Introduction
This book is written as a companion and supplement to DeJong’s The Neurologic Examination, 6th edition. The book has been streamlined, all reference to basic science removed, and the essentials of the clinical examination presented. In addition, novel to medical books as far as I am aware, there are appendices (a “Toolkit”) that contain some commonly used and handy instruments and forms that are often useful in the examination of the neurologic patient, especially in regard to neuroophthalmology. These include: a simple red lens for diplopia testing, a multi-pinhole for assessing visual acuity, pocket vision screeners for examining near visual acuity at near and at a distance of about 6 feet, a primitive but usable version of an OKN tape, 4 red squares with dots to assess color vision in all 4 quadrants, selected color vision plates, an Amsler grid for evaluating central scotomas, a copy of the Blessed memory-orientation questionnaire, and copies of the Glasgow coma scale, the Hunt and Hess scale for evaluating subarachnoid hemorrhage patients, and a diagram of the brachial plexus. Commercial interests would not allow the inclusion of the Folstein mini-mental examination.
The hope is that the Toolkit will elevate the Pocket Guide from a mere abbreviated textbook on the neurologic examination to a useful clinical tool for examining patients. With the Pocket Guide and its accompanying Tools, along with the usual instruments found in the neurologist’s black bag, the examiner should find at hand all the reasonable tools with which to do a complete neurologic examination, to include detailed neuro-ophthalmologic assessment.
The larger textbook, DeJong’s The Neurologic Examination, remains the definitive source for all aspects, common and abstruse, for a discussion of the examination. The Pocket Guide is intended as a brief version, pocket or bag portable, that contains the essentials of the examination as well as many of the tools that are often hard to find when needed most.
NEUROLOGIC DIFFERENTIAL DIAGNOSIS
Pathologic processes behave in certain ways depending on their location in the nervous system, and in certain other ways related to their inherent natures. Neurologists deal in two basic clinical exercises: where is the lesion in the nervous system and what is the lesion in the nervous system: differential diagnosis by location and differential diagnosis by pathophysiology or etiology. The anatomic diagnosis and the etiologic diagnosis aid and support each other. In general, the neurologic examination aids primarily in establishing the anatomic or localization diagnosis and the history aids in the etiologic diagnosis, but there is overlap. The examination also serves to indicate the severity of the abnormality. A dependence on neuro-imaging and other tests as the primary approach to diagnosis causes many errors. Defining the patient’s illness first in terms of anatomy and likely etiology helps insure the appropriate use of neurodiagnostic studies.
The first consideration should be whether the patient has an organic disease or whether the symptoms are likely psychogenic. If the disorder is organic, consider whether the condition is a primary neurologic disease, a neurologic complication of a systemic disorder, a neurologic complication of drug or medication use, or the effects of a toxin.
ANATOMICAL DIAGNOSIS
The patterns of abnormality found on examination help to localize a disease process to a particular part of the nervous system. Clinical features that are particularly helpful in neurologic differential diagnosis include the distribution of any weakness, the presence or absence of sensory symptoms, the presence or absence of pain, the presence or absence of cranial nerve abnormalities and whether they are ipsilateral or contralateral to the other abnormalities on examination, the status of the reflexes, the presence of pathological reflexes, involvement of bowel and bladder function, and the presence or absence of symptoms that clearly indicate cortical involvement. Weakness may be unilateral or bilateral, symmetric or asymmetric, primarily proximal or primarily distal; each of these patterns has differential diagnostic significance. The pattern of sensory abnormalities also provides significant information.
In trying to make an anatomical localization, it may be helpful to organize the nervous system by considering sequentially more peripheral or central structures, beginning either at the cerebral cortex or the muscle. Consider each level where disease tends to have a characteristic and reproducible clinical profile. For example, disease involving the muscle, neuromuscular junction, peripheral nervous system, nerve roots, spinal cord, brainstem, and hemispheres each tend to produce a characteristic clinical picture. Some diseases cause multifocal or diffuse abnormalities, and these are often particularly challenging.
At each major level, disease processes tend to have characteristic clinical features, although with some degree of overlap. By trying to localize the disease process to one or two likely levels, such as muscle or neuromuscular junction, one can then think more systematically about the etiologic possibilities.
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