DR MARTIN SCURR answers your health questions 

Question 

My husband has pitting oedema and the doctor says there is no cure. Is this the case, and is it safe for him to take a long flight with this condition? 

Linda Webb, by email. 

Answer

Oedema is the medical term for s­welling that’s caused by fluid retention. Pitting oedema means that if you apply pressure to the swollen area, then an indent will remain for a few seconds (with non-­pitting oedema, applying pressure will not cause any l­asting indentation — and this has different underlying causes). 

The swelling itself is caused by an increase in the amount of fluid, known as lymph, present in the interstitial space — the area outside of blood vessels and around the cells which make up our tissue. 

The fluid is essentially blood that has been filtered of blood cells by the capillary walls it has pushed through. 

There are a number of conditions that cause this build-up of fluid, such as heart failure, cirrhosis of the liver, kidney disease and disorders of the veins that return blood to the heart — varicose veins (swollen veins), for example. 

I am going to assume that the oedema you describe is of the lower legs. The most common cause of bilateral leg oedema (swelling in both legs) is when the body has trouble sending blood from veins back to the heart. 

This is usually due to severe varicose veins — the blood vessels are grossly widened and so there is less pressure on the blood to flow in the right direction. So blood, rather than coursing along a relatively narrow vessel he may be taking — most commonly a group of drugs called calcium channel blockers, which are prescribed for high blood pressure. 

These medicines cause sodium retention, which inevitably leads to a build-up of fluid. Your GP will have taken these details into account before making his prognosis, and will also have excluded causes such as heart failure, kidney disorders and deep vein thrombosis (blood clots in deep veins). 

If your GP has not recommended any specific precautions, I would assume your husband is safe to take a long flight; it is, however, essential that he wears full-length c­ompression stockings to guard against the swelling worsening in his legs. 

He should also walk along the aisle in the plane once every two hours and stay well hydrated. Seek the advice of the GP again before the flight, in case there are aspects that have not been revealed to me, and ask about the right compression stockings. A prescription is not essential — your pharmacist will be able to provide this hosiery.

Question 

The optician told me I have cataracts, which was a surprise. Aged 74, I don’t know anyone who has had this and I am afraid. How safe are cataract operations? 

Mrs A. Smith, Hampshire. 

Answer 

Cataracts are a clouding of the lens of the eye. The word means waterfall, a reference to the foamy white appearance of the lens in progressed cases. They occur frequently with advancing age and are very common. 

The lens of the eye is composed of a unique protein called crystallin, and over the years this deteriorates and loses its transparency. 

A number of factors accelerate this process, including smoking, e­xcessive alcohol consumption, s­unlight exposure, uncontrolled type 2 diabetes, and some medicines — particularly corticosteroids, which are used to treat diseases such as asthma and arthritis. 

The development of cataracts is painless and the rate at which they develop varies quite widely. Often the first sign may be difficulty driving at night due to glaring headlights, or difficulty reading small print. 

Typically, as in your case, an optician would inform you of the diagnosis. The choice of when to undergo s­urgery — the only available treatment — should be decided by you. 

Since, as you say in your longer letter, you are currently coping with your usual activities, now is not yet the right time for the operation. In due course, your optician may refer you to an ophthalmologist (an eye s­pecialist) and plans will be made for an operation to remove the cataracts, firstly on one eye and then, sometime later, the other. 

The surgery is performed under local anaesthetic and you shouldn’t need to stay in hospital overnight. The operation involves removing the damaged lens and then replacing it with a new synthetic one, carefully chosen to give you ideal vision. 

This takes ten to 20 minutes and there is usually no pain afterwards, and no stitch in the tiny incision made to one side of the iris (the coloured part of the eye). The operation is safe and successful, with more than 95 per cent of eyes having a good sense of vision subsequently. 

I understand that the news that you have cataracts must have come as a shock, and I also understand that the prospect of surgery is rarely an appealing one. However, I cannot reassure you too strongly that, in this instance, when the time comes, it is entirely in your best interest to proceed with it.  

IN MY VIEW… Going outside is the best way to get vital vitamin D 

Following an urgent review, we are now not going to be advised to take vitamin D supplements to reduce our risk of becoming seriously ill with Covid-19. 

We are all told to take the vitamin, which is formed in the skin during sun exposure, in the winter, and many are concerned that staying inside during lockdown has meant we are now at risk of being deficient in the nutrient. 

We know that the vitamin is vital for bone health, but apart from that, hard data about its benefits is l­acking. For instance, while having low levels of vitamin D is associated with an increased incidence of upper respiratory tract infections, are low levels the cause or the effect of the infection? 

That’s why evidence about the vitamin D status of those with Covid-19 was urgently sought. The virus started to spread here at the end of winter, when our vitamin Dlevels are typically low. 

The theory is that vitamin D helps to protect the lining of the respiratory tract. It is also likely that it limits the inflammatory response to the virus — and it’s this response in the lungs that causes much of the severity of the illness. 

However, yesterday, the National Institute for Health and Care Excellence ruled there is not enough good evidence that the vitamin protects against a severe Covid infection. 

The picture is complex and the only advice I can offer is to do your best not to be vitamin Ddeficient, by eating eggs, red meat and oily fish, and exposing your skin to sunshine, but not excessively. 

Also, consider taking a vitamin D supplement as the chances of getting enough sunshine may yet be limited: most doctors recommend getting 1000IU vitamin D3 daily, more than the 10mcg recommended by the Government. 

However, there has been evidence in the past that naturally derivedvitamin D is more effective at p­reventing osteoporosis than supplements. Could this be a reason why we hear that Covid-19 is likely to regress with summer weather?