Mary Broadfoot Walker

Mary Broadfoot Walker (1888 – 13 September 1974) was a British physician who first demonstrated the effectiveness of physostigmine in the treatment of the condition myasthenia gravis.

Mary Walker was born at Croft-an-Righ, Wigtown, Scotland in 1888, one of four children and the daughter of a Judge. After school she trained in medicine at Glasgow & Edinburgh Medical College for Women, graduating with MBChB in 1913. During the First World War she served with the Royal Army Medical Corps at the 63rd General Hospital, Malta. In 1920 she became a salaried Assistant Medical Officer in "Poor Law Service" at St Alfege's Hospital, Greenwich, London, where she worked until 1936. During this time she was awarded Membership of the Royal College of Physicians, London, in 1932. She then worked at St. Leonard's Hospital, Shoreditch, St. Francis' Hospital, Dulwich and St. Benedict's Hospital, Tooting, before retiring to Croft-an-Righ in 1954.

In 1934, while working at St Alfege's Hospital, Dr. Walker discovered that the subcutaneous injection of physostigmine could temporarily reverse the muscle weakness found in patients suffering from myasthenia gravis. She had noted that the symptoms and signs of myasthenia were similar to those found in curare poisoning, and physostigmine was used as an antidote to curare poisoning at that time. The first case of myasthenia gravis successfully treated with physostigmine was published in the Lancet in June 1934.

In 1935 Mary Walker was the first to recognise the association between the condition familial periodic paralysis and hypokalaemia (low blood potassium levels). She also described the glucose challenge test used in diagnosing hypokalaemic periodic paralysis and the use of intravenous potassium in its treatment. During 1935 her research on myasthenia was incorporated into her MD thesis which was submitted via the University of Edinburgh, and for which she received a Gold Medal.

Although she never became a Fellow of the Royal College of Physicians, she was awarded the Jean Hunter Prize in 1962 "for the advancement of research into the treatment of nervous exhaustion and for her original contribution to the fundamental knowledge of the nature of myasthenia gravis, made while carrying out the routine duties of a medical officer at a large metropolitan hospital".

After her retirement in 1954, she continued to work part-time at the Glasgow Royal Maternity & Women's Hospital, and remained active in the field of myasthenia gravis. Her 1973 article also describes the Mary Walker Effect, a clinical sign found in myasthenia gravis. She died in September 1974 at the age of 86.