Thursday, April 30, 2015

WILTIMS #296-9: Hiatus (No, not the hernia)

This is it! The last WILTIMS post of second year. Next week is finals (four exams of impressive unpleasantness) and then we get 6 weeks to study for and take Step 1 of the United States Medical Licensing Exam (USMLE). That's an 8 hour beast of a test on everything we've learned in the past two years. Yaaaaay! So don't be surprised if you don't hear much from me in the next couple months.

As always, thank you for reading and I'll see you in June!

This week was a review, of sorts. We had lectures by the head of the medical laboratory at our hospital on the main blood tests that we are likely to see in the clinical setting starting next year (aka the end of June). As these tests can be used to diagnose or manage nearly any disease we've studied, it makes for a decent all-inclusive review.

MondayIL: The normal reference ranges for lab values are calculated to include 95% of the normal distribution. That means that, on average, 1 in 20 lab values is expected to be slightly high or low in totally healthy individuals. So don't panic if your routine labs come back with one slightly aberrant result!

TuesdayIL: Protein levels in blood are generally included among the anions (negatively charged ions) like chloride (Cl-) and bicarbonate (HCO3-), among others. This is because the vast majority of protein in normal blood is albumin, which is negatively charged. But you have to be careful, because a big change in protein can be caused by other, differently charged proteins, such as gamma globulin. So, for example, the change in charge from a hyperalbunemia (too much albumin) would be exactly opposite that of a hypergammaglobulinemia (too much gamma globulin), even though the change in the amount blood protein could be exactly the same.

Um, no Google. I did not mean necrophiliacs.
WednesdayIL: You can tell if a peripheral blood smear is contaminated with bacteria (rather than having an actual septic infection) by looking for bacteria in the neutrophils (a type of white blood cells). The neutrophils' entire job is to fight and eat bacteria, so if bacteria were so prominent in the blood that they are seen on a blood smear, they would definitely be in the neutrophils too.

ThursdayIL: Blood drawn for coagulation tests must be run within 4 hours due to factor VII (one of the many coagulation factors that allows blood to clot) which has a 5hr half-life. Platelet tests must be run in 2 hours.

Friday, April 24, 2015

WILTIMS #293-5: Oranges, derm and a belly brain cancer

WednesdayIL: An inflamed breast is obviously never someone's idea of a fun time, but in rare cases, it's far worse. The inflammation is usually caused by a bacterial infection, especially during periods where the woman is breast feeding. Unfortunately, the same appearance of inflammation can also be caused by inflammatory breast cancer. This variant of malignant breast cancer is caused by the tumor blocking off the lymphatic drainage from the breast and has a very poor prognosis. If the inflammation progresses far enough, it can cause a peau d'orange or "orange peel" appearance where the breast turns reddish-orange and develops dimples as the swelling tissue pushes out past the hair follicles. I'll let you google that picture on your own.

Thursday: Today was our last gross specimen lab of the year, and we were looking at gynecological pathology. Most of the samples were ovarian and uterine tumors, fairly repetitive over-all. One specimen, however, managed to wake up even the most tuned-out of my classmates. An invasive placenta had grown into the uterine wall, requiring a total hysterectomy - removing the uterus, ovaries, and a 14-week fetus.

Now, we've passed around kidneys the size of a watermelons, lungs as black as coal, and brains of infants, but I've never seen everyone snap to attention as quickly as when we noticed that fetus lying on its side in a pool of preservative in the specimen bin. For me, it re-humanized an already desensitized procedure of looking at bits of dead people. We take for granted that these people lost their organs, and usually their lives, after some valiant but futile effort by our medical colleagues. That's enough to put our minds at ease. But this case provided too much information for us to remain detached. This woman probably went in for a pregnancy check-up and found out that not only would she lose the baby, but with the removal of her reproductive organs, she'd lose the ability to ever try again. Not quite as fun as poking squishy things normally is.

ThursdayIL: A chloasma or melasma is a facial pigmentation change that is associated with pregnancy, hormonal birth control and hormone replacement therapy.

You can develop primary brain cancer (or any cancer, really) from a teratoma. A teratoma, literally "monster-tumor," is a germ cell mass that can grow into any kind of tissue thanks to the undifferentiated nature of its precursor cell type. These tumors are well known for containing fat, hair, lung, bone and teeth, all mushed together at some mid-line place in the body (for embryologic reasons). Teratomas are almost always benign, but any of the tissues within the tumor can, on rare occasions, become cancerous themselves. So, if you're really, really, really unlucky, you can get brain cancer in your teratoma in your uterus. (This story was confirmed by a pathology resident to have actually happened at our hospital in recent years)

TIL: Dermatology lightning round!
Macule: flat, non-palpable lesion less than 1 cm
Patch: same as macule, but >1cm (e.g. café au lait spots)
Papule: raised lesion less than 1cm (e.g. pimples)
Plaque: superficial raised lesion >1cm (e.g. psoriasis)
Nodule: deep/solid raised lesion >1cm
Vesicle: fluid filled less than 1cm (e.g. poison oak/ivy)
Bulla: same as vesicle, but >1cm
Pustule: pus filled lesion of any size
Wheal: firm raised edematous (swollen/red) lesion (e.g. hives)

Wednesday, April 22, 2015

WILTIMS #291-2: ♪♫ mOlé! mOlé, mOlé, mOlé... ♫♪

MondayIL: A whole new kind of mole. No, not this one or this one or this one or even this one. Complete or partial moles are types of abnormal pregnancy caused either by a sperm (or two) fertilizing a genetically empty egg or two sperm fertilizing the same egg. The latter can result in a 69 chromosome fetal mass. As we went over recently, humans can survive with a select few trisomies (an extra copy of a chromosome) but if every chromosome is duplicated, the embryo can't even develop. The resulting "pregnancy" consists of, essentially, a blob of undifferentiated cysts and must be aborted.

Diethylstilbestrol (DES) is an old drug that was used as a prenatal drug but was later found to caused clear cell carcinoma of the vagina, both in the pregnant women that took the drug and in the female children born of these women. DES was restricted from this use in 1971.

Placental invasion of the myometrium (the muscle layer of the uterus) is classified according to the depth of the invasion. Placenta accreta is attachment, increta is invasion and percreta is completely breaking through the myometrium.

Schober's test measures the ability to bend the lower back and is useful in diagnosis diseases like ankylosing spondylitis. To do it, you note the position of the 5 lumbar vertebra and, with the patient standing straight, place one finger 5cm below and one finger 10cm above. When the patient bends to touch their toes, that 15cm distance should increase to 20cm or more. If not, something's wrong.

TuesdayIL: A pessary is essentially a plug that can be used to keep the uterus from prolapsing in patients where surgical repair is contraindicated.

There's a nifty memory tool for remembering the difference between the main  adrenal enzyme deficiencies (see the diagram to the right). With 11β-hydroxylase deficiency, both blood pressure and virility increase; with 17-hydroxylase deficiency, BP goes up but virility decreases; and with 21-hydroxylase deficiency, the BP goes down and virility goes up. All you have to remember is that ones point up!

Monday, April 20, 2015

WILTIMS #288-90: Ol' Blue Eyes

ThursdayIL: You may need to give sugar-water to a diabetic because DKA takes longer to treat than hyperglycemia. One of the more serious acute reactions to diabetes is diabetic ketoacidosis (DKA), where the body makes energy from protein because it can't get the plentiful glucose in the blood into the cells without abundant insulin and functional insulin receptors. This produces ketone bodies and lower the pH of the blood to unhealthy levels. Now when you're treating this condition, you need to give saline fluids, give insulin and monitor potassium. But when the hyperglycemia has been stabilized, you need to switch the fluids to dextrose (a slightly sugary solution) to prevent a deadly hypoglycemic overcorrection while you wait for the dawdling DKA to resolve.

FridayIL: Osteogenesis imperfecta (OI) is an interesting, if awful, disease caused by a defect in either the structure or quantity of collagen, leading to brittle bones, skeletal abnormalities, and one particularly interesting symptom: blue sclera - in other words, the whites of the eyes turn blue. This blueness is caused by the lack of collagen that normally makes the sclera white, allowing you to see the blue mini-veins behind it.

Osteopetrosis (not osteoporosis), which literally means "bone of stone," is a rare bone disease that causes the bone to grow too densely. Somewhat counter-intuitively, the bones become both harder and more brittle. This is the same reason you don't make swords out of the hardest metals and why those ceramic knives you see on late night infomercials are not the greatest investment - they are prone to shattering. One of the signs you may find with this disease is an Erlenmeyer flask deformity.

Stolen and drawn on w/o the permission of:
Brown tumors are not tumors. They are bone lesions caused by hyperparathyroidism where the osteoclasts, cells that break down bone, proliferate to the point that they eat away a hole in the bone. On X-ray this looks exactly like a bone cancer or metastasis. Treating the underlying parathyroid gland overproduction will allow the bone to reform.

Sunday: Today, I had the companion experience to the practice gynecological exam we had a couple months ago: the GU exam. We learned and practiced examining the kidneys, male genetals, potential hernias and the rectum/prostate. All in all, it was so much simpler than the female version.

TIL: What a prostate feels like through gloves and some large intestine.

Thursday, April 16, 2015

WILTIMS #285-7: Bingo!

WILTIMS makes its triumphant return for the 2nd year homestretch! Only three more weeks until finals and then our 6-week dedicated study period for the Step 1 board exam. Yipee!

MondayIL: HbA1c is a great marker for long term hyperglycemia, but is unreliable in patients with changes in red blood cell formation or destruction, as in anemias. Hemoglobin A1c (HbA1c) is an irreversibly modified molecule of hemoglobin that essentially has been floating around in sugary blood so long that it gets chains of glucose stuck to it. This hemoglobin can only be recycled once the red blood cells themselves are recycled every 120 days. If you are anemic, you lost some red blood cells before their 120 days were up, which will skew the HbA1c level.

Hyperpigmentation can be caused by high adrenocorticotropic hormone (ACTH) levels associated with primary adrenal insufficiency. The ACTH molecule comes from pro-opiomelanocortin (POMC), the same precursor as beta endorphin and melanocyte stimulating hormone (MSH). The latter does exactly what its name says, it stimulates the cells that produce pigment in the skin.

TuesdayIL: Diabetes is a particularly annoying chronic disease because it doesn't force you to deal with it. Other conditions, like asthma, hepatitis C and arthritis, all have debilitating symptoms that spike when a patient either doesn't seek treatment or does something that exacerbates the condition. Diabetes just slowly, quietly progresses - making the patient a little more thirsty and need to pee a little more each day for years. Even at more advanced  stages, diabetes just makes you swell and get numb - not exactly ER-worthy symptoms. Thus the undiagnosed stay undiagnosed, and the sick get sicker.

Insulin lispro is an insulin analog made by reversing a lysine-proline amino acid pair in the protein. Hence, lys-pro → lispro.

Neutral Protamine Hagedorn (NPH) is an intermediate-acting insulin analog named for the guy who first figured out how to complex protamine (originally found as, I kid you not, trout sperm basic protein) with zinc and insulin. The aforementioned guy, Hans Christian Hagedorn, also founded the company that would become Novo Nordisk, a major pharma company that specialized in diabetes treatments. 

TIL: Facies is a word. This is one of those words that I just assumed was a typo for "faces," but alas, I was wrong. Facies means a facial appearance that is associated with a disease. So, pretty much just faces...

Old men who are wheelchair bound and double-diapered can become feminized due to the heat of the diapered area interfering with the testes' production of testosterone. Easy fix: less diaper!

Job's syndrome, aka hyperimmunoglobulin E syndrome, is named for the biblical story of Job, because terrible things keep happening to patients with this disease. Common symptoms (and/or punishments from on high) include repeated infections, puss-filled skin lesions, easily broken bones and tooth deformities.

This last fact I learned at a Rare Disease Bingo Night! It was actually lots of fun. We made our own bingo cards from a list of many dozens of rare diseases. One of our deans/professors/radiologists led us through diagnostic studies and descriptions, quizzing us to earn our Xs.

Thursday, April 2, 2015

WILTIMS #282-4: Gland Opening!

Spring break starts tomorrow! Woo! Studying will still be going on, but now I get to shift to reviewing old material. Yay? But before they set us loose, we had to get a start on our new block of material, endocrinology, the study of hormones and glands. See you in a week!

TuesdayIL: When looking at pituitary tumors, they become clinically noticeable from either mass effect or excess hormonal production, but rarely both. This makes sense, since if a tumor secretes a hormone, it will cause more and more problems as it grows and will be noticed due to it's systemic effects before it gets noticed for pushing on the neighboring brain regions.

Neuroblastoma and Wilm's tumors look very similar but Wilm's rarely metastasizes to bone, so if you see bone mets, think neuroblastoma.

WednesdayIL: Near the end of a pregnancy, the pituitary gland is hypertrophied and at the limit of its vascular supply (it's bigger and is barely getting enough blood). Though this growth is useful to produce the hormones needed to maintain the gravid state, it puts the pituitary at risk of infarction (stroke). If there is substantial blood loss during delivery, this can exacerbate the problem. If an infarction happens at this point, it's called Sheehan syndrome. Loss of pituitary function can be pretty subtle and, if it's a small infarct, could go unnoticed for years. The main symptoms are lethargy, anorexia, weight loss and an inability to lactate. Since the pituitary controls the thyroid gland, you can also have hypothyroidism, showing water retention, more fatigue, cold intolerance, among many other symptoms.

TIL: TSH level manipulation with thyroid cancer is complicated. Normally, you want to suppress thyroid stimulating hormone (TSH) in thyroid cancer treatment for the fairly obvious reason that part of the thyroid is already growing out of control (hence the cancer), so stimulating it would be counterproductive. Simple, right? Here's the problem: one of the treatments for thyroid cancer is using I-131, a radioactive isotope of iodine, to kill off cancerous thyroid cells. This is a great targeted form of chemotherapy since the thyroid is the only part of the body that takes up iodine in any significant amount. But in order for the thyroid to do this function, it needs to be stimulated by TSH. So, if this treatment is used you must closely regulate the TSH level so that it's high when you want iodine to be absorbed, but low the rest of the time to deter unwanted growth.

With hyperthyroidism caused by subacute thyroiditis, the thyroid does not actually produce any not hormone than usual. Instead, the inflamed state allows more of the preformed stored hormone to leak out of the thyroid follicles than normal.

My favorite disease of the week is the so-called hamburger thyrotoxicosis, which is community-wide outbreaks of hyperthyroidism caused by the accidental addition of bovine thyroid gland into hamburger meat. Thyroid hormones are very potent and if thyroid tissue gets mixed into a large batch of ground beef, it can cause symptoms in hundreds of people. The practice of using the meat near the neck of the cow is strictly prohibited, so this rarely happens and is more commonly seen when a family farm butchers a cow for their own use and doesn't follow the industry guidelines.