Nils Westermark

Nils Johan Hugo Westermark (1892–1980) was a Swedish radiologist

Westermark was a professor of radiology at the Karolinska Institutet. He spent much of his career at Sankt Göran Hospital in Stockholm, where he served as chief physician of the X-ray department from 1929 until 1957.

Westermark is best remembered for his 1938 description of the characteristic regional pulmonary oligaemia associated with pulmonary arterial embolism, later known as the Westermark sign. His original investigation compared radiographic findings with post-mortem evidence of pulmonary embolism and helped establish one of the classic chest radiograph signs of the disease.

Westermark was an accomplished sailor. At the age of 19 he represented Sweden at the 1912 Stockholm Olympic Games, winning a silver medal in the 8-metre class aboard Sans Atout with a crew that included his brother Herbert Westermark.

Biography

• Born on September 9, 1892 in Stockholm, son of obstetrician and gynaecologist Professor Frans Westermark and Maggie Cnattingius.
• 1911 – Completed secondary school examination (studentexamen) in Stockholm.
• 1912 – Aged 19, represented Sweden at the Stockholm Olympic Games as a crew member of Sans Atout, winning silver in the 8-metre sailing class alongside his elder brother Herbert.
• 1914 – Medicine kandidat (med. kand.), Karolinska Institutet.
• 1919 – Medicine licentiat (med. lic.), Karolinska Institutet.
• 1920–1921 – Worked in the radiology department at Sabbatsberg Hospital.
• 1922–1923 – Assistant physician at the Radiumhemmet, Karolinska.
• 1924–1929 – Worked at the radiology institute of Serafimerlasarettet, initially as amanuens and subsequently assistant physician. Concurrently held appointments in radiology at St Erik’s Hospital.
• 1927 – Submitted his doctoral dissertation, The effect of heat upon rat tumours, an experimental investigation of tumour hyperthermia.
• 1929–1957 – Chief physician of the X-ray and light department at St Göran Hospital, Stockholm.
• 1930 – Awarded med. dr and appointed docent in medical radiology at Karolinska Institutet.
• 1938 – Published On the roentgen diagnosis of lung embolism, describing the radiographic regional pulmonary oligaemia subsequently known as the Westermark sign.
• 1942 – Appointed Knight of the Royal Order of the Polar Star.
• 1946 – Delivered the inaugural Leo G. Rigler Lecture at the University of Minnesota and a Mayo Foundation lecture.
• 1955 – Appointed professor of radiology at Karolinska Institutet.
• Died in Stockholm on January 24, 1980 aged 87.

Medical Eponyms

Westermark sign (1938)

Westermark sign describes regional pulmonary oligaemia on chest radiography distal to pulmonary arterial obstruction, with attenuation or absence of peripheral vascular markings and sometimes abrupt termination of the central pulmonary vessels.

In 1938, Westermark published On the roentgen diagnosis of lung embolism, based on 26 patients with pulmonary embolism confirmed at autopsy, supplemented by a further 18 clinical cases followed radiographically during evolution and recovery. He showed that embolism without infarction could produce a relatively hyperlucent pulmonary territory corresponding to reduced distal vascularisation.

In embolism of the pulmonary artery without infarction we get ischaemia of the branches of the pulmonary artery on the peripheral side of the embolus. On the radiogram this ischaemia appears as a clarified area with diminished vascular design corresponding to the extent of the embolised artery. The vascularisation is however maintained in the central parts of the lung. The vascularisation takes however a rapid end to pass over into the above mentioned area of non-vascularisation.

Westermark 1938

Major Publications

• Westermark N. The effect of heat upon rat tumours. Skandinavisches Archiv für Physiologie 1927; 52: 257-318, 1927
• Westermark N. On the roentgen diagnosis of lung embolism: brief review of the incidence, pathology and clinical symptoms of lung embolism. Acta Radiologica 1938; 19(4): 357-372. [Westermark sign]
• Westermark N. On Tuberculosis of Bronchial Lymph-Glands: A Roentgenological Investigation. Acta Radiologica. 1940; 21(4): 399–422.
• Westermark N. A Simple Method of Localising Foreign Bodies. 1941; 22(4): 490-492.
• Westermark N. On epituberculosis and lung atelectasis. Acta Radiologica. 1941; 22(4): 501-510.
• Westermark N. Roentgen Studies of The Lungs And Heart. Minnesota Press 1948.

References

Biography

• Westermark, Nils. Vem är det: Svensk biografisk handbok. 1939, 1945
• The Radiologist Who Won an Olympic Medal. Cafe Roentgen 2024
• Olympic Sailing: Nils Westermark. Sports-Reference.com
• Olympic Sailing: Nils Westermark. Olympic.org

Eponymous terms

• Maizlin ZV, Cooperberg PL, Clement JJ, Vos PM, Coblentz CL. People behind exclusive eponyms of radiologic signs (Part II). Can Assoc Radiol J. 2010 Feb;61(1):44-53
• Cadogan M. CXR eponyms in pulmonary embolism. LITFL

David Yu

David Yu, M.D., Ph.D. Full time anesthesiologist in the department of Perioperative medicine and Intensive Care (PMI), Karolinska University Hospital, Sweden. Dual board certified in internal medicine, and anesthesiology and critical care. Clinical interests are the critically ill patient, hemodynamic cases, perioperative echocardiography and procedural awareness, and of course all things ECG! | Squiggler |

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