Chronic kidney disease (CKD) is a worldwide public health problem with an 8% to 10% prevalence in the adult population [1]. Data in Africa are rare but the hospital-based prevalence in sub-Saharan Africa is estimated between 2% and 12% [2]. CKD accounted for 1% - 5% of global deaths in 2017 and was the 12th leading cause of death globally [3]. CKD progress in five stages and at end-stage, renal replacement therapy (RRT) either dialysis or renal transplantation is necessary for survival [4].

Haemodialysis (HD) is the main modality of RRT [5] [6]. The outcome of patients on HD is characterized by a high morbidity and mortality rate [7] [8] [9] mainly due to comorbidities and HD complications [10]. These complications affect all body systems, especially the cardiovascular and nervous systems [11]. Neurological complications affect both the central nervous system such as stroke, cognitive dysfunction, and encephalopathy, and the peripheral nervous systems such as autonomic and peripheral neuropathies [12] [13]. These complications are mainly related to uremic toxins, dialysate type, water quality and HD follow-up [13]. They are found in almost 60% of patients with kidney failure (KF) patients [14]. These complications are generally underdiagnosed and consequently less treated, contributing to the morbidity and mortality of affected patients [12] [13]. In Cameroon, HD is the only RRT available and has been expanded considerably in the last decade with an increasing number of patients undergoing this treatment. The mortality rate is high and estimated at 26.8% [15]. Data on neurological disorders amongst KF patients in Sub Sahara Africa are rare. This study aimed to determine the prevalence and factors associated with neurological disorders amongst patients on maintenance HD in a tertiary hospital in Cameroon.

This study aimed to determine the prevalence of neurological disorders and their associated factors in patients on MHD. The prevalence of neurological manifestations was high (85.4%). Cognitive impairment was the most common central nervous system manifestation while sensory polyneuropathy was the leading presentation of neuropathy. Male gender was associated with neuropathic pain while age ≥ 40 years, diabetes was associated with sensory neuropathy and restless legs syndrome.

Few studies exist on the spectrum of neurological disorders in patients on MHD. Most of them assessed specific aspects. Rizzo et al. in a review estimate the prevalence of neurological disorders in these patients at 60% [14]. Our prevalence (85.4%) was higher without the use of electrophysiology study (subclinical screening). An explanation could be the fact that patients in our setting received only 2 sessions of dialysis of 4 hours duration per week, instead of 3 sessions as

CD: Cognitive Dysfunction; PN: Polyneuropathy; NP: Neuropathic Pain; OD: Orthostatic dysfunction; HIV: Human Immunodeficiency Virus; RLS: Restless Legs Syndrome; HD: Hemodialysis.

recommended and also the shortage of dialysis consumables that lead to irregular dialysis sessions. These are factors that contribute to poor dialysis and the accumulation of uremic toxins that are known to be toxic for nerves.

Sensory polyneuropathy was the most present disorder (17.3%) using the MNSI which is a validated score for the diagnosis of peripheral neuropathy [17]. Among these patients, more than half (51%) had other diseases susceptible to induce polyneuropathy such as diabetes, HIV, hepatitis B and C. Mambelli et al. in Italy, and Tiki et al. in Turkishreported respectively a prevalence of 61.3% and 97% for polyneuropathy amongst patients on MHD [18] [19]. These high prevalence in their studies could be due to the fact that they used electromyoneurography, which enables infra clinical diagnosis of neuropathies, and also the rate of patients with risk factors (comorbidities) of neuropathy in their studies was higher.

A decrease in the amplitude of sensory potential was remarkable on the median, ulnar and sural nerves. Whereas the motor conduction velocity was reduced on the peroneal nerve associated to an increased latence interval. As for non-uremic polyneuropathies, excluding diabetes and viral infections that are common in Cameroon [21] [22] [23], another study reported in 20 patients on MHD with neuropathy, four cases of non uremic neuropathy notably one Guillain Barre syndrome, one chronic polyradiculoneuritis, one progressive spinal amyothrophy and a case associated to transplantation [24]. These findings suggest the multifactorial origin of polyneuropathy in our context.

Similar to Mambelli et al., increased age was associated to polyneuropathy as well as type 2 diabetes [18], which generally occurs with age justifying their coexistence as associated factors in our study. Cognitive impairment was present in 52.9% of which 4.8% of cases were recognized dementia. Our results were similar to those of Pereira et al. in Brazil who reported 40% of case [25]. These increased proportions can be explained by the presence of several major cerebrovascular risk factors such as hypertension, diabetes and HIV; and also, by the episodes of cerebral hypo perfusion occurring during dialysis sessions resulting in transient ischemia enhancing nerve cell damage in these patients. In 2012, Kurella et al. in the USA [26], in a series of 80 patients found that 38% of patients had severe dementia. This proportion is far greater than the 4.8% in our study. The mean age of their patients estimated at 61 years (versus 48 years in our study), could have contributed to an increase in the proportion of dementia.

Headache was the main symptom with a prevalence of 48% compared to 44% found by Aladlouni et al. in Morocco [27] and 40% reported by Goksan et al. in Turkey [28]. In Brazil, Antoniazzi et al. then Feitosa et al. respectively had 70 and 76% cases of headache [29] [30]. The main clinical presentations were migraine (48%), tension-type headache (19%) and associated forms (migraine and tension-type headache) in 8% of patients [28]. Sleep disorders were found in 44.4% of patients. These results are similar to the prevalence (44%) of sleep disorders reported in the study Giovanni et al. [31] but about much lower than those reported by Sabry et al. in Egypt (79.5%) and Merlino et al. in Italy (80%) [32] [33]. This difference could be linked to the study method used; in our study, the diagnosis was mainly clinical in contrast with these two studies that used well defined scores in addition to polysomnography.

In our study, the prevalence of restless legs syndrome was 17.8% using IRLSSG criteria. This result is in the range with those of Araujo et al. (21.5%) on a population of 400 patients and Salman et al. in Saudi Arabia (20.3%) on 123 patients using the same questionnaire [34] [35]. Age greater than 60 years was associated with restless legs syndrome, similar to the report of Araujo et al. [34]. This association could be justified by the fact that increased age enhances the degenerescence of descending dopaminergic pathways which could cause restless legs syndrome [35]. Finally, no association was found between restless legs syndrome and comorbidities, nor duration of dialysis, similar to other studies in the literature [34] [35].

Autonomic dysfunctions were frequent in chronic haemodialysis patients. Orthostatic hypotension was found in 15.9%. In our study, diabetes was the second comorbidity (19.1%) inducing severe neuropathies with autonomic dysfunction responsible for orthostatic hypotension. Sasaki et al. in Japan reported a prevalence three times ours (42%) [36]. The mean duration of dialysis in this Japanese study could explain the difference (14 years against 3 years in our study). The mechanism remains yet unknown.

Carpal tunnel syndrome was found in 8.9% of our patients who had a common characteristic of dialysis duration greater than 5 years. In fact, carpal tunnel syndrome is due to the accumulation of Beta-2 microglobulin, in particular and juxta-articular structures. Whereas Beta-2-microglobulin is a uremic toxin mildly eliminated via HD hence the correlation with the duration of dialysis. Using clinical criteria, our result is closed to that reported by Kopec et al. and Mbarki et al. in Tunisia which found respectively 10.4% and 8.3% [37] [38]. However, our finding was low compared to that of Namazi et al. (30.5%) [39]. This could be due to the fact that in their study, an electromyoneurography was performed and the duration on dialysis was much longer (10 years) [39].

This study has shortcomings which include mainly the absence of electrophysiological assessment for diagnostic confirmation and better appreciation of subclinical involvement. But the nature of this study, using validated tools for diagnosis purposes gives an idea of preliminary data and should serve as a baseline for further studies to improve the management of these disorders and comorbidities.

The prevalence of neurological disorders was high among patients on MHD in the DGH affecting up to 4/5 of them. Neurological involvement was numerous and dominated by sensory polyneuropathy and cognitive dysfunction. There is a need to put in place measures to manage these complications and improve the quality of life of affected patients.

Ethical approval was obtained from the institutional review board of the University of Douala, Cameroon. All participants and/or their relatives provided written consent. Patients with neurological disorders were addressed to the neurology unit for further management.

HMP, MNY, TTEG: Study conception and design;

TTEG, FH, GM, NV: data collection and supervision;

TTEG, GM, KFF, TD, HMP: data and analysis and interpretation;

HMP, MNY: drafting of the manuscript;

TTEG, NV, TD, KFF: critical revision of the manuscript;

All authors read and approved the final manuscript.

We are grateful all the patients who agreed to participate in this study

The authors declare that they have no competing interests

Patrice, H.M., Gildas, T.T.E., Hermine, F., Daniel, G.M., Ebenezer, N.V., Denis, T., Francois, K.F. and Yacouba, M.N. (2022) Spectrum of Neurological Disorders amongst Patients on Maintenance Haemodialysis in Douala, Cameroon: A Cross-Sectional Study. Open Journal of Nephrology, 12, 112-123. https://doi.org/10.4236/ojneph.2022.121011