F- CLINICAL ASPECTS OF SPINAL CORD INJURIES
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The mechanism of the vasodilator effect found in cervical lesion is of special interest.
The vasodilatation involves the shoulder, upper chest, neck, ears and face and is of
patchy type, associated with congestion of the naso-pharyngeal mucosa resulting in
blockage of the nasal air passage. It is well known that vasodilatation in the face combined
with nasal congestion is the regular and immediate effect ofparalysis of the vasoconstrictor
fibres following cervical sympathectomy or transection of the cervical cord. However,
there is no evidence that in high cord lesions the vasodilatation in these areas resulting
from excessive bladder activity is due to 'paralytic' vasodilatation as there is every sign
of increased sympathetic activity. On the other hand, if, in high cord lesions, the vessels
of face, neck and upper arms are controlled by the isolated cord, then one would expect
that they would constrict as do the vessels of the fingers. However, they behave as if the
vasoconstrictor influence of the isolated cord were overpowered by an active vasodilator
mechanism excited by the intact carotid sinus nerves or entirely under the control of
higher centres. While the vessels of the hand and fingers are controlled by the isolated
cord and are constricting to a degree that the blood flow drops to zero, as shown in the
pletysmogram, face, neck and upper arms show marked vasodilatation, which has all
the appearance of being a readaptive mechanism. In this connection, it may be remem
bered that vasodilatation in the tongue was found following stimulation of the chorda
tympany (Machol & Schilf, 1928), moreover, the Vidian nerve is thought to mediate
vasodilator fibres for the nasal mucosa (Schilf, 1937). Another possibility for this striking
vasodilator responses may be the release of a powerful vasodilator substance similar to
the effect of the stimulation of posterior spinal roots. Vasodilatation seems to be a pre
dominant function of the vasomotor systems in face, neck and upper chest in man, and
the patchy type of vasodilatation observed during bladder distension in patients with high
cord lesions resembles very much the flushing elicited almost regularly by emotions in
many normal subjects, especially women.
The sudden rise in blood pressure no doubt leads, as shown by the visible engorge
ment of the temporal and supraclaricular vessels, to a sudden increase in intracranial
blood flow and, mechanically, to passive vasodilatation, experienced by the patients as
pounding headache and head-fullness. Therefore, passive vasodilatation may also play a
part in the vasodilator response of the cutaneous circulation in face, neck, upper chest
and upper arms, as well as in the naso-pharyngeal mucosal circulation leading to stoppage
of the air passage (called by some authors Guttmann sign).
The clinical significance of the autonomic hyperreflexia
Knowledge and recognition by the medical and nursing attendants of the various
components of the reflex responses of autonomic mechanisms, especially the cardio
vascular phenomena, is most essential for an appropriate management of paraplegics and
tetraplegics. It must be realized that these reflex responses represent stress or alarm signals
of excessive activity of a viscus in the anaesthetic area of the body and they may be the
only indicator of impending abdominal catastrophy. Complaints of headaches by patients
with high cord lesions, in particular, have to be taken seriously and not be treated casually
by aspirin or other drugs as they may be caused, for instance, by bladder distension due
