How a Forgotten Meaning of Ileus Shaped the Discovery of Meconium Ileus

Few words in medicine have traveled as far, or drifted as far from their origins, as ileus. Coined in antiquity, the term spent more than two thousand years sliding between meanings before clinicians in the early twentieth century used it, almost accidentally, to name one of the most diagnostically important conditions in newborn medicine: meconium ileus. A recent historical commentary by Anthony Zarka of Nemours Children’s Health System, published in Pediatric Radiology, traces that linguistic journey and argues that the story of meconium ileus cannot be separated from the curious, contested history of the word ileus itself.

In classical medicine, ileus referred to a violent, often fatal condition of the abdomen in which the intestines were believed to be gripped by pain and dysfunction. Ancient and early modern physicians used the term for what they described as intestinal colic or a twisting suffering of the gut, a syndrome recognized by severe abdominal distension, vomiting, and collapse. The word carried an aura of dread. For centuries, ileus was less an anatomical diagnosis than a description of a catastrophic clinical picture, one that physicians could observe but rarely explain and almost never treat.

As Ballantyne documented in a 1984 review of the term’s changing definition over three millennia, the modern era brought a decisive shift. By the nineteenth and early twentieth centuries, surgeons increasingly distinguished between mechanical obstruction of the bowel, in which a physical blockage halts the passage of intestinal contents, and paralytic or adynamic ileus, in which the bowel wall simply stops moving. This distinction mattered enormously for practice. A mechanical obstruction demanded surgical relief, while a paralyzed bowel called for decompression, supportive care, and patience. The word ileus, once a single ominous label, had split into two conceptually different diseases, and the tension between those meanings would soon shape how one of pediatrics’ signature conditions was first recognized.

It was against this backdrop that the earliest reports of meconium ileus appeared. In 1905, Karl Landsteiner, the Viennese pathologist better known for his discovery of the ABO blood groups, published a description of intestinal obstruction caused by inspissated, or thickened and dried, meconium, which he linked to pancreatic disease. Writing in German, Landsteiner described a bowel blocked not by a band, a volvulus, or an atresia, but by abnormally dense fetal intestinal contents. His observation connected two organ systems, gut and pancreas, in a way that would prove prophetic, though the full significance of that connection took decades to appreciate.

The term meconium ileus itself emerged in the clinical literature shortly afterward. In 1919, Bullowa and Brennan reported a case of intrauterine intestinal obstruction from inspissated and impacted meconium in the Journal of the American Medical Association, framing the problem as a mechanical obstruction present before birth. Here the older, mechanical sense of ileus was doing quiet work: the authors were not describing a paralyzed bowel but a bowel physically plugged by tenacious meconium. The phrase captured a paradox that would puzzle clinicians for years, namely that a newborn could be born already obstructed by a substance that should have passed harmlessly in the first days of life.

Through the 1920s and 1930s, case reports accumulated. In 1936, Dodd published a case report in the Journal of Pediatrics of intestinal obstruction due to meconium ileus in a newborn infant, and the same year Eliason and Johnson addressed the diagnostic features of ileus in the journal Radiology, reflecting the growing role of abdominal radiography in distinguishing patterns of bowel obstruction. Radiographs allowed clinicians to see dilated loops of bowel and, in some cases, a characteristic granular or ground-glass appearance where thick meconium mixed with air. Imaging gave the condition a visible signature and helped separate it from other causes of neonatal obstruction such as atresia, stenosis, and volvulus.

The decisive conceptual breakthrough came in 1936 and 1938. In 1936, Fanconi, Uehlinger, and Knauer published their description of the celiac syndrome associated with congenital cystic fibromatosis of the pancreas and bronchiectasis, drawing together the intestinal, pancreatic, and pulmonary features that had previously been reported in isolation. Two years later, Dorothy Andersen, in a landmark clinical and pathological study in the American Journal of Diseases of Children, defined cystic fibrosis of the pancreas as a distinct disease and established its relationship to the celiac-like syndrome of infants. Within this new framework, meconium ileus found its place: it was not a random mechanical accident of fetal life but the earliest clinical manifestation of a hereditary disorder that thickened secretions throughout the body.

Once cystic fibrosis was defined, the meaning of meconium ileus settled into its modern form. The condition is now understood as neonatal intestinal obstruction caused by abnormally viscous meconium, the product of deficient pancreatic enzyme secretion and altered mucus, which accumulates in the terminal ileum and cecum and produces a mechanical blockage. In the vocabulary of the early twentieth century, that made meconium ileus a true mechanical ileus, in the tradition of Steele’s 1901 discussion of ileus due to mechanical obstruction to the fecal current, rather than a paralytic ileus of the kind Wathen described in his 1909 JAMA paper on postoperative ileus. The newborn bowel in meconium ileus is not lazy; it is blocked, and it strains against a plug of material too thick to pass.

Zarka’s commentary highlights how this history illustrates a broader point about medical language. The word ileus arrived in the meconium literature carrying its ancient sense of severe intestinal suffering, was refined by surgeons into a distinction between mechanical and adynamic obstruction, and then, in the phrase meconium ileus, preserved a specific mechanical meaning that clinical experience gradually clarified. What began as a descriptive label for a mysterious neonatal catastrophe became, through the accumulation of cases, the application of new imaging techniques, and the recognition of cystic fibrosis, a precise diagnostic entity with a defined pathophysiology. The forgotten layers of the term’s meaning were not lost so much as overwritten, and revisiting them reveals how much of modern terminology encodes older debates.

The story also underscores the value of clinical observation in advance of molecular understanding. Landsteiner linked inspissated meconium to pancreatic disease decades before the genetic basis of cystic fibrosis was known. Bullowa and Brennan recognized intrauterine obstruction before any treatment was possible. Andersen’s synthesis transformed scattered reports into a coherent disease concept. Each step depended on clinicians taking seriously what they saw at the bedside and in the pathology laboratory, and on a vocabulary flexible enough, despite its tangled history, to carry those observations forward. In the case of meconium ileus, the curious history of a single word helped keep a forgotten meaning alive long enough for medicine to give it a name, a mechanism, and eventually a place within one of the most common hereditary diseases of childhood.

Subject of Research: The historical evolution of the term ileus and its role in the recognition of meconium ileus as an early manifestation of cystic fibrosis

Article Title: The curious history of meconium ileus: how clinical experience revived a forgotten meaning

Article References: Zarka, A. (2026). The curious history of meconium ileus: how clinical experience revived a forgotten meaning. Pediatric Radiology. https://doi.org/10.1007/s00247-026-06777-x

Image Credits: AI Generated

DOI: 10.1007/s00247-026-06777-x

Keywords: meconium ileus, ileus, cystic fibrosis, history of medicine, Karl Landsteiner, Dorothy Andersen, pediatric radiology, intestinal obstruction, neonatology, medical terminology, pancreatic disease, clinical history