WBR0130
| Author | PageAuthor::Sapan Patel, M.B.B.S. |
|---|---|
| Exam Type | ExamType::USMLE Step 3 |
| Main Category | MainCategory::Primary Care Office, MainCategory::Emergency Room |
| Sub Category | SubCategory::Head and Neck, SubCategory::Neurology |
| Prompt | [[Prompt::A 67-year-old man presents with a 2-day history of severe dizziness. The symptoms are exacerbated by turning his head and relieved by lying still. He reports nausea and vomiting for the first 2 days of his illness, but successfully eats breakfast on the day he is seen in clinic. He denies hearing loss and tinnitus. His past medical and surgical histories are unremarkable. He has no previous exposure to ototoxic drugs and denies further neurologic symptoms. Physical examination reveals an obviously uncomfortable white male in a wheelchair.Otologic examination is without abnormality. Weber testing with a 512 Hz tuning fork is to midline. Romberg testing indicates right-sided pathology. Cranial nerve examination is normal except left beating nystagmus. Vertigo is experienced after the Dix-Hallpike maneuver. Nystagmus is observed after a few seconds of lying down during the maneuver.The patient is treated with diazepam, which, on follow up, has relieved his symptoms.
What is the most likely diagnosis?]] |
| Answer A | AnswerA::Meniere's disease |
| Answer A Explanation | AnswerAExp:: |
| Answer B | AnswerB::Acoustic neuroma |
| Answer B Explanation | [[AnswerBExp::Acoustic neuroma (sometimes termed a neurolemmoma or schwannoma) is a benign (noncancerous) tissue growth that arises on the eighth cranial nerve leading from the brain to the inner ear. Acoustic neuromas usually grow slowly over a period of years. They expand in size at their site of origin, and when large, can displace normal brain tissue. The brain is not invaded by the tumor, but the tumor pushes the brain as it enlarges. The slowly enlarging tumor protrudes from the internal auditory canal into an area behind the temporal bone called the cerebellopontine angle. Since the balance portion of the eighth nerve is where the tumor arises, unsteadiness and balance problems may occur during the growth of the neuroma. The most common presentation is unilateral hearing loss.]] |
| Answer C | AnswerC::Benign positional vertigo |
| Answer C Explanation | [[AnswerCExp::Benign positional vertigo (BPV) is the most likely cause of this patient’s vertigo. BPV is
not typically associated with hearing loss. Patients have brief episodes of vertigo with positional changes, typically when turning over in bed. This patient had a positive response to the Dix-Hallpike maneuver, which confirms the diagnosis. BPV is due to deposition of calcium debris in the semicircular canals. Medications such as diazepam or meclizine as well as canalith repositioning (Epley’s maneuver) are used to treat the condition. The latter is a series of head rotational positions intended to relocate free floating particles in the semicircular canals.]] |
| Answer D | AnswerD::Viral labyrinthitis |
| Answer D Explanation | AnswerDExp:: |
| Answer E | AnswerE::Vestibular neuronitis |
| Answer E Explanation | AnswerEExp:: |
| Right Answer | RightAnswer::C |
| Explanation | [[Explanation:: Educational Objective: |
| Approved | Approved::Yes |
| Keyword | |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |