Clinical Skill Muse #20: Chvostek Sign and Trousseau Sign

Unfortunately there will never be a Luterman sign....so here's the question: what are these signs, when were they discovered and who were the docs who discovered them? Bonus question..which is more sensitive? And how reliable are they?

The Chvostek sign (also Weiss sign) is one of the signs of tetany seen in hypocalcemia. It refers to an abnormal reaction to the stimulation of the facial nerve. When the facial nerve is tapped at the angle of the jaw, the facial muscles on the same side of the face will contract momentarily (typically a twitch of the nose or lips) because of hypocalcaemia (ie from hypoparathyroidism, pseudohypoparathyroidism, hypovitaminosis D) with resultant hyperexcitability of nerves.

Frantisek Chvostek (1835–1884) was an Austrian surgeon who was born in Moravia, Czech Republic. Chvostek investigated the pathology and treatment of neurologic illnesses, including the use of electrotherapy, and described the sign that was to bear his name in 1876.

Trousseau sign of latent tetany is a medical sign observed in patients with low calcium. This sign may become positive before other gross manifestations of hypocalcemia such as hyperreflexia and tetany, but is generally believed to be more sensitive than the Chvostek sign for hypocalcemia.

To elicit the sign, a blood pressure cuff is placed around the arm and inflated to a pressure greater than the systolic blood pressure and held in place for 3 minutes. This will occlude the brachial artery. In the absence of blood flow, the patient's hypocalcemia and subsequent neuromuscular irritability will induce spasm of the muscles of the hand and forearm. The wrist and metacarpophalangeal joints flex, the DIP and PIP joints extend, and the fingers adduct. The sign is also known as main d'accoucheur (French for "hand of the obstetrician") because it supposedly resembles the position of an obstetrician's hand in delivering a baby.

Armand Trousseau (October 14, 1801 — June 27, 1867) was a French internist. His contributions to medicine include Trousseau sign of malignancy, Trousseau sign of latent tetany, Trousseau-Lallemand bodies (an archaic synonym for Bence Jones cylinders), and the truism, "use new drugs quickly, while they still work." Trousseau was instrumental in creating new modes of treatment of croup, emphysema, pleurisy, goiter, and malaria. He received the prize of the French Academy of Medicine for his classic essay on laryngology which originally appeared in 1837. He was the first in France to perform a tracheotomy, and he wrote a monograph on this as well as intubation in 1851. His textbooks on clinical medicine and therapeutics were both extremely popular and translated into English. Trousseau coined the terms aphasia and forme fruste and popularized eponyms in disease description such as Addison's
disease and Hodgkin's lymphoma.

Trousseau was considered an outstanding teacher. Numerous students of his achieved fame in their own right, including Puerto Rican pro-independence leader, surgeon and Légion d'honneur laureate, Ramón Emeterio Betances. Trousseau’s grandson was the distinguished ophthalmologist Armand Trousseau (1856-1910).

As previously mentioned, Chvostek’s sign is a classic signification of hypocalcemia. However, some studies have demonstrated that hypocalcemia is not the only condition in which a positive Chvostek’s sign may be seen. Other conditions that have produced Chvostek’s sign include rickets, diphtheria, measles, scarlet fever, whooping cough, and myxedema. The sign has also been positive in persons without any known disease. One study demonstrated a positive Chvostek’s sign in nearly 25% of healthy individuals. Another study showed that 29% of patients with laboratory- confirmed hypocalcemia had a negative Chvostek’s sign. In turn, the medical community considers Chvostek’s sign as only a crude indicator of neuromuscular irritability and an unreliable indicator of hypocalcemia.

Click here and here for references.

Maynard

PBL Muse #20: Students in academic difficulty

One of the biggest myths in the medical school process is that once you get into medical school, it is relatively easy to STAY in medical school. Each year, approximately 5% of those who enter fail one or more courses or fail out of medical school entirely. (These numbers are an average and are lower at McMaster) Why does this happen after being subjected to a selection process that is very stringent?

The biggest reason for students failing a course or failing out of medical school is an inability to put in the study time that a very competitive medical school curriculum demands. A sizable proportion of first year medical students may have been able to get through their undergraduate studies by the “last minute knowledge cram” method, only to find that they are in deep trouble fast.

Most of these students will adjust their time management skills and do well enough to pass their coursework but some are not able to make the transition from undergraduate to medical school. These folks find themselves behind their class very quickly and fail to catch up enough to learn the core knowledge required.

Another small proportion of students will have too many personal demands to keep up with their studies. They may be parents or spouses or they may have personal illness that actually prevents them from the mastery of their work. In these cases, a wise Dean of Students will offer a Leave of Absence before the student finds himself/herself in academic difficulty. It pays to alert Karl, Maynard or Kathy Swayze at the first sign of personal trouble. Often the Dean can alleviate the problem and get the student back on track. Again, sometimes the problem is so pervasive, that only a Leave of Absence will allow the student to take care of personal matters and return to academics without penalty.

Few medical students are intellectually unable to master the curriculum. While the amount of information to be mastered is massive, the difficulty of the material is fairly average. This means that the key to keeping yourself academically sound is disciplined study habits that enable you to digest this large body of information in a short period of time. Most students study daily and keep a rigorous study schedule even on weekends.

Many students will become caught in the “no one else is struggling so I must be stupid” trap. Every medical student from time to time will struggle with something. Most students figure out what they need, ask for help and get the task accomplished. Some students will become depressed and procrastinate. Procrastination is the enemy of good scholarship and leads to more depression. Again, chatting with a few classmates or the Dean of Students can often put your problems into perspective and give you new ideas that get you on your way.

Key message is if you see someone struggling please tell Karl, Kathy or myself as soon as possible.

Maynard

Clinical Skills Muse #19: Appendicitis and CT

Acute appendicitis represents the most common specific identifiable cause of an acute abdomen worldwide. Accurate diagnosis of acute appendicitis is often difficult clinically. Although there is some continuing controversy in the surgical and clinical literature, a consensus is emerging regarding the utility of routine CT for most, if not all, adult patients with suspected acute appendicitis. Increasing evidence suggests that even young adult men should routinely undergo CT rather than initial surgical exploration, and there is no convincing evidence-based data that the routine use of CT increases the perforation rate. CT, regardless of the protocol used, permits diagnosis or exclusion of appendicitis and alternative diagnoses accurately compared with the historical 20% negative appendectomy rate.

Furthermore, CT establishes the severity of appendicitis. The paradox is that the increased use of CT may have made accurate diagnosis more difficult in some patients, especially those in the earlier stages of appendicitis. Because patients are being scanned earlier, and because findings may therefore be more subtle or false-negative on unenhanced CT or on CT with oral/rectal contrast only, IV contrast should be considered routinely for imaging all patients with suspected appendicitis. Thin cuts, cine review of images on a monitor, and careful review of the right lower quadrant anatomy, as well as routine scanning of the entire abdomen and pelvis, should be performed in all cases. Radiologists need to appreciate the overlap of normal and abnormal appendiceal sizes, and should use all the CT findings present to make or exclude the diagnosis of appendicitis.

Click here for more information.

Maynard Luterman

PBL Muse #19: So you think you're smart

So here's this week’s question......how well does IQ equate to doing well in school?

Correlations of this magnitude tell us that IQ tests, on their best days, predict 40-50% of school achievement (Applied Psychometrics 101 – square the correlations and multiply by 100 to get the percent of variance explained). This is very good. Yet…50-60% of a person’s school achievement is still related to factors “beyond IQ!”

Today, IQ testing is one of the most common tools in the school system for assessing cognitive ability, classroom placement, need for accommodations and cognitive expectations. But good gracious, 50-60% achievement is beyond IQ! Rather than using IQ to tell us about our limitations, we should look for strengths that tell us what to build on.

What are some of the other predictors? Organization, will, desire, interest, are but a few. So while being smart is a good start its not the end all and be all.

Click here for more information.

Maynard Luterman