Neurology

Welcome at the „Distance Learning” Program of the Department of Neurology, Faculty of Medicine, UD.

Neurology propedeutics. László Oláh. Picture. Slides with audio material and laser pointer.

[Audio] Nervous system can be divided into central and peripheral nervous systems. Central nervous systemem consists of brain and spinal cord, while peripheral nervous system consists of peripheral motor and sensory neurons, radices, plexus, peripheral nerves, as well as sensory receptors. It should be noted that although the lower motor neuron is located in the central nervous system but functionally it belongs to the peripheral nervous system..

[Audio] The neurological examination aims to localize the lesion, to determine whether the symptoms can be caused by one lesion, to determine the affected systems (sensory, motor), and to find the etiology..

[Audio] The neurological examination aims to localize the lesion, to determine whether the symptoms can be caused by one lesion, to determine the affected systems ( senysory, motor), and to find the etiology..

[Audio] Cerebral CT may help to establish the diagnosis of cerebral haemorrhage (immediately after the bleeding), the space occupying lesions, as well as the ischemic lesions ( 12 hours after the ischemia). In some cases native CT can be informative (bleeding, ischemic lesion), but in other cases contrast enhanced CT is necessary ( tumors, abscesses…). On CT you can call the lesion hypodens, isodens, or hyperdens. Hyperdens materials are the followings: blood, bone, calcification, metals. The main advantage of the CT over the MRI that it is cheap, fast, therefore depends less on the patient's movement. However CT might have a significant radiation side effect. The resolution of MRI is much better, however it requires longer time and is worsened by the patient's movement. MRI examination consists of different sequences ( T1, T2, FLAIR, diffusion-weighted image, …) and abnormalities can be named as hyperintense, isointense, or hypointense. Contrast material ( gadolinium containing materials) is also used in MR. Since the MR contrast material changes the T1 relaxation time, T1 weighted images are compared before and after administration of contrast material. T2 weighted images and FLAIR images are sensitive to increased water content. FLAIR (fluid attenuated inversion recovery) differs from T2 weighted image that the intensity of CSF ( cerebrospinal fluid) is reversed (from hyperintense in the T2 to hypointense in the FLAIR). The advantage of FLAIR over T2 is mainly seen in multiple sclerosis, because the periventricular hyperintense foci in MS can be masked by the hyperintense CSF in the ventricles in T2 but not in FLAIR images. Diffusion weighted sequence has a great advantage in ischaemia: diffusion changes occur already in minutes after cerebral ischemia. T2* or susceptibility weighted images are sensitive to breakdown products of haemoglobin, therefore they are useful in or after haemorrhages. MR is superior over the CT in multiple sclerosis, inflammatory diseases, in the posterior fossa, and in the spinal regions with spinal cord (cervical and thoracic regions). In the lumbar region both CT and MRI can be performed, however, MR usually gives better image quality (but CT is enough to detect disc protrusion). MR has no radiation side effect..

[Audio] Ultrasound in neurology is used for visualization of carotid and vertebral arteries (extracranial duplex), as well as of intracranial arteries (transcranial colour coded duplex). B-mode ( brightness mode) shows the anatomy of the vessels, while colour-coded duplex shows the flow in the vessels. Colour coding is based on direction and velocity of flow. Ultrasound is used to detect carotid/vertebral artery stenosis or occlusion, dissection of the vessels. It allows to examine the plaque morphology, as well. Its main advantage is that it is cheap, has a very good temporal resolution, practically is free of side effects and can easily be repeated, therefore suitable for following the vessel pathology in time. Transcranial Doppler is suitable to measure flow velocity in the main intracranial arteries, thus can be used to determine the vasodilatative capacity of the resistance vessels, and to detect microembolic signals (originating from the extracranial carotid arteries or from the heart)..

[Audio] Digital subtraction angiography ( DSA) is used to visualize the vessels ( arteries, veins). At first, picture is made before administration of contrast material. Afterwards image is made after injection of contrast material, and the image before contrast is subtracted from the image after contrast. It allows to subtract the bones and thus offers better image quality. DSA helps to establish the diagnosis of carotid/vertebral artery stenosis/ occlusion, arteritis, sinus/ venous thrombosis. Since it has a radiation side effect, and it is an invasive method, it is only used when ultrasound or CT/ MR -angiography cannot answer the clinical question. During DSA the catheter is inserted through a puncture in the radial or femoral artery and guided to the origin of the vessel of interest. DSA has a major role in neuroradiological interventions, like stenting, aneurysm coiling, mechanical thrombectomy..

[Audio] Lumbar puncture is used to examine the content of the CSF. It may exclude the meningitis and the subarachnoid haemorrhage, but may help to establish the diagnosis in many other neurological diseases ( Guillain-Barre syndrome, meningeal carcinomatosis, vasculitis, …). CSF can be obtained at the cisternal or lumbar level. The content and the pressure of the CSF can be seen on the following slides. In some cases CSF can be artificially bloody due to puncture of vessels in the dura. Artificial bleeding and subarachnoid haemorrhage can be differentiated by different methods. In case of artificial bleeding the CSF gets to be clear ( 3-tubes probe), and if the artificially bloody CSF is obtained, it will be colourless after centrifuge. In contrast, CSF in subarachnoid haemorrhage will be not clearer during CSF sampling and it will remain yellowish after centrifugation..

Cerebrospinal fluid ( Lp ). Clear, colourless Number of cells: 1-4/mm 3 Protein content: 0.3-0.5 g/L Glucose level: 2/3 of the serum glucose Pressure: positive.

Cerebrospinal fluid ( Cp ). Clear, colourless Number of cells: 1-2/mm 3 Protein content: 0.1-0.2 g/L Glucose level: 2/3 of the serum glucose Pressure: zero or negative.

[Audio] EEG shows the electrical activity of the brain. Background activity and pathological waves may help in diagnosis of epilepsy, metabolic encephalopathies, slow virus infection, and encephalitis..

[Audio] Electrophysiological methods are frequently used in the everyday clinical routine. Electroneurography gives information about the conduction properties of the nerves and help to establish diagnosis of polyneuropathies. It allows to differentiate axonal (decreased amplitude) and demyelinating (decreased conduction velocity) polyneuropathies, and the involvement of motor or sensory nerves. Electromyography shows the activities of the muscles at rest or during innervation. It serves for diagnosing myopathy, myositis, and lower motor neuron disorders. Single-fiber EMG allows to diagnose myasthenia gravis ( sensitivity is about 95%). During repetitive stimulation amplitudes of muscle contractions are measured during nerve stimulus (e.g. deltoid muscle contraction during axillary nerve stimulation). Decrease of amplitude ( decrement) is typical for myasthenia gravis. Evoked potentials (visual, auditory, somatosensory) helps to show the involvement of the visual pathway, brain stem and the sensory pathway in different diseases..

[Audio] Neurology deals with the following diseases….

[Audio] During a detailed neurological examination different neurological systems/ structures are examined in the next order..

[Audio] Meningeal signs can be caused by abnormal molecules, cells or microbes in the CSF: viruses or bacteria in meningitis , blood in subarachnoid haemorrhage, carcinoma cells in meningeal carcinomatosis. However, other conditions, like increased intracranial pressure or dehydration may also cause meningeal signs..

[Audio] Neck stiffness, Kernig's sign and Brudzinski's signs are the classical meningeal signs. In case of neck stiffness a resistance can be felt when the head is bent forward passively. Kernig's sign positivity means that the knee cannot be fully extended in the lower extremity when the hip is flexed and this movement causes pain in the lumbar region. Brudzinski's sign is positive when the hip and knee are flexed during passive flexion of the neck. A special position of the patient may also be considered as a meningeal sign ( neck is retroflexed, hip and knees are flexed, the patient is lying on one side). Its explanation that the dura is least stretched in this position, therefore this is the least painful position for the patient. Note that the dura is stretched during the meningeal signs which causes pain that the patient tries to avoid by flexing the knees (Kernig's sign, Brudzinski's sign), or the affected region tries to resist against the movement (neck stiffness)..

Cerebrospinal fluid ( Lp ). Clear, colourless Number of cells: 1-4/mm 3 Protein content: 0.3-0.5 g/L Glucose level: 2/3 of the serum glucose Pressure: positive.

Cerebrospinal fluid ( Cp ). Clear, colourless Number of cells: 1-2/mm 3 Protein content: 0.1-0.2 g/L Glucose level: 2/3 of the serum glucose Pressure: zero or negative.

Cerebrospinal fluid ( Cp ). Clear, colourless Number of cells: 1-2/mm 3 Protein content: 0.1-0.2 g/L Glucose level: 2/3 of the serum glucose Pressure: zero or negative.

[Audio] Besides the specific meningeal signs, general signs may also be present: fever in most cases of meningitis, headache, photophobia..

[Audio] This picture shows the most typical changes of the CSF in bacterial and viral meningitis..

[Audio] If meningitis is proven, CSF sample should be sent to microbiological examination: Antigen test for the most common bacteria (it helps to detect the bacterium that caused the meningitis within several minutes, and may guide the treatment). It also helps to determine whether the patient should be isolated (e.g. meningococcus N. meningitidis) because of the infective origin with high contagiosity. Bacterial culturing should be started before antibiotic treatment, if it is possible. Before the result of the microbiological findings, ceftriaxone combined with vancomycin can be started. This therapy can be changed in the view of the microbiological finding. In case of viral meningitis serological probes may help to differentiate the causative virus. Besides serological tests, herpes PCR may detect specifically the herpes virus, the only virus against an effective therapy ( acyclovir) is available. Steroid is usually suggested in case of bacterial meningitis (to treat the immunological response caused by endotoxins of killed bacteria). Certainly the treatment of the underlying disease is essential ( pneumonia, middle ear infection, endocarditis, mastoiditis, abscesses around the teeth…).

Lumbar puncture - Important notes. Lumbar puncture is contraindicated in case of increased intracranial pressure (ophthalmoscope!!!) in case of thrombocytopenia (<50 G/L) in case of prolonged prothrombin time (INR>1.5), or prolonged APTT (1.5x of the control APTT) Complications of lumbar puncture meningitis!!! pain post puncture headache.

Negative status – examination of meningeal signs https:// elearning.med.unideb.hu/pluginfile.php/200721/mod_resource/content/0/normal_neurological_status.pdf Video – examination of meningeal signs https://elearning.med.unideb.hu/pluginfile.php/200292/mod_resource/content/5/meningealis.mp4.

[Audio] After examination of the meningeal signs, the 12 cranial nerves are examined..

[Audio] Localization of nuclei of the cranial nerves can be seen in this slide. Note that the nuclei third, fourth, sixth and twelfth cranial nerves belong to the group of dorsomedial nuclei, while the other motor nuclei are members of the group of the ventrolateral nuclei..

[Audio] The olfactory nerve serves for smelling. The olfactory fibers ( olfactory nerves) pass through the cribriform plate and end in the olfactory bulb. From here, the olfactory tract runs back and will be divided into 2 parts: the medial olfactory striae go to the hypothalamus, while the lateral olfactory striae reach the amygdala in the temporal lobe. The medial striae end in the hypothalamus, which is our vegetative centre. It explains why bad smells may cause nausea. The lateral striae go to the amygdala, temporal lobe. This is the cause that temporal epilepsy may be associated with olfactory hallucination. Other signs of temporal epilepsy are deja vu, jamais vu feeling, dreamy state, oral automatism, Duff's sign (the patient always touches his/her nose). The limbic system includes the temporal lobe, that is a part of the so called Papez circle. So, smell through the temporal lobe (amygdala) and limbic system may play a role in the emotional life. Just think about the use of parfumes which may influence the emotions..

[Audio] Terms regarding the smelling can be found in this slide..

[Audio] This figure shows the examination of the olphactory nerve..

Negative status – olphactory nerve https:// elearning.med.unideb.hu/pluginfile.php/200721/mod_resource/content/0/normal_neurological_status.pdf Video – examination of olphactory nerve https://elearning.med.unideb.hu/pluginfile.php/200281/mod_resource/content/1/01_nerve.mp4.

[Audio] Examination of the optic nerve includes examination of the visual acuity, the visual field, and the optic disc. Here, the visual pathway can be seen. Retina – optic nerve – optic chiasm (fibers coming from the temporal retinal part remain on the same side, while fibers from the nasal retinal part cross to the contralateral side) – optic tract – lateral geniculate body ( SYNAPSE!) – fibers from the LGB through the optic radiation reach the occipital (visual cortex) It should be noted that the optic radiation runs in a huge area in the temporal and parietal lobes..

[Audio] Examination of visual acuity should always be performed with one eye! In neurology we check the corrected vision i.e., the patient should use his/her eyeglasses during the examination. Visual acuity is examined from 5 m distance by the Snellen or Kettessy chart. If the patient is unable to read even the largest letter, check how far from he/she can count your fingers! If he/she cannot count your fingers, examine whether he/she can see movement or light! Visual acuity is expressed in decimal fraction. Vision of 1.0 refers to a normal vision ( 20/20), while vision of 0.1 means that the patient is able to recognize only the largest letter.√0.1/ 1.0 means that the vision on the right eye is good, however there is a severe decrease of visual acuity on the right eye. It is important to know that sudden unilateral decrease of visual acuity (develops in hours) in young subjects is most commonly caused by retrobulbar neuritis. Cerebral MRI may reveal whether other demyelinating foci can be seen intracranially. However, sudden unilateral decrease of visual acuity (develops in seconds) in older subjects may indicate occlusion of the ophthalmic artery or central retinal artery ( amaurosis fugax). It is usually transient and lasts for several minutes - half an hour. The patient realizes that the curtain goes down (the artery is occluded, therefore the patient sees only darkness) and later the curtain goes up (the embolus is dissolved, the visual acuity returns). Amaurosis is not always transient, but could also be permanent! In case of amaurosis fugax check the carotid arteries by ultrasound, since the ophthalmic artery is a branch of the internal carotid artery. In case of severe ipsilateral carotid stenosis, endarterectomy is suggested to prevent new artery-to-artery embolisation, i.e. stroke. Temporal arteritis ( giant cell arteritis) should also be mentioned. This is a granulomatous inflammation of the branches of the external carotid artery (and also other arteries) which may also cause amaurosis in one eye. This disease mainly affect patients older than 50 y, and they usually have high sedimentation rate (> 50 mm/h). In this case the superficial temporal artery is usually thickened, does not pulsate, associated with headache in the temporal region. Ultrasound and biopsy may reveal the correct diagnosis. The proper treatment is administration of steroid..

Right eye Very poor visual acuity. Left eye Good visual acuity.

[Audio] Amaurosis fugax is caused by hypoperfusion of retina. Ophthalmic artery is a branch of the internal carotid artery ( ICA). Embolus may get into the ophthalmic artery from ICA, or heart, but ICA occlusion may also cause hypoperfusion of retina..

[Audio] Amaurosis fugax is caused by hypoperfusion of retina. Ophthalmic artery is a branch of the internal carotid artery ( ICA). Embolus may get into the ophthalmic artery from ICA, or heart, but ICA occlusion may also cause hypoperfusion of retina..

[Audio] Regarding the visual field, 2 basic rules have to be highlighted. At first, the lens produces reversed image that means that the upper part of the visual field is projected to the lower part of the retina, and vice versa, and the temporal part of the retina is projected to the nasal part of the retina, and vice versa. At second, fibers, originating from the upper part of the retina keeps their superior position through the whole optic pathway (e.g. in the upper region of the optic chiasm, and in the upper part of the optic radiation, i.e. parietal lobe). In contrast fibers, coming from the lower part of the retina remain in the lower region of the optic pathway (e.g. in the lower region of the optic chiasm, and in the lower part of the optic radiation, i.e. temporal lobe)..

[Audio] When the term homonymous or heteronymous is used, it refers to the side. If the visual field disturbance is on the right side in one eye and right side in the other eye, it is called heteronymous. However, when the right side is affected in both eyes, we name the visual field disturbance as right sided homonymous. Be careful! Upper quadrant hemianopsia does not exist!!! Either hemianopsia, or quadrant anopsia!.

[Audio] Let's examine the consequences of damage of the visual pathway: Damage of optic nerve causes ipsilateral blindness. 3) Damage of the optic chiasm results in bitemporal heteronym hemianopsia. 4,5) Damage in the optic tract or visual cortex leads to contralateral homonymous hemianopsia..

Normal visual field.

[Audio] Homonymous hemianopia is very dangerous (much more dangerous than unilateral blindness). In case of homonymous hemianopia the patient can see with both eyes, but only to one direction! However, the patient sees nothing in the other direction with any of the eyes. Therefore these patients cannot drive a car, or bike, and has to be very careful in the everyday life and also crossing the road by walk..

Képtalálatok a következőre: bitemporal hemianopsia.

Examples.

Képtalálatok a következőre: pizuitary adenoma. Képtalálatok a következőre: pizuitary adenoma.

Képtalálatok a következőre: PCA occlusion. Képtalálatok a következőre: PCA occlusion.

Képtalálatok a következőre: cortical blindness. Képtalálatok a következőre: top of basilar artery syndrome.

[Audio] Sudden bilateral ( transient) blindness might be a harmless sign. E.g. at the beginning of collapse many patients complain of blurred vision or loss of vision. Its cause is that the occipital cortex has very high cerebral blood flow, and this area is very sensitive to flow decrease which happens during collapse. However, bilateral blindness may be also a consequence of a severe disease, namely the top of basilar artery occlusion. Since the basilar artery ends in the 2 posterior cerebral arteries which supply the visual cortices, occlusion of the top of basilar artery may close the origins of both posterior cerebral arteries. It results in ischemia in the territory of both posterior cerebral arteries causing cerebral infarcts in both occipital lobes. Since infarct in one occipital lobe causes contralateral homonymous hemianopia, and infarct in the other occipital lobe leads to homonymous hemianopia in the opposite side, this syndrome leads to bilateral blindness (hemi+ hemi= total). This sign is called cortical blindness to differentiate from bilateral blindness caused by bilateral optic nerve damage. It is important to know that in bilateral blindness caused by bilateral optic nerve damage, thus pupillary reflexes are absent. However, since those fibers which are responsible for the pupillary reflex leave the optic pathway before the lateral geniculate body, bilateral occipital infarction does not influence the pupillary reflexes, i.e. the pupillary reflexes are intact in cortical blindness!.

[Audio] Sudden bilateral ( transient) blindness might be a harmless sign. E.g. at the beginning of collapse many patients complain of blurred vision or loss of vision. Its cause is that the occipital cortex has very high cerebral blood flow, and this area is very sensitive to flow decrease which happens during collapse. However, bilateral blindness may be also a consequence of a severe disease, namely the top of basilar artery occlusion. Since the basilar artery ends in the 2 posterior cerebral arteries which supply the visual cortices, occlusion of the top of basilar artery may close the origins of both posterior cerebral arteries. It results in ischemia in the territory of both posterior cerebral arteries causing cerebral infarcts in both occipital lobes. Since infarct in one occipital lobe causes contralateral homonymous hemianopia, and infarct in the other occipital lobe leads to homonymous hemianopia in the opposite side, this syndrome leads to bilateral blindness ( hemi+hemi= total). This sign is called cortical blindness to differentiate from bilateral blindness caused by bilateral optic nerve damage. It is important to know that in bilateral blindness caused by bilateral optic nerve damage, thu pupillary reflexes are absent. However, since those fibers which are responsible for the pupillary reflex leave the optic pathway before the lateral geniculate body, bilateral occipital infarction does not influence the pupillary reflexes, i.e. the pupillary reflexes are intact in cortical blindness!.

[Audio] Visual field can be examined by several methods: Ophthalmologists usually use perimeter. This is the most precise method to determine the visual field, but it requires good communication from the patient, and it is also time consuming. In neurology, the so-called confrontal test is used, when the examiner compares his/her own visual field and the patient's visual field. The two eyes should be examined separately! Ask the patient to close on eye and the examiner should close his/her opposite eye. The patient should indicate when he/she sees the moving fingers. The examiner should move the hand slowly from the periphery to the central part of the visual field, meanwhile he/she moves the fingers. The patient should say „now" immediately, when he/she sees the moving fingers. As it was mentioned, the 2 eyes should be examined separately. (WE USE BILATERAL STIMULI ONLY WHEN WE CHECK THE SO CALLED VISUAL NEGLECT. IN THIS CASE THE PATIENT'S VISUAL FIELD IS NORMAL, HOWEVER, WHEN BILATERAL VISUAL STIMULI ARE APPLIED, THE PETIENT WILL NEGLECT AND THUS WILL NOT RECOGNIZE ONE OF THE STIMULI.).