Good morning and welcome to your Wednesday dose of Your Daily Meds.
Bonus Review: Where does Vitamin K come from? Where is it absorbed? Why is it called Vitamin K?
Answer: We need dietary Vitamin K. We get most of our dietary Vitamin K from leafy green vegetables and meats.
Large amounts of menaquinone (Vitamin K2) is produced by bacterial action in the colon - unfortunately Vitamin K absorption does not occur in the colon. Some of the bacterially-produced Vitamin K is absorbed in the terminal ileum where there are some bile salts present. But, again, we need dietary Vitamin K.
The absorption of dietary Vitamin K is from the small intestine. Remember that Vitamin K is fat soluble and so needs bile salts so that it can initially be solubilised into micelles which facilitates absorption into the circulation (via chylomicron form in the lymphatics).
So, in patients with obstructive jaundice and an absence of bile salts in the small intestine, Vitamin K absorption will be impaired. They might even need some intravenous Vitamin K.
Or what about the intubated malnourished patient with terminal ileitis from Crohn’s Disease. He has normal small bowel bile salts but no dietary Vitamin K? And naturally that little bit of bacterially produced Vitamin K are not going to be absorbed in the terminal ileum…let’s watch his INR go up…
Also the ‘K’ in Vitamin K comes from the German ‘Koagulation’…
Case:
Consider the following ECG:
What is the correct rate, axis and interpretation, respectively?
* 100/min; normal axis; left bundle branch block
* 120/min; normal axis; atrial flutter
* 120/min; left axis deviation; atrial flutter with ectopic beats
* 120/min; normal axis; atrial fibrillation with rapid ventricular rate
* 100/min; right axis deviation; sinus rhythm
Have a think.
Count some little squares and look at the squiggles.
Scroll for the chat.
Investigation:
A 25-year-old male is being worked up for an obstructive respiratory condition. Which of the following respiratory function test results would be most indicative of asthma.
(FEV1 = forced expiratory volume in 1 second; VC = vital capacity; TLCO = carbon monoxide transfer factor; KCO = carbon monoxide transfer factor per unit lung volume; TLC = total lung capacity; RV = residual volume)
* FEV1 ↓↓; VC ↓; FEV1/VC ↓; TLCO →; KCO →/↑; TLC →/↑; RV →/↑
* FEV1 ↓↓; VC ↓; FEV1/VC ↓; TLCO →; KCO →; TLC ↑; RV ↑
* FEV1 →; VC →; FEV1/VC →; TLCO →; KCO →; TLC →; RV →
* FEV1 ↓↓; VC ↓; FEV1/VC ↓; TLCO ↓↓; KCO ↓; TLC ↑↑; RV ↑↑
* FEV1↓; VC ↓↓; FEV1/VC →/↑; TLCO↓↓; KCO→/↓; TLC ↓; RV ↓
(And where down arrow means decreased, sideways arrow means normal/stable etc…)
Have a think.
Remember those flow-volume curve/loop things.
More scroll for more chat.
Rapidamente:
This ECG shows atrial fibrillation with rapid ventricular rate.
The rate is approximately 120/min and with clear atrial fibrillation as P waves are not seen. The QRS complex is narrow at approximately 80ms. The axis is normal. Note there is mild horizontal ST depression in V4, V5 and V6 which is likely rate-related, not due to ischaemia.
Vitality:
Answer a) is most suggestive of asthma. The greatly reduced FEV1 is suggestive of airflow obstruction, as in asthma and COPD. To differentiate asthma from chronic bronchitis and emphysema, it is important to note the carbon monoxide transfer capacity, greatly reduced in emphysema, and the TLC and RV, which is not necessarily increased in asthma, unlike chronic bronchitis.
Thus, answer a) is most suggestive of asthma;answer b) most suggestive of chronic bronchitis, answer c) is most likely a normal respiratory function test result; answer d) is suggestive of emphysema; and answer e) is suggestive of pulmonary fibrosis.
In the case of asthma, lung function tests should be repeated after administration of a short-acting beta-2-adrenoreceptor agonist, such as salbutamol, to observe for any reversibility, such as a large improvement in FEV1 (eg 400mL).
Bonus: Why are newborn infants susceptible to Vitamin K deficiency?
Answer in tomorrow’s dose.
Closing:
Thank you for taking your Meds and we will see you tomorrow for your MANE dose. As always, please contact us with any questions, concerns, tips or suggestions. Have a great day!
Luke.
Remember, you are free to rip these questions and answers and use them for your own flashcards, study and question banks.
Just credit us where credit is due.
