Case1: A 52-year-old man presented with cough and dyspnea, and due to O2 saturation below 90%, he was admitted to ICU in a teaching hospital, a specialized center for COVID patients. Respiratory distress progression led to intubation. PCR test, as well as lung CT-scan, was positive for coronavirus. Routine anti-COVID treatment is in-line with protocols for respiratory care demanding ICU-patients, including broad-spectrum antibiotics, anticoagulant therapy with enoxaparin, vitamin D oral supplement, none steroids anti-inflammatory drugs, and corticosteroids were administered. Due to four limbs, weakness patient was referred for electrodiagnosis 18 days after admission. EMG/NCS test showed an acute motor axonal neuropathy (AMAN), classified as GBS axonal variant neuropathy. Thus, IVIG 15-20 g/day for 5 days was added to his medications plan, and after 3 weeks, the patient was extubated. After a total duration of 50 days, he was discharged with partial dyspnea and relatively good recovery, and he was advised to continue quarantine at home. Table 1 shows demographic, clinical, and para-clinical findings and table 2 shows electrodiagnostic parameters and final EDX diagnosis in this patient.
 Case 2: A 62-year-old man with a history of diabetes and nephrolithiasis was admitted to the hospital due to fever and renal colic. Due to severe pyelonephritis and several unsuccessful dialyses, he underwent nephrectomy surgery. During the hospitalization period, respiratory problems and decreased consciousness were added to the clinical picture, and CT-scan showed the signs of pulmonary involvement with COVID-19, and the patient transferred to ICU. Anti-COVID therapy, including azithromycin, hydroxychloroquine, and other medications due to the above-mentioned protocol were prescribed to him. The patient was referred for electrodiagnosis 15 days after admission due to four limbs muscular weakness. Electrodiagnostic findings were suggestive of acute motor axonal neuropathy (AMAN) or GBS axonal variant neuropathy. IVIG 20 g SD was added to the treatment plan, and broad-spectrum antibiotics due to kidney surgery, diabetes and long-term patient hospitalization were continued. After 3 months, the consciousness level of patient improved, he was still sedated and unable to tolerate weaning from mechanical ventilation; hence, he was tracheostomized and then discharged to home due to his consent. Two weeks later, his clinical status deteriorated due to uremia and decreased in O2 saturation, and he was hospitalized again, and finally, after 2 weeks passed away.
 Case 3: A 76-year-old male patient presented to the hospital with diarrhea and coughing and a history of one-week common cold. Chest CT showed minor pulmonary changes in favor of involvement with coronavirus, and the PCR test was positive. After 5 days of admission, he could not move his legs and could not stand or walk. Therefore, electrodiagnostic tests to evaluate lower limb weakness were performed. During the EDX examination, the patient was absolutely conscious under nasal auxiliary oxygen without intubation or respiratory distress. EMG/NCS showed the mixed type axonal and demyelinating sensorimotor peripheral neuropathy, which could be related to early stages of GBS or one of its axonal variants because only 5 days passed and the findings of electrodiagnostic criteria for typical GBS was not completely fulfilled yet. IVIG 20 g per day for 5 days concomitant anti- COVID treatment was started for the patient, and after 2 weeks of admission, he was discharged to home with good recovery.
 Case 4: A 46-year-old man with dry cough and dyspnea presented to emergency care department. His O2 saturation at admission was 78%, and the PCR test of coronavirus was positive, and lymphopenia and anemia were also detected in laboratory tests. Muscular weakness in four limbs and persistent respiratory distress caused the patient to be referred to the electrodiagnosis center in the rehabilitation department after 22 days of admission for further evaluation to determine the reason for quadriplegia. 
EMG/NCS exam showed a critical illness neuropathy concomitant with myopathy in proximal muscles (CIN/CIM), associated to serum CPK rising. Prednisolone 25 mg daily and IVIG 5 gr SD and then 3 sessions of hemoperfusion were added to baseline anti-COVID therapy, and after 35 days of admission, the patient was discharged to home with good health status.
 Case 5: A 32-year-old female patient who was one of the laboratory sciences staff initially presented with symptoms of common cold and then suffered from fever and respiratory disturbances. At the time of admission, the PCR test was positive, and she was hospitalized in ICU; her clinical picture deteriorated with empyema and pneumomediastinum. Anti COVID-19 treatment and broad-spectrum antibiotics and then hemoperfusion was prescribed. After 70 days of admission due to systemic illness and quadriplegia, she underwent electrodiagnostic tests, and CIM was diagnosed. Long-term admission leads to disuse and muscle mass atrophy, and finally, CIM superimposed on her underlying pulmonary illness. A tracheostomy was performed for her due to prolonged admission and inability to wean from mechanical ventilation. 
At last, after 3.5 months, she was tracheostomized, repeated PCR tests were negative, infections were improved and the patient had a relatively stable condition discharged to home. Now at follow-up evaluation, she has recovered well, her tolerance without supplemental oxygen increased, and she is on the waiting list for decannulation and tracheostomy removal. 
 Case 6: An addict 34-year-old male patient before admission suffered from four limb muscular weakness and myalgia for several days. He was admitted to a local hospital due to myopathy and pneumonia with serum CPK level raised up to 1820 IU/lit. Afterward, he was referred to a specialized center and admitted to the rheumatology department. Bilateral pulmonary consolidations in the bases of two lungs were observed regarding coronavirus involvement. 
O2 saturation was 92%, and serum CPK was still elevated, and the patient was transferred to ICU. 30 days after disease onset, electrodiagnostic tests were performed. The results showed an acute and ongoing myogenic process in all upper and lower limbs muscles which was suggestive of active polymyositis. Prednisolone 60 mg daily, hydroxychloroquine 200mg, IVIG 25 gr for 5 days were prescribed to him associated to other antibiotics and drugs. Two weeks later, PCR testing was negative, but the patient was still intubated and hospitalized in the ICU because of neuromuscular weakness and the inability to weave mechanical ventilation. Then, multiple complications, including pneumothorax, pulmonary thromboembolism (PTE), and consequent tracheal arterial bleeding due to full anticoagulant dose, deteriorated patient's condition. 
At last, he passed away after a total duration of 3 months of hospitalization. All the first 5 patients had areflexia and patient 6 had hyporeflexia. CSF analysis in 2 patients with GBS variants was performed and results are shown in table 1. The summary of clinical and EDX findings of these 6 patients is indicated in tables 1-2.
This study was performed according to the ethical standards, and the local ethics committee approved it with an assigned number of IR.TBZMED.REC1399.534.