(Updated with Answer) The Medical Challenge: Can You Explain These Symptoms?

dentistPeter hates the dentist. The thought of visiting his local conjurer of fancy toothpicks elicits a complex and decidedly unpleasant visceral reaction. Besides the usual anticipation of uncontrolled slavering and high speed drilling, Peter constantly worries about his breath, imagining his dentist cringing behind her mask as she experiences his perceived and perhaps real disabling halitosis.

This time, Peter, a spry 55 year old man, has let his disdain for dentistry impair his better judgment. A known cavity had started irritating Peter 12 months ago. Initially, he ignored it but then as the gnawing pain worsened, he palliated himself with his collection of single malts, taken neat of course. However, the pain began to interfere with his ability to enjoy BBQ pork sandwiches and this he would not have. Off to the dentist.

There he learned that his tooth was not salvageable. It required extraction. “Fine,” barked Peter, who then uneventfully underwent a controlled tooth extraction by the skilled hands of his dentist.

Three weeks later, Peter had resumed life in his dual roles of both an obsequious accountant and a committed but generally annoying husband. At night one evening though, he began to have a fever. And over the next few days, this fever combined with an insidious malaise and dizziness. Quickly though, these symptoms began to pale in comparison to the headache he developed. The headache was constant and unremitting, unresponsive to every over the counter medicine he could purchase. When he came home from work that Friday though, his headache was bringing him to tears. He was sweating. He decided to take a seat on his prized leather couch and wait it out.

A few hours later, his wife returned home and found him with a vacuous stare on the couch, drenched with sweat. Further, she noticed that the left side of his face was droopy. When she asked what was wrong, he muttered some unintelligible syllables. When she asked him to get up, he made some clumsy gestures but did not move his left arm or leg.

At the hospital, Peter was much unchanged. He had a temperature of 40 degrees and a blood pressure of 90/50. An odor of bodily failure filled the room. Simply put, he looked terrible.

What’s going on? What to do?

Check back next week for the explanation.

Photo by PinkStock Photos

To summarize, Peter is a 55 yr old man with a history of having had a tooth extraction who now comes to the hospital with an acute neurologic illness consisting of fever, left sided weakness, and near coma.

The emergency room physicians astutely recognize Peter’s problem as neurologic in nature and thus organize a stat CT scan of the brain. Because of Peter’s symptoms of left sided weakness, we expect to find a lesion of some sort on the right side of his brain (Remember, the right side of the brain controls the left side of the body and vice versa).

(Updated with Answer) The Medical Challenge: Can You Explain These Symptoms?

Figure 1 – Note the arrow pointing to the circular lesion in right side of the brain (Sides are reversed on CT scans).

As pictured above, our suspicious indeed prove correct. Peter does have a lesion on the right side of his brain in an area that would certainly cause left sided weakness (For you hobby anatomists, the lesion is located medial to the genu of the internal capsule, abutting both the caudate nucleus anteriorly and thalamus posteriorly). Needless to say, the abnormality is in a bad spot as its bang next to the fibers that send control signals from the right brain to the left body.

At this point, we know that Peter appears ashen and has a circular lesion pushing into his brain. Because of his co-morbid symptoms of fever, sweats, and few day history of feeling unwell, we can justifiably surmise that Peter has developed a blood infection and an abscess in the brain, likely originating from the tooth extraction he had undergone weeks prior.

Blood infections(bacteremia and/or sepsis) after dental work are thankfully rare phenomena. Interestingly, after any tooth extraction, periodontal surgery, and even tooth brushing, we all have a bit of bacteria enter our blood stream. However, our immune systems are superbly effective at ridding us of these pathogens, usually within 30 minutes of the event. In fact, if you think of the number of times you brush your teeth in a lifetime, the risk of a significant blood infection related to your teeth is vanishingly small. In certain populations of patients, such as those with artificial heart valves, however, the risk is slightly higher. These bacteria can latch onto these prosthetic devices, grow and cause a condition known as infective endocarditis, which if left untreated can lead to a life threatening infection and heart failure. In Peter’s case, he was just extremely, unbelievably unlucky.

Peter is in serious danger. In addition to the infection in his body, he has an organized collection of bacteria(abscess) pushing into his brain. Because this abscess is not supposed to be in the brain, the pressure in the brain increases. When the pressure in the brain increases, neurologic symptoms ensure, which include weakness and eventually coma and/or death if the pressure gets too high.

As such, Peter needs emergent surgery. Because the abscess is located deep in the brain, traditional brain surgery to open the brain at the surface and remove the abscess is not an option, as gaining access to the abscess would endanger important neural structures. Instead, Peter needs a more minimally invasive approach wherein the abscess can be drained with only minimal damage to surrounding neural structures.

As such, Peter underwent a so-called stereotactic drainage of his abscess. In this procedure, a special CT scan is performed which is then loaded into a computer in the operating room. Then using fixed external landmarks on Peter’s head, the location of Peter’s head in real space is married to the images of Peter’s head in virtual space. In doing this, a special wand can be used during surgery to point to exactly where we are in Peter’s brain as the surgery is underway. More importantly, though, it will allow us to plan our placement of a catheter into the abscess and drain it while avoiding other critical structures.

Peter’s operation went smoothly. With the aid of surgery and antibiotics, Peter recovered over the next few weeks. However, he was left permanently weak on the left side of his body due to the damage the abscess wrought on his brain. For us doctors, it was satisfying to know his life was saved but sobering to realize we could not undo all the havoc caused by the infection. For Peter and his family, they were grateful for his survival but appropriately contemplative. Why did this rare event happen to Peter specifically? Why couldn’t modern medicine not only cure his abscess but also fix the weakness in his arm and leg? Why did Peter wait so long to have his tooth examined? Would it have mattered if he had?

The truth is, we just don’t know.

Dr. Rohan Ramakrishna is a neurosurgery resident at the University of Washington in Seattle. His research interests focus on developing novel treatments for tumors of the brain and spine. He completed ...read more

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