Typical sounding atypical diagnostic conundrum -a rare case of Mycobacterium Avium complex (MAC) presenting with multiple cranial nerve involvement

Abstract

BackgroundMAC infections rarely cause symptomatic systemic infection in immunocompetent healthy individuals. This case brings to light a rare such presentation that gives us a learning point about keeping a strong pre-clinical suspicion for this condition in patients whom lung imaging reveals suspicious cavitary lesions. Starting empiric therapy while awaiting culture results may be considered after weighing risks and benefits in order to achieve the morbidity and mortality associated with the disease Case reportA 54 year-old white male presented for evaluation of progressively worsening vertigo, imbalance, vertical diplopia, facial diplegia, bilateral hyperacusis followed by hearing loss, dysphagia, and dysarthria together with unintentional 40 pound weight loss, headache, neck stiffness, and productive cough over 5 months. His neurological exam showed multiple cranial nerve abnormalities. Contrast enhanced MRI head showed mild thickening and enhancement of cranial nerves V, VII, and VIII bilaterally. Biopsy of a cavitary left upper lobe lung lesion noted on CT chest and PET scan along with specimen culture surprisingly revealed Mycobacterium avium complex (MAC). Despite starting treatment, he died 6 weeks after discharge from presumed disseminated MAC. This rare case of MAC in an immunocompetent individual presenting with only multiple cranial neuropathies has not been previously reported. ConclusionMAC related CNS infections are very unusual in immunocompetent patient. Our case highlights one such unique presentation of an immunocompetent male who presented with multiple cranial nerve palsy that was ultimately diagnosed to be secondary to MAC infection. Given its rarity, it is very likely to lead to a delay in diagnosis and this could further delay treatment and poor outcome as in our patient. More extensive reporting of this rare CNS MAC infection in immunocompetent individuals could help understand the disease presentation better and might aid in earlier diagnosis and initiation of treatment.