Adhesive Capsulitis After COVID-19 Vaccination: A Case Series.

Of the many bizarre complications of administration of the COVID 19 vaccine, adhesive capsulitis is almost unheard of, although shoulder injury related to vaccine administration, which by definition has symptom onset within 48 hrs and is caused by faulty injection technique, has been rarely reported. Nine cases of adhesive capsulitis, five males and four females with a mean age of 48.7 ± 12.7 yrs, presenting within 1 mo of intramuscular Covishield vaccine on the ipsilateral deltoid and fulfilling the standard UK FROST Multicenter Study diagnostic criteria are reported. The mean time interval from vaccination until symptom onset was 12.3 ± 3.1 days, and mean symptom duration was 9.4 ± 2.4 wks. Conventional treatment with nonsteroidal anti-inflammatory drugs, followed by intra-articular steroid injection coupled with suprascapular nerve steroid block, improved the pain score and range of movement in 8 wks. The exact pathogenesis remains an enigma, although mechanisms such as local spread via deltoid muscle microvasculature, nerves, or shoulder injury related to vaccine administration causing secondary adhesive capsulitis have been hypothesized. While adhesive capsulitis is a very common diagnosis in the physiatric outpatient setting, the possible association with Covishield vaccination, the Indian version of the Oxford AstraZeneca recombinant ChAdOx1 nCoV-19 vaccine, is almost absent in existing literature and hence likely to be missed by clinicians, which necessitates this report.