by ·0 Comments

When you think “vessel” and “neck,” what words come to mind? For me, the first two words I think of are carotid and jugular. I’ve heard these words used in the vernacular every so often, especially the latter. If someone wants to convey a sentiment of “going for the kill” or delivering a coup de grace, that person can say he or she is “going for the jugular.” Let’s start with this one:

Jugular
Origin: Latin, jugulum (throat)
Named for the fact the jugular veins are near the throat

jugular

There are two jugular veins, one external and one internal on each side of the body. The internal jugular is covered by the sternocleidomastodeus muscle, while the external one is readily visible. These two veins are extremely important because they drain the deoxygenated blood from the head back to the superior vena cava.

What about the other vessel(s) of interest? There is a common carotid artery on both sides of the body, and this artery branches into the internal and external carotid arteries. The former supplies blood to the brain, while the latter supplies blood to the face and head. The etymology is rather interesting:

Carotid
Origin: Greek, karos (stupor)
So called from Galen’s observation that their compression causes stupor/somnolence

carotid rev

If one were to bilaterally massage both carotid sinuses (the point at which the common carotid bifurcates), the baroreceptors of the sinus are fooled into thinking there is a higher-than-normal blood pressure. To compensate, the blood pressure decreases, resulting in a sensation of stupor. Interestingly enough, there is a therapeutic use for this maneuver: the alleviation of supraventricular tachycardia:

Supraventricular tachycardia
Origin: Latin, supra– (above) + ventricle (chamber of the heart; translates to belly, for the ventricles comprise the “belly” of the heart)
Origin: Greek, tachys (swift) + kardia (heart)
A fast pulse due to improper electrical activity above the level of the ventricles

What other afflictions could these vessels suffer from? One thing that can go wrong with the carotid artery is carotid artery stenosis:

Stenosis
Origin: Greek, stenos (narrow/close) + -osis
Condition of narrowness, taken to mean a narrowing

Carotid artery stenosis is oftentimes caused by atherosclerosis, or the reduction of the interior arterial (luminal) diameter due to the accumulation of gunk. This gunk is a lovely mixture of dead cells, cholesterol, and fats.

Atherosclerosis
Origin: Greek, athres (gruel) + sklerein (to harden) + –osis
Condition of the hardening of gruel

Sounds delicious!

by ·0 Comments

What on earth is pyelonephritis? Let’s understand what it actually is by taking a look at its etymological breakdown.

Pyelonephritis
Origin: Greek, pyelos (basin, taken to mean pelvis) + nephros (kidney) + –itis (inflammation of)
Inflammation of the basin and the kidney

At first, this seems cryptic. What does basin refer to, and what exactly does kidney refer to? Starting with the root pyelo-, it denotes “pelvis,” but its base etymology comes from the Greek pyelos (basin). There is in fact such a thing as pyelitis, which would be inflammation localized to the renal pelvis. As for the nephr- root, it of course means kidney, but to be more precise, it refers to the kidney parenchyma. Nephritis on its own denotes the inflammation of the kidney’s functional tissue.

kidney anatomy rev

At the end of the day, pyelonephritis is the joint inflammation of the renal pelvis and the renal parenchyma. A vast majority of the cases are caused by a bacterial agent such as E. coli., and as such, they proliferate in a large portion of the kidney instead of being localized to only the pelvis or the parenchyma.

There are three types of pyelonephritis: acute, chronic, and xanthogranulomatous. Let’s look at the last one:

Xanthogranulomatous
Origin [1]: Greek, xanthos (yellow)
Origin [2]: Latin, granum (grain) + –ula (diminutive) + –oma (mass/proliferation/tumor)
Forming yellow granulomas

Indeed, under the microscope, one would find granulomas—collections of macrophages that try to wall off infections they cannot eradicate. On gross appearance, these granulomas appear yellow because they are macrophages that have been filled to the brim with lipids.

xantho rev

by ·3 Comments

Diabetes is a household name in this day and age. More often than not, people are concerned about their sugar intake in order to prevent diabetes. A quick Google Scholar search will reveal that a high sugar intake does not increase the risk of developing diabetes. But, of course, a chronically-high concentration of glucose in the blood will lead to a variety of problems down the line. An age-old clinical observation of diabetes is the tendency to urinate often, termed polyuria [Greek: poly (many) + ourein (to urinate)]. This is in fact where the word diabetes comes from:

Diabetes
Origin: Greek, dia- (through) + banein (to pass)
To pass through, siphon

What about the two words appended to the end of “diabetes”? They are the following:

Mellitus
Origin: Latin, mel (sweet thing)
Something sweet, honey

Insipidus
Origin: Latin, in- (without) + sapere (to have taste)
Lacking taste, in this case sweetness

Diabetes mellitus (DM) has two types, Type 1 and Type 2. The former is usually ascribed to insulin insufficiency, whereas the latter is usually ascribed to insulin resistance. It is given the name “mellitus” because of glucose in the urine, or glucosuria. The large amounts of glucose in the blood finds its way to the urine, and as a result, makes the urine—the entity being passed through—sweet. The polyuria is caused by the osmotic effect of water “following” the glucose. The quick and easy way that physicians would diagnose diabetes mellitus was to simply taste the urine of a patient suspected to have this condition.

vasopressin rev

On the contrary, diabetes insipidus (DI) is caused by a lack of water control and is not related to diabetes mellitus. This “lack of water control” involves problems with anti-diuretic hormone (ADH) production or ADH insensitivity. The former is termed central DI, since it originates in the central nervous system, and the latter is termed nephrogenic [Greek: nephros (kidney) + -genes (born from)] DI. This lack of mechanistic control stimulates profound thirst to replace the massive amounts of water lost in the urine since the water is not being reclaimed by the distal convoluted tubule and collecting duct of the nephron. However, blood glucose is not affected by this condition, there is no glucosuria, and in turn there is no sweetness in the urine—hence the urine is without taste, or “insipid.”

by ·0 Comments

In colloquial language, we often append the suffix ­-itis to a word to denote a disease or condition of said word. It is in effect an indication of an unhealthy amount of something either abstract or tangible. If someone is being lazy, we can say that he or she has come down with a case of lazyitis. Too much time in front of a computer can afflict you with a nasty case of computeritis. At its roots, –itis means “pertaining to” in Greek, so in some sense, this colloquial use of the suffix is the most faithful to its base etymology.

In more technical language, –itis is used as a medical suffix, and it simply denotes “inflammation of.” I can’t tell you how many times I have heard people use ­–itis to immediately denote “infection of.” Let’s list some examples.

Appendicitis
Origin: Neo-Latin, appendix (something appended, in this case to the colon) + -itis (inflammation of)
Inflammation of the appendix

Bursitis
Origin: Greek, byrsa (hide/skin) + ­-itis
Inflammation of the bursa (a pouch or sack that facilitates motion, e.g., suprapatellar bursa)

Cholecystitis
Origin: Greek, chole (bile) + kystis (bag) + -itis
Inflammation of the gall bladder (which stores bile)

Yes, many times, these conditions come about from infection by a bug that isn’t supposed to be there. But there are many other causes of inflammation, such as:

  1. Trauma
  2. Autoimmune reaction
  3. Drugs
  4. Burns
  5. Radiation

So the next time someone mentions an ­–itis, always remember that the inflammation of the target organ can be caused by something other than infection. If you wish to convey the fact that an inflammation of the appendix is caused by an infection, you can prepend the word with “infectious,” to make it an infectious appendicitis. Or if you are more certain of the cause of this infection, you can use a bacterial/viral/fungal modifier, for a bacterial appendicitis. For a non-infectious cause, you could say the cause for an inflammation of the liver is a drug-induced hepatitis.

Finally, if someone mentions a type of ­­–itis that you are not familiar with, use the word itself to help you out. I remember hearing the term bronchiolitis last year when learning about COPD (chronic obstructive pulmonary disease). I didn’t know what bronchiolitis was until I stopped for a second to think about it: the inflammation of the bronchiole(s). Contrast this with bronchitis, which is the inflammation of a main stem bronchus.

lung anatomy rev

So, given this, let me know in the comments what these terms are and what their most common causes are:

  1. Cholangitis
  2. Colitis
  3. Pneumonitis
  4. Endocarditis
  5. Vasculitis
  6. Phlebitis
  7. Gastroenteritis