In this cross-sectional study, a total of 118 patients with clinical presentation of AFP were assessed with regards to demographic, clinical and diagnostic data and final diagnosis.
In our study, the average age of patients was 6.09 ± 3.60 years old which was higher than most of the other study results. 44.9% of cases were between 5-10 years old and 37.3% of them were under 5 years old, whereas the most common age in children for AFP had been reported under 5 years old in other researches 3-6-7-8-9-10. Sex differences was according to the previous studies, as well as systemic and neurologic manifestation and examination findings 1-6-7-9-10.
In the present study, the most four common causes of AFP were included: Guillain-Barre syndrome, viral myositis, transverse myelitis and VAPP. Guillain-Barre syndrome was the most common etiology similar to previous reports 1-2-6-8-10. Regarding Guillain-Barre syndrome as the most common cause of AFP and in respect of its treatable nature, it seems that good prognosis could be expected in most cases of AFP in children. In addition, with regards to the normal results of brain imaging in the majority of patients, we can conclude that it is not necessary to consider neuroimaging in the initial steps of approach to AFP, and implementing it can be postponed depending on the patient's clinical scenario.
Moreover, it’s important to note that the prevalence of AFP was more common in the second half of the year, which can be due to the prevalence of respiratory infections and their role in the onset of the specific diseases such as GBS 1-2.
In terms of other causes of AFP, some inconsistent findings were noticeable in comparison with previous studies. Viral myositis was found as the second etiology of AFP in our study that was in contrast with other studies which mentioned transverse myelitis as the second common etiology for AFP 6-9-11. However, it should be noted that viral myositis was not included in the list of major causes of AFP in other childhood studies. With regard to the significant prevalence of viral myositis in the present study, the necessity of being more attentive to this entity should be considered in clinical approach to AFP in children. Since some patients with the diagnosis of viral myositis had no pain, with only symptoms of paralysis, it would be suitable to consider the assessment of muscle breakdown biomarkers such as serum CPK and aldolase levels during diagnostic process of AFP in children 7-9.
Furthermore, apart from our study, there has been no report of VAPP in other researches carried out in Iran for two probable reasons: first, our study was performed in a large pediatric referral hospital which serves as the scientific headquarters of the country, and second, better diagnostic equipment and facilities such as immune deficiency research center in this hospital made this detection possible 6-10-12-13.
In addition, no case of traumatic neuritis was found in this study, whereas in some studies it was mentioned as one of the potential common causes 6-14. This should be clarified that children with traumatic injuries are not usually referred to CMC hospital.
In the present study, no case of poliomyelitis was detected, compatible with all studies since 1995 on AFP in children, the date of last report of polio in Iran. However, several Middle Eastern countries still stand as high-risk regions regarding poliomyelitis because of the lack of mass vaccination and migration trend among those countries 6-15. Except for a study in Iraq that reported several polios (the last one dating back to the year 2000), in the researches in other countries no case of polio was reported 3-12-14. It is necessary to mention that sending stool sampling to investigate poliovirus has been done according to the WHO standard guidelines, but the reason that the results of stool investigation only existed for 80% of patients was a limitation in this study due to issues such as early discharge of the patient, non-polio diagnosis before hospitalization, inability to have the sample due to constipation and not informing the referral health center for stool sample for poliomyelitis.
Finally, based on the present study, we designed a diagnostic algorithm to approach children with AFP in the emergency room. This algorithm is used to improve clinical decision making by planning more assessments, treatment strategies and outcome of treatment. It should be mentioned that detection of poliovirus by stool sampling is recommended for all AFP patients according to WHO guidelines. The algorithm presents a step by step approach to a child by considering AFP etiologies. At first, central nervous system (CNS) associated causes should be ruled out through signs of CNS involvement, and if it is negative, a test for intoxication would be required in the next step. If all these steps are negative, a clinical suspicion of Peripheral Nervous System (PNS) or spinal cord involvement will be raised, and consequently more related investigations to confirm the diagnosis are obligatory (figure 2).