In an effort to reduce the number of patients who suffer from the flu each year, the Centers for Disease Control and Prevention has made a concerted effort to vaccinate as much of the general public as possible against the flu1-5. This has resulted in an increase in those receiving the flu vaccine from 57 million in 2004 to 2005 to more than 145.9 million in 2016 to 20172. The effectiveness of the vaccine varies yearly, with reported side effects from the vaccine including fever, cough, headache, seizures, myalgias, Guillain-Barré syndrome, and shoulder injury related to vaccine administration (SIRVA)2,4-6.
SIRVA was first discussed in 2010 as a complication of deltoid muscle vaccine injections resulting in loss of motion, subacromial/subdeltoid bursitis, or palsy of the anterior branch of the axillary and radial nerves5. The following case details a patient who received a flu shot and developed unremitting shoulder pain for 10 months before presenting to our office for treatment. This report describes the presentation, workup, and treatment of this problem.
The patient was informed that data concerning the case would be submitted for publication, and she provided consent.
A 51-year-old healthy, fit woman with no significant medial or surgical history presented to our office with 10 months of unremitting left shoulder pain and loss of motion after administration of a flu shot into the left posterior deltoid, distal and slightly anterior to the posterolateral border of the acromion. Before the flu shot, she had no history of shoulder issues and was able to work out and play recreational level sports. The patient's presenting symptoms included anterior and lateral shoulder pain, pain with shoulder flexion and abduction, and night pain. She denied paresthesias, fevers, chills, and night sweats. She initially presented to a primary care sports medicine (PCSM) specialist 2 weeks after the flu shot. Her shoulder pain had been managed conservatively by the PCSM physician before presenting to our office. Her radiographs at presentation did not demonstrate osseous abnormalities (Fig. 1-A), and an initial magnetic resonance imaging (MRI) (2 months after the flu shot) demonstrated a partial-thickness rotator cuff tear with a small hyperintense area on the posterior aspect of the rotator cuff footprint (Figs. 1-B and 1-C). Based on a strong temporal relationship between the influenza vaccination, placed relatively high on her left upper arm, and the onset of her left shoulder symptoms the day after the injection, there was a concern that her symptoms were related to the injection.
The differential diagnosis included infection, traumatic injury, or immunologic reactive inflammation. An ultrasound-guided joint aspiration was performed (3 months after the flu shot), and the sample was evaluated for the presence of aerobic and anaerobic bacteria, fungi, and mycobacteria. Ten aerobic bacterial cultures demonstrated no growth after 5 days of incubation. Ten anaerobic cultures had no growth after 14 days of incubation. Nine fungal cultures had no growth after 4 weeks of incubation, and 7 cultures for mycobacteria had no growth after 8 weeks of incubation. Because of the presence of a prolapsing mitral valve, 2 blood cultures were obtained, which showed no growth. In addition, serologic studies for Lyme disease were negative (both immunoglobulin G and immunoglobulin M Enzyme Immunoassay (EIA)). Studies for rheumatologic disease, including antinuclear antibodies, rheumatoid factor, and human leukocyte antigen-B27, were also negative.
During the conservative treatment course of anti-inflammatory medications and physical therapy, the patient developed adhesive capsulitis (approximately 3 months after the flu shot). This was treated with 2 ultrasound-guided intraarticular steroid injections after the aspiration of the glenohumeral joint was demonstrated to be negative for infection.
On presentation to our office, she had tenderness to palpation over the anterior fibers of the supraspinatus, with no evidence of muscle wasting. She had normal shoulder range of motion (ROM), with the exception of diminished active abduction (100° on left vs. 170° on right) and internal rotation (5 spinal levels less than the right side). Her strength examination was normal, with the exception of infraspinatus weakness (4/5). A repeat MRI was obtained (10 months after the flu shot and 8 months after the initial MRI), which demonstrated a significant increase in the signal within the humeral head with bony erosion (Figs. 1-D and 1-E). Given the change in MRI appearance, she was referred to an infectious disease specialist who recommended rheumatologic blood work (inflammatory markers, metabolic panels, etc.) and a computed tomography (CT) scan. The lab, including an erythrocyte sedimentation rate and C-reactive protein, were normal. However, the CT scan demonstrated a large lytic lesion in the posterior proximal humerus (Fig. 1-F). A CT-guided needle biopsy of the bone and soft tissue performed at that time (now 11 months from the flu shot) was inconclusive.
A left shoulder arthroscopy with bone and soft-tissue biopsy and debridement was performed (13 months after the flu shot) (Figs. 2-A through 2-F). At the time of arthroscopy, there was evidence of patchy synovitis in the joint with a focal synovitic area at the site of the lytic lesion and a bone defect in the posterior aspect of the humeral head, adjacent to the infraspinatus insertion. Tissue cultures were taken from throughout the anterior capsule, posterior capsule, and synovium. A spinal needle was then used to localize the defect, and an incision was made for insertion of a 7 mm core biopsy needle. The core biopsy was taken from this defect, with debridement of unhealthy-appearing tissue in and at the edges of the defect. Additionally, tissue samples were taken from various locations within the joint. All cultures came back negative.
Each location shared inflammatory features of varying degrees. Tissue from the anterior capsule (Fig. 3-A) consisted of synovium that showed papillary hypertrophy with a moderate degree of hyperplasia of the synovial lining layer. There was a moderate degree of chronic lymphoplasmacytic inflammation that had a high proportion of plasma cells, some of which contained more than 1 nucleus. Tissue from the posterior capsule (Fig. 3-B), adjacent to the bone erosion, also showed papillary hypertrophy with greater degrees of hyperplasia and chronic inflammation imparting a much higher degree of cellularity including lymphocytes, plasma cells, and stromal elements. Tissue from the defect in the posterior aspect of the humeral head (Fig. 3-C) showed inflammatory destruction of the articular cartilage and bone. The superficial cartilage showed inflammatory destruction of the cartilage with Weichselbaum lacunae and a small amount of pannus. The bony endplate was focally destroyed, and the bone while eroded was demonstrating remodeling activity. The marrow space showed replacement of the fat by dense and loose fibrous and fibromyxoid tissue associated with a variable dense inflammatory infiltrate that was composed of lymphocytes and plasma cells, some of which, as elsewhere, contained more than 1 nucleus.
Postoperatively, the patient was placed into a sling for immobilization for 2 weeks, followed by the initiation of shoulder ROM exercises. Once full ROM was obtained, a supervised shoulder strengthening program was begun. By 1-year follow-up, she has regained full passive and active ROM in all directions, and strength and functional capacity have returned to normal. No new imaging was obtained given her full functional status with no complaints.
Although most patients experience transient shoulder pain after a flu shot into the deltoid, persistent, unremitting shoulder pain after a flu shot should raise suspicion for a reactive inflammatory process within the shoulder4-6. A lytic lesion within the humeral head has not previously been described as one of the manifestations of SIRVA, but this patient clearly developed an acute, localized, destructive inflammatory process secondary to a deep administration of the flu shot. SIRVA can be debilitating, and patients suffering from this often obtain advanced imaging in the form of an MRI. Previous studies have found bursitis on ultrasound and fluid collections in the deep regions of the deltoid, rotator cuff tendons, and subacromial bursa, with associated tendonitis on MRI. However, no studies have reported the CT findings, which in our patient were impressive. This patient developed significant lysis of the posterior humeral head at the infraspinatus insertion secondary to a localized inflammatory reaction, likely secondary to a deep administration of the flu shot. Her symptoms progressed significantly over time, likely with an initial insult and inflammatory response that developed into a significant, unremitting, localized inflammatory reaction, as demonstrated by the sequential MRI.
Cross et al. discussed proper injection techniques and highlighted that shots given too deep where they hit the bone, or into the subacromial space, can cause SIRVA4. This patient likely had the shot administered very deeply, causing mechanical and chemical irritation of the posterior humeral head, leading to an inflammatory cascade that was not responsive to the ultrasound-guided intraarticular cortisone injection performed to manage the adhesive capsulitis. Once the area of inflammatory tissue was removed and healthy bone/tissue was stimulated at the time of arthroscopy, the patient's body was able to mount a response to heal the injured area. The take-home point from this report is that orthopaedic surgeons must be wary of patients with new-onset shoulder pain after flu shots as their presentation can mimic a rotator cuff tear, impingement, or bursitis, but may be also caused by an inflammatory process with the potential for development of focal erosive changes in the bone. Standard conservative treatments of these conditions will not afford the patient symptomatic relief. Repeat imaging should be obtained to look for lesion progression, and a CT scan should be obtained to outline and better characterize the defect. If this inflammatory process is not considered and repeat imaging is not obtained, the surgeon may operate on a partial-thickness rotator cuff tear or other incidental findings on MRI and X-rays that are not actually the cause of the patient's pain.
1. Huang HC, Singh B, Morton DP, Johnson GP, Clements B, Meyers LA. Equalizing access to pandemic influenza vaccines through optimal allocation to public health distribution points. PLoS One. 2017;12(8):e0182720.
3. Haber P, Moro PL, Cano M, Lewis P, Stewart B, Shimabukuro TT. Post-licensure surveillance of quadrivalent live attenuated influenza vaccine United States, Vaccine Adverse Event Reporting System (VAERS), July 2013-June 2014. Vaccine. 2015;33(16):1987-92.
4. Cross GB, Moghaddas J, Buttery J, Ayoub S, Korman TM. Don't aim too high: avoiding shoulder injury related to vaccine administration. Aust Fam Physician. 2016;45(5):303-6.
5. Atanasoff S, Ryan T, Lightfoot R, Johann-Liang R. Shoulder injury related to vaccine administration (SIRVA). Vaccine. 2010;28(51):8049-52.
6. Cook IF. Subdeltoid/subacromial bursitis associated with influenza vaccination. Hum Vaccin Immunother. 2014;10(3):605-6.