Doctor's Review: Medicine on the Move

December 13, 2017
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Point well taken

How the lumbar puncture came to be one of medicine’s most precious diagnostic procedures

Few diagnostic tools in the physician’s arsenal are as effective as the lumbar puncture... and few are as feared by patients. Indeed, neurologists claim that it’s easier to procure patient consent for craniotomies than it is for LPs. Of course, the spinal tap does not merit its dubious reputation these days since side effects are quite rare and reports of accidental paralysis exaggerated.

The spinal tap has several scientists to thank for its rise to diagnostic prominence, but before any of these pioneers could presume to puncture that most precious of conduits, others pontificated upon the presence and significance of cerebrospinal fluid for centuries.

Liquid gold

Hippocrates was the first to hint at the existence of CSF in the fourth century BCE. He was also the first to identify the ventricles and even diagnosed “water on the brain,” though he certainly didn’t have a decent solution to the problem, nor did he note any connection between the two. During his second-century animal dissections, Galen found a clear fluid in the ventricles as well.

Nobody mentioned CSF again until 1692 when Italian anatomist Antonio Maria Valsalva (1666-1723) — a researcher with a penchant for tasting human exudate — took note of a clear liquid after slicing through a dog’s spine. No word what it tasted like, though he almost certainly did help himself to a little since he was known to imbibe far more unpalatable samples like gangrenous ooze.

Valsalva’s disciple, Domenico Cotugno (1736-1822), discovered real honest-to-goodness subarachnoid CSF in humans in 1764. The reason nobody had found it sooner is because it was common practice to chop the heads off cadavers before examining the brain during autopsies or anatomical studies, and so all the fluid surreptitiously leaked out. About 90 years later, a fellow by the name of Faivre pinpointed the choroid plexus as the source of CSF.

But while the mysterious liquid was known to exist, it wasn’t until English physician Walter Essex Wynter (1860-1945) came along that a living patient’s CSF became at last less elusive. Inspired perhaps by the relative success of the drainage tubes used to treat severe edema in the limbs of “dropsy” patients during the Victorian age, Wynter applied the same reasoning to those suffering from an accumulation of a different sort of fluid.

Making the cut

In February of 1889, in a last-ditch effort to treat a three-year-old boy with raised intracranial pressure resulting from meningitis caused by an ear infection, the London-based Wynter made a small midline incision at the second lumbar vertebrae and inserted a thin cannula fitted with a rubber tube into the dura to drain the fluid. It was a significant — albeit ill-fated — moment in medicine. Although the procedure did provide temporary relief, the patient died.

One year later, Wynter tried again, this time, in an attempt to treat an 11-year-old girl; a two-year-old boy and a one-year-old girl, all with tubercular meningitis, were also subjected to Wynter’s magic. The trio didn’t make it — Wynter failed to account for the infection, focusing instead on the excess of fluid — but scientists began to take note when Wynter published his experiments in The Lancet in May 1891.

While most of Wynter’s contemporaries were looking at the new technique as a way to drain cerebrospinal fluid in patients suffering from diseases like meningitis and hydrocephalus, a brilliant and steady-handed German doctor had a different idea. Could it be that removing the seemingly benign liquid might be better employed as a diagnostic tool?

Meningitis management

The man who would not only improve the technique for accessing the fluid, but also shift the way in which CSF would forever be used was Frankfurt-born Heinrich Irenaeus Quincke (1842-1922). A graduate from the University of Berlin in 1863, Quincke quickly became a standout in surgery and internal medicine. In 1872, he ingeniously tinted the CSF of dogs red by injecting the subarachnoid space with sulphide mercury so he could trace its flow. The following year, he was appointed Professor of Internal Medicine at the University of Berne.

For the next 15 years, Quincke researched edema, intracranial hypertension, hydrocephalus and other related topics. He focussed not only on treatment, but on diagnosis… and meningitis was one of the primary causes of these conditions. Unfortunately, at the time, there was no reliable or expedient way to determine whether or not a patient’s symptoms were definitively caused by this dreaded infectious disease.

In 1888, Quincke subjected a 12-year-old boy to six CSF drainings from the cerebral ventricles using a trephine — basically, a cylindrical blade — through holes bored in his skull. Sadly, but not surprisingly, the boy died. Quincke refined his technique and in December of 1890 he performed his first successful lumbar puncture on a 21-month-old boy in a coma on the verge of death. By using a thinner cannula injected between the third and fourth lumbar vertebrae, he withdrew fluid three times over three-day intervals. The boy survived.

Not long after, the doctor employed his thinner-needle technique to treat the severe headache of a young man suffering from chronic hydrocephalus of unknown origin. The lumbar puncture relieved his symptoms immediately with no ill after-effects.

During his LPs, Quincke paid careful attention to the fluid pressure before and after each procedure, and tested for levels of proteins and sugar within the fluid. From the get-go, he was interested in using the punctures as a diagnostic tool and proved his point when he identified tubercle bacilli in the CSF of affected patients. Quincke reported his findings at an internal medicine conference in Weisbaden in 1891... just one month before Wynter’s landmark paper appeared in The Lancet. Within months, he had successfully treated 10 more patients.

Suddenly, physicians were availed of a relatively safe and effective way to diagnose meningitis. “Quincke’s puncture,” as it came to be known, had grown well beyond its original use. Building on both Wynter’s and Quincke’s work, anesthesiologists soon developed effective methods of spinal anesthesia using at first cocaine, then other more suitable drugs. The suffering masses breathed a collective sigh of pain relief.

CSF thief?

Meanwhile, on this side of the Atlantic, physicians were also learning the value — and hazards — of messing around with cerebrospinal fluid. Dr Arthur H. Wentworth, an assistant professor of medicine at Harvard, is widely credited with being the first to import Quincke’s lumbar-puncture technique to North America. He aggressively pursued the testing of CSF to diagnose meningitis in kids, but some people — particularly the very vocal anti-vivisectionist movement at the time — were outraged by his experiments charging that he performed spinal taps on kids who weren’t even sick.

Wentworth defended his samples from 29 healthy babies and toddlers as necessary for a control group, naively publishing his findings in 1893 — a decision that eventually led to his arrest on charges that he stole CSF fluid unethically from his young patients. In his defense, he stated: “The diagnostic value of puncture of the subarachnoid space is so evident that I considered myself justified in incurring some risk in order to settle the question of its danger. If it proved harmless, then one need not wait until a patient becomes moribund before resorting to it.”

The well-meaning doctor was acquitted, but his career was ruined. Although he was about to be named the first pediatrics professor at the brand-new Johns Hopkins Medical School, the offer was quietly revoked.

Indeed, Dr Wentworth was right. The lumbar puncture remains an invaluable tool in the diagnosis of infectious diseases like meningitis and encephalitis, inflammatory disorders like multiple sclerosis and Guillain-Barré Syndrome, as well as certain cancers.

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