Immune and Infectious Diseases

Many immune-mediated diseases and infections affect the central and peripheral nervous systems. The common feature that characterizes both immune-mediated diseases and infections is a subacute temporal profile. Immune-mediated disease can affect only the nervous system or involve the nervous system as part of a systemic illness, as in vasculitis and connective tissue disease. Multiple sclerosis (MS), the most common disabling neurologic illness of young people, is the prototypical immune-mediated disease of the central nervous system (CNS).

Movement Disorders

Movement disorders are neurologic syndromes in which movement is either excessive (hyperkinesia) or too little (hypokinesia). A general term used for both hyperkinesia and hypokinesia is dyskinesia, which is defined as difficulty performing voluntary movements. The prototypic hypokinetic movement disorder is Parkinson disease (PD). Other terms used to describe this movement disorder are bradykinesia (slowness of movement) and akinesia (loss of movement).

Weakness

Weakness is a common complaint. Most patients use the term weakness to imply fatigue, general illness, or myalgias. Determining whether a patient has actual neuromuscular weakness can be a diagnostic challenge. Disease of the motor system can occur at all levels of the nervous system. This chapter considers disorders of the lower motor neuron, including disorders of muscle (myopathies), the neuromuscular junction, and motor nerves.

The Neurologic Examination

The neurologic examination is the most important part of the evaluation of a patient who has neurologic symptoms or disease. The information obtained from the history and physical examination is needed to generate a differential diagnosis, to select the appropriate diagnostic tests, and to initiate appropriate therapy.

Neuro-oncology

Neuro-oncology is a rapidly evolving specialty involving the study of cancer and the nervous system. The nervous system can be affected by cancer directly, indirectly, or as a result of treatment-related adverse effects. The diagnosis and treatment of cancer of the nervous system require the skills of several medical disciplines to help patients with this serious and complex medical problem.

Diagnostic Tests

The diagnostic tests used most often to evaluate patients who have disease of the central nervous system (CNS) include cerebrospinal fluid (CSF) analysis, electroencephalography (EEG), evoked potentials, electromyography (EMG), computed tomography (CT), and magnetic resonance imaging (MRI). These tests should be used to supplement or to extend the clinical examination.

Headache

Headache is a universal problem, with a lifetime prevalence of 99%, and it is the most common reason for neurologic referral. Headache may be of little clinical significance or it may represent the onset of a life-threatening illness. To the patient, the symptom is always of major concern, and the relationship you establish with the patient at the initial visit will determine the success of treatment.

Cerebrovascular Disease

Transient ischemic attack (TIA) is an episode of focal neurologic dysfunction (brain, spinal cord, or retina) caused by ischemia. The clinical symptoms usually last less than 1 hour, and there is no evidence of acute infarction. Central nervous system infarction is defined as cell death attributable to ischemia with clinical, neuroimaging, and/or neuropathologic evidence of permanent injury. In the absence of imaging and pathologic evidence, clinical stroke is established by the persistence of symptoms for 24 hours. Silent infarction, discovered by imaging, has no known symptoms but remains an important issue in secondary stroke prevention.

Spells

Spells are transient disorders that indicate reversible alterations in neuronal excitability. Transient disorders can affect the central or peripheral nervous system and can be generalized or focal. Examples of generalized transient disorders are generalized seizures, syncope, concussion, and cataplexy. Examples of focal transient disorders are focal seizures, transient ischemic attacks, migraine, transient mononeuropathies, paresthesias, muscle cramps, and tonic spasms.

Cognitive Loss

This chapter discusses dementia, memory loss, and other cognitive dysfunction. Dementia is diagnosed when cognitive or behavioral symptoms interfere with the ability to function at work or at usual activities. This represents a decline from previous levels and is not explained by delirium or major psychiatric disorder. The criteria for dementia include a minimum of 2 of the following cognitive or behavioral impairments: 1) impaired ability to acquire and remember new information, 2) impaired reasoning and handling of complex tasks, 3) impaired visuospatial abilities, 4) impaired language functions, and 5) changes in personality, behavior, or comportment.