The enemy called platelets

All major news organisations should have one or two well-trained medical doctors available as a part of their news teams as consultants


Platelets, platelets, platelets! Over the last few weeks these pesky little blood cells have become rather famous.

These particular blood cells first hit the big time due to the dengue fever epidemic. And, then, came the falling platelet count of our former three-time prime minister, Mian Muhammad Nawaz Sharif. I must admit that Mian Sahib does manage to develop diseases during his incarceration that force our most honourable superior courts to grant him bail for health reasons.

Pakistani politicians often fall sick when incarcerated. If memory serves, a former chief minister of the Punjab spent perhaps a couple of years of his jail time in the VIP suite of the Punjab Institute of Cardiology.

The way that most jailed VIPs get out of jail is that the hospital they reside at for treatment of their serious medical problems is declared a ‘sub jail’ and so technically they are still incarcerated. Not being a legal historian, I cannot be sure but I think that Mian Sahib is the first ‘convicted’ prisoner that has been actually let out of jail and allowed to go home or to a hospital of his choice for a period of time, essentially as a free man, so that he can be ‘properly’ treated for his ailment until he is better, if not completely cured.

If indeed this conditional freedom on health grounds becomes a legal precedence then I suppose that the schizophrenic patient on ‘death row’ should be let out for treatment of his ailment and re-jailed and executed once he is cured. Unless, of course, he has already been executed.

My purpose today is not to get involved in the legal intricacies of Mian Sahib’s legal situation and whether it sets an important legal precedence. I do really want to talk about platelets and about press reportage of medical conditions.

Blood as it circulates within the body does not clot, or in other words stays in a liquid form. But there are abnormal conditions when it will clot within the body. The most common and perhaps best known is ‘deep vein thrombosis’ (DVT) where blood clots in the veins — usually in the legs.

DVT is a serious condition and often occurs in people who do not move around, especially if they are sick or after major surgery. These clots from the legs can move into the heart, causing the heart to stop, or the lungs to cause them to stop functioning properly. DVT is a condition that deserves a separate discussion.

Now back to the platelets. Why does the blood not normally clot inside the body? Think of the inside lining of our blood vessels as the covering on the ‘non-stick’ Teflon frying pan. Nothing sticks to the pan unless it gets scratched.

Similarly, nothing in the blood sticks to the inside of the blood vessels unless the blood vessel walls get ‘scratched’ or injured. Once the inside wall of the blood vessel gets scratched like the Teflon pan, our pesky platelets come into action and stick to the damaged area, cause a clot to cover it and prevent blood from leaving the body.

That is how small injuries stop bleeding. Typical example being a superficial cut on the skin or the place where a vein is punctured for an intra-venous injection or for drawing blood for a blood test. Of course, a major injury will continue to bleed because the platelets cannot plug up that large an area.

So, platelets are needed to prevent or stop small bleeding. Over forty years of practice of medicine and surgery I must admit that I have seen many patients with low platelet counts and yet have rarely if ever seen any one of them ever die from it. The exception is, of course, after major surgery.

It is good to have enough (between 150 thousand per ml to about 400 thousand per ml) ‘good’ platelets. But these good platelets are the ‘enemy’ for people with blockages in the heart arteries that cause heart attacks. What causes a heart attack? Basically, fatty deposits occur under the walls of a heart artery that might eventually cause a disruption (ruptured plaque) of the normal wall. Once this disruption (scratch on the Teflon) occurs, platelets start sticking to this area eventually causing a blood clot.

This blood clot then blocks this artery and usually produces a ‘heart attack’ or the death of heart muscle supplied by that artery. Most of the modern cardiac medicine is focused on preventing this from happening. And so it is our pesky platelets that come into play. Medicines like aspirin are given to beat down the effectiveness of the platelets so that they might not stick and start a clot.

The other area where platelets are the enemy is in patients who have heart artery stents put in. Stents are placed to keep a narrowed artery open. However stents are a foreign material inside an artery and platelets, therefore, might try and stick to them causing their closure. So aspirin and ‘super’ aspirins are given to stent patients to keep their stents open.

To put it in perspective, the largest heart artery is probably a bit smaller than a lead pencil and the average artery treated with a stent is probably just a bit larger than the lead inside that pencil. Considering the small size (between two and three millimetres in diameter) of these arteries and the stents, even a small clot inside one of them can produce closure and a heart attack.

While cardiologists are trying to make platelets less effective, cardiac surgeons are on the other end of the spectrum. During open heart surgery, platelets get damaged with the use of the heart lung machine. And surgeons desperately need an adequate number of effective platelets in a patient’s body after a heart operation to make the ‘surgical’ bleeding stop.

If platelet count drops to dangerous levels, usually below ten thousand per ml, then transfusion of platelets is required to prevent serious internal or external bleeding. In Pakistan, until Mian Sahib’s recent platelet problem, the commonest cause of low platelets was dengue fever.

Now to a mini rant about press coverage of medical problems. Mian Sahib all by himself has allowed TV anchors and other members of the press to become overnight experts on all of Mian Sahib’s health problems. Sadly, these TV anchors, even if they once attended medical college, are no longer well informed enough to discuss these health problems.

Reportage of medical problems affecting our political leaders and captains of industry, especially after they are incarcerated is becoming an important part of news coverage. Therefore, in my opinion, all major news organisations should have one or two well trained medical doctors available as a part of their news teams as consultants.

And finally a few last words about platelets. The frequent need for platelet transfusions for dengue fever patients as well as Mian Sahib makes it important that proper and safe blood banks are made available as widely as possible. And that all these blood banks should have the capability to ‘fractionate’ blood into its components like ‘packed’ red cells, fresh frozen plasma and of course pooled platelets.

The writer has served as Professor and Chairman, Department of Cardiac Surgery, King Edward Medical University

Nawaz Sharif's illness brings focus on platelets and its significance in humans