Differential Diagnosis

The patient's presentation of progressive bilateral sensory neural hearing loss, unsteadiness, and history of flu-like illness, headache, recurrent conjunctivitis, and glaucoma suggests an underlying condition that could be autoimmune, infectious, or inflammatory in nature. Given the absence of family history of autoimmune diseases and normal brain CT, the differential diagnoses can be categorized as follows:

• Single most likely diagnosis
  • Multiple Sclerosis (MS): Although MS typically presents with optic neuritis, spinal cord lesions, and brainstem lesions, atypical presentations can occur, especially in young females. The history of flu-like illness and headache could be a clinically isolated syndrome (CIS) that preceded the development of MS. However, the lack of typical MS lesions on brain CT and the specific constellation of symptoms (especially the prominent auditory and ocular involvement) makes this less likely but still a consideration due to the wide variability of MS presentations.
• Other Likely diagnoses
  • Cogan Syndrome: This is an autoimmune disorder characterized by recurrent conjunctivitis and keratitis, often associated with vestibular-auditory symptoms, including hearing loss. The patient's history of recurrent conjunctivitis and progressive bilateral sensory neural hearing loss makes this a strong consideration.
  • Vogt-Koyanagi-Harada (VKH) Disease: This is a multisystem autoimmune disorder that can present with ocular (including glaucoma), auditory, and meningeal symptoms. The patient's history of glaucoma and hearing loss, along with the previous flu-like illness, could suggest VKH, although the typical skin and hair findings are not mentioned.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Neurosyphilis: Despite the absence of reported syphincter dysfunction, neurosyphilis can present with a wide range of neurological symptoms, including hearing loss and ocular abnormalities. It is crucial to rule out syphilis due to its treatable nature and potential for severe complications if left untreated.
  • Lyme Disease: This tick-borne illness can cause neurological symptoms, including meningitis, encephalitis, and cranial neuropathies, which might explain the hearing loss and other symptoms. The history of flu-like illness could be consistent with the early stages of Lyme disease.
• Rare diagnoses
  • Susac Syndrome: A rare autoimmune endotheliopathy that affects the brain, retina, and inner ear, leading to symptoms such as hearing loss, vision changes, and ataxia. The patient's combination of hearing loss, glaucoma, and unsteadiness could suggest this diagnosis, although it is rare and typically presents with more prominent visual and cognitive symptoms.
  • Sarcoidosis: This multisystem granulomatous disease can affect any part of the body, including the nervous system, eyes, and ears. While less likely, sarcoidosis could explain the patient's constellation of symptoms, including hearing loss and glaucoma, especially if other systemic symptoms or findings suggestive of sarcoidosis are present.

Each of these diagnoses requires careful consideration and further investigation to determine the underlying cause of the patient's symptoms. A comprehensive diagnostic approach, including laboratory tests, imaging studies, and potentially lumbar puncture or biopsy, may be necessary to establish a definitive diagnosis.