Disclosures: Ashley M. Eaves, MD: No financial relationships or conflicts of interest

Case Description: One to two days after a hornet stung the patient’s right temple, he developed severe, right periscapular pain radiating into his arm. This was immediately followed by right hand weakness and aching, paresthesias and numbness in the medial antebrachial cutaneous (MABC) nerve distribution, the palmar and dorsal ulnar hand, the fifth and half of the fourth digits. After several weeks his symptoms stabilized, but weakness persisted at 8 months. He denied diabetes, trauma, surgery, neuromuscular disease, and viral illnesses or vaccinations proceeding symptom onset. Magnetic resonance imaging (MRI) revealed STIR hyperintensity in the infraclavicular plexus/posterior cord and mild cervical spine degenerative changes. Right intrinsic hand muscles were atrophied with associated 4/5 strength, full strength in the remainder of the right upper extremity, a positive Wartenberg’s, negative Spurling’s, negative Hoffman’s, and 1+ deep tendon reflexes bilaterally.

Setting: Tertiary care hospital.

Patient: A 56 year old, previously healthy man. Assessment/

Results: There was electrodiagnostic (EDX) evidence of right-sided, incomplete axonal sensorimotor lower trunk brachial plexopathy. Acute changes on needle EMG were seen in the abductor pollicis brevis, first dorsal interosseus, adductor digiti minimi (ADM), extensor indicis proprius, and flexor carpi ulnaris. EMG findings were normal in the right extensor digitorum communis, pronator teres, deltoid, biceps, triceps, pectoralis major, latissimus dorsi, and cervical paraspinals. Sensory responses to the MABC and ulnar nerve to the small finger were absent. There was diffuse slowing and reduced amplitude of the right ulnar motor nerve to the ADM, likely consistent with axonal loss of fast fibers.

Discussion: This is the first reported case, to our knowledge, of lower trunk Parsonage-Turner Syndrome following a hornet sting. The reduced muscle recruitment and decreased but intact motor responses on EMG indicate good prognosis for further recovery with therapy.

Conclusion: History, clinical exam and EDX findings are important in the diagnosis of PTS.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/parsonage-turner-syndrome-after-a-hornet-sting-a-case-report/