East Azerbaijan is located in the northwest of Iran, a cold climate zone. It has a total area of 47 821 km2. According to the official census data, the total population of children 0–15 years was estimated 6465267 over the study period.
In this population-based cross sectional research, medical history and clinical features of 143 cases with Guillain-Barre syndrome between 2001 and 2006 were studied. The setting of the study was Tabriz Children Medical Centre, is the largest children medical center in the north-west area of Iran. This medical centre is a 200-bed acute care university hospital providing tertiary referral care for critically ill patients.
As part of World Health Organization's (WHO) certification process for polio eradication, Iran has been systematically registering children under 15 years old with acute flaccid paralysis since 1995. However, the local policy for acute flaccid paralysis (AFP) surveillance program is that all cases of AFP should be referred to Tabriz Children Medical Centre. All subjects are routinely examined by expert child neurologist (Mohammad Barzegar, the principal investigator of this project) within 7 days of notification. The GBS cases (under 16 years) were then diagnosed and aascertained based on the criteria defined and introduced by Asbury and Cornblath [1
Data collected included age, gender, chronological information, preceding events, neurological features functional grade of motor deficit and laboratory findings. The functional status at the time of maximum deficit was graded according to Hughes scale of disability as follows: 0: healthy, 1: minor signs and symptoms and is capable of running; 2: able to walk 5 meters without assistance, but is unable to run. 3: able to walk with assistance, 4: confined to bed or chair bound, 5: requires assisted ventilation, and 6: died [14
Poliovirus infection was excluded by cultures that are routinely performed for patients with acute flaccid paralysis as a requirement of the national program of poliomyelitis eradication.
All children underwent at least one electro diagnostic evaluation at the acute phase of disease (from day 1 to 27, average 6.5 days). A Medelec Synergy electromyography machine was used for this assessment. Nerve conduction studies included motor nerve conduction (MNC), sensory nerve conduction (SNC), and F-wave response studies were performed using the standard techniques of supramaximal percutaneous nerve stimulation and surface electrode recording. MNC studies were done on the ulnar, tibial and deep peroneal nerves and SNC on median and sural nerves. Each value of nerve conduction was compared with age matched normal data reported by Parano and colleagues [15
]. Needle EMG was done for any denervation and motor unit action potential changes in all patients in at least two proximal and two distal limb muscles. Patients were classified as having axonal or demyelinating type based on the electrodiagnostic criteria reported by Cornblath and colleagues [16
]. For each patient, the first neurophysiologic study was reviewed.
Approval for this study was obtained from National Public Health Management Centre of Tabriz University of Medical Sciences where a funded project is routinely assessed/approved in terms of methodology, ethical and financial issues.
Incidence rates and descriptive statistics were calculated to document the epidemiological features of the Guillain-Barre syndrome in the area. Data from the Ministry of Health, Statistics Office, were used to estimate the expected frequencies of the syndrome in the East Azarbaijan province to assess the time trend.