DVT and PE: Causes, Symptoms, Treatment, and Prophylaxis
Signs and symptoms of DVT (deep vein thrombosis) are often misleading or non-existent. But left untreated, the condition can lead to PE (pulmonary embolism) and possible death.
If you're experiencing mysterious or unexplained aches and pains in your leg or foot, make sure your doctor examines you for DVT. Apart from saving you a lot of trouble, it could save your life.
In this article, I recount my own experience of DVT and PE, showing how confusing symptoms can be and why you might need to question your doctor's opinion. I also share my accumulated knowledge of causes, symptoms, treatment, and preventative measures.
DVT and PE: What You Need to Know
What Is DVT?
DVT is a clot (or thrombus) within a large vessel of the deep vein system. It typically forms in the lower leg, thigh, or pelvis, but may occur in the arms, kidneys, intestine, liver, or brain.
How Clots Are Formed
When a vessel is injured, clotting factors consisting of fibrin (a protein) and platelets (a type of blood cell) clump together at the site of the wound to form a clot, which acts as a plug to stop the bleeding.
DVT occurs when a clot forms within an intact vessel.
What Causes DVT
Lack of Activity
Lack of activity is the most well-known cause of DVT. When we are inactive, circulation slows, causing blood to accumulate in the lower extremities. This is a usual daily occurrence, with normal blood flow resuming the moment we begin to move again.
But over extended periods, there's an increased risk of clots forming in the accumulated blood. Situations where this may occur include surgical operations lasting more than 60 to 90 minutes, being on bed rest for more than three days, wearing a cast, and car journeys or flights of more than four hours.
Because DVT often occurs during or after long haul flights, it's sometimes referred to as "economy class syndrome."
Damaged Blood Vessels
If a vessel narrows or becomes blocked due to damage, restricted blood flow may cause a clot to form. Such damage can occur through surgery of the legs, hips, pelvis, or abdomen, as well as broken bones and muscle injuries.
Who Is at Greater Risk?
Lack of activity and damaged blood vessels can cause anyone to develop DVT, but for some people the risk is greater.
- Pregnant women: Due to elevated estrogen levels, which raise the value of certain clotting factors, the risk of developing DVT increases throughout pregnancy and for up to six weeks thereafter.
- Women using hormone drugs: For the same reason, risk increases for women using the contraceptive pill or receiving hormone replacement therapy (HRT). But risk level depends on how the drug is administered; transdermal is considered safer than oral. Another consideration is whether the drug incorporates progestin; there's no risk attached to the progestin-only pill, but women being treated with both estrogen and progestin are at greater risk than those being treated with estrogen only.
- People with cancer: Cancers of the pancreas, stomach, colon, lungs, and ovaries, among others, release substances that raise the level of clotting factors. It's therefore essential to carry out all age-appropriate screenings once DVT has been diagnosed. DVT is also a side effect of certain cancer treatments.
- People with bowel diseases: Insufficient fluid intake or loss of fluid leads to a thickening of the blood, which in turn facilitates clotting. Due to the dehydrating effect of diarrhea or problems absorbing fluids, people with gastrointestinal disorders (e.g., Crohn's disease and ulcerative colitis) are at particular risk.
Risk also increases if you are a smoker, obese, older than 40, have previously experienced DVT, and/or have a family history of DVT, which may indicate a genetic mutation affecting the clotting mechanism.
Symptoms of DVT
You may experience no symptoms at all, or one or more of the following:
- An ache or cramp-like pain that usually begins at the back of the calf. It may intensify when putting weight on it.
- Your leg, ankle, or foot may be swollen, warm to the touch, itchy, and/or discolored; usually red, blue, or purple.
- Veins near the skin's surface may be tender to the touch and swollen.
What Is PE?
Pulmonary embolism occurs when part of a clot in another body region, usually a leg, breaks off and travels to the lungs.
When PE results from DVT, the condition is called venous thromboembolism or VTE.
The Difference Between Thrombosis and Embolism
A thrombus is a clot that remains at the site at which it was formed. An embolus is something (anything) that travels through the blood stream before lodging in a vessel that is too narrow for it to pass.
Symptoms of PE
You may experience no symptoms at all, or one or more of the following:
- Shortness of breath, often sudden.
- A sharp chest pain that worsens when coughing, inhaling, bending, or eating.
- A dry cough.
- Coughing up bloody sputum.
- Rapid breathing.
- Rapid or irregular heartbeat.
- Blue lips and/or nails.
- Low blood pressure.
- Feeling lightheaded or faint.
Unless symptoms of DVT are also present, there's a good chance that most of these won't be associated with PE -- not even by a health professional. But most worrying is that the first symptom of large or numerous clots can be sudden death.
An Account of My Symptoms
My initial symptoms differed to any of those listed above, which led to a delayed diagnosis.
- Sunday, September 17, 2017: At home working at the computer, I suddenly sensed something slip or move within my lower left leg. Afterwards, it felt as though there were a huge, boil-like lump in the arch of my foot, which caused pain only when standing and walking. Internet research indicated that I may have developed plantar fasciitis, an inflammation of the ligament connecting the heel to the toes.
- Friday, September 22, 2017: The pain had worsened. The only way I could get about was by bicycle using my toes to pedal. After running his hands over my leg and foot, an orthopedist advised that I wear a bandage and take a magnesium supplement. Although unable to make a diagnosis, he ruled out plantar fasciitis and DVT. I later learned that it's impossible to detect DVT with the bare hands.
- Monday, September 25, 2017: Cycling to work, I had to keep stopping for breath, which meant gasping for air with what seemed like limited lung capacity. On reaching the office, I had a coughing fit so violent that I had to leave the room. I wondered if I was suffering the long-term effects of the 40 to 60 a day cigarette habit I'd quit five years earlier. But over the next few days the symptoms passed, including the pain in my foot.
- Sunday, October 8, 2017: At home working at the computer, I again felt something move in my lower left leg, leaving me this time with a cramp-like pain at the back of the calf.
- Monday, October 9, 2017: Similar pains developed in my right leg, and I was once again short of breath. Internet research indicated the possibility of PE resulting from DVT, but the orthopedist had ruled this out. A further possibility was chronic venous insufficiency resulting from varicose veins, which can be situated deep within the leg. As a precaution, I purchased a pair of compression socks.
- Tuesday, October 10, 2017: I informed my employer that I'd be visiting a doctor the following morning. The pain in my right leg had vanished, but risen to the thigh in the left, and I was still short of breath. Removing my compression socks that evening, I noticed that my left foot was slightly swollen and had turned purple. Suspecting DVT and PE, I took a taxi to the nearest emergency room.
How I Was Diagnosed and Initial Treatment
After summarizing my symptoms, a doctor at the reception mockingly dismissed the notion that I might have developed DVT. If I had, she said, my foot would be warm to the touch and red, not purple. But on closer inspection, she realized immediately that it was DVT.
I was then taken for a chest x-ray (spiral CT scan) followed by an ultrasound scan. Clots were detected in both lungs and my calf.
The first night was spent in intensive care where I received the anticoagulant heparin, which was administered by infusion. The purpose of this was not to break the clots up, but to prevent them getting larger and more clots forming. The following day, I was moved to a general ward and put on apixaban, an oral anticoagulant.
Anticoagulants are often referred to as "blood thinners," possibly because they're known to increase the risk of bleeding. What they actually do is reduce the blood's ability to clot.
Currently, oral anticoagulants are split into two categories: vitamin K antagonists and non-vitamin K antagonists.
Vitamin K Antagonists (VKAs)
Put very simply, VKAs disrupt the vitamin K cycle in order that vitamin K reliant clotting factors are disabled. Consequently, vitamin K is the antidote, which is useful in the event of major bleeding, but inconvenient on a day to day basis -- patients are subject to dietary restrictions, regular monitoring, and continuous dosage adjustments. Warfarin is the most well-known anticoagulant of this type, but is being gradually replaced by non-VKAs.
Non-Vitamin K Antagonists (Non-VKAs)
(Also known as novel oral anticoagulants (NOACs) and directly acting oral anticoagulants (DOACs))
Non-VKAs include apixaban, edoxaban, and rivaroxaban, which are collectively referred to as xabans. Because these inhibit the clotting factor Xa directly, there are no food interactions.
A further non-VKA is dabigatran, which inhibits the clotting factor IIa (thrombin).
A major disadvantage of VKAs has been the absence of a reliable antidote, but the FDA was able to approve a drug called idarucizumab for dabigatran in 2015, and andexanet alfa for xabans in 2018.
Safety of Non-VKAs
With regard to bleeding incidents, tests on non-VKAs have so far produced only inconclusive results. For example, apixaban seems to be one of the safest, but it isn't yet known if this is down to the drug itself or the constitution of the persons tested. Therefore, you should be over-cautious and take nothing for granted.
My Experience With Apixaban
Apixaban (trade name Eliquis) is the only oral anticoagulant I've used so far. The dosage for the first week was 20 mg daily, 10 mg for the next six months, then 5 mg as a lifelong preventative measure: tests concluded that I have a prothrombin gene mutation, which puts me at increased risk of developing further thrombosis.
Up to now I've experienced no significant side effects. I've occasionally encountered traces of blood in my stool, but this is normal according to my doctor. However, what is normal for me may not be normal for you; it's imperative that you tell your doctor of any irregularities, regardless of how minor or irrelevant these may seem.
Prior to undergoing a gastro- and coloscopy, I stopped apixaban for 48 hours with no adverse reaction. This is necessary before any procedure where bleeding may occur, but always check with a doctor first.
How Using Apixaban Affects My Daily Life
On a day to day basis my life continues as before. I obviously avoid activities that easily lead to injury, like wet shaving and contact sports. Due to the anticoagulant effect of non-steroidal anti-inflammatory drugs, like aspirin and ibuprofen, the only painkiller I use is paracetamol. Because alcohol is known as a "blood thinner," it's recommended to consume no more than two standard drinks per day; I prefer to avoid it altogether.
Because apixaban can lead to uncontrolled bleeding, I carry a patient alert card at all times in case of accident or emergency surgery (see photo above).
Compression Socks and Stockings
As a preventative measure against post-thrombotic syndrome, a possible long-term condition resulting from DVT, it's recommended to wear a compression sock or stocking for at least two years after diagnosis. By then, symptoms will have subsided, particularly discoloration and swelling.
Knee- or Thigh-Length?
If the thrombus and subsequent swelling are confined to the calf, you'll probably be told to wear a knee-length sock. Because I experienced pain in my thigh, I wear a thigh-length stocking.
How Compression Socks and Stockings Work
The strong elastic with which compression socks and stockings are made places pressure around the leg to prevent blood flowing backwards. For the treatment of DVT, graduated compression is used, whereby the stocking fits tightly around the ankle, and less so towards the calf and/or thigh.
Strength is measured in mmHg (millimeters of mercury). Mine measure 23 - 32 mmHg, meaning they are 32 around the ankle and 23 around the thigh. This is referred to as grade 2 strength, which is recommended for the treatment of DVT.
A good fit is critical. This is achieved by measuring the narrowest part of the ankle, the broadest part of the calf, and the length from the floor to the knee. For thigh-length stockings, measure the length from the floor to the top of the inside leg, and add the broadest part of the thigh.
Caring for Compression Socks and Stockings
Body substances impair elasticity, therefore, wash daily using a mild, liquid detergent for delicate fabrics, and hang out to dry naturally. Never machine wash or tumble dry. This way, your socks or stockings will remain in relatively good condition until you need to replace them -- usually after six months.
Putting On Compression Socks and Stockings
My first stocking was put on for me while in hospital. Unfortunately, the heel wasn't properly aligned to my own heel, which left a welt and a great deal of pain. Before pulling the sock or stocking on, make sure the seam at the top is lined up to the center of your heel exactly.
The Sigvaris website has an array of instructional videos showing how to put on various types of compression hosiery.
Extra tip: To prevent them falling down, thigh-length stockings usually have a silicone top similar to the one featured in the video below. But it won't work if you apply any kind of moisturizer or talc, and you may have to shave your thigh.
Exercises and Extra Tips
Do these three very simple exercises whenever you find yourself sitting for extended periods, especially when in a confined space:
- Stretch your leg out before you and whip your foot to and fro.
- Keeping it on the floor, rock your foot from heel to toe. You should notice some strain in the calf.
- Lift your foot from the floor, thus raising the knee and activating the thigh.
Each exercise should be repeated several times at least every hour.
The following tips were given by my doctor:
- Before stepping out of the shower, run cold water over your calf. This causes the veins to contract and the blood to flow more forcefully.
- Raise the foot of your bed by about six inches to prevent the blood flowing backwards while you sleep.
This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.
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© 2019 John Rickson