Radial nerve or plexus lesion after SARS-CoV-2 vaccination in an anticoagulated nonagenarian?

The article by Radlberger et al.[1] is impressive, but some points require discussion. The first point is that the location of hematoma argues against vaccination as the cause. Because BNT162b2 vaccines are typically injected intramuscularly into the deltoid muscle, one would expect a hematoma in this muscle, but not in the armpit. What technique and needle were used for the injection? Has spontaneous bleeding from a subclavian or axillary artery aneurysm been ruled out? A second argument against vaccination is the latency between vaccination and the onset of clinical symptoms. If this is due to the injection, symptoms can be expected to appear immediately after vaccination. The second point is that weakness of forearm flexion, in either pronation or supination, cannot necessarily be explained by a radial nerve lesion. Elbow forearm flexion, regardless of whether it is performed in supination or pronation, usually occurs with the brachial biceps and brachial muscles, which are innervated by the coracobrachial nerve, which originates from radices C5 and C6. Only the brachioradialis muscle, which also contributes to forearm flexion, particularly in the neutral position, is innervated by the radial nerve.[2] What was the level of weakness? Since the radial nerve also innervates the extensors of the elbow, one would expect that the index patient would also have weakness in elbow extension, but this was apparently not the case. The third point is that there is no mention of whether the muscles innervated by the axillar, coracobrachial, median, or ulnar nerves also showed weakness.[3] Was left shoulder inward and outward rotation and shoulder abduction or adduction weak? Was there also a weakness for shoulder anteflexion or retroflection in the left extremity? Given the location of the hematoma, one would expect that the patient had a left brachial plexus lesion rather than entrapment of a single sensorimotor nerve.[3] In this context, we should know whether there was evidence of acute denervation on needle electromyography in the proximal and distal muscles in a distribution suggesting a left brachial plexus lesion. The fourth point is that it is not mentioned whether sensory fibers were also affected. Even if the patient denied sensory deficits, it is conceivable that there was also subclinical impairment of sensory fibers of the left median, ulnar, and radial nerves, which could be documented using nerve conduction studies (NCSs). A fifth point is that the outcome of hematoma removal and radial nerve lesion has not been reported. There are also follow-up NCSs missing. A sixth point is that coagulation parameters are missing, especially antifactor-Xa. Did it show therapeutic values above 0.5? Was the international normalized ratio (INR) elevated? Was the activated partial thromboplastin time (aPTT) prolonged? Did the patient have renal insufficiency? Has she taken rivaroxaban regularly? We disagree with the statement that “vaccine safety did not appear to be a problem even in patients with comorbidities.”[1] There is considerable evidence that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccinations can be harmful to individual patients, causing not only mild or moderate side effects, but even severe and sometimes fatal complications.[4] Availability of data and material All data are available from the corresponding author. Author contribution JF was responsible for the design and conception, discussed available data with coauthors, wrote the first draft, and gave final approval. SM: contributed to literature search, discussion, correction, and final approval. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.