3yr old with enlarged optic nerves?

Hello,

The implication is that he may have raised intra-cranial pressure, in my humble opinion. I will try to explain.

The skull of anybody, is a hard sealed case. The skull-bone case, can't expand any at age 3 (although newborns, have two soft spots in their skull which can). Any sort of "extra something," which appears in there along with the brain, struggles to find room for itself, - and the result is that the "pressure" inside the skull rises a bit.

The right and left optic nerves, come out from the front of the brain to their respective eyes, and join on to them at the back. If you look inside anybody's eyes with a lighted telescope thing, you see the "optic nerve head" set among the other retina things. Raised intra-cranial pressure is transmitted down each optic nerve, and bulges the optic nerve head outwards ; you can see this as "enlarged" optic discs.

I don't know if you want me to go into this any further. At the risk of worrying you, raised intra-cranial pressure can be caused by a harmless (benign), or by a cancerous growth inside the brain. The other big possibility is a mild form of hydrocephalus, I will try to explain.

This raised pressure, is primarily a raised _fluid_ pressure. As you know, the brain and spinal cord are everywhere bathed in a special clear watery fluid, called the "cerebro-spinal fluid" or the CSF for short.

A couple of inner chambers inside the middle of the brain, manufacture this watery fluid. Then it circulates in and around the brain and spinal cord : after a while the "stale" CSF is re-absorbed, and replaced with fresh.

If there is a blockage of any sort in the circulation channels, the CSF can't circulate and be re-absorbed properly. So the fluid pressure inside the skull rises : this is another cause of raised intra-cranial pressure, and is popularly called "hydrocephalus," or "water on the brain."

A blood-clot forming inside the skull, also raises the intra-cranial pressure, but you don't mention your son having sustained any sort of head injury? Even a mild one?

A brain abscess, (which is the same idea as a large boil in the skin), is a local collection of pus inside the brain, and is the end-result of a bacterial brain infection. A brain abscess occupies space, and so can cause raised intra-cranial pressure, but usually the patient is ill with signs of an infection, - fever, shivers, vomiting.

The dog tapeworm, if its eggs get into human food via infected dog-poo, can cause an enlarging fluid-filled cyst inside the brain (containing the worm itself). This causes raised intra-cranial pressure too, - but in the normal way of things I would think it unlikely in your son's case. There are other types of "infectious brain cysts," but these are probably even less common.

An MRI scan as you know, is a "picturing" brain test, based on shining powerful magnetic pulses on it. The test is harmless, unlike a CT scan, which is basically a 3-dimensional X-ray, and involves shining a moderate dose of X-radiation on the brain.

However, an MRI scan is very noisy! and involves sliding the patient on a stretcher into the big magnetic coil of the machine. I expect you have been advised to accustom your son to these ideas of loud noise and mild claustrophobia.

An MRI scan is better than a CT scan at visualizing _soft_ tissue structures like the brain ; hard structures like bone don't show up so well.

In my humble opinion, they will be looking for any solid new growth, blood-clot, abscess or cyst, inside your son's skull. Also, they will look for general hydrocephalus, which shows up as dilatation and expansion of the two fluid chambers inside the middle of the brain, which I mentioned before.

Another jargon term you may hear, is "space-occupying lesion." Any solid thing like a growth, a blood-clot, an abscess or a cyst "occupies space," and as I tried to explain at the beginning, there is only so much space inside the skull, - and the brain occupies most of that already.

I hope this is of some help, if not entirely good news. Clearly there's a wide range of possibilities.

If you need any other "medical-ese" de-coding, or any medical background expanded into normal English, please do not hesitate to ask me ; I am very sorry about your little boy, and hope he will be all right.

As you know, this resource is entirely "pro bono," entirely free. My motivation is that I am recently retired from medical practice, and enjoy keeping my hand in. Although there is no "certification" or "guarantee" of this ; you could look at some of my other answers, to test my reliability.

Best wishes,

Belliger

retired uk gp

drpeter@phl.org.uk