Electrolytes and the renin-angiotensin-aldosterone axis in traumatic quadriplegia
Claus-Walker, J.; Spencer, W.A.; Carter, R.E.; Halstead, L.S.
Archives of Physical Medicine and Rehabilitation 58(7): 283-286
1977
ISSN/ISBN: 0003-9993 PMID: 880002 Document Number: 110598
Patients paralyzed by a physiologically complete transection of the cervical spinal cord rapidly undergo a redistribution of their body fluids and electrolytes which increases their susceptibility to episodes of electrolyte and blood pressure imbalance. The causes of the electrolyte changes in the extracellular fluids and whether these causes are affected by the duration of paralysis, by wheelchair sitting and by the kinetics of the urinary flux were studied. Electrolyte changes may be caused by a chronic increased renin release, stimulating angiotension II and aldosterone secretion. To test this hypothesis, plasma renin activity, plasma and urine aldosterone, and plasma and urine K and Na were measured in 42 quadriplegic patients throughout the initial period of rehabilitation and during their additional hospitalization. Supine plasma renin activity and aldosterone are increased in quadriplegic patients. The increases in supine renin and aldosterone are greater during the first 8 mo. of paralysis than afterwards. Supine renin and aldosterone are increased to a much larger extent in bed-ridden patients than in those with daily wheelchair activity. Upright renin and aldosterone sampled in patients sitting in a wheelchair are higher than the supine values. Neither supine nor upright renin and aldosterone is influenced by the kinetics of the urinary flux.