NEURAL DISORDERS - Medicine for Mountaineering and Other Wilderness Activities - page 185

nervous system disease. Acetazolamide, which is frequently administered to treat or pre-
vent acute mountain sickness, commonly produces similar symptoms. Total anesthesia is
rare.Anesthesia ofanentire limb oranentire limb below aspecific level, a“stocking” pat-
tern,isduetohysteriaratherthanorganicdisease.Thedistributionofnervesdoesnotallow
this pattern of anesthesia to be produced by disorders that are not of emotional origin.
Individual Nerve Loss
Dysfunction of nerves that originate in the brain—cranial nerves—causes highly varied
symptoms.Disturbedfunctionofnervestotheeyesmaycauseblindness(occasionallylim-
ited to only a portion of the field of vision), paralysis of eye movements, or double vision.
The pupils may fail to contract when exposed to light or may differ greatly in size. Vision
may be blurred.
Disordersofnervestothemusclesoftheface,acommoncomplicationofLymedisease,
cause weakness or paralysis of facial movements and drooling on the affected side. Swal-
lowing is impaired when the nerves to the muscles of the throat are affected, and fluids
mayberegurgitatedthroughthenoseoraspiratedintothelungs.Disturbancesofthenerves
to the ear cause ringing or buzzing, vertigo, or hearing loss. Damage to other nerves may
cause loss of smell, loss of taste, severe facial pain, weakness of the muscles of the neck,
or impairment of respiration.
Damage to the nerves originating in the spinal cord causes paralysis or sensory disturb-
ances, commonly anesthesia, in the portion of the body supplied by the injured nerve(s).
Reflexes such as the knee jerk may be lost.
Other Signs and Symptoms
Blood clots, tumors, infections, or any disorder that increases pressure within the skull
can cause nausea and vomiting, the latter typically occurring without warning. A slow
pulse and a wider-than-normal separation of diastolic and systolic blood pressures are also
typicalofincreasedintracranialpressure.Headacheassociatedwithnervoussystemdisease
isoftensevere.Feverwithcentralnervoussysteminfectionsisoftenhigh.Inothernervous
system disorders, the temperature is normal or only slightly elevated.
COMMON NERVOUS SYSTEM DISORDERS
Thecommonnervoussystemdisordersareusuallynotveryseriousandarefrequentlybrief
in duration.
Headache
Headache is a very common ailment suffered occasionally by all but a few fortunate in-
dividuals. Often a specific cause for a headache cannot be identified, and the disorder is
thought of as a disease in itself, although it is often a symptom of another illness. Head-