Medical milestones, landmark publications, and notable births and deaths associated with May 21.

Events

1946 — Los Alamos physicist Louis Slotin (1910-1946) suffered a fatal criticality accident (“blue flash” and heat wave) during a plutonium core experiment and died nine days later. The case later became part of a nine-case clinical series (published in 1952) defining the early course of acute radiation syndrome. Timeline recorded as initial nausea, vomiting → brief “well” phase → toxic phase with fever, GI injury, infection and marrow failure. These observations helped shape modern ARS descriptions and supportive-care principles.

1997 — A previously healthy 3-year-old boy in Hong Kong died from acute respiratory distress due to viral pneumonia. Influenza A(H5N1) was later isolated from his tracheal aspirate, the first known human case of H5N1 avian influenza. This early signal that triggered intensive investigation and surveillance during the 1997 Hong Kong outbreak

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Births

1835 – František (Franz) Chvostek (1835-1884) Czech born, Austrian physician; described Chvostek sign (1876)

1860 – Willem Einthoven (1860-1927), Dutch physician and physiologist; introduces the term ‘electro-cardiogrammem‘ and the first practical electrocardiogram (ECG) in 1903, and the Einthoven triangle (1912)

1868 – Richard Clarke Cabot (1868-1939), American physician. Described Cabot- Locke murmur (1903); Cabot Rings (1903); and formally introduced the term “Courvoisier’s Law”

1899 – Niels Lauge-Hansen (1899-1976), Danish Radiologist; defined Lauge-Hansen classification of ankle fractures (1950)

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Deaths

1906 – John Henry Bryant (1867-1906), English physician; described the Blue Scrotum Sign of Bryant (1903)

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Further reading

• Hempelmann LH, Lisco H, Hoffman JG. The acute radiation syndrome: a study of nine cases and a review of the problem. Ann Intern Med. 1952 Feb;36(2:1):279-510
• Wellerstein A. The blue flash 2016
• Platt-Mills B. The Blue Flash: How a careless slip led to a fatal accident in the Manhattan Project BBC 2023
• Isolation of Avian Influenza A(H5N1) Viruses from Humans. CDC 1997
• Mounts AW et al. Case-control study of risk factors for avian influenza A (H5N1) disease, Hong Kong, 1997. J Infect Dis. 1999 Aug;180(2):505-8.