Quiz Answer: C (Direct injection of botulinum toxin)

Explanation: This patient exhibits adductor spasmodic dysphonia, a focal dysphonia affecting the adductor laryngeal muscles during speech. It is rare, but it most commonly presents in middle age, around the 4th decade. In these patients, the vocal fold adductor muscles spasm, closing the vocal folds too tightly and cutting off the voice on words beginning with vowels or on vowels in the middle of words. Voice therapy is typically attempted first, as it is noninvasive. However, its efficacy is limited, and direct injection of botulinum toxin (BT) into the laryngeal muscles has been shown to be more effective. BT injection reduces tight glottic closure, and it is typically repeated after every 3 months. Surgical denervation-reinnervation of the recurrent laryngeal nerve has been shown to benefit patients, but this is generally done after attempting BT injections.

Reference:

Hyodo M, Asano K, Nagao A, et al. Botulinum Toxin Therapy: A Series of Clinical Studies on Patients with Spasmodic Dysphonia in Japan. Toxins (Basel). 2021;13(12):840. Published 2021 Nov 25. doi:10.3390/toxins13120840.

Ludlow CL. Spasmodic dysphonia: a laryngeal control disorder specific to speech. J Neurosci. 2011;31(3):793-797. doi:10.1523/JNEUROSCI.2758-10.2011

B (Dysphagia)

Explanation: This patient most likely has a carotid body tumor (CBT), the most common type of paraganglioma found in the head and neck region. On clinical examination, CBTs are more mobile transversely compared to vertically (Fontaine’s sign). While most cases are asymptomatic, vagal dysfunction causing dysphagia or dysphonia is the most common cranial nerve dysfunction observed (B).

Other cranial nerve palsies (CN VII, IX, XI, XII) are comparatively less common. Involvement of CN XII would cause tongue deviation to the side of the tumor rather than away (A). Hearing loss is extremely rare in CBTs and would not present bilaterally with a unilateral CBT (C). CBTs are not associated with vision loss (D)–ipsilateral vision loss may instead be seen in carotid artery stenosis or temporal arteritis, neither of which present as seen in this patient.

Reference: Cleere EF, Martin-Grace J, Gendre A, Sherlock M, O'Neill JP. Contemporary management of paragangliomas of the head and neck. Laryngoscope Investig Otolaryngol. 2021;7(1):93-107. Published 2021 Nov 26.

Image: Hoang VT, Trinh CT, Lai TAK, Doan DT, Tran TTT. Carotid body tumor: a case report and literature review. J Radiol Case Rep. 2019;13(8):19-30. Published 2019 Aug 31.

https://www.ncbi.nlm.nih.gov/ pmc/articles/PMC6738487/