Great Student Blog

I came across this blog while looking for evidence that getting students to do dissections themselves improves exam performance. Suggest you scroll through some of the past entries: they are well worth the read.

Missing for a While...

Yes I know I have been too busy to keep this up, but here it goes again. For those of you who need a good revision of the cranial nerves, take a look here.

Interesting Medical Blogs

Once you start blogging, you begin to realise how much good stuff there is out there. Take a look at the BMJ blog. There is something for everyone.

Cinemeducation: Wit

The next movie to be screened is called Wit. It will be shown on Wednesday Nov 21 at the KSU Common Room at 2.30 followed by a discussion at 4pm. Times will be confirmed later. If you can't make it for the screening but wish to join the discussion, contact Daniel Azzopardi at MMSA. I will post some links to the movie later. It's a great movie. Don't miss it.

Biochemistry That Matters

but that apparently you have not covered yet....

A patient with familial hypercholesterolaemia undergoes a detailed serum lipid and lipoprotein analysis. Studies demonstrate elevated cholesterol in the form of increased LDL without elevation of other lipids. This patient's hyperlipidemia is best classified as which of the following types?

A. Type 1
B. Type 2a
C. Type 2b
D. Type 3
E. Type 5

The correct answer is B.

Hyperlipidemia has been subclassified based on the lipid and lipoprotein profiles. Type 2a, which this patient has, can be seen in a hereditary form, known as familial hypercholesterolemia, and
also in secondary, acquired forms related to nephritic syndrome and hyperthyroidism. The root problem appears to be a deficiency of LDL receptors, which leads to a specific elevation of cholesterol in the form of increased LDL. Heterozygotes for the hereditary form generally
develop cardiovascular disease from 30 to 50 years of age. Homozygotes may have cardiovascular disease in childhood.

Type 1 (choice A) is characterized by isolated elevation of chylomicrons.

Type 2b (choice C) is characterized by elevations of both cholesterol and triglycerides in the form of LDL and VLDL.

Type 3 (choice D) is characterized by elevations of triglycerides and cholesterol in the form of chylomicron remnants and IDL.

Type 5 (choice E) is characterized by elevations of triglycerides and cholesterol in the form of VLDL and chylomicrons.

Physiology Question Explanation

Only one of you attempted this question, which actually is extremely important. Hence it's worth re-stating together with the explanation for all you clinical students out there.

A 26-year-old man is admitted through the emergency department to the hospital for a heroin overdose. His heart rate is 45 beats/min, and his blood pressure is 75/40 mm Hg. Which of the following best depicts the results from an arterial blood sample ?

pH PaCO2 (mm Hg) HCO3- (mEq/L)
A. 7.22 66 26
B. 7.34 29 15
C. 7.40 40 24
D. 7.47 20 14
E. 7.49 48 35

The correct answer is A.

This man has a respiratory acidosis. Overdose with drugs that suppress ventilation (e.g., heroin, morphine, barbiturates, methaqualone, and "sleeping pills") often causes hypercapnia. In patients with an intact renal response, the respiratory acidosis causes a compensatory rise in plasma HCO3-, which lessens the fall in pH. However, the renal response requires several days to develop fully. The plasma HCO3- of 26 mEq/L (normal: 22-28 mEq/L) for this man is typical of acute respiratory acidosis with little or no renal compensation.

Choice B reflects metabolic acidosis.

Choice C is normal.

Choice D reflects respiratory alkalosis.

Choice E reflects metabolic alkalosis.

Mastication Question

Question: Contraction of which muscles contributes most to the backward movement of the lower jaw during the process of mastication?

Answer: Mastication is a complex process involving alternating elevation, depression, forward movement, and backward movement of the lower jaw. The backward movement step is accomplished by the posterior fibers of the temporalis muscle.

The digastric helps to depress the lower jaw during chewing.

The lateral pterygoid helps to move the lower jaw forward during chewing.

The medial pterygoid helps to elevate the lower jaw during chewing.

The mylohyoid helps to depress the lower jaw during chewing.

Letter to God

Dear God,

As You undoubtedly know, there is a little argument down here about intelligent design and evolution. If You really did create us in a day, and if You ever find humans worth another try, there are a few anatomical modifications that we hope You might consider the next time around.

As it happens, Lord, some of the organs You included in the mix have not turned out so well. Tonsils and appendixes don't seem to be especially useful apart from keeping surgeons occupied, or as clues to infection with "mad cow disease." And sinuses. Even if they do lighten the head, all they ever do is get infected. Couldn't we just have stronger neck muscles?

Our perversity in wanting to walk upright, when it is clear that this was not Your intention, has led to some real problems with our spines and leg joints. Would it be possible for You either to fix the pelvis at a right angle to prevent us from this error, or strengthen our weight bearing joints? We also hope You will anticipate our penchant for portable email devices by designing tiny little fingertips to operate the keys.

And the aesthetically splendid symmetry—could You extend it even further? It would certainly cut down our problem with trauma and strokes to have each side of our brain perform exactly the same functions. The rest of the head is outstanding, as are the limbs, but when we get into the thorax and abdomen, we have a few requests. You probably did not intend us to discard our diet of berries and nuts for fatty meats and pastries, but that's what happened, with disastrous consequences to our cardiovascular systems. Two hearts and a lipid-resistant lining to blood vessels would be just the thing (or give us an enzyme that transforms our preferred cuisine to harmless molecules).

We found out about alcohol, Lord, so it would be nice to have a liver (and maybe a pancreas) in reserve. Or You might remove the enzymatic chain that metabolises alcohol and make us too sick to consume it. Ditto for all the other drugs we seem so prone to abuse.

Thanks to Your gracious allotment of intelligence, we are on the verge of creating plenipotentiary cell banks, but there is a serious unresolved problem of individual compatibility. Somewhere—perhaps in redesigned sinuses, if for some reason You prefer that we keep them—there might be a little storehouse of such cells that could be tapped into when the need arises.

Despite the beautiful symmetry and economy of design with which we are blessed, it has occurred to us that the placement of our genital and excretory organs in such close proximity was either done to remind us of Original Sin, or because there did not seem to be a satisfactory anatomical alternative. Could You think about this? No obvious repositioning arrangement comes to mind, but some kind of retractable underarm mechanism might be practical.

In fact, this whole survival of the species thing deserves some rethinking. The delicate balance between the pleasures of sex and the pain of reproduction has been an issue for our womenfolk, who have borne the brunt of the pain. Maybe if they were given only two or three eggs together with a comfortable course of pregnancy and childbirth, the need for an endless succession of menstrual periods and the hot flushes of menopause could be eliminated without endangering our continued existence here on earth.

We hope, Lord, that You do not take offence at these suggestions, which are offered in all humility from creatures who surely do not fully understand the reasons that went into Your marvel of design, from its coating of skin to its molecular engineering, and we are truly grateful for Your efforts on our behalf.

PS: We know You have a sense of humour, Lord, but could you please do something about adolescence?

---

Paul Brown, BMJ, June 2006

Medical Maltese

Attention ALL international students. Today is your last chance to register for the crash course in Medical Maltese starting Wednesday. Classes will be held at the Medical School (SLH for 2 weeks, then transferring to MDH) from 2 to 3.30pm.

Be there or be square....

Muscles of Mastication

Some of you appeared confused by the muscles of mastication last week. Try this one:

Contraction of which of the following muscles contributes most to the backward movement of the lower jaw during the process of mastication?

A. Digastric
B. Lateral pterygoid
C. Medial pterygoid
D. Mylohyoid
E. Temporalis

Correct answer and explanation next week.

Achieving Your Childhood Dreams

"Achieving Your Childhood Dreams", the inspirational and moving "Last Lecture" given by Professor Randy Pausch (www.randypausch.com) at Carnegie Mellon University (Sept 2007).

Have patience with the intro….it’s worth it.

Surgery Question

Must not forget our third year students struggling with surgery. Here is one for you:

Crohn's disease:

A. Is caused by Mycobacterium paratuberculosis.
B. Is more common in Asians than in Jews.
C. Tends to occur in families.
D. Is less frequent in temperate climates than in tropical ones.
E. Is improved by smoking.

Physiology That Matters (Almost Medicine)

A 26-year-old man is admitted through the emergency department to the hospital for a heroin overdose. His heart rate is 45 beats/min, and his blood pressure is 75/40 mm Hg. Which of the following best depicts the results from an arterial blood sample ?

pH PaCO2 (mm Hg) HCO3- (mEq/L)
A. 7.22 66 26
B. 7.34 29 15
C. 7.40 40 24
D. 7.47 20 14
E. 7.49 48 35

Correct answer and explanation will be posted next week.

Biochemistry That Matters

And for those of you more interested in biochemistry, here is another:

A patient with familial hypercholesterolaemia undergoes a detailed serum lipid and lipoprotein analysis. Studies demonstrate elevated cholesterol in the form of increased LDL without elevation of other lipids. This patient's hyperlipidemia is best classified as which of the following types?

A. Type 1
B. Type 2a
C. Type 2b
D. Type 3
E. Type 5

Neurophysiology

Just to prove that this site is about more than anatomy, here is a neurophysiology question for Year 2 students:

Administration of an experimental drug that acts on PNS myelin is shown to increase the space constant of an axon in a peripheral nerve. Action potentials traveling down the axon would be predicted to be

A. faster
B. larger
C. slower
D. smaller
E. unchanged

Correct answer and explanation will be posted next week.

Coming Clean on Hand Hygiene

An interesting study conducted in part by your fellow students. Would be good to repeat this at MDH in a few months.

Introduction: Hand hygiene is universally recognized as one of the most effective ways to reduce the cross-transmission of hospital acquired infections. Successful strategies to improve hand hygiene compliance require a baseline knowledge of hand hygiene practices.

Methodology: A direct observational method was used to collect data about hand hygiene practices amongst medical doctors by a group of trained medical students during their clinical assignments. To prevent any bias during the observation, the purpose of the study was not disclosed to the doctors; they only knew that they were being observed for infection control practices. A structured data collection sheet was used to direct the observations. Data on hand hygiene practices was collected during routine clinical work over a number of weeks. Observers recorded the professional grade of physician observed, speciality, location, activity performed, method used, and facilities available.

Results: A total of 898 observations were recorded. Overall compliance before and after doctor-patient contact was 22.7% and 33.5% respectively. Within specialties, hand hygiene practices were lowest in obstetrics and gynaecology and highest in specialized surgical units. Poorest compliance was evident in house officers before patient contact, while the most compliant was the registrar group, following examination. Alcohol hand rub was the preferred method in the wards whilst hand washing was mainly utilised in the outpatient setting.

Conclusion: Hand hygiene amongst doctors in St Luke’s Hospital is low and could be a factor in the high MRSA endemicity.

S Chetcuti, M Montefort, E Scicluna, M Borg, Malta Medical Journal, Sept 2007

Cranial Nerve Quiz

Which cranial nerve exits the skull base at the pars nervosa of the jugular foramen?

Quiz Response

Closure of the neural tube occurs around day 26 of embryonic life.

As the neural tube forms, the closing process is critical, occurring from the cranial to the caudal end as the anterior neuropore closes around day 24, the posterior around day 26. This is a critical event, as defects in closure may result in spina bifida or other neural tube defects. The risk of a neural tube defect can be decreased by folic acid supplements.

Lubricating Plastic Specula Does Not Affect Microbiology

The widespread practice of not lubricating plastic vaginal specula because of fears of interfering with bacteriological sample processing has been shown to be invalid. A water based lubricant, Aquagel, had no effect on colony counts when different dilutions of Neisseria gonorrhoeae were cultured, nor did the gel alter the results of standard assays for Chlamydia spp. Without lubrication, plastic specula are more difficult to insert and cause more discomfort, so they should no longer be used in this way.

L Kozakis, J Vuddamalay and P Munday Sex Transm Infect 2006;82: 263-4