Cardiovascular autonomic neuropathy in non-diabetic Nigerian patients with chronic renal failure

Abstract

Aims: To determine the frequency of cardiovascular autonomic neuropathy (CAN), its pattern and clinical predictors in Nigerians with non-diabetic chronic renal failure (CRF). Methods: A total of 120 subjects comprising 60 pre-dialysis CRF patients and an equal number of age- and sex-matched healthy controls were studied. Five standard cardiovascular reflex (CVR) tests namely: heart rate response to deep breathing, Valsalva manoevre and posture, as well as blood pressure response to hand grip and posture were used to evaluate the cardiac autonomic functions. A pre-tested questionnaire was administered, with neurological examination and serum biochemical investigations also included in the evaluation. Results: The frequency of CAN in non-diabetic CRF was 65%. Dysfunction of both the parasympathetic and sympathetic divisions of the ANS occurred in CRF patients. Significant impairment in all the heart rate reflex tests (39%) and blood pressure response to the handgrip tests (28%) occurred in patients with CAN. Symptoms of autonomic neuropathy with clinical correlation with CAN included: constipation (60%), hyposialism (51%) and hypohidrosis (33%), whilst those of peripheral neuropathy were: loss of sensation (50%) and numbness (40%). Of the biochemical parameters, serum creatinine and urea had significant correlation with autonomic neuropathy. Conclusion: Autonomic neuropathy is common in Nigerian patients with non-diabetic CRF, especially in those with symptoms of constipation, hypohidrosis, numbness and prickly sensations.