the evidence as to whether or not the diagnosis of shaken baby syndrome can be made. Susan M. Carden, MBBS, FRANZCO, FRACS Melbourne, Victoria, Australia doi:10.1016/j.survophthal.2008.10.010