Michael Peel BMJ 1997;315:829-830 (4 October)

Editorials  Hunger strikes  Understanding the underlying physiology will help doctors provide proper advice  Hunger strikes in different parts of the world are regularly in the news.  Doctors with an interest in human rights may be asked to give independent  medical advice to an asylum seeker intending to start a hunger strike. Several  recent articles have addressed the ethics of treating hunger strikers,1 2 but  there is less information available on the physiological issues. It is essential  to understand both these issues to be able to advise the individual  appropriately.  There have been several studies of fasting for a few days, but in the past 15  years only three studies have described voluntary total fasting for prolonged  periods. The first was of a monk who tried to fast for 40 days for religious  reasons but was forced to stop on day 36 because of unacceptable symptoms.3 The  second was of four adults who were planning to fast indefinitely. One became  very unwell on day 38, and the others ceased fasting on day 40.4 The third was a  retrospective study of 33 South African political prisoners on hunger strike for  up to 28 days.5  Hunger strikes have been around since Roman times, and the suffragettes brought  the tactic to public awareness in Britain earlier this century. Gandhi fasted at  least 14 times but never for more than 21 days. After the second world war Ancel  Keys published an extensive review of people subjected to prolonged starvation  and a study replicating these conditions in the laboratory.6 The hunger strikers  of the Maze Prison in Belfast in the early 1980s died after 45-61 days, but no  results have been published.  For the first few days of starvation the body uses its stores of glycogen in  liver and muscle.7 This is accompanied by glucagon induced naturesis, with  substantial weight loss. The next phase lasts up to day 10-14, during which time  glycogen stores are exhausted and certain amino acids take over as the substrate  for gluconeogenesis. This is associated with a loss of muscle, including heart  muscle. In the final phase protein is protected, so that it forms only about 10%  of energy source. Most energy comes from ketones produced by the breakdown of  fatty acids. When fat stores are used up there is catastrophic protein  catabolism, but generally other complications arise first.  Conclusions from studies recommend independent medical monitoring after a weight  loss of 10% in lean healthy individuals.7 If the pre-hunger strike weight is  unknown, a maximum of 10 days' hunger strike, or a body mass index of less than  16.5 kg/m2, should be the trigger. Major problems arise at a weight loss of  about 18%.  The main disabling symptom is feeling faint and dizzy. Hunger strikers learn to  stand up very slowly and may become almost bed bound. This may affect their  ability to state their case. Bradycardia and drop in blood pressure are well  recognised as effects of even relatively short fasting and were seen in all the  individuals studied closely.4 5 Orthostatic hypotension was present by about day  20 in all cases in which it was recorded and in at least one case was almost  disabling. Weakness and lightheadedness was common. The cause of this is not  clear, but could be partly due to electrolyte imbalance. Although thyroxine  concentrations are maintained in fasting, tri-iodothyronine is converted rapidly  to an inactive metabolite, thus reducing effective thyroid function. This is an  important physiological protective function but will lead to weakness and a  sensation of feeling cold. Abdominal pain was described by around three quarters  of those studied, even in the early stages.5  Dehydration is a risk in voluntary total fasting, as individuals may lose their  feelings of thirst and hunger.1 This is in complete contrast to prolonged severe  undernutrition, where people may drink to relieve feelings of hunger.6 Average  fluid intake needs to be maintained at around 1.5 l/day. Ideally water should be  supplemented with up to 1.5 g sodium chloride (half a teaspoon of salt) per day.  More than this may precipitate hypokalaemia, and monitoring of potassium  concentrations may be helpful where possible.  Of the five individuals monitored closely, one developed symptomatic  hypokalaemia, which eventually needed intravenous rectification. This individual  went on to develop acute Werneke's encephalopathy. The risk is increased by  ingested glucose; some hunger strikers eat small amounts of chocolate that are  brought in by friends trying to help.  The study of detainees showed 77% of hunger strikers to be clinically depressed  at the time of admission to hospital, measured by an independent psychiatrist,  although they also demonstrated features similar to those of the post-traumatic  stress syndrome.5 Emotional liability is a later feature of voluntary total  fasting.  Once a hunger strike of more than three weeks is over, re-alimentation is  potentially dangerous. Werneke's encephalopathy has been recorded in patients  taking inappropriate food after fasting. Ingesting carbohydrate after fasting  will also cause a reverse of the initial naturesis, causing measurable weight  gain and potentially acute oedema. In South Africa, diluted proprietary lactose  free balanced feed was used until a light diet was tolerated.5 Elsewhere, boiled  vegetables have been the nutrients taken in the initial period. The patient  needs to consume small amounts of food which are high in neither processed  sugars nor protein. Hospital monitoring needs to be continued for several days  after eating has restarted.  Cardiac problems are potential hazards of refeeding. Hypokalaemia is a risk, and  a sudden increase in fluid volume can precipitate cardiac failure as the  physiological load is increased. The bradycardia and hypotension of starvation  resolve and often overshoot.6 The exact cause is unclear. These fatalities may  be related to loss of cardiac muscle in parallel to skeletal muscle loss. The  deaths were also associated with prolonged QT intervals on electrocardiographic  monitoring. Laboratory studies showed that the QT interval was one of the  variables that took the longest to recover on refeeding.6  Hunger strikers are not aware of the complex physiological processes that they  are disrupting or the risks on restarting eating. Doctors working with hunger  strikers must be aware of the processes and potential problems so that they can  advise them fully.  *Michael Peel, Senior medical examiner a a Medical Foundation for the Care of Victims of Torture, London NW5 3EJ

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