2 Case PresentationThe ED consults you on a 15 year old female with LE numbness and weakness.Previously healthySymptoms began 4 days go with back painSubsequent development of numbness and weakness of both legsHas lost control of urination and defecationGeneral exam: + for palpable suprapubic massNeuro Exam: normal except forLE 0/5 throughout and symmetrically with hypotoniaBelow the umbilicus, there is complete loss of light touch, temperature and pinprickBLE with impaired vibration sensePoor rectal toneDTRs absent in BLE, toes muteDifferential?
4 Localizing Spinal Cord Lesions Upper Motor NeuronLower Motor Neuronaka supranuclear, neuron is in CNSweaknessspastic, increased toneincreased DTRs (muscle spindle threshold decreased)clonus: contraction of one group mm initiate monotactic reflexes in their antagonistssome atrophy- disusetoes upno fasciculationsaka infranuclear, nuclear; CNS neuron or PNS fibersWEAKNESSflaccid, decreased tonedecreased DTRs (efferent limb interrupted)no clonusATROPHYtoes downfasciculations present (exotoxicity)
5 Localizing the Lesion, continued HistoryOnset of symptomsIncontinenceSexual dysfunction (depending on age)ExamMotortonestrengthReflexesDTRsclonusSensorypain and temperaturevibration, joint position sensesensory level on the trunkfurther dermatomes on the extremities
6 Spinal Cord Lesions Acutely: Spinal Shock Initial injury with flaccid paralysis and mute reflexes, including plantarGradual recovery and development of UMN, LMN signsUpgoing toes first to developTransverse myelitis: relate to level of lesion; gradual onset; MRI with contrastMS: related to level of lesion; gradual onset; MRI with contrastMass: eg tumor, abscess: related to level of lesion; gradual onset; MRI with contrastStroke: typically anterior cord; MRI with diffusion and ADC mapPain in a band around the abdomenSymptoms related to level of lesion; sudden onsetBrown-Séquard Syndrome: cord hemisectionIL: weakness, loss of fine touch, vibration, proprioception distal to the lesionCL: loss of pain and temperature 1-2 levels below the lesionAtlantoaxial instability: C1-2 articulationDown syndrome: transverse ligament instability; 10-30% of Down syn patientsSubluxation symptoms are those of cord dysfunction at those levels
7 PREP questionDuring the health supervision visit for a 6 week old boy, his father expresses concern that his son “doesn’t look like” his other children. Growth parameters are normal except for a head circumference of 35.5 cm (<5th percentile).On PE, you note that the infant does not appear to fixate or track your face visually. There is a “slip through” on vertical suspension and “draping over” on horizontal suspension. DTRs are brisk. Moro reflex is present and brisk.Of the following, the MOST likely cause of this infants hypotonia is:Anterior horn cell diseaseCongenital brain malformationCongenital myasthenic syndromeCongenital myopathySpinal cord disease
8 B. Congenital brain malformation HypotoniaLocalize! UMN versus LMN signs, axial vs appendicularTake into account growth parameters, especially HC, as well as features such as trackingRegarding the other choices:A. Anterior horn cell disease: wouldn’t cause microcephaly or increased reflexesC. Congenital myasthenic syndrome: wouldn’t cause microcephaly or brisk reflexesD. Congenital myopathy: no microcephaly or poor visual trackingE. Spinal cord disease: wouldn’t cause microcephaly or poor visual tracking