White matter lesions on MRI–a question and some answers

I thank one of my readers Sandy for writing in.  Sandy asks some important questions. As a lot of you may be dealing with some of the same issues as her, I am reproducing her question here. My answers to her query follow.

Again thank you Sandy for writing in.

Sandy

Dear Dr.

In june I experienced some very unusual headaches that felt think electrical shocks throughout my head. One night I experienced the worst headache of my life in my forehead only. It lasted all night and in the morning it was better; however I experienced dizziness and if I bent over a swell of pain would radiate through my head. A week later I experienced an eye problem and was told that it was uveitis. Because uveitis can be caused by a virus or autoimmune problem, I immediately began testing for an autoimmune problem. During this testing I continued to experiece overall nerve pain in by head (forehead, temple, back of head) as well as neck pain, should nerve pain through fingers, neck, ankels), joint & chest pain. The only positive test result showed a high ANA test of 1:640 but all other blood tests(c-reactive protein, RF, Sed Rad, SM etc..) were normal. I also had an MRI and the radiologist noted several tiny foci white matter in the frontal lobe area. He indicated that it is may or may not be of clinical significane but could be small vessel ischemia disease or possible dymlienation. I wonder if there is a correlation to the several headache I had in my forehead with the MRI results. My neurologist initially said I had occpital headaches and is normally caused by a pinched nerve; but after receiving this MRI, I don’t think he has it right. I feel the headaches and vision problems along with the other symtoms correlate together. Should I be concerned about this MRI. I don’t feel that this is MS because I’m not having muscular/walking issues; but greatly concerned that if these headaches continue, cognitive problems could occur. Your opinion would be greatly appreciated.

From MRI white matter lesions: does it represent MS?, 2008/09/26 at 2:24 PM

 

Dear Sandy,

                      thank you for writing in. Your case history is intriguing, since I do not have all the details my assessment is severly limited.  I can though tell you that white matter lesions are commonly seen when patients undergo a MRI study of the brain. Some of the times these white matter lesions (also referred to as white matter hyperintensities (WMH), this is because they appear as bright white spots on the MRI) are incidental findings and may have nothing to do with the reason the MRI was done in the first place. Let me explain. Lets assume you come to see me since you have being lately experiencing headaches. I order an MRI because I want to rule out a brain tumor. MRI result comes back. There is no brain tumor but incidentally note is made of several scattered white matter hyperintense lesions. Likely in the case I describe above, the WMHs are incidental findings and not the cause of the patient’s severe headaches.

So what do these white matter lesions represent? Many diseases can cause white matter lesions in the brain MRI.  One of the diseases usually mentioned in MRI reports is multiple sclerosis. Patients rightly get scared that they may have MS. While multiple sclerosis is characterized by white matter lesions (we call them plaques in the case of MS) which are scattered in the brain, I want to re-emphasize that not all white matter lesions represent MS (see my website for more details http://braindiseases.info). In the case of MS, the plaques are scattered in the brain in a particular way. Moreover if you do not have any signs or symptoms of MS (your examination is normal), more than likely the white matter lesions do not represent MS. The diagnosis of MS is clinical, at times supplemented by tests like MRI brain, CSF/ spinal fluid examination and evoked potentials.

A lot of work has been done to determine the significance of white matter lesions. The thinking now is that they represent ischemia (lack of blood flow) in the small blood vessels of the brain. Hence they are also at times referred to as ischemic small vessel disease. Hence these lesions are more commonly seen in the MRI of patients who have cerebrovascular risk factors like hypertension, diabetes and high cholesterol as well those that smoke. Their incidence increases as we age (meaning you are more likely to see them on the MRI of someone who is 60 and above rather than someone who is in his 20’s).

They have been reported in the MRI of patients who suffer for migraine. The reason they are more commonly seen in migraine patients is again not fully elucidated but the thinking is that migraine is due to vascular causes and hence WMHs are more common in these patients.

While I cannot comment of your case in particular, you have a positive ANA though rest of the autoimmune markers are negative and your ESR is low. I would rule out the usual suspects, vasculitis though remains in the differential and it would be reasonable to make sure you do not have any underlying vasculitic etiology.

Your last question is important. Though there is no direct correlation between the extent of WMHs in the brain and the development of cognitive decline, as I stated earlier they become more common as we age. People who have extensive white matter disease in their MRI frequently do exhibit cognitive deficts when carefully tested for. Whether this represents a form of vascular dementia is not clear.

I would advise you to follow with your PMD and neurologist. They would be the best people to guide further diagnostic workup and treatment.

Personal Regards,

Nitin Sethi, MD