As someone who has been affected by infant pyloric stenosis (PS) and has remained interested in this condition, I have been fascinated by what the publicly available medical literature of the 1970s contributes to my knowledge and understanding of PS.
My overview of this material draws on no less than 21 reports, and I’ll have to devote two posts to the information I have found. Time keeps me from providing links to all these articles, but interested readers are invited to contact me about these.
As in the 1950s and 1960s, it is clear that during the 1970s the spotlight of the medical journals continued to move from merely describing PS to statistical and other research work to better understand this mysterious malady.
What have I found the most significant features and findings of the medical world’s work on PS during the 1970s?
It seems that work mushroomed on the causes of infant pyloric stenosis and the profile of its sufferers: half the reports belong to this area. Their subjects covered just some of the still many unknowns of PS, but they nevertheless make an impressive list.
A large study of PS cases in three large Belfast hospitals in Northern Ireland was based on 521 cases over 13 years (1957-69). It found a bias towards higher social classes (notably the children of doctors and police), breast feeding, being first-born and being winter-born. It found that the mother’s age was not a factor. The size of the pyloric tumour was usually found to be related to the size of the patient, rather than to age or the duration of PS symptoms. The babies’ subsequent growth and development were in the anticipated range. PS infants had a higher incidence of other disorders, but without any clear link with particular conditions (except hiatus hernia, a malformation of the oesophagus) or their severity. The babies also had various hernias more often, likely as a result of vomiting, the surgery or more crying in a weakened state.
Genetics and heredity
Three of the articles dealt with what we can learn from the fact that PS runs in some families. Several studies of twins have shown that identical twins both have PS quite often but fraternal twins no more commonly than siblings. This shows that in families, heredity plays a much larger role than environment, contrary to the suggestion that it’s a family’s food, surroundings and lifestyle that causes PS to cluster in some family trees.
A brief report concerned triplets born in 1973 all having PS, confirmed at surgery.
A telling 1979 report concerned a man who had been operated on for PS having three sons with the same condition. A genealogical table of his family showed that both his parents had relatives with PS, but that none of his wife’s relatives had it. So it was suggested that the man’s parents carried genes predisposing to PS and transmitted these to him in such quantity that he and all his children acquired the condition.
This led the writer to conjecture that there are a number of different genes which may all predispose one to PS, and that it is necessary for a certain number of these genes to code for the condition to develop. It further seems that the female makeup is protected to some degree so that a greater genetic load is required for girls to acquire PS. This greater genetic load would also explain why the children of female patients are more likely to develop PS rather than those of male patients.
Ethnicity and PS
A number of studies dealt with the fact that among ethnic groups, Caucasians have the greatest incidence of PS.
A 1974 letter from a doctor in Barbados made several observations –
1) Several British and European countries had reported a falling incidence of PS, from around 4 to 2 per 1,000 live births.
2) At the same time the trend was upwards in other countries such as the West Indies.
3) A study in Hawaii confirmed the relatively high incidence of PS among Caucasians whilst recording no cases among the State’s 11,274 Chinese infants born in a given period. The authors of this report claimed that cultural differences were of minor importance in Hawaii, that medical facilities were shared, and that their findings reflected variations in susceptibility which were determined by race.
A Singapore Medical Journal article in 1976 also dealt with this subject. With no studies of PS incidence published from comparable Asian countries, and with Singapore being a truly multi-cultural State, it was an ideal location for a study on the ethnicity of PS incidence. A review of 141,215 live births in Singapore during the three years 1972-74 showed the Chinese as having 21.2 PS babies per 100,000, the Indian population 35, and the Malays 9.7. The comparable figure among Caucasians would be between 200 and 400!
Heredity vs environment
Two studies dealt with the relationship between mothers and their PS-troubled babies. A 1974 article found that on the basis of 526 patients not only do very few PS babies have A and AB blood, but that their mothers have it even less often, suggesting another possible factor in the pre-natal environment increasing the possibility of developing PS. The report mentioned that experimental work in dogs had succeeded in reproducing PS in pups born to mothers who were treated with pentagastrin during pregnancy. This animal model may be relevant to the disorder in humans and indicates a mechanism by which a mother can affect her child before its birth.
A 1976 medical genetics journal also studied the mother-fetal interaction for gastrin production and sensitivity, whilst several other studies make it clear that the link between maternal gastrin and infant PS is far from established. The article states however, that only 37% of PS cases having a clear genetic factor, and yet this is the only clear guidance that can be given to parents who seek genetic counselling. We must continue the search for environmental factors to account for the other risk factors and cases.
Another report on the blood group distribution of 486 patients also noted the excess of O and B blood groups among PS sufferers, and on the basis of blood bio-chemistry it suggested a possible association between the development of PS and the efficiency of fat absorption in the infant.
Mothers and prenatal stress
100 mothers of infants who had had PS surgery in the Cardiff region of South Wales were studied for a 1978 report. It found that these mothers were normal people: the personality dimensions of neuroticism and extroversion as measured by the Eysenck Personality Inventory showed no significant differences between the subjects and the norm. The situation which can give rise to the birth of a PS baby is therefore not one of neurotic individuals over-reacting to everyday events, but of normal people reacting to particularly stressful events. During the interview the subject mothers were found to be significantly more anxious than the average. The researchers conclude that normal mothers who have been subjected to an increased number of particularly stressful events during pregnancy have an increased risk of giving birth to a child with hypertrophic pyloric stenosis. I have mentioned in another post that I believe my PS was related to the stress factors my mother suffered in 1945.
Several studies on the follow-up of PS surgery and its long-term effects were published in the 1970s.
The November 1971 Scandinavian Journal of Gastroenterology reported a follow-up survey of 14 PS patients 21 – 27 years after their surgery. It found that minor stomach discomfort was common and two had somewhat more severe symptoms. Acid secretions were generally also higher than average but still within the bounds of normal. Barium meal studies showed no gastric, pyloric or duodenal abnormality, but two suffered from gastric retention, the delayed emptying of the stomach and probably linked with the pylorus’ functioning. However, none of the 14 reported “dumping”, a term that describes a group of uncomfortable or painful but poorly understood symptoms that affects many patients after gastric surgery including the pylorus.
Another Scandinavian study, this one from Sweden, was based on follow-up interviews conducted in 1970 with 195 PS boys in relation to their military service; all had been medically treated (as happened more commonly in Europe) at the Children’s Hospital in Gothenburg between 1922 and 1942. This study was covered in two separate reports; it found that morbidity (the incidence of illness, disease and death) was no higher among PS sufferers than the general population; in fact the incidence of peptic ulcer at age 50 was less than half the norm. But especially when PS came with severe malnutrition it seemed to affect negatively adult height and weight, as well as performance in intelligence and adaptability tests, and in men their general fertility and the siring of girls.
However, an Israeli study of 228 infants were operated on for PS between 1946 and 1977 at the Tel-Aviv Municipal Medical Center was even more concerning. 41 of these patients aged from 15 to 30 years were evaluated for morbidity (the incidence of illness, disease and death) in the area of gastrointestinal diseases and their possible link with the operation. 24 of the 41 patients had gastrointestinal symptoms, including dyspepsia, diarrhea, constipation, and abdominal pains. X-ray examination of the stomach was performed on 31 patients, in order to examine the structure and function of the stomach. Five patients showed clear signs of ulcer disease, four in the duodenum and one in the stomach. Another five patients showed mild deformation of the duodenal bulb (the pyloric end of the duodenum) and two showed signs of gastritis (inflammation of the stomach lining). No correlation was found between the severity of the congenital PS and the presence of later illness or disturbances.
The fifth report on the long-term effects of PS is one I have mentioned in another post, a study that has been circulated quite widely on the effect of PS starvation on learning. A number of specific learning abilities together with the general adjustment of 50 subjects aged 5 to 14 who had had PS were studied and compared to those of 44 siblings and 50 matched controls. Starvation resulting in a reduction of more than 10% of the expected body weight in infancy is quite common in PS cases, and was associated with poorer learning abilities, especially those involving short-term memory and attention.
On a more positive note, a project reported in a 1975 Pediatrics journal found that PS and its surgery do not increase the incidence of allergies and asthma.
Many parents are affected by their baby’s continued vomiting after PS surgery, but this is hopefully mild and passing, the result of bruising from the handling of the baby’s stomach. However, a British report published in 1979 dealt with a more serious possible cause. The study found that of 72 PS infants who had surgery at a Sheffield hospital, 36% “experienced moderate to severe postoperative vomiting of sufficient intensity to cause the postoperative feeding regimen to be modified or interrupted.” Two factors were found to be significant: significant damage to the lining of the oesophagus was found in 30% of patients, and others had vomited blood before surgery, caused by damaged oesophagus. Babies with these problems had a prolonged stay in hospital. It was recommended that doctors check the oesophagus of PS babies before surgery to anticipate and treat this damage.
Two observations to end with…
- The results of research will often depend to some or a large extent on the aims, parameters and methodology of the project. Several reported finding mentioned here are disputed by other reports I have read, for example the likelihood of the mother’s gastrin secretion affecting her baby before birth, and the relationship between breast feeding and PS.
- It is clear that the causes and effects of infant pyloric stenosis are complex, and despite much research work having been done over more than a century, many of them are still unknown or just partially understood. Yet I have found the available reports give me a much better “feel” and some understanding of quite some of the whys and wherefores I have about my own PS story.
Next blog – some more interesting material about infant pyloric stenosis from the 1970s.