The clinical-anatomical case studies included in this section of the website are drawn from actual patients I have seen over the past 35+ years of clinical neurology practice. A handful of the patients were contributed by colleagues of mine. Otherwise, the vast majority were patients whom I saw and followed for variable periods of time. Since they are actual patients, rather than contrived cases, their findings occasionally vary somewhat from the “textbook”, but this allows the student or resident to have a more true-to-life experience.
The case studies follow the traditional patient encounter: namely, a short history, followed by the findings on neurological examination, leading to a series of questions concerning the structures involved by the pathological process and the “localization of the lesion” (i.e., Where is the lesion?). These steps are followed by questions relating to the nature of the pathological process (i.e., What is the lesion?), and, finally, which diagnostic studies might verify or support the student’s impressions. In that these cases were collected over a period of more than 30 years, the studies included at the end of most cases illustrate the history and evolution of neurological investigation during this period of time, especially in the area of neuroimaging.
In this manner, the case studies lead the student or resident through the four steps that constitute the “Clinical Method of Neurological Patient Evaluation”. A short description of this process is included below.
In order to organize the case studies for the student, they are grouped, somewhat artificially, into three large categories: (1) those that deal with pathological processes involving the spinal cord, brain stem, cranial nerves, and blood supply to the CNS; (2) those involving the major motor and sensory pathways or systems; and (3) those relating to the visual pathways, thalamus, and cerebral cortex. This sequence follows the progression of many first year neuroanatomy courses. The section of the website containing pretest and post-test examination questions is organized in a similar fashion.
Finally, I want to emphasize that the case studies included in this website are meant to highlight the process of clinical-anatomical lesion localization and pathological diagnosis. Treatment and management issues are not stressed. As knowledge in the neurosciences progresses, treatment and management guidelines will change, but the basic process of neurological patient evaluation will remain the foundation of the diagnosis, treatment, and care of patients with neurological impairment.
NEUROLOGICAL PATIENT EVALUATION
The ultimate goal of evaluating a neurological patient is to arrive at a diagnosis of the disorder in terms of its localization and pathology within the nervous system. The process of achieving that goal can be broken down into four distinct stages, although in practice these stages tend to merge and overlap. These four stages are: (1) reviewing the symptoms (history), (2) eliciting and evaluating the signs (examination), (3) determining the structures involved and their location by analyzing the symptoms and signs (anatomical diagnosis), and (4) determining the nature of the pathological process (pathological diagnosis). This process obviously requires a thorough understanding of functional neuroanatomy and the basic features of at least the common diseases that affect the nervous system.
SYMPTOMS. Symptoms are the abnormal or unusual (subjective) experiences or phenomena that a patient relates to a physician in describing the “history” of his or her illness. The nature of the symptom tells one the pathway or structure involved. For example, weakness is due to motor system involvement, and the quality of the weakness and its associated signs indicate which part of the motor system is involved. Likewise, the type of sensation lost will suggest the sensory pathway involved. In this fashion, the physician reviews each symptom in detail by asking the patient appropriate questions.
Each symptom should be analyzed in terms of the nature of its onset, distribution, course, and present status. For example, an abrupt onset suggests pathological processes like bleeding or vascular occlusion. A slowly progressive disorder over the short term is seen in mass lesions, whereas such a progression over the long term is characteristic of the so-called degenerative disorders. An exacerbating and remitting course is seen in demyelinating diseases, although it can occur in other situations also. The distribution of the symptoms provides information concerning the structures involved and therefore the localization of the lesion. The course of the symptoms provides information regarding the tempo and, as mentioned above, the nature of the disorder. A comparison of the severity of the symptoms at the onset of the illness and at the time of evaluation provides similar information.
SIGNS. Signs are the objective “findings” one elicits during the physical examination. The nature of these findings helps one determine the structures whose functions are disturbed by the disease process. One should therefore be familiar with the meaning of the various signs. One should base the diagnosis on “solid findings” and not on equivocal observations. One should look closely for signs that will explain the symptoms the patient has been describing.
ANATOMICAL DIAGNOSIS. An analysis of the symptoms and signs will lead to a determination of the structures involved in the disease process. You may want to write down the symptoms and signs in separate columns and try to determine, in a third column, the possible structures that, if diseased, would lead to those symptoms and signs.
The next step is to see whether there is a common location in the nervous system where these structures lie close enough to each other so that a single lesion in that area can explain all the manifestations of the disease. If this is not possible, one should conclude that the pathological process is located in multiple areas.
PATHOLOGICAL DIAGNOSIS. The process of arriving at a pathological diagnosis requires a synthesis and integration of all of the above information. All of the aspects of the history (i.e., symptoms) mentioned above must be correlated with the findings (or signs) obtained during the physical examination in order to localize the disease process (or lesion) as precisely as possible. Once the lesion has been localized and the onset, tempo, and progression of the disease process has been identified, a pathological diagnosis can be determined if one has sufficient knowledge and experience in clinical medicine. Ancillary procedures and studies are helpful at this stage of the diagnostic process.