American College of Physicians: Internal Medicine — Doctors for Adults ®

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Saturday, August 13, 2011

Interesting neuro case for doctors who hate neurology

Yesterday, I presented the case of a woman with double vision and ptosis and challenged you all to a game of "spot the lesion." To be honest, I found this stuff impenetrable as a medical student and it was only by sheer force of will that I was able to commit it to memory for exactly long enough to pass a test on it before immediately purging it from my memory. I did this several times for various board exams and such, but it never really "stuck." Hated neuro beyond words, I did.

As mind-numbing as I found it all in the abstract, I get excited about these cases in application. I may not remember where exactly the internal capsule is or what it does, but when I see someone with an interesting neuro deficit due to a lesion there, all of a sudden it makes so much more sense, and is, dare I say it, cool. I know, kinda sad.

This case is as classic (and cool) as you will ever see. It's a complete palsy of the Oculomotor Nerve (CN 3 for those keeping score at home).

So how do you approach figuring that out?

First of all, it's unilateral. Note the movements of the left eye are all normal. Some other things, systemic diseases, can cause ptosis (the droopy eyelid) or diplopia (double vision), so think neuromuscular stuff like myasthenia gravis, botulism, etc. But those are usually bilateral. As an isolated right-sided finding, however, that should prompt you to think about either a central cause or a direct neuropathy. But central causes of this sort of thing are not likely, because the oculomotor nuclei are located deep in the midbrain, and are crossed, so a stroke or something bad there is not likely to give unilateral or isolated neurological findings. Therefore, we know it's a peripheral neuropathy. Yay! But which one?

The ptosis, especially a complete paralysis of the levator palpebrae, should be a huge red flag that the third nerve is involved. Even I remember this mnemonic from medical school: The III is the pillar that holds the eye open; the 7 is the hook that closes it.

Then you look at the pattern of movements that the eye has lost and note that it matches the oculomotor muscles which are innervated by the third nerve.

She can abduct it, so CN6 is intact, but up, down and adduction are shot, which are all CN3. The fact that with straight gaze and lateral gaze the right eye is a bit down compared to the left is due to the preserved function of CN4. Thus, the classic pattern of CN3 palsy, "down and out."

Then you look at the pupil. It's big, so you know this isn't a Horner's syndrome, though that wouldn't cause ophthalmoparesis either. And it's not reactive, either. The most common cause of acquired CN3 palsies is diabetic microvascular ischemia, one of the many peripheral neuropathies that the sugar causes. But those are usually pupil-sparing. This involves the pupil, so something is compressing or otherwise pissing off the nerve directly.

The solution (as for just about everything in neurology, it seems) is to order your MRI, but in this case, you definitely want an MRA as well. Because the next most common cause of CN3 palsy is compression by an aneurysm (notoriously the PCA, posterior communicating artery). The deficit can apparently be intermittent with an aneurysm. But all sorts of things can do it, and the treatment will depend on the cause. It could be direct compression from a pituitary tumor, or a cavernous sinus thrombosis. If the patient presents with stiff neck and meningismus, either subarachnoid hemorrhage or meningitis should be considered, as they can do this. Demyelinating diseases can also do this, so if all else fails and if the demographic makes sense, consider MS. In older patients, consider arteritis, too. Herpes zoster can also rarely do this, though it's more classically the seventh nerve. These can occur post-traumatic, but be sure that the pattern of the deficit matches the nerve and that you're not going to miss an orbital wall fracture! I recently saw a patient with a post-traumatic transient internuclear ophthalmoplegia, which was also pretty cool. Sadly, I didn't have the presence of mind to get pics of that one.

In the incident case, the MR showed a suprasellar mass invading the cavernous sinus, most likely a pituitary macroadenoma:

Not something you can see commonly, but very classic, and a nice opportunity to review and relearn all the neuroanatomy we learned in medical school, but in the context of a real case.

This post by Liam Yore, MD, appeared at Get Better Health, a network of popular health bloggers brought together by Val Jones, MD. Better Health's mission is to support and promote health care professional bloggers, provide insightful and trustworthy health commentary, and help to inform health policy makers about the provider point of view on health care reform, science, research and patient care.

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Blog log

Members of the American College of Physicians contribute posts from their own sites to ACP Internistand ACP Hospitalist. Contributors include:

Albert Fuchs, MD
Albert Fuchs, MD, FACP, graduated from the University of California, Los Angeles School of Medicine, where he also did his internal medicine training. Certified by the American Board of Internal Medicine, Dr. Fuchs spent three years as a full-time faculty member at UCLA School of Medicine before opening his private practice in Beverly Hills in 2000.

And Thus, It Begins
Amanda Xi, ACP Medical Student Member, is a first-year medical student at the OUWB School of Medicine, charter class of 2015, in Rochester, Mich., from which she which chronicles her journey through medical training from day 1 of medical school.

Auscultation
Ira S. Nash, MD, FACP, is the senior vice president and executive director of the North Shore-LIJ Medical Group, and a professor of Cardiology and Population Health at Hofstra North Shore-LIJ School of Medicine. He is Board Certified in Internal Medicine and Cardiovascular Diseases and was in the private practice of cardiology before joining the full-time faculty of Massachusetts General Hospital.

Zackary Berger
Zackary Berger, MD, ACP Member, is a primary care doctor and general internist in the Division of General Internal Medicine at Johns Hopkins. His research interests include doctor-patient communication, bioethics, and systematic reviews.

Controversies in Hospital Infection Prevention
Run by three ACP Fellows, this blog ponders vexing issues in infection prevention and control, inside and outside the hospital. Daniel J Diekema, MD, FACP, practices infectious diseases, clinical microbiology, and hospital epidemiology in Iowa City, Iowa, splitting time between seeing patients with infectious diseases, diagnosing infections in the microbiology laboratory, and trying to prevent infections in the hospital. Michael B. Edmond, MD, FACP, is a hospital epidemiologist in Richmond, Va., with a focus on understanding why infections occur in the hospital and ways to prevent these infections, and sees patients in the inpatient and outpatient settings. Eli N. Perencevich, MD, ACP Member, is an infectious disease physician and epidemiologist in Iowa City, Iowa, who studies methods to halt the spread of resistant bacteria in our hospitals (including novel ways to get everyone to wash their hands).

db's Medical Rants
Robert M. Centor, MD, FACP, contributes short essays contemplating medicine and the health care system.

Suneel Dhand, MD, ACP Member
Suneel Dhand, MD, ACP Member, is a practicing physician in Massachusetts. He has published numerous articles in clinical medicine, covering a wide range of specialty areas including; pulmonology, cardiology, endocrinology, hematology, and infectious disease. He has also authored chapters in the prestigious "5-Minute Clinical Consult" medical textbook. His other clinical interests include quality improvement, hospital safety, hospital utilization, and the use of technology in health care.

DrDialogue
Juliet K. Mavromatis, MD, FACP, provides a conversation about health topics for patients and health professionals.

Dr. Mintz' Blog
Matthew Mintz, MD, FACP, has practiced internal medicine for more than a decade and is an Associate Professor of Medicine at an academic medical center on the East Coast. His time is split between teaching medical students and residents, and caring for patients.

Everything Health
Toni Brayer, MD, FACP, blogs about the rapid changes in science, medicine, health and healing in the 21st century.

FutureDocs
Vineet Arora, MD, FACP, is Associate Program Director for the Internal Medicine Residency and Assistant Dean of Scholarship & Discovery at the Pritzker School of Medicine for the University of Chicago. Her education and research focus is on resident duty hours, patient handoffs, medical professionalism, and quality of hospital care. She is also an academic hospitalist.

Glass Hospital
John H. Schumann, MD, FACP, provides transparency on the workings of medical practice and the complexities of hospital care, illuminates the emotional and cognitive aspects of caregiving and decision-making from the perspective of an active primary care physician, and offers behind-the-scenes portraits of hospital sanctums and the people who inhabit them.

Gut Check
Ryan Madanick, MD, ACP Member, is a gastroenterologist at the University of North Carolina School of Medicine, and the Program Director for the GI & Hepatology Fellowship Program. He specializes in diseases of the esophagus, with a strong interest in the diagnosis and treatment of patients who have difficult-to-manage esophageal problems such as refractory GERD, heartburn, and chest pain.

I'm dok
Mike Aref, MD, PhD, FACP, is an academic hospitalist with an interest in basic and clinical science and education, with interests in noninvasive monitoring and diagnostic testing using novel bedside imaging modalities, diagnostic reasoning, medical informatics, new medical education modalities, pre-code/code management, palliative care, patient-physician communication, quality improvement, and quantitative biomedical imaging.

Informatics Professor
William Hersh, MD, FACP, Professor and Chair, Department of Medical Informatics & Clinical Epidemiology, Oregon Health & Science University, posts his thoughts on various topics related to biomedical and health informatics.

David Katz, MD
David L. Katz, MD, MPH, FACP, is an internationally renowned authority on nutrition, weight management, and the prevention of chronic disease, and an internationally recognized leader in integrative medicine and patient-centered care.

Just Oncology
Richard Just, MD, ACP Member, has 36 years in clinical practice of hematology and medical oncology. His blog is a joint publication with Gregg Masters, MPH.

KevinMD
Kevin Pho, MD, ACP Member, offers one of the Web's definitive sites for influential health commentary.

MD Whistleblower
Michael Kirsch, MD, FACP, addresses the joys and challenges of medical practice, including controversies in the doctor-patient relationship, medical ethics and measuring medical quality. When he's not writing, he's performing colonoscopies.

Medical Lessons
Elaine Schattner, MD, FACP, shares her ideas on education, ethics in medicine, health care news and culture. Her views on medicine are informed by her past experiences in caring for patients, as a researcher in cancer immunology, and as a patient who's had breast cancer.

Mired in MedEd
Alexander M. Djuricich, MD, FACP, is the Associate Dean for Continuing Medical Education (CME), and a Program Director in Medicine-Pediatrics at the Indiana University School of Medicine in Indianapolis, where he blogs about medical education.

More Musings
Rob Lamberts, MD, ACP Member, a med-peds and general practice internist, returns with "volume 2" of his personal musings about medicine, life, armadillos and Sasquatch at More Musings (of a Distractible Kind).

Prescriptions
David M. Sack, MD, FACP, practices general gastroenterology at a small community hospital in Connecticut. His blog is a series of musings on medicine, medical care, the health care system and medical ethics, in no particular order.

Reflections of a Grady Doctor
Kimberly Manning, MD, FACP, reflects on the personal side of being a doctor in a community hospital in Atlanta.

The Blog of Paul Sufka
Paul Sufka, MD, ACP Member, is a board certified rheumatologist in St. Paul, Minn. He was a chief resident in internal medicine with the University of Minnesota and then completed his fellowship training in rheumatology in June 2011 at the University of Minnesota Department of Rheumatology. His interests include the use of technology in medicine.

Technology in (Medical) Education
Neil Mehta, MBBS, MS, FACP, is interested in use of technology in education, social media and networking, practice management and evidence-based medicine tools, personal information and knowledge management.

Peter A. Lipson, MD
Peter A. Lipson, MD, ACP Member, is a practicing internist and teaching physician in Southeast Michigan. The blog, which has been around in various forms since 2007, offers musings on the intersection of science, medicine, and culture.

Why is American Health Care So Expensive?
Janice Boughton, MD, FACP, practiced internal medicine for 20 years before adopting a career in hospital and primary care medicine as a locum tenens physician. She lives in Idaho when not traveling.

World's Best Site
Daniel Ginsberg, MD, FACP, is an internal medicine physician who has avidly applied computers to medicine since 1986, when he first wrote medically oriented computer programs. He is in practice in Tacoma, Washington.

Other blogs of note:

American Journal of Medicine
Also known as the Green Journal, the American Journal of Medicine publishes original clinical articles of interest to physicians in internal medicine and its subspecialities, both in academia and community-based practice.

Clinical Correlations
A collaborative medical blog started by Neil Shapiro, MD, ACP Member, associate program director at New York University Medical Center's internal medicine residency program. Faculty, residents and students contribute case studies, mystery quizzes, news, commentary and more.

Interact MD
Michael Benjamin, MD, ACP member, doesn't accept industry money so he can create an independent, clinician-reviewed space on the Internet for physicians to report and comment on the medical news of the day.

PLoS Blog
The Public Library of Science's open access materials include a blog.

White Coat Rants
One of the most popular anonymous blogs written by an emergency room physician.

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