Thread: Neurology Clinical Cases

Basal Ganglia Lesion - VASCULAR - HEMORRHAGE IN THE GLOBUS PALLIDUS

A Sample Case: A right-handed 65 yr old man had suffered a stroke. Reduced pain and temperature sense as well as spasticity, weakness, and a positive Babinski were still present on his left side but all symptoms were gradually lessening by 2 yrs after the stroke. However, he gradually developed slow, involuntary movements of his hands and feet which were marked by severe hyperflexion and hyperextension which often left his hands fixed in bizarre poses for several seconds. His wife reported that the abnormal movements were not present when he was asleep.

His general physical exam was unremarkable including the CV system. The neurologic exam showed him to be alert and well oriented with respect to time and place. Cranial nerves were normal. The limbs were somewhat weaker on the left side with slightly brisker deep tendon reflexes. New findings included abnormal posturing and writhing movements at the joints of the hands and feet on the left. When seated and asked to hold the arms outstretched the left arm wandered about while the left leg did the same. The writhing interfered with voluntary movements and automatic movements such as his gait. There was no dysmetria or intention tremor on either side.


Explanation -

The left-sided hemiparesis of both limbs, and other symptoms of the upper motor neuron syndrome, is due to injury of corticospinal fibers on the right. It is probably not due to a cortical lesion since memory and mental status were always normal. Development of athetoid involuntary movements on the left after a period of time following the stroke suggests injury to the right globus pallidus and/or its efferent pathways, which may become evident upon resolution of the injury, i.e., swelling and edema, to the corticospinal fibers. Since the globus pallidus influences the ipsilateral thalamus and motor cortex the symptoms appear on the opposite side due to the crossing of pyramidal tract, though which the influence of the basal ganglia is expressed.

Sudden onset, suggests a cerebrovascular event rather than a space taking tumor or degenerative process. Weakness and athetoid movements also are suggestive of a small localized lesion in the vicinity of the globus pallidus and internal capsule. The vessels which supply the globus pallidus and the adjacent posterior limb of the internal capsule are the lateral striate branches of the middle cerebral artery.

Basal Ganglia Lesion - DEGENERATIVE - HUNTINGTON'S DISEASE

A Sample Case: A 40 yr old man slowly became aware of irregular involuntary movements in all his extremities. At first the movements were slight and described as "fidgety" or clumsy but in time the aimless movements became more severe and on occasion caused stumbling and interfered with his routine chores. He felt tired since the movements did not permit him to get adequate rest but his wife reported that they were not present when he was alseep. In addition, family members noted that he had slowly become emotionally labile and from his job came reports of uncharacteristic rudeness and vulgarity.

The general physical exam was normal. His history included the death of his father at about 50 yrs from some ill-defined disease which included mention of a mental disorder and description of "fits". The patient seemed not to have a firm grasp of time or place. Other cognitive tasks, e.g., simple arithmetic or following instructions were subnormal even though he had no problem in comprehension or memory. The rest of the neurologic exam of was mostly unremarkable except for severe loss of muscle tone and hyporeflexia in addition to the writhing movements in his arms, which he could not voluntarily prevent. In walking he stumbled because of spasmodic irregular movements which occurred in his legs.


Explanation -

The patient demonstrates the major signs of Huntington’s disease, predominantly an autosomal dominant disorder (traced in the USA to 6 immigrants from England in 1630). It is characterized by progressive choreiform movements and dementia, usually beginning in the late 30s - 40s and death occurring 15 - 20 yrs later. Change in mental status is gradual beginning with an alteration in personality; it becomes a memory dysfunction with global decline in intellect associated with loss of neocortical cells or basal ganglia pathways to the prefrontal cortex.

In this patient there were no signs of cranial nerve involvement or disease of the ascending sensory or descending motor pathways, except for the hypotonia and hyporeflexia without weakness. Such motor findings indicate a movement disorder which, in association with the cognitive dysfunction and family history, suggests Huntington’s disease. (Movement disorders, e.g., globus pallidus and subthalamic nucleus, often will have motor weakness and sensory loss because of involvement of the adjacent internal capsule.) The major pathology is massive bilateral loss of cells of the head of the caudate and putamen with lesser involvement of the globus pallidus and thalamus. The bilaterality, diffuse symptomology, and slow onset suggests a degenerative disorder rather than one of vascular or neoplastic causation.

Basal Ganglia Lesion - DEGENERATIVE - PARKINSON'S DISEASE

A Sample Case: A 62 yr old woman noticed a painful cramping in her left foot which caused her to go to the doctor. Co-workers noticed a slight shakiness in her hands and, in retrospect, described her face as less animated and her walk as slower. After a period of time she had difficulty rising from her chair and when walking had suffered several falls; she tended to attribute these to her generalized tired feeling.

Her past medical history revealed several disorders unrelated to her current complaints. Her general physical condition was good. The neurologic exam showed her to be alert, well-oriented with respect to time and place, and with good comprehension. Her speech was clear though somewhat soft. Blinking was somewhat infrequent and her eyes seemed to be open wide. There was a slight tremor in her lower jaw that was not obvious when she spoke. There were no other obvious cranial nerve signs. Sensory examination was normal as were strength and deep tendon reflexes. There was however increased resistance to passive stretch in both flexors and extensors at the wrist, elbow, and shoulder. The hand, but not the foot, showed a rhythmic tremor of 4-5/sec which was suppressed when she was asked to write or to extend her hands; her writing seemed to be unusually small, i.e., micrographia. The patient was slow to rise from her seated position and if pushed from in front or back when standing tended to move with many short steps (antero-, and retropulsion). There was little swinging of her arms when she walked but there was no dysmetria or other cerebellar signs.


Explanation -

Early signs of Parkinson’s disease are usually subtle and may involve one side before the other or include the upper and/or lower extremities. A tiredness, fatigue, and cramping may be due to the advancing rigidity. Psychologic depression and the most severe motor signs may occur late in the disease.

Her cranial nerves were largely unaffected except for the tremor of the jaw and the wide, unblinking eyelids. The expressionless face ("masked facies") is a sign of this disease. Strength and reflexes of the limbs, upper and lower, were normal. There was resistance to passive stretch in the opposing flexors and extensors upper extremities, i.e, "rigidity"; the presence of a noticeable concomitant tremor is described as "cogwheel" rigidity. In later stages of the disease the body is flexed at the waist and at the elbow, an indication that the strength of the flexors in rigidity is greater than that of the extensors. Her hand demonstrated tremor and micrographia. The latter is an indication of the slow movement with decreased amplitude (bradykinesia) which characterizes all movements in Parkinson’s disease. Difficulty in rising from a chair or bed, lack of arm swing in walking, tripping, and short steps are all suggestive of Parkinsonian bradykinesia, rigidity, and inability to make the automatic postural adjustments necessary in standing and walking.

Bradykinesia, rigidity, and tremor at rest are the cardinal signs of Parkinson’s disease, a chronic, progressive, degenerative disease associated with loss of neurons in the substantia nigra. The slow onset indicates that its etiology is not vascular; the eventual bilateral symptoms indicates that it is not a neoplasm. The substantia nigra has controlling influence at many levels related to the basal ganglia and movement especially via its input to the caudate/putamen.

Cerebrum Lesion - VASCULAR - OCCLUSION OF THE MIDDLE CEREBRAL ARTERY

A Sample Case: A 60 yr old anatomist was demonstrating a dissection when he suddenly dropped the forceps from his left hand. At the same time his speech became slurred and as he left the room he dragged his left foot.

In the emergency room his wife related his history which included high blood pressure which was elevated; other vital signs were normal. He was alert and well oriented with respect to time and place and his comprehension was good. In spite of some slurring of speech he was coherent and the content was good. On examining the cranial nerves it was obvious that his eyes were consistently directed to the right and when asked to look to the left his eyes would not pass the midline. The visual exam showed a left homonymous hemianopsia. He could wrinkle his brow on both sides but in attempting to blow out his cheeks only the right side responded. There was a spastic paresis of the left arm and leg. Pain, temperature, and light touch were preserved over the body and face on both sides but but discriminative touch and proprioception were impaired on the left and he was unable identify objects placed in his left hand.


Explanation -

Left spastic hemiparesis of the arms and legs indicates an upper motor neuron lesion at least above the mid-cervical cord; weakness of the left lower face rules out the cord and suggests a lesion above mid-pons on the right side involving the corticospinals and corticobulbar fibers. Left-side loss of proprioception and astereognosis with sparing of pain and temperature can occur with right-sided sensory pathway lesions above the thalamus because although discriminative touch and proprioception is recognized only at cortical levels pain and temperature can be appreciated by the thalamus.

Frontal eye fields (area 8) of the cortex are located just anterior to the area controlling muscles of the face in area 4. Both areas project through the genu of the internal capsule. Destructive lesions of area 8 on the right cause the eyes at rest to deviate to the right due to the activity of area 8 on the left and the eyes cannot be deviated past midline to the left upon command. To account for facial and leg paresis might require postulating a broad lesion of the cerebral cortex including the medial side of the hemisphere (for the foot-knee paresis) and the frontal motor cortex laterally down to the lateral fissure (for facial weakness) - this would be unlikely. However, motor and sensory fibers implicated are compacted in the genu and posterior limb of the internal capsule so this is a more reasonable site.

Left homonymous hemianopsia occurs with lesions of the right visual pathways behind the optic chiasm. Optic radiations form the most posterior fibers of the internal capsule; optic radiations also run deep to the cortex of the parietal and temporal lobes. The abrupt onset of symptoms and history of high blood pressure suggested a vascular event. Neither the anterior nor posterior cerebral arteries supply all of the involved fibers implicated in this case. However, the middle cerebral artery supplies the lateral aspect of the cerebrum and the much of the deeper lying white matter, injury to which can explain all the symptoms.

Cerebrum Lesion - VASCULAR - OCCLUSION OF THE POSTERIOR CEREBRAL ARTERY


A Sample Case: Upon awakening a young school teacher went to her class and was astonished to find that she could not read the materials on her desk. She tried to read small printed items then large printed items but could not comprehend them.

At her neurologic exam she was intelligent, alert, and well oriented. She demonstrated a right homonymous hemianopsia but other cranial nerves were normal as was her muscular strength and sensory systems. She understood information presented orally or auditorily but could not name letters of the alphabet shown to her visually though she could identify and name them by touch. Her response to letters presented visually was to describe their shape but she could not name what they were. When asked to write her insurance information she did so accurately but couldn’t read back what she wrote.


Explanation -

An homonymous hemianopsia is due to injury to the visual pathway behind the optic chiasm - a visual defect in the right visual field is due to injury on the left side. Such a visual defect would not in itself cause an inability to read, the left visual field would be used instead. Language functions are usually a property of the left hemisphere and injury could result in language difficulties of motor or receptive types. She shows that her motor speech, whether spoken or written, is normal and information presented orally or by touch is handled well. She demonstrates a pure alexia - an inability to read.

Her post-chiasmal lesion on the left has deprived her left calcarine cortex, which ordinarily would deal with language, of direct visual input. The left visual field and its visual pathway to the right hemisphere is intact (otherwise she would be blind). Visual information from the right visual cortex would ordinarily be transferred to the left hemisphere through the corpus callosum for integration of visual field information. However, here the callosal fibers are damaged. The language dominant left hemisphere gets neither direct input from the right visual field nor indirect input from the left visual field via the corpus callosum hence she cannot comprehend written words.

The suddenness of the loss suggests a vascular etiology and the symptoms are referable to branches of the posterior cerebral artery. Vascular studies demonstrated an occlusion in branches of the left posterior cerebral artery supplying the calcarine cortex and adjacent splenium of the corpus callosum.

Cerebrum Lesion - VASCULAR - OCCLUSION OF THE ANTERIOR BRANCH OF THE MIDDLE CEREBRAL ARTERY

A Sample Case: A 55 yr old woman awoke but couldn’t get out of bed due weakness of the right arm and leg. Her husband spoke to her and she understood him but she was unable to speak in response.

The patient was alert and oriented and followed commands well. She had bruits in both carotid arteries but otherwise the cardiovascular system was normal. Past medical history was unrelated to the present condition. There was no papilledema. The doctor found that the patient had a flattened nasolabial fold on the right and was unable to smile or show her teeth on the right; the brows could be wrinkled symmetrically upon command. When she was asked to protrude her tongue it deviated to the right. Other cranial nerve functions were unaffected. The upper right extremity was very weak, with spasticity and hyperreflexia. The lower limb was less weak with mild hypertonia, hyperreflexia, and a positive Babinski sign. Cerebellar function was unaffected. The sensory exam was normal.

Her speech was very halting. Its content was appropriate but she had difficulty finding the right words and her sentences were short and incomplete. When asked direct questions she would answer appropriately but only with a yes or no response or she would correctly point to an object. Her speech was also slurred making words difficult to understand.


Explanation -

Spastic paralysis (on the right side) was more severe in the arms than the legs. This is suggestive of a left upper motor neuron lesion (corticospinals) at cortical levels rather than in the internal capsule where the fibers of both limbs are compact and so the weakness of upper and lower extremities is more likely to be of equal severity. Slurred, poorly articulated speech (dysarthria) and a tongue which deviated to the right upon protrusion suggests that corticobulbars on the left are also involved. Right-sided paralysis of the lower face indicates corticobulbar involvement on the left.

In addition to slurring of speech, which has to do with the mechanics of sound production, she had trouble with language itself (aphasia), i.e., there were problems in finding the right words to define objects and forming words into sentences. There was no indication of problems with comprehension of language but rather its expression, i.e., motor aphasia. Language functions are usually represented in the left hemisphere.

(In addition to paresis and paralysis of the right limbs, due to the left sided lesion, the patient had an apraxia of the left limbs. Apraxia is the inability to carry out a command for a motor act even though the patient understands the command and has no weakness or incoordination. This patient was asked to scratch her left knee with her left hand, which had no signs of weakness; she made a vague gesture toward her knee, demonstrating comprehension, but didn’t complete the task. Later she used her left hand to adjust the hem on her skirt to cover her left knee. This apraxia is explained by the lesion to the motor cortices including Broca’s motor speech area. The command to scratch is first comprehended in the Wernicke’s speech area in the left temporal lobe. Connections exist (arcuate fasciculus) from Wernicke’s area to Broca’s area and the left motor cortex. The left arm responds to the command when the right motor cortex is activated by crossing fibers coming from the left motor cortex via the corpus callosum. In this case injury to the left motor cortex injures those crossing fibers and so the command is poorly executed.)

The suddenness of the onset of the symptoms suggests that a vascular event has occurred rather than a slowly growing mass. The symptoms suggest that the most severely affected area is the lateral surface of the frontal lobe, i.e., the precentral gyrus (areas 4,6) containing the motor cortex serving the head, arms (and to a lesser extent the legs) and in addition, Broca’s motor speech area (area 44,45). These areas are served by branches of the middle cerebral artery. An angiogram confirmed an occlusion in anterior branches of the middle cerebral artery.

Cerebrum Lesion - NEOPLASMS - MENINGIOMA

A Sample Case: A 25 yr old man was playing basketball in a local league when he noticed that his legs were becoming uncharacteristically tired and stiff feeling. At other activities he was less noticeably affected but over a period of weeks the weakness increased even with less strenuous tasks. Except for headaches, which awakened him from sleep, he had no other complaints.

His general physical condition was very good and he had no significant family history or past medical conditions of note. He was alert and well oriented with respect to time and place. He comprehended and spoke well. The cranial nerve exam was normal except for papilledema. His sensory exam was normal for pain, temperature, touch, proprioception, and vibration. His motor exam showed normal strength, tone, reflexes, etc. for both upper extremities but both lower extremities were weak, showed spasticity, and there were bilateral Babinski signs.


Explanation -

Weakness and spasticity of both lower extremities without involvement of the upper limbs indicate an upper motor neuron syndrome of the lower limbs suggesting a lesion in a location where the representation of both legs are close together but separated from the arms. Such locations would be the lateral funiculus of the spinal cord below T1 or the midline of the hemispheres. The spinal cord lesion would likely include the posterior white columns producing loss of conscious proprioception, which in this case was unaffected. The hemispheres are a more likely site since the leg area is far from the arm and motor and sensory functions are separated by the central sulcus.

Papilledema and headache suggested increased intracranial pressure. The gradual onset of symptoms plus radiographic evidence ruled out aneurysms, infarction, and hemorrhage but a midline mass growing on the falx cerebri was detected. A meningioma was diagnosed and removed.

Cerebrum Lesion - NEOPLASMS - TEMPORAL LOBE GLIOMA

A Sample Case: At first the patient was troubled by the fact that he didn’t know how he ended up at a distant bus stop far from his home but finally dismissed the thought. He had also payed little attention to a spate of headaches during the last several months. At home he asked his wife about the source of the smell of cabbage but she responded that she wasn’t cooking and that she couldn’t smell anything unusual. She then noticed that he was making grimacing faces which included lip-smacking and swallowing. He went to the TV set but did nothing but stare above it. His wife recognized that something was wrong but none of her queries to him were met by reasonable responses. In about 15 mins he returned to his chair and his responses to his wife became normal. However, he did not acknowledge his odd behavior when his wife told him of it though he had a vague recollection of a strange odor.

At the hospital this 40 yr old man appeared perfectly normal with respect to mental status. Cranial nerves were normal except for an upper left quadrantic anopsia. Other sensory and motor findings were normal.


Explanation -

His wife’s description of his short-lived actions including the olfactory hallucination and lack of memory of the event suggest seizure activity. Combined with chewing, lip movements, and swallowing the seizure suggests a focus in the olfactory-related areas of the medial and inferior aspect of the temporal lobe.

While the seizure activity described is suggestive of the lobe involved, i.e., temporal, the visual loss indicates more precisely the side and location of the lesion. The homonymous left-sided visual field loss indicates a post-chiasmal lesion on the right. Optic radiation fibers of the superior visual fields loop far forward into the temporal lobe. EEG studies also confirmed abnormalities that were consistent with a lesion of the anterior-medial pole of the temporal lobe.

The history of headache preceding the other signs suggested the slow growth of a space-taking mass which was confirmed by MRI. Biopsy indicated a glioma.

Cerebrum Lesion - ABSCESS - PARIETAL LOBE

A Sample Case: A 50 yr old anatomist was having increasing difficulty in teaching his laboratory section because of an inability to do accurate dissections. Headaches had been his constant companion during this time but a generalized seizure forced him to go to the hospital.

When responding to questions related to the his medical history, the patient was not responsive as long as the doctor stood on his left side; he did respond to questions when the doctor stood on his right side. His attempts at dressing were ineffective since he only slipped his right arm into his shirt but ignored his left arm. His responses to questions, while fluent, were without emotional expression.

Cranial nerve examination showed that upon examination of visual fields he had full vision in each eye. However, if the doctor’s fingers were wiggled simultaneously within his visual field then he would not recognize movements in his left visual field. He had a spastic hemiparesis of the left extremities and the left side of his face in the mouth area drooped. There was minor diminished pain sensation and 2-point touch on the left, but there was an marked inability to accurately recognize numbers by touch when traced in the left palm (graphesthesia). Simultaneous touch to identical regions on both his arms was not perceived on the left even though touch was identified if the touches were not simultaneous (extinction). Copying simple illustrations was inaccurate in that the left sides of the objects were omitted.


Explanation -

There is a upper motor neuron syndrome involving the left face, arm, and leg caused by injury, at cortical levels, of cells of origin of the right corticospinal and related fiber tracts; fibers of this tract originate from both the frontal and parietal lobes. Diminished sensation was minor suggesting that the sensory pathways and primary somesthetic cortices were probably intact. Left sided graphesthesia, extinction, and ignoring the left visual field suggest that the lesion probably is in the right cortex. Such sensory deficits, i.e., acquisition and recognizing primary sensory data but with deficits in integrative functions as demonstrated by graphesthesia, extinction, tactile agnosia, etc., occurs with lesions of the parietal lobe, especially in the area of the supramarginal and angular gyri (areas 40 & 39). Failure to pay attention to the left space as indicated by his drawings, impaired visual recognition, inattention to people, and dressing apraxia is common with lesions of the right parietal lobe.

The slow progression of symptoms followed by a seizure does not suggest a vascular event but rather a growing mass culminating in an irritative phenomenon. Radiologic evidence showed a right parietal lobe abscess.