There are five common signs and symptoms used by clinicians to detect the presence of neurological diseases. These include headache, weakness, mood swings, fever, and nausea and vomiting. Central nervous system (CNS) diseases also have common unifying symptoms. Since these symptoms are largely shared by many vastly different diseases, they are rarely diagnostic in and of themselves.
Stiffness in the neck, back, or extremities; loss of motor control; seizures; paralysis; vision problems; speech problems; excessive drowsiness; altered consciousness; and amnesia or extreme forgetfulness are all symptomatic of central nervous system disease.
When clinicians suspect an infectious nervous system disease is the cause of a patient’s symptoms, there are a range of diagnostic tools available to isolate the causative agent. Assessing the contents and pressure of cerebrospinal fluid with a spinal tap is often a useful diagnostic. Intracranial pressure can be measured to determine if inflammation of the brain or surrounding protective tissue is present. A computerized tomography scan, commonly referred to as a CT scan, can provide detailed body images useful for detecting abnormalities. Electroencephalography (EEG), magnetic resonance imaging (MRI), and specialized X-ray scanning are also sometimes used for diagnostic purposes.
A pathogen, toxin, or other agent that preferentially affects or attacks the nervous system is said to be neurotropic. All common groups of pathogens—bacteria, fungi, viruses, and parasites—can cause nervous system diseases. Misfolded proteins called prions can also cause fatal degenerative neurological disease.