Friday, January 30, 2015

WILTIMS #245-8: Mega-post 2 - The Revenge

Friday: Today I got to give another presentation about the science behind smoking and lung cancer at a local school for a club that I'm involved in at our school. Compared to the very upscale middle school at which we had previously presented, this was a much rougher school in a poorer neighborhood, but I think I had even more fun and had a better chance of making an impact.

FridayIL: Though they can cause sedation, benzodiazepines cannot cause full blown anesthesia or coma.

MondayIL: Subarachnoid hemorrhage is most often caused by "berry" aneurysms. These are little berry-like bubbles that sometimes form around the junctions between the blood vessels of arteries in the circle of Willis in the brain. They weaken the vessel walls, much like if you poked into a balloon with your finger, causing a thinner, finger-shaped bubble to protrude from the otherwise normal balloon. If the balloon were ever going to pop, it'd pop in that thin bubble.

Tuesday: Snow day!

WednesdayIL: Bupropion (Wellbutrin) is an antidepressant that is also used to aid in smoking cessation. Patients were so upset by seeing that they were being prescribed an antidepressant, even if it was for a different indication, that the company started producing the same drug under a second name (Zyban) so that people would take the prescription without worrying about the stigma of being on antidepressant medication. What does this say about our society's feelings on mental illness?

TIL: If a brain lesion causes a gaze preference (someone's eyes skew to one side at rest), you can usually differentiate from symptoms caused by ischemia (loss of blood flow) or seizures. If ischemia is the cause, then the patient will look toward the side of the head that the lesion is on, whereas seizures cause the patient to look away.

Hemorrhagic stroke often causes headache and lethargy, whereas an ischemic stroke does not.

Seizures can confusingly cause the symptoms of a stroke, like muscle weakness, in the hours and days post seizure.

For carotid stenosis (hardening of the arteries supplying the brain due to athlerosclerotic plaque formation) the original treatment was to cut open the neck and carotid artery to physically scrape out the plaque on the artery walls - this is called a carotid endarterectomy. Once stents were invented everyone hoped that it would be a great, less invasive alternative to the major surgery that is the endarterectomy. But they quickly realized that the act of placing the stent increased the risk of breaking off a part of the plaque and causing a stroke - exactly what we were trying to prevent in the first place. So now, surgery is the first line treatment again and stents are only used if surgery is contraindicated.

Oculus uterque means "both eyes."

Friday, January 23, 2015

WILTIMS #244: Neuro strikes back!

Today we transitioned from respiratory diseases to neurological ones. Didn't you take an entire class on neuro last year? you might reasonably ask. Yes. And though that class was much more centered on the anatomy, we sure did an awful lot of pathology too. The same goes with learning neuro drugs in our behavioral science class last year, which we are duplicating in pharmacology now. There will be lots of overlap, but that neuro/behavioral block was brutal and we could use a refresher as we approach boards. I will, however, try not to repeat things from last year's blog posts.

TIL: Gerstmann's syndrome is a disorder caused by a lesion in the inferior parietal lobule of the dominant hemisphere of the brain. It has a very specific constellation of symptoms:
 • Dysgraphia/agraphia (inability to write)
 • Dyscalculia/acalculia (unusual difficulty with math)
 • Finger agnosia (inability to distinguish the fingers on the hand)
 • Left-right disorientation
Remember, just because you're bad at math or remembering your left from your right, doesn't mean you have a neurological disorder. All of these symptoms are compared with your baseline. 

One interesting symptom you can test to detect optic neuritis (inflammation of the optic nerve) is red desaturation. This is when a part of the vision in one or both eyes is damaged in such a way that red doesn't look as red as red should look. Parts of the field of vision will look more pink or orange when viewing a true, rich red.

Hoffmann's sign is used to demonstrate heightened reflexes in the muscles of the hands. This is the upper limb version of the Babinski sign, which looks at the curling of the toes when you scratch from the heel to the toes of the foot. With Hoffmann's, you grasp the patient's middle finger and sorta flick the nail. If the thumb twitches significantly, that's a positive sign and indicates heightened reflexivity.

Radiculopathy, unfortunately, does not mean an excellent disease. Instead, it refers to any neuropathy centered specifically around dysfunction of the nerve roots. The "radic-" part of the word actually shares a root with radish: radix, latin for root. Yep, that's the root of root.

WILTIMS #243: Where'd you get those peepers?

Backlogged post number two!

TIL: Atropine, the anticholinergic medicine used to treat COPD, is a very old drug derived from several types of plants. Also known as the active ingredient of belladonna, nightshade and mandrake among others, it has been used for thousands of years for its many medical effects (including dilating Cleopatra's eyes for cosmetic purposes). It was also smoked in various forms as recently as the 1800s. This is no longer the recommended drug delivery route.

Inhaled corticosteroids are used to treat various respiratory conditions and can cause oral thrush. This is when a white matte of yeast grows on the tongue and it's usually seen in immunocompromised patients, especially those with AIDS. So what's the connection here? Corticosteroids have many effects including bronchodilation (which is why we use them to treat asthma) and immunosuppression (which is why we use them to combat inflammatory conditions). The latter mechanism suppresses the immune system specifically in the mouth when bigger droplets in the aerosol don't make it all the way to the lungs.

WILTIMS #242: Boop!

I'm a bit behind this week entirely because I was waiting to insert these pics/gifs. You're welcome.

TIL: Burkholderia cepacia is a nasty bacterium that causes infection in the lungs of vulnerable patients, especially those with cystic fibrosis. Cystic fibrosis causes dangerously thick and abundant mucus secretions which can block the airways of the lungs. The lungs can't clear the blockages and opportunistic bacteria thrive in the moist tissue behind the mucus plugs, causing all manner of havoc. B. cepacia is very resilient and can be a life altering infection for CF patients. Fear of this infection is so great that affected patients may be shunned from CF support groups because its so dangerous to the other CF patients.

Bronchiolitis obliterans organizing pneumonia is my favorite disease of this respiratory block thanks to its wonderful abbreviation, BOOP. Hopefully, no one has ever been told by a barely straight-faced doctor, "After reviewing the tests, we think that you can be diagnosed with... [suddenly the doctor's voice jumps up by an octave] BOOP!" Bronchiolitis obliterans can actually be a very severe condition marked by the gradual occlusion of terminal bronchioles by fibrotic inflammatory tissue. But thanks to the internet, all I can think of when it's brought up is:






Saturday, January 17, 2015

WILTYIMS #241: Pulmonary grab bag

TYesterdayIL: Whispered pectoriloquy, literally "breast speaking," is a term for when you can hear a whisper through the stethoscope while listening to a person's lungs. Normally, the sounds of a whisper are nearly entirely made from the scratchy passage of air through the mouth and upper throat, unlike with normal speech, where the bulk of the sound is from the vibrations of the vocal cords resonating through the whole upper airway. If a whisper is resonating, then it is a sign that there is fluid and/or swelling in the upper airways of the respiratory tract, changing the normal conduction of sound through the tissues of the chest.

Jim Henson died of a Strep pyogenes pneumonia. This is unusual for Group A Strep, as this bacterium is sometimes called, since it is better known for causing strep throat, rheumatic fever, scarlet fever and glomerulonephritis (kidney infection), among others.

An uncorrected left-to-right cardiac shunt can progress to a right-to-left shunt; this process is termed Eisenmenger syndrome.The left side of the heart is under higher pressures and facing greater resistance than the right side. This pushes blood through any hole in the central wall, or septum, of the heart. In small amounts, this isn't a big deal because the blood from the left is already oxygenated. But all the blood that leaks through the hole is essentially extra pressure for the lungs to deal with and after a while they learn to fight back by constricting the pulmonary arteries. This increases the resistance and pushes blood from the right to the left. Now deoxygenated blood is leaking through to the systemic circulation, causing what is termed a shunt. No bueno.
The progression of Eisenmenger syndrome (http://www.medscape.org/viewarticle/557721)

Every 10 mmHg increase in PaCO2 (partial pressure of carbon dioxide in the pulmonary arteries) explains approximately .08 of a decrease in pH. You can use this calculation to see if there is a chronic acidosis or alkalosis hidden underneath an acute pH change.

Thursday, January 15, 2015

WILTIMS #240: It's a mystery!

TIL: Pleural plaques are associated with asbestosis (and feel really weird to the touch). These pathological features are like rectangular islands of plastic glued on to the balloon-like elastic surface of the parietal pleura, the thin connective tissue that separates the lungs from the ribcage.

Sarcoidosis is a true medical mystery. It's a disease of exclusion, which means that you can only diagnose someone with it once you've ruled out everything else. There is no confirmatory test to prove someone has it. But unlike other diseases of exclusion (e.g. idiopathic pulmonary fibrosis), this isn't just a name given to a vague collection of symptoms to make people feel better than if we just said we don't know what they have.

Sarcoidosis is a specific disease with characteristic symptoms, we just have no idea what causes it. It seems like immune system dysfunction is a part of the puzzle, but what is the trigger? There is a genetic component, but it's not fully explained by that either.

One of my favorite things in college was the first time I took classes on material that was so advanced or specific that my professors truly didn't know part of their material. If my high school teachers didn't know something, it was because they personally just didn't know; in college, it was because no one knew... yet. It's fun still being in a field that is so tied to the bleeding edge of research that the textbook is always being rewritten.

WILTIMS #239: Where's Waldo's NSAID?

Here is a concept map I made from just one lecture in Pharm! Everyone reading this should recognize at least a few of these. Can you find aspirin?


TIL: The mnemonic for the signs of sleep apnea, STOPBANG. A patient needs to display ≥3 of these features to warrant an expensive and time intensive sleep study to confirm the diagnosis.

Snoring
Tired
Observed apnea (by a spouse or partner)
Blood Pressure (>140/90)
BMI (>35)
Age (>50)
Neck circumference (>16/>17 for F/M)
Gender (M)

Tuesday, January 13, 2015

WILTIMS #235-8: Mega-post

Apologies for the lack of posts over the last week. Though I was still adding things to my "to blog about" list, I simply couldn't find the time to fact check, expand on and edit everything. So here is the first of what will likely be a new trend of occasional mega-posts.

FridayIL: 11-beta-hydroxysteroid dehydrogenase-2 converts cortisol to cortisone which prevents it from overwhelming the mineralocorticoid receptors to which they bind equally well as to their own glucocorticoid receptors. Isn't pharmacology fun?!

Sunday: This was the day when we were taught how to do a breast and pelvic exam on and by expertly trained women. Even though they are generally not trained as medical professionals, they know everything about the gynecological exam and, more importantly, how it feels (both physically and emotionally) to be the patient. I can't imagine not having this service and having to do one's first real gyn or breast exam on an actual patient. It almost seems unethical. Anyways, here are some of my takeaways:

SundayIL: Bad technique is bad. No kidding, right? More specifically, bad technique causes pain. Patients are bad at speaking up about pain and will just bite their tongue and go home. The results of the pap smear and physical findings of the gyn exam are usually normal. After a few repetitions of this, patients start to associate pain with normal results and think that pain is normal. Pain, when proper technique is used, can be a sign of something wrong, and if patients don't speak up about it, dangerous pathology can go missed.

There is a very small range of acceptable terminology associated with the breast and pelvic exams. Unlike nearly every other time in medicine, you can use too colloquial of terminology in this setting. Normally, you strive to cut down any technical jargon, but when you are touching personal areas, you might want to stick with "examine" over "look at," "touch" or "feel." You should avoid accidentally using euphemisms like "down there." You should, whenever possible, use unusual palpation techniques, so as not to evoke any association with the types of touching that a sexual partner might use. There's a lot of thought that needs to go into doing these exams in a respectful way.

MondayIL: Egophony literally means to sound like a goat. In medical terms, this is when you ask the patient to make an "e" noise and when listening through a stethoscope you hear an "a" in certain regions. The change is due to the physics of sound propagating through an extra dense layer of tissue or fluid, typically at the border around a pleural effusion or area of consolidation.

An ideal alveolar-arterial (A-a) gradient can be estimated by the formula (age / 4) + 4. This measurement is useful in differentiating the different causes of hypoxemia.

Today: Today's facts might seem a little out of left field compared to the topics of recent posts (except for Sunday's, which is also an exception). All of today's facts were taken from my preceptor experience, where I follow around a doctor in a real office and pretend like I know anything about medicine. It's terrifying and stressful but sometimes wonderfully rewarding and motivating.

TIL: Endovenous ablation is a procedure where a laser is used to essentially seal up insufficient and/or varicose veins in the legs. This can relieve some of the pain and most of the associated cosmetic defects with these overwhelmed veins.

Frozen pelvis is when the normally free-floating organs of the female pelvis become fibrotically linked and stick together. A common cause of this condition is endometriosis, when pieces of menstrual tissue float up the fallopian tubes and implant in the abdominal cavity.

Whereas pneumothorax, hydrothorax, hemothorax and chylothorax are, respectively, air, water, blood and lymph in the chest cavity, hemithorax just means half of a thorax. Relatedly, my preceptor is a troll.

Thursday, January 8, 2015

WILTIMS #234: Everyone love's a slinky!

Lungs are like a slinky. If you hold a slinky in your hands vertically, the top coils will be widely
spaced out and the bottom ones will be compact. The air sacs of the lung work the same way; higher up they are overfilled with air and at the base they are tiny and densely packed. I already got this concept but I thought the slinky metaphor was easily the best way I'd heard of explaining it. This all becomes very important regarding the ventilation/perfusion (V/Q) ratio gradient in the lungs, which explains a lot of the locational specificity of certain lung lesions.

TIL: Whereas apnea is the complete lack of breathing, hypopnea is merely a reduction in airflow (and is more fun to say!). hi-POP-knee-uh!

The hypoglossal nerve (which controls the muscles of the tongue) fires very slightly ahead of the phrenic nerve (which controls the diaphragm (and thus breathing)) to get the tongue out of the way before a big breath. Alcohol delays the hypoglossal nerve from firing which can cause sleep apnea.

WILTIMS #233: Have you or someone you know been annoyed by lawyer ads?

TIL: ...why all those annoying law office ads about asbestos target people with mesothelioma. I already knew that asbestos can cause mesothelioma (which is a cancer of the pleural tissue surrounding the lungs) as I'm sure anyone who watched TV in the past few years has learned as well. What I learned today was that asbestos actually causes significantly more lung cancer than mesothelioma. The reason that lawyers pounce on patients with the latter is that lung cancer can be caused by many things (most often smoking) whereas practically all mesothelioma is caused by asbestos. Mesothelioma is an almost guaranteed win in court if the asbestos exposure is well documented.

Atelectasis is the collapse of part or all of a lung.

An air bronchogram is a radiological finding where air-filled bronchi are made weirdly visible because of contrast with pathologically dense adjacent alveoli (air sacs). The density can be caused by many things including edema (fluid), cancer, and atelectasis.

Silhouette sign is a misnomer for the radiological finding of the loss of a silhouette sign. This is when a normally crisp border as seen on a x-ray image is unusually fuzzy, indicating that some pathological process is present.

Tuesday, January 6, 2015

WILTIMS #232: You may feel some slight discomfort...

Today we started preparing for what will undoubtedly be the most uncomfortable part of our training this year: the GU/GYN exam. We listened to a lecture with all manner of uncomfortable diagrams before heading upstairs to practice male/female genital, breast, and rectal exams on rubber mannequins. All of this is in preparation for practicing of real, live people in the coming months. These people are experts on teaching these techniques using their own body and perform such a great service to the medical community by ensuring that the first people inexperienced medical students try these rather invasive techniques on are not real patients.

My first of these sessions is on this coming Sunday, so expect a very non-specific bonus post this weekend!

TIL: Phimosis and paraphimosis are terms relating to the pathologic immobility of the foreskin of the uncircumcised (or partially circumcised) penis. Phimosis is when the foreskin is too tight around the glans (or tip) of the penis and won't retract. Paraphimosis is when the foreskin has been retracted past the glans but can't return to its resting position.

Pterygium is a really weird looking growth on the surface of the eye (it's really cool and/or gross looking so I won't post it here, but if you have the stomach, click through to the wikipedia article for more). It's also known as "Surfer's Eye" and is thought to arise from damage to the cornea from excessive sun exposure. Pterygium is not actually dangerous, but may require a procedure to periodically cut it back if it progresses to the point of blocking the pupil and reducing vision.

One of the only times in medicine that you want to purposefully keep a patient's blood pressure artificially high is in the immediate aftermath of an ischemic stroke. The idea is to hyperperfuse the brain tissue (give it even more nutrients than it needs) to try to minimize the damage following a hypoxic event like a stroke.

WILTIMS #231: And here... we... go!

We've only just returned from winter break and it's already apparent that this term is going to get rather chaotic. Pathology and pharmacology continue, starting with the respiratory system and continuing, organ system to organ system before winding down in early May. Then we are set free for a 6-week dedicated study period before sitting for Step 1 of the United States Medical Licensing Exam (USMLE). This 8-hour behemoth of a test is the number one piece of each medical student's portfolio used by hospitals to pick residents in the specialties that will define our careers.

Given the added test prep I'm already adding to my daily schedule, I will be purposely trying to keep the time spent on writing for this blog to a more reasonable length than I have in the past. I am King Emperor God of Procrastination and I've spent far too many hours debating the wording of this self-imposed time-suck rather than actually studying the information I'm trying to write about. So apologies (or maybe you're welcome) for the briefer format that will hopefully develop in the near future.

TIL: Gas exchange in the lungs only takes 0.25 seconds and your entire blood volume travels through the lungs every minute.

The thinnest parts of the lung tissue, specifically the type 1 pneumocytes that separate the air filled alveolar sacs from each other, can be 100x thinner than the width of a human hair.