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NeurologyIn the

Neurology diseases of the nervous system are treated. The border to psychiatry is partly fluid. In Germany, neurology has emerged as a sub-specialty from internal medicine. The organ systems considered in neurology are the central nervous system, i.e., the brain and spinal cord and their surrounding structures and blood-supplying vessels, and the peripheral nervous system, i.e., the nerves in their course outside the spinal canal including the connecting structures with muscles and the skeletal musculature.

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Table of contents

The clinical method in neurology

Neurology is considered to be a complicated medical specialty. The hurdles to understanding neurological disorders are high not only for lay people, but also for medical students and physicians because of the special training required to understand how the nervous system works. Access to neurology is complicated by the fact that there are a large number of rare diseases in this field. In addition, many textbooks are structured in a way that is confusing to the beginner. An introductory chapter to this specialty at this point can therefore be no better or easier than the traditional ways of accessing this science.

Definitions

First of all, an explanation of some terms that will be used repeatedly in what follows.

– As Clinical symptoms refers to the complaints that are noticed by patients and lead them to the doctor: Pain, nausea, weakness, etc. – As clinical signs is the term used to describe changes that patients usually do not notice, but that can be detected by a doctor through a physical examination (for example, a nystagmus). – A Syndrome is a group of simultaneously occurring signs of the disease. – The term clinical spectrum is the sum of all the symptoms and signs that a patient with a certain disease can get, but does not have to get, and that are causally related to the disease. – If one considers a disease primarily from the point of view of clinical medicine, it is characterized by its Cardinal symptoms Defined. – As diagnostic criteria or pathognomonic criteria for a disease, one designates the combination of symptoms and signs, in the presence of which the diagnosis of this disease may be made. – As Diagnosis is the term used to describe the process of recognizing and correctly naming a disease. – As Differential diagnosis is the listing of similar clinical pictures, the finding of alternatives to a presumed diagnosis and the process of finding the only correct diagnosis among all possible diagnoses.

The patient as a guide

All textbooks of neurology emphasize the special importance of the clinical examination of the patient. The exact questioning of the patient and the physical examination oriented to the complaints is extremely important in neurology. In the course of this examination, the physician forms hypotheses about the nature of his patient's disease. He is guided here by his knowledge of how the nervous system works (neuroanatomy, neurophysiology), his knowledge of the various neurological diseases and his experience, the so-called clinical eye for typical combinations of complaints and signs in certain diseases. Based on these hypotheses, a guess is made as to which region of the nervous system could be damaged (site of damage in the sense of a neurological-topical diagnosis). Then a specific examination is carried out, which should confirm or disprove the hypothesis about the place of damage. The following case examples will illustrate this approach.

Case study I: CSF resorption disorder

A male patient, about seventy years old, is brought to the neurological consultation by his relatives. It is reported that the grandfather has had repeated falls recently but has not injured himself; in addition, he has become forgetful and it has been noted that he has difficulty urinating. When specifically asked, the relatives report that the complaints came with time and that the whole thing has been going on for at least two years. Then the patient is physically examined. The neurologist asks the patient to walk around the room: He shows a clumsy gait and lifts his feet only slightly when walking. The working hypothesis is now: a dementia with bladder emptying disorder and so-called "magnetic" gait, which has existed for about two years and was accompanied by an increase in complaints, could have its cause in a CSF resorption disorder. First, a CCT of the skull is performed. Due to the suspected CSF resorption disorder, one expects so-called ballooned lateral ventricles with a marginal and preferably frontal hypodensity. Since the CCT shows this finding, a therapeutic-diagnostic measure is carried out: in the so-called. Fisher test is performed by means of a lumbar puncture to test ca. 30 to 40 ml of nerve fluid is collected. This measure should improve the complaints. About 10 minutes after the lumbar puncture the patient shows an improved gait. His memory disorder will remain unaffected. The urinary incontinence is most likely to improve later on. The patient is referred to the neurosurgeon with the diagnosis of "hydrocephalus malresorptivus" for implantation of a ventriculo-peritoneal shunt system for the purpose of permanent drainage of excess neural fluid.

Case study II: Brain tumor

A 32-year-old man is brought to a hospital emergency room after falling at work, sustaining a head laceration and being unconscious. Since no one observed the fall, he is initially treated in a dazed state in the outpatient clinic by a trauma surgeon. The patient complains of weakness in the right arm and explains that this is new. After the head laceration is treated, the patient is presented to the neurologist, who notes a drop in the arm hold on the right side. The neurologist suspects that the patient suffered a fall in the context of a first-time seizure (the patient could not remember anything) and interprets the arm paresis as sog. Todd's palsy after a seizure attack. This consideration is somewhat speculative, as Todd's paralysis usually lasts only a few minutes in younger patients. The performed CCT examination shows a left high parietal round hypodensity. Absence of vascular risk factors in a young patient makes ischemic cerebral infarction unlikely cause of fall and arm paralysis. A tentative diagnosis of astrocytoma is made. Confirmed by a brain biopsy.

Case report III: Brainstem infarction

A 62-year-old woman is brought to the emergency department with a sudden onset of gait unsteadiness. She also complains of a new onset "hoarseness". The patient is diabetic. Suffers from high blood prere. She reports she injected her insulin pretty much an hour ago, took her blood prere medication, and then felt strange and fell when she got up. Relatives then immediately took her to the emergency room. A gait test shows that the patient can stand only with assistance, although her strength in the legs is unimpaired. Inspection shows that her right upper eyelid is slightly drooping. When the neurologist holds up a mirror to her, she sees that her right eye is "crooked". The examination shows an abolished temperature sensation in the area of the left arm. As expected, a CCT of the brain skull shows no abnormal changes. On Doppler sonography of the extracranial brain vessels, the right vertebral artery is missed. The tentative diagnosis is: ischemic cerebral infarction of the dorsolateral pons in the area supplied by the posterior inferior cerebellar artery right due to occlusion of the right vertebral artery.

Case report IV: Meningitis

A 24-year-old man is brought to the emergency room of the hospital. The patient's father reports that his son is a regular soldier and is at home on leave. At noon of the day of admission he complained that he was feeling badly. Complains of increasingly severe headache and begins to feel cold. Since he no longer responds properly to speech, he is taken to the nearby hospital. The young man makes a severely ill impression, he cannot stand and answers questions only with difficulty and trembles severely. A rectal temperature measurement reveals 39.4° C. The neurologist performs a physical examination: he grasps the patient's head with both hands and slowly moves it to the right and left. Even this movement causes significant pain to the patient, who is lying in bed with legs drawn up and head slightly bent backwards. Based on these findings: fever, headache, clouding of consciousness, neck stiffness and the medical history (the patient is a soldier), a tentative diagnosis of meningococcal meningitis is made and appropriate hygiene measures for the staff are ordered. After a native CT to rule out signs of intracranial prere (free cisterna ambiens), a lumbar puncture is performed. Immediately initiated antibiotic therapy based on the clinical findings.

The stepwise approach to diagnosis in neurology

From these examples, one can see the different levels in the neurological approach to clinical ies.

First step: history, clinical symptoms, clinical signs, technical findings

During the history taking, the time dimension is important (s. a. course of the disease):

peracute during seizure, the patient falls from full health. Acute In ischemic cerebral infarction, gait unsteadiness and hoarseness present within a few minutes. subacute in meningitis, within hours an extremely severe clinical picture develops. chronic in hydrocephalus malresorptivus, the symptoms develop insidiously over months or years.

When an initial hypothesis has been made based on the history, one makes sure of some details again:

– The patient with the head laceration is too young for an ischemic cerebral infarction. – The older woman with the inability to stand has vascular risk factors. – The feverish young man with the severe headache is a soldier (meningococci are found in nasopharyngeal swabs in 20% of all soldiers).

Specific physical examinations are then performed:

– The arm holding test in the young man with the seizure. – testing of temperature sensitivity in the old woman with inability to stand, hoarseness and crooked eye (just hold the metal handle from the reflex hammer under the cold water of the sink and give it to the patient first in the left and then in the right hand, the patients immediately notice the difference). – the very careful turning of the head in the meningitis patient. – the gait test in the old man: "Please walk around the room."

– The CCT findings in the young man are ambiguous only on the surface: round hypodensity always suggests a tumor. What is irritating in this case is that the patient said that the arm paralysis came on suddenly. – The inconspicuous CCT finding in the older woman is expected. In the CCT, one cannot see a brainstem infarction. – In the case of the young man with meningitis, a cerebrospinal fluid culture is absolutely necessary for pathogen detection. However, the decision about diagnosis and therapy is made without any technical diagnostics (except fever taking). – The CCT finding in the old man with the "magnetic" gait is good support for the initial hypothesis, but too nonspecific.

This systematic approach facilitates a neurological examination.

Second step: interpretation of the obtained data in physiological and anatomical terms

The young man with the head laceration has arm paralysis. Reflex testing can be used to determine whether the paralysis is central or peripheral: if the muscle stretch reflexes in the right arm are weakened, this indicates damage in the course of the nerves outside the spinal canal (peripheral lesion). If reflexes are accentuated, this indicates damage to the spinal cord or brain (central lesion).

The old lady with the speech disorder has a so-called "crossed" symptomatology: the drooping upper eyelid right (a Horner syndrome) and the disturbance of temperature sensitivity left. A "crossed" symptomatology is typical for the brain stem due to anatomical conditions. The posterior small cerebellar artery is commonly involved.

The most important clue in the feverish young man is his bent posture when lying down, which is typical for irritation of the meninges and spinal cord membranes. If the patient also has a fever, it is obvious that the irritation of the meninges has an infectious cause (usually bacterial). The fact that the young man is a soldier supports the suggestion that meningococcal meningitis is present.

Third step: syndromal formulation and anatomical diagnosis

An isolated central arm paralysis in the young man with the head laceration is rather unusual. The neurologist probably did not examine the patient carefully and missed the discrete, centrally caused paralysis of the mimic muscles (see facial nerve palsy) on the right and possibly a mild aphasic disorder. However, it is crucial to reach the goal quickly and safely. The combination of the first seizure in a ca. 30 year old man and the described CCT findings is highly suspicious for an astrocytoma.

The old lady with the brainstem infarction is a prime example of so-called topical diagnostics in neurology. The combination of a Horners syndrome with a contralateral disorder of temperature sensitivity always points to the brainstem and there to the area of the pons. Crucial to understanding the disorder is that the brainstem area contains core areas of cranial nerves on the one hand, and pathways for motor function and sensitivity on the other. The close proximity of these structures at this location in the brain leads to disturbances in distant parts of the body that are supplied by these structures.

The febrile young man does not have a lesion at a specific site in the nervous system, he has a disturbance in an entire organ system, namely the entire cerebral membranes. This also causes the severity of the disease and the great risk of numerous complications such as generalized seizures, coma and respiratory paralysis.

Fourth step: Pathological or etiological diagnosis

In the case of the young man with the head laceration, the neurologist does not actually make a definitive diagnosis. In this case, the final (pathological or etiological) diagnosis is made by the pathologist on the basis of a brain biopsy. The task of the neurologist is to pave the way there.

The etiological diagnosis in the case of the elderly lady is probably an embolic occlusion of a cerebral artery due to arteriosclerotic changes in the upstream pathway resulting in an ischemic infarction of the brain area originally supplied by the vessel. A so-called border zone infarction due to a lumen reduction (stenosis) of the upstream vessels caused by arteriosclerosis would also be possible.

In the case of meningitis, the bacterial toxins released by the infection and the body's defense response are the cause of the dramatic course of the disease, which, if left untreated, is very likely to result in death.

Summary of all the steps: The clinical method in brief

AnamnesisA man presents to the emergency room and explains that he has felt something wrong with his face for about an hour. The man is 65 years old, he is a smoker and suffers from hypertension.

Physical examinationThe neurologist asks him to close both eyes tightly and to "show his teeth". The eyelid closure is complete on both sides, but the grimacing of the mouth succeeds only on the right side.

Conversion of the findings into neurophysiological terms: These findings are indicative of a central facial paresis on the left side.

Syndromal formulation in the sense of a neurological topical diagnosisNow the neurologist checks if his amption can be confirmed that a syndrome of the precentral region on the right side is present: he lets the patient hold both arms in front of him with closed eyes: the left arm shows an inward rotation. The neurologist suspects the location of the lesion in the right cerebral hemisphere in the so-called precentral region.

Etiological diagnosis: Since the patient has vascular risk factors (age, smoking, hypertension), an ischemic cerebral infarction is diagnosed in the service area of the cerebral artery right suspects. This amption can be confirmed or refuted by a CCT examination and especially by a transcranial Doppler sonography of the vessels supplying the brain.

The Treatment is then made according to the therapy guidelines for cerebral infarction patients.

Summary of the diagnosis

The clinical method in neurology can be described as follows: Data are collected by questioning the patient or the patient's relatives about the history and by a physical examination. These data are interpreted based on physiological and anatomical knowledge and a hypothesis is formulated (anatomical diagnosis). Specific technical examinations are then performed to confirm or refute the hypothesis. This leads to a final pathological or etiological diagnosis, which usually also has a well-defined name. On the basis of verified empirical values from clinical studies, a therapy is then agreed with the patient.

In older textbooks of neurology, one occasionally finds simple mnemonic sentences regarding this main principle of neurology, such as "The Principle of Six W's" by Mumenthaler:

What caused the disease? (anamnesis) When the patient is diagnosed? (Findings) Wo sits the lesion that can cause such symptoms? (topical diagnosis) WWhy does the patient fall ill?? (etiologic diagnosis) Wowhere does the disease process lead? (prognosis) Wow to treat? (therapy)

Specific to neurology is the question of the Where, the so-called topical diagnosis. Although this principle also plays a role, for example, in the diagnosis of myocardial infarction, it is a defining feature for the entire field of neurology. This fact is explained by further selected (constructed) case examples, in which errors in the clinical method are illustrated.

Error in the application of the clinical method

The main mistake in the application of the clinical method is not applying it consistently. Especially beginners, but also experienced physicians tend to perform technical examinations in cases where they are unsure or do not know what to do, in the hope that this will lead to a diagnostic clarification. This way often leads astray or costs time and money unnecessarily and sometimes even hinders the establishment of a correct diagnosis. To illustrate this, here are some case histories (some abbreviated and constructed) in which the physicians in question did not consistently apply the clinical method. A ten year old child is seen in a dazed state. Brought to hospital emergency room with a head laceration. The cause of the fall is initially unclear. Still in the emergency room the child suffers a seizure. Since this does not subside, the patient is intubated and ventilated in an emergency and the seizure status is interrupted by means of anesthesia. The neurologist consulted suspects encephalitis. A CCT and a cerebrospinal fluid (CSF) examination do not reveal any groundbreaking findings. The child initially continues to be ventilated in an intensive care unit. During attempts to reduce the depth of anesthesia, seizures occur again. Another neurologist is consulted to clarify the situation. The neurologist first takes a detailed history. The tentative diagnosis is "encephalitis". The task is to find a possible causative agent. The relatives provide the following information: there was no travel abroad, the child has a pet cat, and a sibling died as a result of HIV disease. General physical examination revealed the following: right axillary lymph node swelling and bilateral conjunctivitis. This constellation of findings allows the following tentative diagnosis: encephalitis caused by the causative agent of cat scratch disease (Bartonella henselae). This suspicion could be confirmed by serological examinations of the cerebrospinal fluid. The detection of encephalitic foci in the putamen are confirmed by magnetic resonance imaging. The therapy consists in the administration of macrolide antibiotics, cotrimoxazole or rimfampicin. The child recovers. The disease heals without consequences. The mistake was that in the acute situation and also later no detailed anamnesis was taken. In this case, only the history and non-neurologic examination findings provide clues leading to the causative agent and the diagnosis of Bartonella encephalitis (pet cat, axillary or cervical lymph node swelling). The striking bilateral conjunctivitis is a concomitant of this rare encephalitis (only a few dozen cases have been described worldwide).

Case study II: A young man with a cerebral infarction

An approximately 35-year-old man is admitted to the hospital with signs of acute ischemic cerebral infarction. According to work colleagues, he had fallen, then suddenly complained of malaise and spoke slurredly. In the admission situation, the patient shows right arm and facial paralysis, he is dazed and aphasic. The event is less than 45 min old. CCT examination still shows no early signs of cerebral infarction. Doppler and duplex sonographic examination of the neck vessels shows evidence of occlusion of the left internal carotid artery (ACI). The diagnosis is left ACI occlusion with ischemic cerebral infarction in the left mediastinal territory. Lysis therapy is initiated. Paralysis and speech disturbance are completely regressing. Doppler sonography still shows a high-grade flow obstruction of the ACI on the left side. However, the patient has no vascular risk factors. For this reason, the medical history is reviewed again. The patient reports that he fell shortly before the event and had a very unfortunate fall with the left side of his neck against the edge of a table. The suspected diagnosis of dissection of the internal carotid artery is confirmed by magnetic resonance imaging of the neck vessels. The mistake was not to have questioned the patient's companion in detail about the circumstances of the fall.

Case study III: A young woman with a bladder and rectum emptying disorder

In the emergency room of a hospital, a young woman presents at night with a bladder and rectal emptying disorder. She reports having unusual constipation for days and now she has not been able to urinate since yesterday and is having trouble walking. She is in pain. Is restless. The neurologist on duty notes decreased sphincter tone, palpates an overflow bladder, and finds mild bilateral leg paralysis with muscle tone elevation (latent spastic paraparesis). Lumbar puncture is performed after bladder catheterization. Because the CSF findings are unremarkable, the duty physician considers performing a magnetic resonance imaging (MRI) scan of the entire spine with contrast and consults with his senior physician. The latter examines the patient during the night itself and orders the administration of several antibiotics and antivirals. The service physician did not trust the clinical. Wanted the suspected diagnosis confirmed with technical procedures. Such an approach is misleading. The patient has myelitis (infection of the spinal cord) caused by viruses. In the early stages of the disease, CSF. MRI of the spinal cord to be unremarkable. Therefore, therapeutic measures are carried out even if the clinical diagnosis cannot yet be confirmed by technical examinations.

Neurological examination techniques

A sophisticated diagnostic technique is still the domain of neurology today. In this context, the so-called neurological-topical diagnosis is considered ideal: based solely on the patient's report of his complaints (anamnesis). A physical examination without technical aids should indicate the exact site of damage in the nervous system. This requires precise questioning of the patient and his relatives, great experience in the clinical examination of patients and very precise theoretical knowledge of the theory of disease and the structure and function of the nervous system. In this way, more than 90% of all relevant diagnoses in neurology can be made.

Taking a history in neurology

The peculiarities of history taking in neurology result from the nature of neurological diseases. In some diseases, the onset is a long time ago, so that patients do not have an accurate memory of it. Then, patients often do not find the right words for the phenomena that interest the neurologist. Thus, sometimes a paralysis is confused with a sensory disturbance, a coordination disorder is described as if it were a paralysis, and sometimes headaches and facial pain are confused, etc. In such cases, the physician must structure the patient's medical history. In other words, one must have an idea of the ailments the patient might have and then inquire exactly what the disorder is and match the hyopthesis formed, the patient's description and one's own view and the findings of the physical examination. Since this is often not possible during the first consultation, neurology takes time. It is always worthwhile to ask patients about their complaints and to involve relatives in order to complete the picture of the patient's disorder.

Some histories can be structured completely. This includes, for example, the questioning of patients with headaches and seizure disorders. In epilepsy, the neurological history of these disorders includes the following aspects: Onset of the disease, occurrence of febrile seizures in childhood, frequency of seizures per unit of time (week, month), diurnal association (occurrence at certain times of the day), precipitating factors, do patients feel when a seizure is coming (aura), how long does the seizure last, are patients unconscious, does tongue biting (at the tip of the tongue or on the side of the tongue) occur, If witnesses have observed the seizure, can they describe the motor expressions, are the eyes open or closed during the seizure, how do the patients fall down, What medications in what doses have been previously prescribed, have they been effective in suppressing seizures, have medications been taken regularly, have medication levels been determined? In the case of headache and facial pain, the questionnaire is structured in a similar way, but special questions about the nature of the pain are added.

Finally, it is to be said that an anamnesis is always oriented to the complaints of the patient and to the suspected disease. A patient with the first manifestation of an inflammatory disease of the central nervous system is questioned differently than a patient with Parkinson's disease. Sometimes the only information available in an emergency situation is the history of other patients. Some patients cannot give any information about their disorder at all (small children, animals in animal neurology). Such situations are always a special challenge.

The physical examination in neurology

The physical examination in neurology is time-consuming. It requires patience and active cooperation from the patient. Cranial nerve functionThere are twelve cranial nerves. the function of each cranial nerve can be checked in a neurological examination. Since this is very time-consuming, cranial nerves are usually only examined "orientatively. This means that an incomplete examination is made on the amption that everything is probably in order. However, if a cranial nerve disorder is suspected, each individual function must be examined in detail in case of doubt. The first two cranial nerves are the olfactory nerve for the sense of smell and the optic nerve for the sense of sight. Smell is tested with olfactory substances (z. B. with coffee powder) and the visual field by means of so-called finger perimetry. Cranial nerves III, IV and VI control the movements of the eyes (follow the movement of a finger of the doctor). The fifth cranial nerve is the trigeminal nerve. It sensitively supplies the face. Motor the masticatory muscles. The facial nerve is the seventh cranial nerve. It motorically supplies the mimic musculature. The eighth cranial nerve is for hearing-. Organ of equilibrium responsible. Here the tuning fork test is used. It makes sense to test the sense of balance only if it is disturbed. The patients then have a feeling of dizziness. For this purpose, there are special methods that can be used to provoke vertigo. The ninth cranial nerve is the glossopharyngeal nerve. It helps with swallowing and also mediates taste in the back third of the tongue (where you taste bitter). The tenth cranial nerve is the vagus nerve, it mediates the vegetative parasympathetic innervation of the internal organs. It also provides sensory to the pinna of the ear. Motor the soft palate. The eleventh cranial nerve controls part of the neck muscles. The twelfth cranial nerve (nervus hypoglos) moves the tongue.

Motor function: The motor function is examined in various aspects. Different methods can be used to measure the force of each muscle group. Partially also those of many individual muscles are tested. To explain the principle an example: The movement of the hand is made possible by three different nerves: radial nerve, ulnar nerve and median nerve. The failure of one of the three nerves leads to characteristic changes: Disturbances of sensibility, impairment of strength, in the long run an atrophy of the muscles (muscular atrophy) and weakening of the respective reflexes. In the case of the median nerve (for example, due to an injury in the area of the elbow), the function of the nerve can be impaired. Since the median nerve supplies the flexor muscles for the thumb, index and middle fingers, the patient's hand will not be able to develop full strength during fist closure. It is not possible to open the screw cap of a bottle with the hand in question. The musculature of the ball of the thumb is degenerated over time.

ReflexesDuring a neurological examination about ten so-called muscle stretch reflexes can be tested. At this point, only one of these reflexes will be briefly explained for explanatory purposes. Generally known is the patellar tendon reflex: One hits with a reflex hammer lightly on the tendon, which leads below the kneecap to the front side of the shinbone. Provided the leg under examination is positioned so that the lower leg can swing freely, the triggering of the reflex will cause the leg to extend at the knee: The lower leg swings forward (this is the reflex response). The principle is that by striking the tendon the associated muscle (Musculus quadriceps femoris) is briefly stretched. The nerves supplying the muscle emerge from the spinal canal in the region of the lumbar spine (L3,4). A reflex arc is used to initiate the reflex response. If, due to a tie change in the area of the nerve exit points of the corresponding lumbar vertebral bodies, parts of the intervertebral discs press on the nerve roots, this results not only in pain but also in a functional restriction. The muscle is no longer properly innervated. Leads thus to a weakness of the extension of the leg. Moreover, the reflex response is affected in such a way that it is weakened in lateral comparison with the healthy side. The weakened reflex indicates the so-called "peripheral" paralysis. The site of the lesion is not in the central nervous system (brain or spinal cord), but in the peripheral nervous system, in this case in the area of the nerve root.

SensitivityThere are four different sensory qualities: touch, prere, position of the extremities, pain and temperature. The surface of the human body can be divided into distinct areas in terms of sensitivity. This division of the surface of the body into sensitive areas (dermatomes) looks different in each case, depending on whether a nerve root or a nerve is damaged in the further course. In the case of damage to the median nerve, one experiences numbness in the area of the palm between the thumb and index finger (median supply area). If the disc between the third and fourth lumbar vertebrae presses on the respective nerve root, one suffers a numbness in the corresponding supply area, which extends from the outside of the thigh to the inside of the lower leg.

Coordination: Disturbances in the coordination of movements can have various causes. In case of a dysfunction of the cerebellum, a so-called ataxia can occur. Such a movement disorder causes them to overshoot the target. This can be tested, for example, by means of a pointing test (with closed eyes, place the index finger in a large arc on the tip of the nose). Sensitivity disorders also lead to impairment of the locomotor system. Alcoholism and diabetes are common causes of sensory neuropathy in which there are disturbances in peripheral nerve function, preferably in the lower extremities with numbness. Since the patients do not feel the ground properly, they walk unsteadily and broad-based (sailor's gait).

Muscle toneSome diseases (multiple sclerosis, Parkinson's disease) cause typical changes in the toning of the muscles. Normally, limbs can be moved passively without resistance when patients relax. People with multiple sclerosis often show a spastic gait disorder (the gait looks spindly and awkward) and one can feel the increased muscle tone in the legs by bending and stretching the patient's relaxed leg at the knee. A sudden increase in resistance to movement is felt, which decreases when the force is reduced. The same applies to the so-called rigor of the muscles in Parkinson's disease. A characteristic sign for this disease in this context is the so-called. cogwheel phenomenon. The neck stiffness comes from an irritation of the meninges. This can be seen above all in the protective posture of the patient. This is tested by various maneuvers that slightly stretch the meninges (z. B. bending forward of the head). However, the examination is very painful for patients with meningitis.

Pyramidal tract signs: The pyramidal tract consists of a bundle of nerve cell processes that run uninterrupted from the frontal brain to the first switching points in the spinal cord. These cells are something like a pacemaker of the voluntary movements. The name pyramidal tract comes from a structure in the brainstem (the pyramis), through which the pyramidal tract runs. If this bundle of nerves is interrupted at any point, a typical loss of function occurs: a spastic paralysis (reduction in strength with muscle tone increase). The causes can be completely different: an injury to the spinal column and spinal cord, a circulatory disorder in the brain stem, a cerebral hemorrhage in the area of the so-called capsule or a tumor in the cerebral cortex at the corresponding location. In addition to the paralysis and the increase in muscle tone, so-called pyramidal tract signs are then often found. One means thereby primarily the lifting (Dorsal extension) of the big toe when brushing the sole of the foot on its outer edge (Babinski reflex).

Further examination procedures: Special examinations are performed for various diseases. So one can check with certain procedures the sweat secretion or the adjustment of blood prere and pulse with load. After strokes, the motor functions of speech are tested if there is dysarthria or the grammatical functions of speech in case of aphasia. disturbances of complex movement sequences without impairment of strength. Sensations we call apraxias (an example would be putting on a jacket). Some patients do not notice their newly developed deficit after a stroke (anosognosia). Sometimes a visual field loss occurs after a stroke, which patients do not notice. Failure to notice this disturbance is called neglect. For these phenomena there are special examination methods. Another special field is the neurological examination of consciousness-impaired patients and young children.

In summary, it can be said that the examination methods which have been briefly presented here and of which only an incomplete selection could be given, are irreplaceable for the recognition of neurological disorders. No technical procedure can take the place of attentive observation and empathetic conversation and the many different maneuvers and tests. The goal of all these procedures is to make a diagnosis and thus determine which neurological disease is present.

Technical examination procedures in neurology

The technical methods of examination in neurology are very diverse.

By examination biological material such as blood (laboratory values), cerebrospinal fluid (CSF diagostics), tie samples of nerves and muscles, and genetic analyses can be used to diagnose a number of diseases.

Another group of examination procedures is the measurement electrical phenomena, Such as those of brain waves (electroencephalography (EEG), evoked potentials), muscle functions (electromyography, EMG), electrical functions of nerves (nerve conduction velocity by electroneurography, ENG), and transcranial magnetic stimulation.

The vessels supplying the brain can be examined by ultrasound (extracranial and transcranial Doppler and duplex examinations) and invasive procedures (z. B. angiography) are examined.

Imaging techniques for imaging the brain and spinal cord are computed tomography (CT), magnetic resonance imaging (MRI) and the so-called functional imaging techniques: Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT), Functional Magnetic Resonance Imaging (fMRI) and Magnetoencephalography (MEG).

The clinical method and the clinical reality

The references to errors in the application of the clinical method were intended to express the fact that in everyday clinical practice, the clinical method is sometimes not followed. Most textbook authors agree with the conviction that technical examinations must not replace the clinical method. It is also true that the performance of technical examinations should fulfill the function of testing clinical hypotheses. In short, computed tomography should not replace clinical diagnosis. Whenever these basic rules are violated in a diagnostic procedure, there is a high risk of making mistakes or not being able to make a diagnosis at all. Before the neurological diseases are outlined in a special chapter, the course of the clinical method in neurology must be supplemented by another step. It is a syndromic formulation of all the knowledge that has been gained so far. Specifically, this means: Do the data (medical history, findings, and neurophysiological considerations) allow a patient's complaints to be assigned to one of the known neurological syndromes? This question is the necessary final step before a neurological diagnosis can be made and will be discussed in more detail in the next section.

The neurological syndromes

A syndrome is a group of simultaneously occurring signs of a disease. There are about a dozen syndrome groups in neurology. In each syndrome group, numerous syndromes. To each syndrome belong different neurological diseases, which are moreover classified in a completely different way from the syndromes. First of all, the different groups of syndromes are mentioned and briefly characterized.

The Syndromes of the peripheral nervous system subdivide the syndromes, which concern disturbances of the nerves in their course outside the spinal canal. These are the mostly traumatic lesions of peripheral nerves, plexuses, nerve roots and the border cord as well as polyneuropathies.

The term cerebral syndromes first the four groups brain local syndromes summarized. These are the hemisphere syndromes, the brainstem syndromes, the extrapyramidal syndromes and the cerebellar syndromes. These syndrome groups can be subdivided even further.

Five different syndrome groups are summarized under the term spinal cord syndromes: the complete cross-sectional syndromes, the hemiplegic syndrome of the spinal cord, the central spinal cord syndrome, the posterior cord syndrome and the anterior horn syndrome.

There are five different neuroophthalmological syndromes: Olfactory groove syndrome, sphenoid wing syndrome, orbital apex syndrome, Forster-Kennedy syndrome and sinus cavernosus syndrome.

The vertigo (Vertigo) is divided into two types: the vestibular and the non-vestibular forms.

There are three different neurootological syndromesthe pyramidal tip syndrome, the jugular foramen syndrome and the cerebellopontine angle syndrome.

Two different groups can be distinguished meningeal syndromesAcute and chronic meningeal syndromes.

There are three different Cerebral prere syndromes: the transfalcial, the mesencephalic and the bulbar entrapment. To it correspond the different forms of the disorder of consciousness in the section Neuropsychological syndromes.

There are five different Headache types, which can be considered as syndrome groups: vascular seizure headaches, idiopathic seizure facial neuralgias, diffuse continuous headaches with acute onset and those with gradual onset, and localized continuous headaches.

A special group in the neurological syndromology are the four different CSF syndromes.

The vertebragenic syndromes are differentiated according to their localization: cervical, thoracic and lumbar spine.

Finally, five different groups of neuropsychological syndromes are distinguished: severe disorders of consciousness, aphasias, apraxias, agnosias and amnesias. vascular diseases: these include in particular the ischemic cerebral infarction. The different forms of cerebral hemorrhages. – Basal ganglia disorders: this includes, above all, Parkinson's disease. Nerve injuries: in cooperation with neurosurgeons. Trauma surgeons treat all forms of nerve injuries. – neoplasms: Tumors of the brain, spinal cord and peripheral nerves. – Intervertebral disc diseases: all forms of mechanical nerve root irritations that do not require surgery or do not require immediate surgery are treated by neurologists. seizure disorders: these include the treatment of epileptic. Non-epileptic seizure disorders. – Inflammatory diseases of the central nervous system: these include mainly bacterial and viral infections of brain and spinal cord ties and membranes. – demyelinating diseases: this includes primarily multiple sclerosis. – Primary degenerative diseases: these include the dementias, the so-called. motor neuron diseases (amyotrophic lateral sclerosis, spinal muscular atrophies) and degenerative cerebellar diseases (hereditary ataxias). – Dysraphic disorders (the so-called. occlusive diseases) and malformation diseases (phakomatoses). – diseases of the peripheral nervous system: (polyneuropathies). – muscular diseases: muscular dystrophies, myotonies and inflammatory muscular diseases, myositides. – disorders of neuromuscular transmission: primarily myasthenia. – Headaches and facial pain: primarily migraine.

Therapeutic principles of neurology

For many years, neurology was considered a discipline in which very elaborate diagnostic procedures were used and few therapeutic options existed. This has changed fundamentally in the last few years. Many neurological diseases are much more treatable today than they were a few decades ago. A decisive factor in improving the care of stroke patients is the imaging diagnostics that have now become routine and allow a distinction to be made between ischemic cerebral infarcts and cerebral hemorrhages. For the treatment of Parkinson's disease, different groups of drugs are available today. In the treatment of seizure disorders, freedom from seizures can be achieved in many cases if patients cooperate sufficiently. The infectious-inflammatory diseases of the nervous system are almost all completely curable with early diagnosis. Multiple sclerosis is still not curable, but since the introduction of interferons, the course of the disease can be better controlled. For most degenerative diseases of the nervous system, the malformations and congenital muscle diseases, the treatment options remain very limited.

Peculiarities of animal neurology

Neurology is also a major challenge for veterinarians, who are burdened with additional handicaps in addition to the great complexity of the nervous system. On the one hand, in contrast to the human neurologist, he is only in the rarest cases a specialist who has to treat "only" neurological cases.

Another problem is the wide species range. Findings from human medicine can only be transferred for a few diseases, since other mammals, birds, or even reptiles show significant neuroanatomical and -functional differences, and the clinical picture of a particular neurological disease may differ considerably depending on the species. Even a severe stroke with complete loss of the supply area of the arteria cerebri media, which causes a complete hemiplegia in humans, only leads to mild disturbances of the postural reflexes in sheep, but hardly to an impairment of the gait pattern. The most conspicuous is still a torticollis, but this can have many other causes. This is due to the differences in the crossing of the pyramidal tract and the very different importance of the pyramidal and the extrapyramidal system for the movement patterns.

The neuroanatomical diversity is also responsible for the fact that many neurological diseases in animals are insufficiently researched. Animal neurology is a relatively young science, with only a few designated specialists and low budgets, which can at best study the most important diseases more intensively, and this only in the most widespread representatives of domestic animals (especially horses and dogs). In the case of exotic species, the veterinarian must always extrapolate from species he knows.

Another problem is the limited communication. In human neurology, the intensive questioning of the patient, the anamnesis, is an important element of diagnostics. An animal can of course only tell the veterinarian a little, a questioning before and during the diagnostics is not possible. The veterinarian is dependent on the observation skills of the animal owner, sometimes also exposed to his imagination. The animal can make pain expressions, but already these are strongly varying not only between species, but also individually. Thus, an animal with a certain disease, can bear possible pain stoically, especially still in the stress of the treatment room, another, actually healthy animal, react to certain manipulations hypersensitive or aggressive. Important diagnostic criteria such as two-point discrimination, i.e., the ability to distinguish the local origin of a pain stimulus, cannot be measured in animals. The animal can express pain, but cannot tell the veterinarian whether it is experiencing the second pain in the same or a neighboring location.

Finally, veterinary medicine is much more cost-oriented than human medicine. In farm animals, complex diagnostics or treatments are usually excluded from the outset. But also in hobby animals the medical effort must always be tolerated by the owner or the patient. can also be borne financially. Cost-intensive large-scale equipment such as CT or MRI are only available in very few large veterinary clinics. And even an elaborately confirmed diagnosis does not necessarily lead to an (affordable) therapy (if it is possible at all), which is unsatisfactory for both sides, owner and veterinarian in the end.

Disease groups

The neurological diseases of domestic animals are usually divided into eight disease groups, which are referred to, following veterinary and vitamin D with the acronym VETAMIN D can notice:

Vaskular diseases (lat. vas=blood vessel): This group includes all vascular diseases such as malformations, hemorrhages, or ischemias. Vascular diseases are relatively rare in animals, only infarctions of the spinal cord occur somewhat more frequently. Enflammations: This group includes viral (z. B. Rabies), bacterial (z. B. Listeriosis), mycotic, parasitic or immunopathological inflammation of the nervous system. TSpatial diseases: Here are classified all diseases due to mechanical causes that have a direct or indirect (z. B. caused by traumatically induced hemorrhage) damage. Anomal anomalies: Anomalies are congenital malformations that can be either genetic or caused by infections during prenatal development. Metabolic-toxic diseases: This group includes all diseases caused by deficiencies of nutrients, vitamins and trace elements or by endogenous toxins (e.g. B. urea) are caused. Idiopathic diseases: Idiopathic (without an identifiable cause) diseases do not show any identifiable morphological changes in the nervous system, but only functional disturbances such as z. B. epilepsy. Neoplasia: This complex includes neoplasia, i.e. all tumor diseases. These can be tumors of the nerve cells, whereby in animals almost without exception tumors of the glial cells (gliomas) occur. A second group are tumors originating from mesenchymal ties, such as meningiomas. Degenerative diseases: Degenerative diseases are caused by pathological deposition of substances (z. B. amyloidosis), by the death of special nerve cell populations or by demyelination of the nerve tracts (leukodystrophy) and are mostly hereditary.

Historical aspects

Neurology as we know it today is very much linked to developments in the field of anatomy and histology. Only since regular post-mortem examinations have taken place, and especially through the development of the microscope, have structures and their interrelationships been elucidated.

The first indications of "neurological" treatment attempts are obtained from archaeological findings. About 10.000 v. Chr. the first trepanation was performed. The opening of the skull is one of the few tangible treatment methods, because the changes in the bone can still be detected after thousands of years. Several hundred skulls opened in this way have been found worldwide. Most of these interventions were survived by the patients, which can be proven by regeneration processes of the bone. The technique of the time was so sophisticated that the dura mater was not normally opened, an essential prerequisite for survival. The reasons for such interventions can only be speculated, but neurological symptoms such as severe headaches, epileptic seizures or ritual acts can be amed.

The first documents describing neurological symptoms originate from Egypt, where around the 14th century the skulls were found. Century v. Chr. Headaches, epilepsies and dizzy spells have been described. One also finds first anatomical descriptions of the brain and surrounding structures. Furthermore, neurological symptoms caused by accidents, such as paralysis or bleeding from the nose and ear in the case of skull fractures are mentioned. Likewise, various pictorial representations of different neurological diseases can be found.

Ancient

Pythagoras and Anaxagoras were the first to describe the brain as the seat of thought, sensation and the soul, and to describe the connection between brain and nerves. In contrast to these traditions, Hippocrates is known to have written about these diseases.

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