Given the task definition, example input & output, solve the new input case.
Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.
Example: In 1582 the united provinces invited francis, duke of anjou to lead them; but after a failed attempt to take antwerp in 1583, the duke left the netherlands again. after the assassination of william of orange (10 july 1584), both henry iii of france and elizabeth i of england declined the offer of sovereignty. however, the latter agreed to turn the united provinces into a protectorate of england (treaty of nonsuch, 1585), and sent the earl of leicester as governor-general. this was unsuccessful and in 1588 the provinces became a confederacy. the union of utrecht is regarded as the foundation of the republic of the seven united provinces, which was not recognized by the spanish empire until the peace of westphalia in 1648.
Output: In what year did francis, duke of anjou leave the netherlands?
The generated question is perfect. Because the question is based on second sentence of the input passage and its answer is 1583.

New input case for you: Puffy hand syndrome is a complication of intravenous drug abuse, which has no current available treatment. Arm and forearm edema are voluminous and cause functional and aesthetic disturbances. We report two cases successfully treated by low-stretch bandages. A 40-year-old man and a 34-year-old woman, both intravenous drug users, with puffy hand syndrome were hospitalized for 11 days. Treatment included daily multilayer bandaging. Lymphedema volumes calculated by utilizing the formula for a truncated cone decreased by 16% on the left side and 12% on the right side for the first patient and 31 and 17% for the second. Hand circumference decreased 4.3 cm on the left side and 3.2 cm on the right side in case 1, and 2.5 cm and 1.9 cm respectively for case 2. The patients were taught self-bandaging techniques during their hospital stays. Elastic gloves were fitted at the end of treatment. Reduction of lymphedema volume remained stable after 18 months in one patient while for the second patient further treatment and hospitalization were required due to poor compliance. The pathogenesis of this edema is probably multifactorial: venous, lymphatic insufficiency and the direct toxicity of injected drugs. Lymphedema treatment currently consists of low-stretch bandaging and wearing elastic garments, which is effective in decreasing the volume of puffy hand syndrome.
Output:
What causes "Puffy hand syndrome"?