The Pattern of Neurological Disorders; Revisited Prevalence Data of a Dedicated Neurology Clinic in Sudan

Background: The diverse modes in geographical locations, environmental factors, genetic and racial characteristics play a complex role in determining the pattern of neurological disorders worldwide. Determining the pattern of neurological disorders enables health policymakers to plan evidently for service, training, and research priorities. Few prevalence studies in neurology were conducted in Sudan. Methods: This is a retrospective hospital-based study that reviewed the medical records of patients who attended a Dedicated Neurology Clinic (DNC) in Omdurman, the national Capital of Sudan, for 24 months, from January 2016 to January 2018. This study aimed to determine the DNC pattern of neurological disorders as a representative subset prevalence in Sudan. Neurologists conducted the medical workup for diagnosis after at least two visits. All patients have ethically consented. Results: The total number of patients was 1050. Only 749 patients (71.3%) fulfilled the inclusion criteria. The mean age was 46.5 ± 1.9, and males were 45.3%. 72% were from the Capital. The presenting symptoms were headache (16.6%), seizures (11.5%), limbs weakness (11.2%), and lower percentages for other neurological symptoms. The commonest diagnoses were Stroke 12.4%, Epilepsy 9.3%, Primary Headache 8.8%, Movement Disorders 7.3%, Peripheral Neuropathy 6%, DeHow to cite this paper: Elsayed, M., Hamid, O.A.A., Tonga, R., Elsadig, S.M., Ahmed, M.H., Ahmed, M. and Saeed, M.K. (2021) The Pattern of Neurological Disorders; Revisited Prevalence Data of a Dedicated Neurology Clinic in Sudan. Case Reports in Clinical Medicine, 10, 339-358. https://doi.org/10.4236/crcm.2021.1011043 Received: August 25, 2021 Accepted: October 29, 2021 Published: November 1, 2021 Copyright © 2021 by author(s) and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ Open Access


Introduction
The diverse modes in geographical locations, environmental factors, genetic and racial characteristics play a complex role in determining the pattern of neurological disorders worldwide. The burden of these diseases contributes significantly to the mortality rates in Sub-Saharan Africa, as revealed in an extensive systematic review by Connor et al. [1]. Moreover, neuro-psychiatric illnesses are responsible for 37% of healthy life lost due to adult disability in low-income countries [2]. Mortality due to neurological disorders was estimated at around 12% [2] [3], where aging represents a challenge to all health structures, including Africa [4].
The number of epidemiological studies in the third world is limited due to the cost of transportation and logistics in these countries. In low-income countries, patients with neurological disorders suffer from low diagnosis and treatment rates due to many factors [5]. Nevertheless, data produced from such research will help local health authorities to plan and the international bodies to fund priorities [6]. Furthermore, it can add answers to clinical questions, promote neurology training, and enhance specialized research. Medical records review was adopted to investigate different disciplines previously [7] and proved its usefulness and impact to define the clinical characteristics of some diseases [8] [9].
The UK Third National Morbidity Survey reported the commonest presentations, which ended in referral to the neurology service. These were ordered as headache, dizziness, spine symptoms, fits, and stroke symptoms [10]. Consultations for headache and epilepsy together may constitute 25% of the neurologist workload, as stated in a multi-center study in the UK [11], giving these disorders more influence on the daily work. The neurological disorders were estimated as 19% of the hospitalized cases in a district general hospital in Ireland [12]. On a population-based scale, 3.6% were predicted to need neurological care at one point during their life [13]. A multi-center study enrolled 18

Methodology
This is a descriptive retrospective hospital-based study.

Exclusion Criteria
Patients who had a single visit to DNC and patients who had two visits to DNC but did not satisfy the diagnostic criteria either for insufficient workup, assessment failure, or because they were referred for a second opinion were excluded.

Diagnosis
Neurology consultants diagnose each patient after a minimum of two clinic visits.

Evaluation Tools
All enrolled patients were assessed at least twice by a senior consultant neurologist for the same diagnosis. Tools for assessment included personal interviews,

Data Analysis
The coding plan was discussed with the statistician, and data was entered in SPSS version 25 for analysis. After then, the results were displayed in tables and figures.

Ethical Clearance
Ethical clearance was taken directly over the phone from the competent patient or the guardians of the non-competent. Few records (n = 28) ethical clearance was waived by the Tertiary Center Ethical Committee.
All patients had free access to their medical data through a medical report and follow-up cards. Any competent patient was counseled or the next of kin for the incompetent. They had given their verbal consent to participate in the study.
Data was secured in the hospital under the confidentiality regulations of the Sudan Medical Council (SMC).

Demographic Data
The sample size of this study was 749 patients.
Of the reviewed patients, 11.2% expressed their suffering of a degree of disability due to their neurological disease. Regarding the number of visits needed to confirm the diagnosis, 56.2%, 27.1%, 8.5%, 4.5%, and 1.5% required two, three, four, five, and Six visits, respectively. The rest of the percentages were more than six visits.

Patterns of Neurological Diagnosis
Regarding the diagnoses, 12.4% (n = 93) had stroke, among which ischemic type was 81%, other hemorrhagic stroke types were 19%. Cerebral Venous Thrombosis either sinus, cortical veins or combined was found in 1.7%, and retinal vein occlusion in 0.1%. Generalized epilepsy was diagnosed in 6.5%, and the focal epilepsy in 0.5%. Non-epileptic attacks were in 1.5%, and vasovagal attacks were in 0.3%. Temporal lobe sclerosis were found in 1.9% as reflected in their MRI brain with epilepsy protocol.
Lumbo-sacral root disorders mainly due to spondylotic changes were found in 14.2%. Cervical radiculopathy with or without myelopathic changes was found in 6.4%. The cases with cervical or dorsal myelitis due to different causes were in 0.8%.
Primary Headache syndromes were diagnosed in 8.8%, among which Tension-type headache was 39%, and Migraine was 61%. No Cluster headache or trigeminal Autonomic Cephalgias were encountered.
Movement disorders were found to be 7.3% of the total sample in which Idiopathic Parkinson's disease was 5.7%. In comparison, Parkinson's Plus syndromes were 0.2%, among which Multiple System Atrophy (MSA) was found in 0.1% as well as progressive Supra Nuclear Palsy (PSP). Wilson's disease 0.2%, Essential Tremors was found in 0.2%, stiff person syndrome 0.2%, dystonia 0.4% and chorea 0.1%. The idiopathic Parkinson's disease was 78% of the movement disorder representing the commonest category.
Idiopathic Bell's Palsy was found in 1.2%, while trigeminal neuralgia (TN) was present in 1.1%, 0.2% for each Oculomotor third nerve, and Abducens 6th nerve palsy. Ischemic optic neuropathy was found in 0.1%. Peripheral neuropathy was found in 3.5% (n = 26), where Distal diabetic sensory peripheral neuropathy Case Reports in Clinical Medicine (DDSPN) was found in 1.7%. Carpal Tunnel Syndrome was in 2.3%, while Axonal Sensory Motor Neuropathy in chronic inflammatory demyelinating polyneuropathy (CIDP ) was found in 0.7%. Herpes zoster and postherpetic neuralgia in 0.1%. Myasthenia Gravis (MG) was found in 0.5%. Other cerebellar syndromes were found in 0.4%. All types of hereditary ataxia with or without family history were found in 0.5% and the same for muscular dystrophy, which was 0.3%. Ataxia telangiectasia (AT) was found in 0.1%. Possible Multiple Sclerosis (MS) in 1.2%, monophasic transverse myelitis in 0.3%, and Neuromyelitis Optica Spectrum Disorders (NMOSD) in 0.1%. Vertigo and other vestibular disorders constituted 1.5%.
Space occupying lesions were found in 3.9%, being either primary, secondary neoplasms, or granulomas and abscesses. The spinal metastasis was found in 0.1%. Central nervous system infections, including meningitis, encephalitis, empyema, and Pott's disease, were found in 1.4%, while Pott's disease alone was 0.5%. Leprosy was present in 0.1%.
Anxiety disorder was found in 1.5%, while conversion syndrome presenting with different neurological presentations was 1.1%. Hyperactivity attention deficit disorder HAAD was found in 0.1%. Cerebral palsy was found in Stiff person syndrome was found in 0.3%. Non-neurological disorders constituted 3.6%.

Discussion
The mean age in this study was relevant to the mean age in other studies but in a lower fashion as some listed studies targeted only the elderly population. In our report, the elderly patients, i.e., 60 years and above, were 27%, while patients between 40 -60 years were 12%. It reflects the accumulation of morbidity in old age and common neurological clusterings like stroke and spine disorders in the elderly. This conforming to the concept reflected in 2009 by Asekomeh et al. and stating that more trials are needed to address neurology in the elderly population, even in Africa [17]. The percentage of pediatric patients was low because the study area was an adult neurology clinic. However, access to specialized services and pediatric neurologists in the underdeveloped world is a great challenge.
A small percentage of 0.7% was from outside the country, which echoes the health status in this part of the world, the rarity of specialized consultations, and common health structures and dares. A higher percentage of 3.7% was reported in Cameroon by Callixte et al. If we scale it on a higher level, West Africa has fewer regional conflicts than East Africa, which may have affected the easiness of transportation across countries.

Stroke and Other Cerebrovascular Diseases
In our study, stroke was 12.4% which is relatively consistent with the study of Komolafe et al., which reported 11.8% of stroke in adults in a University Hospital in Nigeria. The study used the ICD 10, and diagnoses were made by the neurologist [18]. However, our figure was higher than the descriptive OPD study of Callixte et al. [14] in Cameroon, which enrolled 912 patients and reported stroke in only 7%. This pattern is less likely to be related to sample size differences but may indicate different risk factors for stroke or discrepancies in the more rural catchment area. As we know, rural areas tend to have more healthy lifestyles, organic food, and less pollution.
The study of neurological patterns in patients 70 years old and above by Dehurst, F. in 2012 reported a higher percentage of 29% for patients receiving appropriate treatment among 349 patients. However, this may be because of the smaller sample size, selection bias, higher likelihood of stroke in old age, and co-morbidities. The same author in 2013, using the ICD-10 in a community-based prevalence study in Tanzania, reported a lower percentage of 23% for stroke.
Another study by Anand et al. in a teaching hospital in India reported stroke in 19.1%. However, 27% were above 40 years, in comparison to our study, which revealed almost 40% above forty years. In Anand et al. study, 70% were males, and it is well-known that gender is a non-modifiable risk factor for stroke and may have contributed to that study's higher percentage.
The percentage of stroke was lower than the previous percentage found by the author of this paper in a similar study to determine the pattern in 2012 (12.7% versus 20.7%) [19]. This is due to the difference in sample size, and the first study included patients from OPD and ER while the second one only enrolled OPD cases hence missing cases of acute stroke. Nevertheless, overall the stroke in this study was the commonest neurological disorder and matched the systematic review done by Connor et al. 2007 that reported the burden of stroke in a black population of Sub-Saharan Africa. Table 1 will show the differences and similarities between the two studies among different neurological patterns in the same town.
One goal of this study was to re-evaluate the pattern of neurological diseases after few years of the first research. It had adopted almost similar setting of the population with exension of the observers. It is interesting to recognize that the stroke, headache, movement disorderscerebral venous sinus thrombosis had

Epilepsy
It is essential to recognize that neurological disorders constitute 3.6% of the need for neurology service, while hospital settings reflect a 19% -12.3% [12] [13]. Hence, defining the pattern of the second common neurological disorder like epilepsy is essential. The current study reported epilepsy and seizures to be 11.5% which is the lowest reported percentage among all studies listed here. The highest percentage was 32.9% in a university hospital in West Africa. There is no clear explanation for this from our side. Even in our previous preliminary report and despite a smaller sample size, it was found to be 16.6%. Among the different studies listed here, it ranged from 20% -32% [5] [16]. However, most of the epilepsy patients prefer to follow up in the general hospital OPDs as it is a chronic condition. The affordability issue may have played a role in this DNC concerning a common episodic disorder that may be followed up with the same neurologist in the public hospital. However, it still stands as the 2 nd commonest neurological condition after stroke, which conforms to international literature.

Headache
The 3 rd commonest neurological diagnosis encountered here as 8.8% as compared to a relatively similar percentage found by Callixte et al. 7 reported by Dewhurst, F. in 2013 [16]. Still, the latter was a community-based study and included the elderly population only who may have other causes for the headache like anemia, UTI, glaucoma, and cervicogenic headache. Komolafe et al. [18] reported a lower figure of 6.7%. Moreover, endemic diseases in Africa like Malaria plays a role in headache as a common symptom.

Movement Disorders
Our figure of 6.2% for movement disorder, including 5.9% for Parkinson's disease, was precisely similar to the community-based study of Dewhurst 2013, which was 5.9% for Parkinson's disease [16]. Moreover, movement disorders were near our previous findings in a general teaching hospital, which was 7.7%.
On the other hand, it was not relevant to Komolafe

Peripheral Neuropathy (Unspecified)
The percentage of this disorder as 6 % was higher than Anand, K. S. (3.7%) and Elsayed, M (3.6%) [19] [20]. However, there was a clearly higher percentage in another two studies using the ICD-10, but the two studies had a 50% difference in their report of peripheral neuropathy (Callixte et al. 2015 and Dewhurst et al.
2013 [14] [16]. The former was an OPD study, while the latter was an epidemiological community study which explains the lower percentage in hospital-based studies. Komolafe et al. [18] reported a lower rate of 2.3%. The differences expressed here can be explained by the vast majority of diseases and substances that cause peripheral neuropathy with the accumulation of locally endemic diseases like leprosy, HIV, and Tuberculosis in different areas.

Others
It is exciting and ambiguous to find a lower percentage of infectious conditions in a sub-Saharan country in Africa. However, as the cases were only reviewed in Case Reports in Clinical Medicine a tertiary center clinic, but as expected, many cases will be presenting dramatically to the ER and would have been missed in this OPD review. Hence, this will explain the 1.4% encountered here for infectious conditions. It is higher than the 0.6% reported by Komolafe et al. [18] in a hospital-based study in Nigeria, where we also expect a higher range of infectious conditions. It is essential to mention here that Pott's disease was a typical encounter in our review besides brain tuberculomas which raises the paramount importance of clinical attention to these serious endemic diseases with high morbidity, disability, and mortality. Dementia diagnosis depends on the clinical evaluation, imaging by MRI and neuro-psychology testing. The documented follow-up is a major tool to consolidate the final diagnosis. Dementia was reported here as 3.4%, which is slightly higher than 2.6% found by Komolafe et al. while Callixte et al. reported a higher percentage of 11.2%. Our review's breakdown of these percentages showed Alzheimer's disease as the commonest (2.1%) of the total cases and 53% of dementia cases. The frontotemporal lobe dementia FTLD being ten times less (0.2%), while vascular Dementia came second with 1.9%. This percentage order conforms to the international literature as Alzheimer's disease is the commonest followed by Vascular Dementia and then the rest of the subtypes [21] [22].
Demyelinating disorders, including possible multiple sclerosis and other transverse myelitis, were reported as 1.6%, which conforms to what has been found previously in 2012 as 1.8%. Nevertheless, regarding their severe disability, they must be encountered as an important category in Africa's neurological disorders.
Interestingly, the percentage of cerebral venous sinus thrombosis and cortical thrombosis is almost static in 2012 and 2018, being 1.7% and 1.8%, respectively. Therefore, the consensus and experts' opinion in the neuroscience society in Sudan SSNS is "this condition is emerging as a serious potentially treatable condition with major disability and mortality in the young population and pregnant women which deserves more research and health awareness in certain target groups".
Tumors reported here were higher than in the 2012 study (3.9% versus 1.2%) [19]; however, all space-occupying lesions were included in this study. This may have added some granulomatous and abscesses to the percentage.

Limitations
The limitations here include a single clinic view and a single professional assessor. There were no follow-up details for specific neurological disorders. The lack of advanced testing like genetic and special immune tests in few diagnoses may have cornered the diagnostic plasticity. The location of the study in the Capital may not reflect the nationwide pattern. Finally, the application of ICD 10 was not performed.

Conclusion
This is a neuro-epidemiological hospital-based study; where Stroke syndromes were the most common neurological disorders. Then epilepsy, headache, movement disorders, and peripheral neuropathy, Dementia mostly conforming to the international and regional data. Similarities between the paper of 2012 and this paper in some disorders may reflect a near percentage of the actual pattern in Sudan, especially demyelinating disorders, peripheral neuropathy, and cerebral venous thrombosis. MRI scans are more likely yielding in neurological disorders than CT scans. Further epidemiological/multi-center studies will help determine the natural pattern of neurological disorders in Sudan.

Consent for Publication
The consent for publication was obtained from both the patients and Alia's Specialized Hospital ethical committee.

Availability of Supporting Data
The data is stored in Alia's Specialized Hospital, Khartoum Sudan, under the regulations of the Sudan Medical Council.

Authors Contributions
Dr. M E was responsible for the literature review, neurological assessment of the patient, writing of discussion, and references. Dr. Omer Aladil was responsible for designing and validating the questionnaire, verifying the demographic data,

Annex
The pattern of neurological disorders; Revisited prevalence data of a Dedicated Neurology Clinic in Sudan.

Questionnaire
For the data collector, competent patient and Co-patient Next of kin All questions contained in this questionnaire are strictly confidential and are used only for research purposes where no disclosure will point to the patient.