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عدد الاوراق (2)
31/7/2012Hemiplagia
Paralysis indicates weakness that is so severe that the muscle cannot be contracted at allparesis refers to weakness that is mild or moderate.
"hemi-" refers to one half of the body, "para-" to both legs, and "quadri-" to all four limbs
plegia" signifies severe weakness or paralysis
Hemiparesis results from an upper motor neuron lesion above the midcervical spinal cord; most such lesions are above the foramen magnum
The pyramidal tract is of crucial importance for our ability to perform precise, voluntary movements.
The tract is formed by axons of neurons with their cell bodies in the cerebral cortex, as indicated by its other name, the corticospinal tract.
The axons descend through the internal capsule, the crus cerebri (cerebral peduncle), the pons, and the medulla).
Most of the fibers cross to the other side in the lowermost part of the medulla and continue downward in the lateral funicle of the cord, to finally establish synaptic contacts in the spinal gray matter.
The presence of other neurologic deficits helps to localize the lesion
language disorders, cortical sensory disturbances, cognitive abnormalities, disorders of visual-spatial integration, apraxia, or seizures point to a cortical lesion
A "pure motor" hemiparesis of the face, arm, or leg is often due to a small, discrete lesion in the posterior limb of the internal capsule, cerebral peduncle, or upper pons
Some brainstem lesions produce "crossed paralyses," consisting of ipsilateral cranial nerve signs and contralateral hemiparesis
The absence of cranial nerve signs or facial weakness suggests that a hemiparesis is due to a lesion in the high cervical spinal cord, especially if associated with ipsilateral loss of proprioception and contralateral loss of pain and temperature sense (the Brown-Squard syndrome).
Aetiology
Acute or episodic hemiparesis usually results from ischemic or hemorrhagic stroke, but may also relate to;hemorrhage occurring into brain tumors
a result of trauma
a focal structural lesion or inflammatory process as in multiple sclerosis, abscess, or sarcoidosis.
Evaluation begins immediately with a CT scan of the brain and laboratory studies
Subacute hemiparesis that evolves over days or weeks has an extensive differential diagnosis.
A common cause is subdural hematoma, especially in elderly or anticoagulated patients, even when there is no history of trauma.
Infectious possibilities include cerebral abscess, fungal granuloma or meningitis, and parasitic infection.
Weakness from primary and metastatic neoplasms may evolve over days to weeks.
AIDS may present with subacute hemiparesis due to toxoplasmosis or primary CNS lymphoma.
Chronic hemiparesis that evolves over months is usually due to a neoplasm or vascular malformation, a chronic subdural hematoma, or a degenerative disease.
Noninfectious inflammatory processes, such as multiple sclerosis or, less commonly, sarcoidosis, merit consideration.
Approach to Patients with Hemiplegia
When did the event start?
What is the total duration of the illness?
What were the initial presenting symptoms?
What was the exact mood of onset?
When was the max. deficit noted, at beginning or later?
What was the progress of initial symptoms?
What were the associated symptoms in CNS or other symptoms?
Examination
Is he or she able to co-operate in interview and ex.?Ex. Including emotional state, memory, intelligence, speech, gait, cranial n., motor, sensory, cerebellum.
Signs of meningeal irritation, head injury, raised ICP.
What is the site of localization of lesion?
Cortex: Partial deficit, speech involvement ,cortical sensory abnormalities, higher cognitive functions, focal seizuresetc.Sub cortical : hemiplegia
Internal capsule: dense hemiplegia, absence of speech deficit or seizures.
Thalamic: hemiplegia, hemianopia, hemisensory loss, hyperpathia
Brainstem: crossed hemiplegia
Upper cervical spinal cord: Brown-Squard syndrome