Background
Non-communicable diseases (NCD) have assumed significant contribution in the morbidity and mortality globally [
1], this has resulted in the strain in the health systems in lower income countries especially those in sub-Saharan Africa which have been struggling with infectious diseases. In Tanzania similar trend of increasing burden of NCD has been documented [
2]. Musculoskeletal conditions which result in long term disability, pain and poor quality of life are reported to have high global burden which prompted a decade of bone and joint campaign (2000–2010) established jointly by European League Against Rheumatism (EULAR) and World Health Organization (WHO) with the aim of creating awareness about musculoskeletal conditions globally [
3,
4].
There has been a long-standing myth that musculoskeletal disorders are rare in Africa and this myth has been partly supported by limited capacity to diagnose these conditions and lack of health care providers’ awareness [
5,
6]. There is limited information about the magnitude of these conditions in Sub-Saharan Africa (SSA) which is home to more than 350 million children [
5]. Few studies and case reports from this region have documented common occurrence of these conditions especially for adult population [
6].
Rheumatic disorders accounted for 0.32% of all paediatric admission in 2011 at Getrude’s Children’s Hospital in Nairobi, Kenya as reported by Migowa et al. [
7] The commonest rheumatic condition reported was inflammatory arthropathy which accounted for 42.3%, other conditions documented included septic arthritis, Kawasaki disease and rheumatic fever [
7].
A retrospective review of paediatric rheumatic disorders for 5 years conducted at Lagos State University Teaching Hospital by Olaosebikan et al., revealed juvenile idiopathic arthritis as the commonest paediatric rheumatic disorder accounting for 49.1%, other rheumatic conditions noted in that review included juvenile systemic lupus erythematosus, juvenile systemic sclerosis, juvenile dermatomyositis, fibromyalgia and hypermobility syndrome [
8]. The spectrum of rheumatic conditions reported in that review illustrates the prevalence of these conditions in children of SSA.
Juvenile idiopathic arthritis is reported as the most common paediatric rheumatic disorder globally [
9]. Several studies conducted in SSA have described this condition in children; Chipeta et al. described 78 children with JIA in a retrospective study conducted at University Teaching Hospital, Lusaka Zambia, of these 43 were females and 35 were males and an average age at disease onset of 8.7 years [
10].
Two case reports have been published documenting existence of paediatric rheumatic conditions in Tanzania. Noorani et al. described two cases of Kawasaki Diseases who were managed at one of hospital in Tanzania while Grijsen et al. described a four-year-old girl who presented with dermatomyositis [
11,
12]. The lack of information on the burden of rheumatic disorders among children in Tanzania prompted this study to be carried out at Muhimbili National Hospital.
Discussion
There is dearth of information regarding rheumatic disorders in lower income countries particularly in the sub-Saharan region, this scarcity of data is even more severe for paediatric rheumatic disorders. Fifty-two children who presented with rheumatic disorder to the paediatric department at Muhimbili National Hospital in Dar es Salaam, Tanzania were identified in this retrospective study. Thirty-two (61.5%) out of 52 children with rheumatic disorder were females and the mean age at presentation was 9.5 ± 4.3 years.
Presentation age noted in our study is lower than what was reported in a study conducted among Indian children reporting mean age at presentation of 11 ± 3.3 years, age at onset of symptoms for Indian children was reported to be 9.1 ± 3.6 years [
13]. Olaosebikan et al. reported much older age at presentation (14 ± 4.4 vs 9.5 ± 4.3), which might be attributed to the setting of their study which was the adult rheumatology clinic [
8]. Late presentation is common in developing countries which have poorly established paediatric rheumatology services, this is depicted by the older mean age at presentation noted in our study and those from India and Nigeria as compared to studies from developed countries like US [
14].
Predominance of female children was observed in our study, this is like report by Olaosebikan et al. from Nigeria, this similarity is partly attributed to the predominant rheumatic disorders note in the two reports whereby juvenile idiopathic arthritis was the most frequent condition [
8]. Migowa et al. and Patra et al. reported predominance of male children in their reports, of interest is the fact that Patra et al. observed predominance of JIA as was a case for our findings, while Migowa et al. did not document JIA [
7,
13].
Consistent with reports from other studies on rheumatic disorders in children joint pain was the most frequent clinical feature noted in this study, musculoskeletal pain was reported in 91.2% of children with rheumatic disorders in Nigeria which is close to our report of 84.6% [
8]. Constitutional symptoms also featured in this study and highlighting the importance of considering paediatric rheumatic disorders as possible differentials for children with this presentation [
8,
15]. Fever was noted as presenting feature in 46% of participants, this might not be attributed entirely to rheumatic conditions, since malaria and other tropical infectious conditions are common in Tanzania.
The most frequent rheumatic disorder noted in our study was JIA which accounted for 54% followed by JSLE 15% then MCTD and JDM each accounting for.
7%. This result support previous reports in sub-Saharan region with predominance of JIA, as was reported by Okong’o et al. and Olaosebikan et al. in studies conducted among children in Cape Town, South Africa and Nigeria respectively [
8,
16]. Similar findings were reported from studies conducted in other regions of the world as described in India, Austria and Yemen [
13,
17]. Majority of participants with JIA had polyarticular form, which is similar to findings by Weakley et al. from a study conducted in Cape Town, South Africa, this may reflect the fact that children who were referred were those who were very sick [
18].
Mixed connective tissue disease (MCTD), Kawasaki disease, Takayasu arteritis, vasculitis, Sjogren syndrome and CRMO featured in this study. One of the two participants with vasculitis had IgA vasculitis. From these findings it is evident that different paediatric rheumatic conditions are common Tanzania, this was also depicted in the previous case reports from Tanzania [
11,
12]. The pattern of rheumatic disorders presented by this study break the myths that these conditions are not existing in the region, and in fact some conditions like SLE are reported to be more common among people of African descent [
19].
Four participants had juvenile dermatomyositis in this study, this is one of the very rare connective tissue disorders, whose incidence is estimated to be 2–4 children per million population [
20,
21]. Two of these participants were dead at the time of collecting data as was noted from the charts. Diagnosing dermatomyositis is usually challenging and rely on clinical criteria with no known confirmatory diagnostic tests requiring good clinical acumen [
22]. Dermatomyositis has been described among African children as was noted by Faller et al. and Okonkwo et al. in Johannesburg and Cape Town respectively [
23,
24]. Patients with JDM may also present to neurologists and dermatologists because of various patterns of manifestations [
25].
Kawasaki disease, Takayasu arteritis and IgA vasculitis were observed in this study, our findings which are consistent with reports from India, South Africa and Kenya and demonstrate existence of these rare rheumatic disorder in Tanzania [
7,
13,
16,
26]. Kawasaki disease has been previously described from Tanzania in a case report by Noorani et al. [
11] Interesting Olaosebikan et al. did not find any case of vasculitis in a study conducted in Nigeria [
8].
Laboratory tests were performed for participants enrolled in this study including autoimmune markers which were taken to private laboratories. Viral screening for Human Immunodeficiency Virus (HIV), Hepatitis B virus and Hepatitis C virus were carried out for 24 (46.2%), 22 (42.3%) and 22 (42.3%) participants respectively and were all negative. HIV prevalence in Tanzania is estimated to be 5.5%, and HIV testing is advocated for patients at risk [
27]. more than half of participants were not tested for HIV. Testing for HIV is important as arthritis has been reported to be one of manifestation of HIV infection in children [
28]. The lowest haemoglobin level observed in this study was 3.1 g/dL and 35 (67.3%) out of all participants had anaemia. Several factors could have contributed to the noted burden of anaemia including worm infestation, dietary deficiency and chronic inflammation.
Tests for determining disease activity were also performed in this study, these included erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine kinase (CK) and lactate dehydrogenase (LDH). Imaging studies were utilized for evaluating participants with Kawasaki diseases and Takayasu arteritis. Typical findings of Takayasu arteritis were described in this study with involvement of aorta and its branches consistent with report by McCulloch et al. [
25]
Treatment of paediatric rheumatic conditions is reported to be challenging in developing countries lower income countries because of difficulties in diagnosis, late presentation as well as limited option with medications [
6,
9,
26]. .Patients with JIA in this study were treated mainly with prednisolone and methotrexate. Refractory JIA was treated with combination of methotrexate with leflunomide or sulfasalazine. Only on patient was noted to have used biologic tocilizumab for treatment of JIA which was used for a short duration of 4 months. These drugs are not available in the country, so parents had to buy them from overseas. One participant with JIA had bilateral hip replacement surgery following complication of long-term use of steroids.
There are unmet needs of care for children with rheumatic disorders in Tanzania as reflected by high mortality for JSLE and JDM and severe associated morbidity of children recruited in this study as depicted by high burden of anaemia. Paediatric rheumatology services introduced by the paediatric nephrologist at MNH is a positive step in establishing proper care for children in Tanzania and there is a need to support this initiative with short term training for primary care physicians and general paediatrician so that they can identify children with rheumatic disorders timely and prevent complications and mortality [
9,
29].
This study was conducted at Muhimbili National Hospital, which is the national referral hospital, therefore these findings might provide reasonable baseline data for Tanzania. However, it is possible that the study setting might have missed children who presented to other departments including dermatology and orthopaedics, some children could have been misdiagnosed and other might have died before being referred to MNH.
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