Tuesday, March 31, 2009

STI: Suddenly blind

March 26, 2009

Suddenly blind

By Dr Ang Peng Tiam 


It was one of the most dramatic phone calls to my clinic. Clearly agitated, my radiology colleague told me: 'We just started doing your patient's hepatic angiogram. He complained that he cannot see."


'What? Are you sure?' I asked in disbelief.


My patient was having an X-ray of the liver to study its blood supply before starting treatment for his cancer.


Following that call, an urgent consultation with a neurologist and a look at the magnetic resonance imaging (MRI) scan of the brain confirmed our worst fears: My patient had suffered a rare but previously reported reaction to the intravenous contrast used.


This 'contrast' is a pharmaceutical agent injected into the blood to highlight the blood vessels in X-ray studies.


A patient who has such a reaction would indeed be able to see one moment and totally nothing the next with his eyes wide open.


I hurried to the ward, not knowing what to expect. To my amazement, my patient was calm and deep in prayer with the family around his bedside. I explained that the vision loss was likely to be due to the intravenous contrast and plainly told him this was the first time in my 27 years of medical practice that I have heard of, and now witnessed, such an unusual complication.


I reassured him that a quick review of the medical literature confirmed previous occurrences - the blindness is usually transient.


The main treatment is the use of steroids and anti-platelet agents.


Although the reports indicated that the majority of patients regained their sight after a few days, what bothered me was the fact that a few never regained their sight.


I called around and spoke to several senior neurologists. Only one had seen a similar occurrence some years ago. That patient recovered his sight after several days.


I prayed and hoped my patient would recover too.


Sadly, two weeks have passed and my patient has not regained any meaningful sight. He can now see light and motion but not enough for him to identify objects or form. A repeat of his MRI confirmed that he had suffered a stroke of the occipital lobe at the back of the brain. This interprets images detected by the eyes.


I still cannot believe this happened. What are the odds?


Every day, many patients are given the intravenous contrast as they undergo computer tomogram (CT) scans, coronary angiograms (to study the blood vessels of the heart), intravenous pyelograms (to study the flow of urine in the urinary system) and other radiological studies.


Except for the occasional skin reaction and possibly mild renal impairment, the use of intravenous contrast is relatively safe.


And yet, here is a man whose eyes are open but who cannot see. There seems to be little else that can be done, besides continuing the medication as prescribed by the neurologist for the stroke.


Or is there, perhaps, some better medicine? When I last reviewed the patient, he remained strong in the belief that God will heal him and that his sight will return.


There is a growing body of evidence that faith can bring us health. Those who attend religious services have been shown to have a lower chance of dying within one year compared to those who did not attend. Sceptics would say this is because of the healthier lifestyle among people who worship regularly.


We often cannot tell cause from effect among the various confounding factors in such comparative studies. Suffice it to say, there is an observable difference.


Dr Andrew Newberg, an associate professor of radiology and psychiatry, describes a cancer patient whose cancer shrank when given an experimental drug.


When the patient was told that the drug was ineffective in other patients, the cancer grew again. He was given sterile water and told that this was a more potent form of the earlier medication. The tumour shrank again. However, the patient eventually died from the cancer.


If faith in a drug can have such a profound effect on an individual, how much more so can faith in God and the teachings of religion on devout followers? The science of religion on the brain is absolutely fascinating. Medical scientists have demonstrated that prayer and meditation increase the activity and size of a part of the brain called the parietal lobe. How this may improve the well-being of the believer remains unclear.


The important lesson is that patients, and their belief systems, have an important role in the healing process. Be it faith in God or in the medicines and drugs or simply faith in their doctor, patients must believe they will recover.


On our part as physicians, we need to acknowledge the limits of our abilities when we explain a prognosis. We simply do not know when all is lost, we do not know that miracles cannot happen and, if we err, let us err on the side of hope, rather than despair.


What once was lost, may yet still be found. My patient remains blind as I write, but he, and I, believe that one day he will see.




Dr Ang, the medical director of Parkway Cancer Centre, has been treating cancer patients for nearly 20 years. In 1996, he was awarded Singapore's National Science Award for his outstanding contributions to medical research.

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