Nodding Syndrome: A Scoping Review

Abstract

Nodding syndrome (NS) is a debilitating yet often neglected neurological disease affecting thousands of children in several sub-Saharan African countries. The cause of NS remains unknown, and effective treatment options are lacking. Moreover, knowledge regarding NS is scarce and is based on a limited number of publications, with no comprehensive overview published to date. Therefore, the aim of this scoping review was to summarise the current evidence and identify existing knowledge gaps in order to help clinicians, scientists, and policymakers develop guidelines for prioritising this severe condition. We searched the Medline (Ovid), Embase (Ovid), Scopus, and Global Health Library databases in accordance with the PRISMA extension for scoping review guidance and in accordance with the Joanna Briggs Institute guidelines and methodology for a scoping review, using keywords describing NS. We then extracted and presented the original data regarding the epidemiology, aetiology, pathophysiology, clinical features, diagnosis, management, and outcomes of NS, as well as community perceptions and the psychosocial and economic impact of NS. Out of 1470 identified articles, a total of 69 were included in this scoping review. Major gaps exist in understanding the aetiology and pathogenesis of NS. Future research is urgently needed not only to address these gaps, but also to study the treatment options, epidemiology, and psychosocial and economic impacts of NS. Innovative interventions and rehabilitation programmes designed to address the psychosocial and economic burdens associated with NS are also urgently needed.

Nodding Syndrome: Clinical Characteristics, Risks Factors, Access to Treatment, and Perceptions in the Greater Mundri Area, South Sudan

“…Nodding syndrome (NS) is an overwhelming neurodegenerative disease of unknown etiology. It has affected children and young adults from poor communities in multiple sub-Saharan Africa countries, including Tanzania, South Sudan, Uganda, the Democratic Republic of Congo (DRC), Cameroon, and the Central African Republic [ 1 ]. It often presents with distinct clinical features, including head nodding and other seizures that are often associated with debilitating complications, including impaired cognitive and physical development and delayed sexual maturity [ 2 , 3 ].…”

“…It often presents with distinct clinical features, including head nodding and other seizures that are often associated with debilitating complications, including impaired cognitive and physical development and delayed sexual maturity [ 2 , 3 ]. Previous attempts to identify a potential cause have focused on infections, nutritional deficiencies, toxins, autoimmune disease, hormonal and metabolic derangements, and genetic factors, but all were inconclusive [ 1 ]. Control of Onchocerca volvulus and its vector, the blackfly, by community-directed treatment with ivermectin (CDTI) and larviciding of rivers was proposed to prevent new cases of NS [ 4 , 5 ].…”

“…Control of Onchocerca volvulus and its vector, the blackfly, by community-directed treatment with ivermectin (CDTI) and larviciding of rivers was proposed to prevent new cases of NS [ 4 , 5 ]. However, certain communities in the affected areas believe that NS is transmitted from person to person and therefore can be prevented by avoiding contact between cases and other family members or peers through eating and sleeping separately [ 1 ]. To further unravel the many unknowns around NS, we conducted a community-based study, investigating the clinical characteristics, potential NS risk factors, access to treatment and perceptions about NS transmission.…”

Nodding syndrome: A key role for sources of nutrition?

“…Nodding syndrome (NS) is a pediatric epileptic and apparently progressive encephalopathy of unknown etiology that has been present in several east African countries, including first-case reports in impoverished communities in Tanzania (1934), South Sudan (1991), Uganda (1994), Democratic Republic of Congo (2016), Cameroon (2018) and Central African Republic (2019), with possible cases in Liberia (1983). Currently estimated prevalence rates include 0.3% in Uganda, 0.4% in Democratic Republic of Congo, 0.7% in Tanzania and 4.6% in South Sudan [ 1 ]. Onset of head nodding, which precedes or accompanies convulsive seizures, occurs in 2–18-year-old children [ [2] , [3] , [4] , [5] ], more of whom than healthy controls were born pre-term and were infected with the nematodes Onchocerca volvulus and Mansonella spp.…”

“…Nodding syndrome has been the subject of two recent systematic reviews that surveyed reports relating to NS etiology, including infections, malnutrition, toxins, autoimmune, hormonal, metabolic, genetic and psychiatric factors [ 1 , 13 ]. One hypothesis is that NS is a form of onchocerciasis-associated epilepsy [ 7 ] secondary to autoimmunity driven by molecular mimicry between tropomyosin in O. volvulus (OV) and leiomodin-1 in brain tissue [ 14 , 15 ].…”