A 25-year-old man injured his neck in an MVA 2 years ago. He has proprioception loss in his right foot, paralysis of the right lower extremity, and pain sensation loss on part of his left bodyPart of the C4 in his spinal cord broke off, his spinal cord was getting larger as it was going up, causing his symptomsMaking a Neurologic Diagnosis:The neurologic clinician attempts, with each patient, to answer:1) -Where is the lesion?2) -What is the lesion?Lesions of the nervous system can beAnatomic - with dysfunction resulting from structural damage (stroke, trauma, and brain tumors)Physiologic - reflecting neuronal dysfunction in the absence of demonstrable anatomic abnormalitiesSymptoms are subjective experiences from the disorder ("I have a headache"; "The vision in my right eye became blurry a month ago")Signs are objective abnormalities detected on examination or via laboratory tests (a hyperactive reflex or abnormal CSF protein level)sometimes patients can have both symptoms and signsManifestations of Neurologic Disease May Be Negative or PositiveNegative manifestations reflect damage to neurons-result from loss of function (hemiparesis, impaired sensation, loss of memory)-Parkinson disease-multiple sclerosisPositive abnormalities result from inappropriate excitation of neurons-These include seizures (caused by abnormal cortical discharge) and spasticity (from the loss of inhibition of motor neurons)Head Trauma:Blunt (‘closed’) or caused by a penetrating missileSkull may be fractured and depressed, tearing brain coverings and brain itselfHematomas:tearing of the middle meningeal artery causes bleeding into extradural space (epidural hematoma)-as the clot explans, the brain is compressed. Coma happens hours after the blow.tearing of vein across the subdural space causes a gradual seepage of blood - subdural hematomaMeningitis: inflammation of the meninges from infection with viruses, bacteria, etc-viral meningitis is mild and self-limiting-bacterial or fungal meningitis damages cranial nerves and brain (proceeds to raised intracranial pressure, brain displacement, deathVentricles:Lecture 3 (January 20)Computed Tomography (CT):distinguishes tissue density (no density = black)machine moves around a still patientnon-invasive, fast, painlessavailable in all ERsCT scanner rotates a narrow x-ray beam around the head. The quantity of x-ray absorbed in small volumes (voxels [volume elements]) of brain, measuring 0.5 mm x 1.5 mm, is computed. Amount of x-ray absorbed in any slice of the head can be thus determined; absorption is proportional to density of the tissue. Black/white pictures of head slices are displayed; black represents low-density and white high-density structures.A series of 10 or 20 scans, each reconstructing a slice of brain, is required for a complete study.Magnetic Resonance Imaging - MRIMagnetic field + radio wavesUsed to see:edemahemorrhagetumorstakes 40-60 min, like motionless, noisy, not always availablespatial distribution of elements with an odd number of protons (such as hydrogen) within slices of brain can be determined by their reaction to an external radio frequency signalPositron Emission Tomography (PET)Motor Pathways by origin1. Corticospinal Pathways – neurons in cortex terminate in spinal cord - from the motor system down to the spine.2. Brainstem origins - Named for cell group from which they originate: (tectospinal, rubrospinal, reticulospinal, vestibulospinal) - from brainstem to spine3. Corticobulbar Pathways – neurons in cortex terminate in brainstem - CN motor nuclei - from contex to brainstemMotor Pathways by positionLateral Corticospinal Tract – innervates motoneurons in lateral ventral horn - large, main one. If lesioned you would lose voluntary movement.2 neurons in lateral corticospinal tract (voluntary movement, limbs). This pathway is long. If you’re 7 ft tall, the upper motor neuron is about 5 ft.Poliolesion in ventral root near lower motor neuron can cause paralysis - stab woundRubrospinal Tract – near lateral corticospinal tract - targets upper limb flexor motoneuronsOrigin: red nucleus in midbrainFibers cross in midbrain and projectcaudally in lateral brainstemCase 3: Anterior spinal artery infarctwhen you repair an aortic aneurysm you have to clamp the aortalesion in anterior (front) lumbar spinal cord - loss of blood in anterior spinal artery (anterior spinal artery syndrome)MRI of a spinal epidural abscess due to tuberculosis A Sagittal T2-weighted free spin-echo MR sequence A hypointense mass replaces the posterior elements of C3 and extends epidurally to compress the spinal cord (arrows) B Sagittal T1-weighted image after contrast administration reveals a diffuse enhancement of the epidural process (arrows) with extension into the epidural spaceAbscess in epidural space, crushing the spinal cord.Symptoms:sensory part of the spinal cord being impaired because of the location of the abscess. The dorsal column (dorsal part of the spinal cord, fascicullus gracillus and fasciculus coneatus)If it’s mild, they give him antibiotics. IF legs and arms start to feel heavy surgery is required.Symptoms: loss of vibration and loss of position sense (not weakness because it’s just affecting the dorsal part of the spinal cord)MRI of syringomyelia associated with a Chiari malformation Sagittal T1-weighted image through the cervical and upper thoracic spine demonstrates descent of the cerebellar tonsils and vermis below the level of the foramen magnum (black arrows) Within the substance of the cervical and thoracic spinal cord, a CSF collection dilates the central canal (white arrows)Central canal is affected - pain and temperature cross over at the central canal (loss of bilateral pain and temperature)Cape loss - trunk - means legs are normal. Lets are okay because they crossed overUpgoing toes - upper motor neuron sign (hyperreflexia, upgoing toe are first order motor neuron signs in the upper motor neuron)Ventral horn - hand atrophyboth lower and upper motor neuron lesionCase 6: Transverse myelitistingling in middle of his trunk - dorsal columnarms normal, legs no feeling and no strengthlesion in spinal cord, (between cervical and lumbar)Transverse myelitisspinal cord swollen. Transverse - side to side (at T6-T7) myelitis (inflammation of spinal cord)Treatment is steroids but not always effectiveCase 7: B12 defdorsal column, back of the spinehyperreflexia (descending pathway) two upper motor neuron signs - deep tendon reflexer