An interstitial pregnancy is a uterine but ectopic pregnancy; the pregnancy is located outside the uterine cavity in that part of the fallopian tube that penetrates the muscular layer of the uterus. The term cornual pregnancy is sometimes used as a synonym, but remains ambiguous as it is also applied to indicate the presence of a pregnancy located within the cavity in one of the two upper "horns" of a bicornuate uterus. Interstitial pregnancies have a higher mortality than ectopics in general. Anatomy
The part of the Fallopian tube that is located in the uterine wall and connects the remainder of the tube to the endometrial cavity is called its "interstitial" part, hence the term "interstitial pregnancy"; it has a length of 1–2 cm and a width of 0.7 cm. Its borders are the opening (ostium) of the tube to the endometrial cavity within the uterus and, laterally, the visible narrow segment of the tube. The area is well supplied by the Sampson artery which is connected to both the uterine and the ovarian arteries. Surrounded by uterine muscle (myometrium) it can expand significantly when it hosts a pregnancy. Interstitial pregnancies can be confused with angular pregnancies; the latter, however, are located within the endometrial cavity in the corner where the tube connects; typically those pregnancies are viable although a high rate of miscarriage has been reported. A pregnancy located next to the interstitial section laterally is an isthmic tubal pregnancy.
The association between streptococci and scarlet fever was confirmed by Alphonse Dochez and George and Gladys Dick in the early 1900s.Also in 1884, the worlds first convalescent home for people with scarlet fever was opened at Brockley Hill, Stanmore, founded by Mary Wardell.Nil Filatov (in 1895) and Clement Dukes (in 1894) described an exanthematous disease which they thought was a form of rubella, but in 1900, Dukes described it as a separate illness which came to be known as Dukes disease, Filatovs disease, or fourth disease. However, in 1979, Keith Powell identified it as in fact the same illness as the form of scarlet fever which is caused by staphylococcal exotoxin and is known as staphylococcal scalded skin syndrome.Scarlet fever serum from horses blood was used in the treatment of children beginning in 1900 and reduced mortality rates significantly.In 1906, the Austrian pediatrician Clemens von Pirquet postulated that disease-causing immune complexes were responsible for the nephritis that followed scarlet fever.Bacteriophages were discovered in 1915 by Frederick Twort. His work was overlooked and bacteriophages were later rediscovered by Felix dHerelle in 1917. The specific association of scarlet fever with the group A streptococci had to await the development of Lancefields streptococcal grouping scheme in the 1920s. George and Gladys Dick showed that cell-free filtrates could induce the erythematous reaction characteristic of scarlet fever, proving that this reaction was due to a toxin.