A 60-year-old woman comes to the emergency department complaining of a severe, sudden-onset headache accompanied by nausea. She has had mild diplopia for the past 3 months. The patient has a long history of hypertension and diabetes mellitus type 2. Her blood pressure is 160/90 mm Hg and heart rate is 80/min. Physical examination shows right-sided ptosis, mild anisocoria, and nuchal rigidity. There is no ataxia. Which of the following is the most likely diagnosis?

Question

A 60-year-old woman comes to the emergency department complaining of a severe, sudden-onset headache accompanied by nausea.  She has had mild diplopia for the past 3 months.  The patient has a long history of hypertension and diabetes mellitus type 2.  Her blood pressure is 160/90 mm Hg and heart rate is 80/min.  Physical examination shows right-sided ptosis, mild anisocoria, and nuchal rigidity.  There is no ataxia.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

Explanation: 11ec2b69_c192_653c_8f63_cb5610472656_MD0005_00 The patient's symptoms are suggestive of a subarachnoid hemorrhage. The constellation of sudden-onset headache, nausea, and nuchal rigidity is characteristic. She demonstrates signs of right cranial nerve III (CN III) palsy (ptosis and anisocoria), a typical finding with posterior communicating artery aneurysms (about 20% of cerebral aneurysms) due to the proximity of the nerve to the artery's path. This finding can also be seen in cavernous-carotid aneurysms, but these are uncommon. The patient's history of diplopia may have been due to right CN III neuropathy (mass effect from the unruptured aneurysm). (Choice A) Brainstem gliomas present with signs and symptoms of progressive brainstem involvement, including ataxia, cranial nerve palsies, and motor and/or sensory abnormalities. (Choice B) Lacunar strokes manifest as relatively limited neurologic dysfunction (eg, pure motor strokes), but headache and nuchal rigidity are not typically present. (Choice D) Posterior inferior cerebellar artery aneurysms frequently result in ataxia and bulbar dysfunction. (Choice E) Trigeminal neuralgia presents as recurrent brief attacks of facial pain in the distribution of CN V. Educational objective: Cranial nerve III palsy is a typical finding in patients with a posterior communicating artery aneurysm. References: Oculomotor nerve palsy by posterior communicating artery aneurysms: influence of surgical strategy on recovery. (http://www.ncbi.nlm.nih.gov/pubmed/22937927) Size and location of ruptured and unruptured intracranial aneurysms measured by 3-dimensional rotational angiography. (http://www.ncbi.nlm.nih.gov/pubmed/16378842)

A 60-Year-Old Woman Comes to the Emergency Department Complaining of a Severe