Injuries of nerves and their consequences - Reflex Sympathetic ...

68 INJURIES OF NERVES.
very often disclose the presence of an unsuspected neuritis,
and I feel very sure that, far more often than is
thought,
some such condition lies behind very many of the cases
of what we treat as sciatic neuralo^ia.
Sclerotic alterations of nerves may possibly arise without
the aid of neuritis, but this is at least doubtful; nor
do I know any signs by which old chronic neuritis can be
clinically diagnosed from sclerosis.
It is
surprising how great may be the apparent structural
change wrought by neuritis before the power to move
on motion of
is
remarkably interfered with. The pain
course limits motility, and may thus lead to error;
but, as
a rule, tactile sensation is more altered than motor power,
and even the former may not suffer gravely until late in
the case. Nearly always I have found, somewhere in the
limb, hypersesthetic regions where a touch was more unpleasant
than deep pressure. The skin over the nerve
trunk is apt to be thus affected, and when leeches are
used on this part, their first effect is often painful, and
they sometimes occasion an unusual amount of swelling
and annoyance.
Prognosis. — The future of any case of long-continued
subacute neuritis is rather a dark one, and is
grave in
proportion to the length of nerve involved, and the extent
to which it has traveled in a central direction ;
since if it
has passed up as far as the parept plexus, so as to be
beyond surgical reach, the case may usually be regarded
as one to be relieved, but rarely to be cured.
Pathological results of neuritis. — The primary
effect of inflammation
of a nerve is to render it more vascular, to
to an effusion of serum within the main
enlarge and increase its vessels, to cause an enormo;i3
development of its connective tissue elements, and at first
to render the nerve less firm, owing partly to this hyperplasia,
and partlj'
sheath and between the nerve fibres. The secondary