Posts Tagged ‘hyponatremia’

Memory issues Part 1: Is it Alzheimer disease or something else?

Saturday, March 9th, 2013

'Alzheimer's disease', under 'Alzheimer's'A while back I read an article in the Wall Street Journal with the intriguing  title, "Detective Work: The False Alzheimer's Diagnosis." The story was that of a man who developed problems in the memory and movement arena, was treated for Parkinson's and eventually found to have normal pressure hydrocephalus (NPH), a buildup of the cerebrospinal fluid (CSF) that surrounds and helps protect the brain and spinal cord.

Hydrocephalus, sometimes called "water on the brain," can occur at any age, but is more commonly seen in infants and seniors. When it is present in the very young, often due to a birth defect in which the spinal column doesn't close properly, it puts pressure on the brain and skull usually resulting in an abnormally large head and a bulging of the fontanel, the soft area on the top of the baby's head. It's treated, in many cases, by insertion of a shunt, a tube placed in one of the brain's ventricles (these are a communicating set of cavities filled with CSF). The tube has a one-way valve and is tunneled under the skin of the patient and usually empties into the abdomen.

The other age group in which hydrocephalus is seen more commonly is the over 60 age group. But it can certainly happen to younger adults as well.

One morning in 1990, when I was forty-nine, my wife noted I was having considerable difficulty with a particular kind of memory; the ability to recall something that was just told me was impaired. I turned out to have a benign mass in the center of my head (the technical term is a colloid cyst of the third ventricle) and had it removed by a neurosurgeon. Although the pathologist said it was benign, its location in that crucial area could have resulted in major brain damage or even sudden death.

If that were to happen today, it could be removed via endoscopic neurosurgery (an endoscope is a tube, usually flexible, for visualizing the insides of a hollow organ; it typically has one or more channels to enable passage of forceps or scissors). That procedure takes 45 minutes to an hour, is done via a one-inch incision and the patient goes home in one or two days.But, as you can see by clicking this link and then the photos in the article, colloid cysts have fairly large draining veins and they need to be most carefully attended to.

An MRI can guide the neurosurgeon's path

An MRI can guide the neurosurgeon's path

In my case, prior to the advent of the neurosurgical endoscope, the mass was removed the typical old-fashioned way by making several round holes in my skull and then the cyst itself. One of the veins leaked and I had a major seizure in the recovery room. That left me with a good-sized scar; on an MRI it's more of a cavity in the front part of my brain.

The scar impaired my short-term memory. I've managed to compensate, writing reminders and keeping a calendar, but I developed an interest in Alzheimer Disease and related memory issues, many of which are age-related and some of which are reversible.

The article on "False Alzheimers," notes that >100 medical conditions can present with memory loss, confusion and personality changes. Medications, or drug-drug interactions should be high on the list of things to rule out. An April 2012 article on autopsy studies of over 900 patients thought to have Alzheimer disease found over a sixth had been misdiagnosed.

The prevailing opinion is that NPH is the cause of five or six percent of all patient felt to have dementia. Adult-onset hydrocephalus is different in many respects from that which happens in the very young. It results from a gradual blockage of the conduits that normally drain CSF. It's not uncommon for the person with NPH to think that their symptoms are typical for the aging process.

But difficulties in focusing your eyes, an unusual series of headaches, personality changes, seizures, leg weakness and/or sudden falls should be investigated; it's wise to see your physician if  any of these occur, especially if there are associated memory problems.

Then there are, as Dr. Daniel Schacter, the former Chair of Harvard's Psychology  Department calls them, "The Seven Sins of Memory ," age-related memory issues that we all will likely encounter as we grow older. Being absent-minded, blocking the retrieval of a piece of information (It's on the tip of my tongue), or not remembering a complex chemical formula you learned for a college freshman course fifty years ago all can be totally normal. His book on the subject book revolves around the theory that "the seven sins of memory" are similar to the proverbial "seven deadly sins," and that if you try to avoid committing these sins, it will help to improve your ability to remember. Schacter, on the other hand, argues that these features of human memory are not necessarily bad, and that they actually serve a useful purpose in memory.

My comment over the years has been, "Whenever I put a fact in the front of my mind, one falls out the back."

So don't assume the worst if you forget something; on the other hand, don't ignore memory problems if they are persistent.





Hyponatremia in marathon runners

Thursday, August 30th, 2012

Marathon runners can have race-related major medical problems; most don't.

I recently read an article on patents who appear to have Alzheimer's when they present to a physician's office or an Emergency Room, but actually have some other disease or problem. An old friend visiting now us is an ER doc and said, "I see that all the time; it's usually hyponatremia,"

As a nephrologist, I've also seen a number of patients with mild to severe hyponatremia ,i.e., a relatively low blood sodium concentration, said to be the most common metabolic problem seen in the United States.  The normal numbers are 135 to 145; anything under 130 is termed severe hyponatremia; under 120 is critical, life-threatening hyponatremia.

In doing my background research, I found a Boston Globe article on a tragedy that occurred in the 2002 Boston Marathon. So I'll follow that thread for this post and discuss background data on other sodium issues later.

Most of us are familiar with a marathon as a long-distance race; actually it's 26 miles and 385 yards (there's a fascinating story behind that being the distance) and world record times are just over two hours for men and about twelve minutes longer for women.

In that 2002 race, one relatively inexperienced runner (this was only her second race at that distance) seemed to be doing well six miles from the finish, but then started to have problems. She told a friend she felt rubber-legged and dehydrated. Then she collapsed, became comatose and died. The autopsy conclusion was that hyponatremia secondary to drinking too much Gatorade had precipitated brain swelling that led to her death. She was only the second death in the over 100-year history of that marathon. Blood samples were studied by a Harvard staff physician and five years later in the  American Journal of Medicine that physician and collaborators published an article, "Hyponatremia due to SIADH in Runners,"

So what does that weird acronym mean? It stands for Syndrome of Inappropriate Anti-Diuretic Hormone (ADH) secretion. Let's start from scratch even if I get too basic. A syndrome is a group of symptoms and signs (the latter being observed by a second person) that together characterize a disease or disorder. A diruetic is something that increases urine flow. A hormone is a chemical produced by a gland or cell in our bodies that has an effect on other cells or tissues.

ADH is secreted by the pituitary gland, a pea-sized structure at the base of the skull that has so many functions it's sometimes called the master gland. This particular hormone controls the ability of water to pass through the cells in the walls of tubules in the kidneys and therefore be retained in the body. If no ADH is present, then no water can pass through those walls. The more ADH present, the more water can pass through.

An October, 2005, article in The New York Times was titled "Marathoners Warned About Too Much Water." But most who run the distance, even those who feel puny at some point and seek  medical  help for non-injury reasons, have normal to slightly high sodium levels. They've lost a little weight through sweating, but the medical director of the NYC marathon stated, "There are no reported cases of dehydration causing death in the history of world running." NB. The four deaths in the 2005 Great North Run in England on a warm, sunny day have been cited to be dehydration-related, but not by medical evidence that I've been able to find.

On the other hand, a 2005 article in the New England Journal of Medicine, looking at "Hyponatremia among Runners in the Boston Marathon," enrolled 766 participants in the 2002 race, did not measure their sodium levels before the gun sounded, but 511 came to the research station at the finish line and 489 of those gave a blood sample (most of the ones who didn't had a close connection for an airplane flight).

Thirteen percent had low sodium levels, with 37 of 166 women (22 percent) and 25 of 322 men (8 percent) in that group. Three had sodium levels under 120. Hyponatremia was strongly tied to weight gain, so the authors' conclusion was they were drinking too much water or sports drinks (it's important to realize that these have a relatively low sodium content).

Over-loading with fluids can lead to serious problems.

The Harvard researcher and his co-authors termed this as exercise-associated hyponatremia (EAD), measured ADH levels and those of Interleukin-6, a protein that's released from damaged muscles and can lead to ADH secretion. They concluded that EAD cases meet the criteria for SIADH. An increase of 3% of the runners' body weight would correlate to a decrease in serum sodium to less than 130.

So how do we avoid more hyponatremic deaths among marathon runners? Education seems the primary answer and perhaps weighing slower runners during the race. I can envision a scale a runner steps on (without stopping) with a relay of information to a point a short distance further on where race advisors could shout, "Number 3277, quit drinking any more fluids."