Выбрать главу

Following Dr. Russell's suggestion, I drove onto the grounds of the Royal Vic, forked over ten dollars, and began cruising the lot. I was on my third pass when I spotted brake lights. An Audi pulled out and I shot forward and into the space, thus avoiding the necessity of tuning to FM 88.5 for a parking update. My watch said two fifty-five.

I arrived at Russell's office sweaty and panting from my dash down avenue des Pins and my trek through the hospital. It had begun to mist, and my bangs lay damp and limp across my forehead. When the doctor looked up, an expression of doubt crossed her face.

I introduced myself and she rose and held out a hand. Her hair was gray, cut short and swept to the side. Her face was deeply creased, but her grip was as strong as that of any man. I guessed she was somewhere in her sixties.

"Sorry I'm late. I had a little trouble finding you." That was an understatement.

"Yes, this building is confusing. Please sit down," she said in English, gesturing at a chair opposite her desk.

"I had no idea this place was so large," I said, seating myself.

"Oh yes. The MNI is engaged in an enormous range of activities.

"I know the institute is world famous for its epilepsy research." I slipped off my jacket.

"Yes, more epilepsy surgeries are performed at our hospital than at any other center in the world. The surgical technique of cortical resection was pioneered at this institution. Studies in the mapping of cerebral function began with epilepsy patients here more than sixty years ago. It was that work that paved the way for the MRI and PET brain mapping going on today."

"I'm familiar with Magnetic Resonance Imaging but what is PET?"

"Positron Emission Tomography. Like MEl, it's a technique used to image brain structure and physiology. Our McConnell Brain Imaging Centre is rated as one of the world's leading facilities."

"What other research do you do?"

"A tremendous amount of groundbreaking work has emanated from the MNI. The development of electroencephalograph', the concept of focal and generalized epilepsies, new methods of frameless stereotactic surgery contributions to postglandin biochemistry in the nervous system, localization of dystrophin skeletal muscle. I could go on and on.

I was certain she could. Dr. Russell was obviously proud of her employer. I smiled encouragement, though I understood only part of what she had listed.

She leaned back and laughed. "I'm sure you are not here for a lecture on the Neuro."

"No, but it's fascinating. I wish I had more time. But I know you're very busy and I don't want to take up any more of your day than necessary.

I took the container from my purse and handed it to her. She looked at it, then unscrewed the cap and slid the implant onto a piece of paper on the blotter of her desk.

"This is an old one," she said, turning it over with a pencil. "I don't think they've made this model for years."

"What is it?"

"It's a ventriculo-peritoneal shunt. They're implanted for the treatment of hydrocephalus."

"Hydrocephalus?" I knew the term, but was surprised to hear her say it. What other misfortunes would I learn about this child?

"It's commonly known as 'water on the brain,' but that's not really accurate, although that's a literal translation from the Greek, hydro being water, and cephalus being head. Cerebral spinal fluid is constantly produced in spaces in the brain called ventricles. Normally it circulates through the four ventricles, and flows over the brain's surface and down the spinal cord. Eventually the CFS is absorbed into the bloodstream, and the amount of fluid and pressure in the ventricles stays within acceptable limits.

"But if drainage is blocked, fluid will accumulate, causing the ventricles to swell and press on the surrounding tissue."

"So hydrocephalus refers to an imbaiance in the amount of CSF produced and the rate at which it drains from the ventricles."

"Exactly."

"And, as the CSF builds up, it causes the ventricles to enlarge and the pressure inside the head to increase."

"You've got it. Hydrocephalus can be acquired or congenital, which is not to say hereditary. The term simply means the condition is present at birth."

"I found the shunt in a normal-looking skull. Doesn't hydrocephalus result in increased head size?"

"Only in infants, and only if left untreated. As you know, with older children and adults the bones of the skull are already formed."

"What causes it?"

"There are lots of reasons for inadequate CSF drainage. Prematurity puts an infant at high risk. And most babies with spina bifida have hydrocephalus."

"Spina bifida involves a neural tube defect?"

"Yes. The problem occurs during the first four weeks of gestation, often before the mother knows she's pregnant. The embryo's neural tube, which develops into the brain, spinal cord, and vertebral column, fails to form properly, leading to varying degrees of permanent damage."

"How common is it?"

"Entirely too common. It's estimated that spina biflda affects one in every thousand babies born in the United States, and about one in seven hundred and fifty born in Canada."

"I recovered no vertebrae, sol have no way to know if my young lady had spina bifida."

Russell nodded in agreement, then continued her explanation.

"There are many other causes of hydrocephalus besides spina bifida." She ticked them off on her fingers. "It can result from brain hemorrhage. The inflammation and debris resulting from brain infections, such as meningitis, can block drainage pathways. Tumors can cause compression and swelling of brain tissues and result in poor drainage. So can certain types of cysts. And hydrocephalus can be familial."

"It can be inherited?"

"Yes. Though that's rare."

"So where does the shunt come in?"

"There is no way to cure or prevent hydrocephalus. For the past forty years the most effective treatment has been the surgical insertion of a shunt. The one you've brought is a bit outdated, but it's really pretty typical.

"Most shunts are just flexible tubes placed into the ventricles to divert the flow of CSF. They consist of a system of tubes with a valve to control the rate of drainage and to prevent back flow. The early ones diverted the accumulated CSF into a vein in the neck, then into the right atrium of the heart. Those are called ventriculo-atrial, or VA shunts. Some VA shunts are still used, but there are problems associated with them, including infection, and, though rare, heart failure due to blockage of blood vessels within the lungs by particles of blood clot flaking off the shunt's catheter tip. Most shunts now drain into the peritoneal cavity They're called VP shunts."

She indicated the device I'd pulled from the skull.

"This is a VP shunt. In the living patient you would have been able to feel the bottom tube ninning under the skin that overlies the ribs. That part of the device is missing."

I waited for her to go on.

"The peritoneal cavity is large and can usually handle any amount of fluid delivered by the shunt. Another advantage of draining into the abdomen is that the rhythmic contractions of the intestinal organs move the tip of the catheter around. That motion prevents its becoming blocked or sequestered in scar tissue.

"When do these things go in?"

"As soon as hydrocephalus is diagnosed. As much as thirty-six inches of tubing can be placed in the abdomen of a neonate. As the child grows, the tubing unwinds to accommodate the increased length of the torso."

"I found a small hole in the skull, near the parieto-temporal junction."

"That's a burr hole. It's drilled during surgery to insert the upper end of the shunt into the brain. They're usually made behind the hairline, either at the top of the head, behind the ear, or in the back."

Russell's eyes flicked to a round metal clock on her desk, then back to mine. I was anxious to learn what difficulties might be caused by hydrocephaly, but knew the woman's time was limited. That research would be up to me.

I gathered my jacket and she returned the shunt to its jar, curling the paper and allowing the device to slide gently into place. We rose simultaneously and I thanked her for her help.