الفهرس 
Pathogenesis of SCDOnly 14 pages are availabe for public view
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Abstract
Sickle cell disease (SCD) is the most common genetic disease of the blood. It is an autosomal recessive inherited hemoglobinopathy. It is characterized by chronic hemolytic anemia and episodes of painful vaso-occlusive crises (VOC).
VOC resulting in occlusion of vasanervosum and infarction of nerves, can lead to cranial nerve neuropathies particularly, trigeminal neuropathy, mental neuropathy, as well as, peripheral nerves mononeuropathy multiplex or distal sensorimotor demyelinating polyneuropathy.
Peripheral nervous system involvement in SCD is under-appreciated, as silent subclinical peripheral neuropathy involvement does occur. Moreover, SCD peripheral neuropathic involvement may be obscured by the severity of central nervous system complications.
Emphasizing peripheral and cranial neuropathy in SCD will increase the recognition of such complications and ultimately providing new insights into their prevention and treatment.
Electrophysiological studies (EPS) are objective, noninvasive and potential useful methods for diagnosis of symptomatic trigeminal and peripheral neuropathy, as well as, for detecting subclinical involvement of these nerves. Application of orthodromic recording of mental sensory nerve action potential (SNAP) in concert with trigeminal evoked potentials (TEP) are sensitive tools for the investigation of trigeminal nerve sensory afferents and the central components, respectively.
Computed tomographic (CT) of the mandible is an important tool to assess patients with mental neuropathy. CT imaging of the mandible performed in several planes can yield an accurate anatomic image of the mandibular canal diameter, and the dimensions of the mental foramen on the buccal side of the mandible.
The aim of our study was to detect the possible association between SCD (HbSS) and either trigeminal or peripheral neuropathy as well as, the pattern of trigeminal and peripheral neuropathic lesion in SCD patients, and correlate the results with clinical & laboratory results, and also with CT findings of the mandible.
We conducted our study on fifty adult patients with SCA and ten healthy subjects a control group. Our patients were divided into two groups. group (I) included thirty SCA patients, who were clinically free of any symptoms or signs of peripheral or trigeminal neuropathy. group II included twenty SCA patients, who had symptoms and/or signs of either peripheral or trigeminal neuropathy.
We performed EPS for trigeminal nerve (including nerve conduction study (NCS) of inferior alveolar nerve (IAN), TEP and blink reflex) and for peripheral nerves (motor and sensory NCS of bilateral median, ulnar, tibial, common peroneal and sural nerves and somatosensory evoked potentials (SSEP) of both median nerves) to detect either symptomatic or subclinical trigeminal and peripheral neuropathy. Mental foramen (MF) dimensions; height and width and mandibular canal (MC) diameter were assessed in group II patients and controls using CT scan images in axial and cross-sectional views.
Our study revealed:
As regards NCS of IAN: our study revealed abnormal findings in group I in 16/30 (53.3 %) of patients, while in group (II) there was abnormal findings in 17/20 (85%) of patients.
On comparing group I patients & controls, as well as, both patients groups (group I and group II), there was a statistically significant difference as regards IAN latencies and amplitude, and high significant difference as regards nerve conduction velocity (NCV).
On comparing group II & controls, there was high significant difference as regards all IAN parameters.
As regards TEP, on comparing (group I patients with control group), as well as, (group II with control group), there was high significant difference as regards all parameters of TEP.
On comparing group I and group II patients, there was non-significant difference as regards all parameters of TEP, except P19 latency which showed a statistically significant difference between both patients groups.
As regards Median SSEP, comparison between group I & controls showed a statistically non-significant difference as regards N20 latency, and a statistically significant difference as regards P25 latency. Comparison between group II & controls showed a statistically significant difference as regards N20 and P25 latencies. While, N20/P25 amplitude showed a statistically high significant difference between both patients groups; group I and II with controls.
Comparison between group I and group II patients showed a statistically non-significant difference as regards all parameters.
As regards sensory NCS, on comparing (group I patients with control group), and (group II with control group), as well as, both patients groups together (group I and II), our results showed high significant difference regarding SNAP amplitude of median, ulnar and sural nerves,
On comparing group I patients with controls, there was significant difference as regards sensory latency and NCV of median, ulnar and sural nerves, except that sural latency showed non-significant difference.
On comparing group II with controls group, there was highly significant difference as regards sensory latency and NCV of ulnar nerve and NCV of sural nerve, while there was significant difference as regards sensory latency and NCV of median nerve and latency of sural nerve.
On comparing group I and II patients, there was sidnificance difference as regars sensory latency of sural and ulnar nerves and sensory NCV of ulnar nerve.
As regards motor NCS, On comparing group I patients with controls, there was significant difference as regards CMAP amplitude, amplitude decay percentage, and NCV of median, ulnar, tibial and peroneal nerves, as well as, F-wave latencies of median and ulnar nerves. While, distal motor latency of all studied nerves showed non-significant difference.
On comparing group II patients with controls, our study showed high significant difference as regards CMAP amplitude, amplitude decay percentage, and NCV of median, ulnar, tibial and peroneal nerve. F-wave latencies of median and ulnar nerves showed. Regarding, distal motor latency, there was significant difference between group II patients and controls for median and ulnar nerves, and high significant difference for peroneal nerves, while tibial nerves showed non-significant difference.
On comparing group I and II patients, there was significant difference as regards distal motor latencies of ulnar, and peroneal nerves, and CMAP amplitude of ulnar nerve, and amplitude decay percentage of the four studied motor nerves and NCV of ulnar, median and peroneal nerves.
As regards MF dimensions and MC diameter, comparison between group II and controls showed a statistically significant difference regarding MF (height and width) and MC diameter.
Our results showed positive significant correlation as regards:
TEP waves latencies with frequency of VOC and HbS% in group II patients.
TEP waves latencies with previous mandibular pain in group I patients.
P19 latency with previous mandibular pain in group II patients.
N13 latency with current mandibular pain in group II patients.
N13/P19 amplitude with duration since last VOC and HbF % in group II patients.
IAN latency with frequency of VOC, total bilirubin and HbS% in group II patients.
IAN latency with previous mandibular pain in group I and II patients.
IAN amplitude and NCV with duration since last VOC in group II patients.
IAN NCV with HbF % in group II patients.
N13 and P19 latencies with headache.
TEP waves latencies and IAN latency with mandibular nerve sensory affection clinically in group II patients.
N13/P19 amplitude and IAN amplitude with ipsilateral MF height, width and MC diameter in group II patients.
IAN NCV with NCV of ulnar sensory nerve and sural nerve in group I patients.
IAN NCV with NCV of median sensory nerve in group II patients.
Frequency of VOC with sural and ulnar sensory latencies in group I patients.
Frequency of VOC with median, ulnar and peroneal distal motor latencies and median amplitude decay percentage in group II patients.
Duration since last VOC with amplitude of ulnar and peroneal nerves in group II patients.
Duration since last VOC with NCV of median, ulnar and peroneal nerves in group II patients.
Our results showed negative significant correlation as regards:
TEP waves latencies with duration since last VOC in group I patients.
TEP waves latencies with HbF % in group II patients.
N13/P19 amplitude with previous mandibular pain in group I patients.
N13/P19 amplitude with frequency of VOC in group II patients.
N13/P19 amplitude with HbS % and total bilirubin in group II patients.
IAN latency with duration since last VOC and HbF % in group II patients.
IAN amplitude with frequency of VOC and previous mandibular pain in group I and II patients.
IAN NCV with HbS % and total bilirubin in group II patients.
P19 latency and IAN NCV with ipsilateral MF height, width and MC diameter in group II patients.
N13 latency with ipsilateral MF width in group II patients.
N30 latency and IAN latency with ipsilateral MF height and MC diameter in group II patients.
IAN NCV with mandibular nerve sensory affection clinically in group II patients.
Duration since last VOC with sural and ulnar sensory latencies in group I patients.
Frequency of VOC with median and peroneal NCV in group II patients.
Frequency of VOC with ulnar and peroneal amplitude in group II patients.
MC diameter with previous mandibular pain in group II patients.
Duration since last VOC with median, ulnar and peroneal distal motor latencies and median amplitude decay percentage in group II patients.