Chien-Jung   Lu

CASE REPORT:
A 74-year-old man noticed weakness of hands 2-3 days after he accepted the second dose of mRNA-1273 COVID-19 vaccine. He soon became unable to walk within one week. Initially, muscle power of bilateral hand grasping was most severely affected. He had stayed on at the nadir for 3.5 months until the diagnosis of CIDP was made. Nerve conduction studies showed typical evidences of acquired demyelinating, but no sural spare pattern. He was treated with intermittent pulse steroid therapy. Two weeks after treatment, INCAT disability score improved from 10 to 4, but remained at 4 thereafter: arm disability score was 3 and that of leg was 1, which suggested muscles of upper limbs were more severely affected.

DISCUSSION:
CIDP is a great imitator. The typical form usually progresses slowly. However, its onset could be acute and its progression could be rapid. Such acute-onset CIDP could mimic GBS, but both diagnoses were overlooked in this patient because the speed of onset and progression was so fast. CIDP could be mistaken for acute worsening of cervical compressive myelopathy because both disorders would get benefit by steroid therapy. As with this patient, asymmetric dorsiflexion of both feet was initially mistaken for a co-morbid L5 radiculopathy because of common morbidity of lumbar spondylosis. CIDP consists of a variety of atypical variants. As to the atypical features of this patient, the first was acute onset. The second was asymmetric weakness which was significantly worse on upper limbs and distal muscles. Weakness of typical CIDP is present in a non-length- dependent pattern, affecting both proximal and distal muscles in similar degrees. As with this patient, upper limbs were more affected than lower extremities in MADSAM. The third was no “sural-sparing” pattern, which implied distal sensory involvement. The latter two atypical features pointed to the diagnosis of MADSAM. Therefore, the diagnosis of this patient was acute-onset MADSAM which combined acute onset with asymmetric sensorimotor features. The incidence of such “rare and rare” variant of CIDP was unknown. Clinical diagnosis depended greatly on nerve conduction studies which showed evidences of acquired demyelination, including slowing of conduction velocities, prolongation of sensory and motor latencies, prolonged F-wave latencies, and motor conduction block. The unique finding of both acute and chronic acquired demyelinating neuropathies, the so-called sural sparing pattern, was not found in this patient. It may suggest sensory involvement of MADSAM was more than typical CIDP. EMG demonstrated reduced recruitment of normal morphology motor unit potentials with secondary axonal degeneration and reinnervation. Active denervation change was not found. CSF analysis was usually not necessary when the clinical manifestations and electrophysiological studies were consistent with CIDP, but it may be helpful for inconclusive case. When collected, albuminocytologic dissociation is anticipated. Basic serum laboratory studies were performed to exclude alternative or confounding diagnoses. The screening for a monoclonal gammopathy was also negative. Therefore, the occurrence of this atypical CIDP was supposed to be triggered by mRNA- 1273 COVID-19 vaccination. Cases of inflammatory demyelinating polyneuropathy after COVID-19 vaccination had been reported worldwide. Most of the cases were GBS characterized by facial diplegia occurring after adenovirus-vectored vaccines(4-7). In some patients GBS deteriorated again after some weeks from onset, or several relapses occurred; in these patients a diagnosis of acute-onset CIDP was then considered. Therefore, diagnosis of acute-onset CIDP was challenging at the beginning of this disease. Only fewer cases of CIDP triggered by ChAdOx1 vaccines had been reported(4,8,9). CIDP after vaccination was a rare event, accounting for about 1.5% of all patients with CIDP. Time of vaccination to symptom onset ranged from 2 days to 8 weeks. To the best of our knowledge, this is the first case of acute- onset MADASM after receiving mRNA-based COVID-19 vaccine in Taiwan. For most treatment-naïve patients with CIDP, recommendations of immune-modulatory treatments consist of intravenous immune globulin (IVIg), plasma exchange, and glucocorticoids. Initial treatment with glucocorticoids appears more effective at achieving long- term remission(10,11). In a retrospective study, 60% of patients were responsive to glucocorticoids, with 61% of treatment responders achieved remission(12). Currently, we prefer the use of pulse rather than daily glucocorticoids for initiation and initial titration of dosing(13). Although not confirmed by clinical trials, pulse dosing may have both a greater chance for early efficacy, higher durability of response, and a better side effect profile. We typically start with an initial dose of IV methylprednisolone (1,000 mg/ day) for three days, followed by 1,000 mg one day a week for four weeks(14). Limited observational data suggest that IV therapy is associated with less weight gain and fewer cushingoid features but possibly more restlessness and sleep problems compared with oral therapy(14). In sum, this was a case of vaccine-triggered CIDP. Diagnosis was delayed because the clinicians overlooked hyperacute-onset polyneuropathy. Delay in diagnosis may influence prognosis. As with this patient, he was a steroid responder, but did not get complete remission. In accordance with findings of electromyography, incomplete remission may suggest secondary axonal degeneration. We reported this case, and hoped the clinicians could early recognize this disease.