What is acute anorexia?

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Acute anorexia nervosa is the most advanced stage of anorexia nervosa, which is a very serious mental health disorder. It is the deadliest of all eating disorders and has the highest rate of death of all psychiatric disorders. (1) Sometimes called severe anorexia or extreme anorexia, this stage of anorexia is characterized by a body weight of less than 65% of a person’s “ideal” body weight. (2) Someone with acute anorexia also has the same health complications associated with anorexia, but they are more severe and occur more frequently.

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Signs and symptoms of acute anorexia 

People who suffer from anorexia have a distorted image of their bodies and an intense fear of gaining weight and severely restrict their food intake, limiting both calories and types of food they eat. They may also purge to keep their weight low, by vomiting or using laxatives or diuretics, and/or exercise excessively to burn calories. These behaviors can lead to extreme weight loss, severe malnutrition and life-threatening medical complications. 

In acute cases, the person will often exhibit the same signs of less severe anorexia, such as weight loss, expressing the need for control, skipping meals, irritability, and depression. Those with more severe cases of anorexia will additionally showcase signs related to complications they're experiencing.

Complications of severe anorexia

Severe anorexia can affect nearly every organ. Those suffering from anorexia may experience one or more of the following complications:

Heart complications

A person's cardiovascular health is affected by extreme anorexia. Without the proper nutrients, the heart's structure and function can change. (1) Some medical conditions affecting the heart include:

  • Mitral valve prolapse: The heart has four valves. One of those valves is the mitral valve, and it's responsible for allowing blood flow from the left atrium to the left ventricle. Sometimes, extreme anorexia causes the blood's pathway to close, resulting in mitral valve prolapse. Mitral valve prolapse is a chronic condition but often not life-threatening. Symptoms include an irregular heartbeat, shortness of breath, fatigue, and dizziness.
  • Heart failure: When the heart is too weak to pump blood, it can lead to heart failure. Heart failure does not mean the heart stops working, but it can cause shortness of breath, fatigue, and rapid heart rate. 
  • Cardiac arrest: This is a life-threatening condition when the heart suddenly stops beating. Signs of cardiac arrest are sudden and include collapsing, no pulse, no breathing, and a loss of consciousness. 

Gastrointestinal complications

People with severe anorexia are at risk for gastrointestinal complications due to weight loss and malnutrition. (1) Some conditions include:

  • Gastroparesis: Food moves through the digestive tract by muscle contractions in the stomach. Those muscle contractions slow down or stop with gastroparesis, preventing the stomach from emptying. Signs and symptoms of gastroparesis include vomiting, nausea, bloating, abdominal pain, feeling full after eating small portions, and changes in blood sugar levels. If left untreated, gastroparesis can lead to dehydration and malnutrition. 
  • Liver damage: Those with extreme anorexia tend to have elevated levels of the enzyme aminotransferase, signaling liver damage. Those with liver damage may experience stomach pain, dark urine, fatigue, yellowing of the skin, nausea, and vomiting. 

Skin complications

Skin complications are common among those with extreme anorexia. In mild cases, the individual may have dry or itchy skin. They may develop xerosis cutis, dry skin that becomes irritated, painful, and cracked. (1) If left untreated, xerosis cutis can cause oozing skin, rashes, and peeling. 

Bone and muscle complications

Bones and muscles have trouble developing and staying healthy without the proper nutrients. A few complications that may arise in people with severe anorexia are: 

  • Sarcopenia: Sarcopenia is when the individual loses skeletal muscle mass and strength. (2) The condition is associated with aging. Still, signs and symptoms, such as weakness and the loss of visible muscle definition, are seen in all ages of people with severe anorexia. 
  • Osteoporosis: This condition affects the bones, causing them to weaken with time and putting an individual at risk for breaks and fractures. Signs and symptoms of osteoporosis include back pain or a stooped posture.

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Treatment for severe anorexia

In extreme cases of anorexia, doctors often start by addressing life-threatening complications. Treatment can include a variety of medications and surgeries to keep all the body's organs functioning. Some may also require hospitalization so doctors can monitor vitals, such as hydration levels. 

Once complications are under control, patients typically undergo a refeeding process. Initially, the individual may require a feeding tube to fuel the body. It's vital to re-feed under medical guidance to lower the risk of refeeding syndrome, a potentially fatal condition caused by sudden shifts in electrolytes. (3)

Recovering from severe anorexia

Getting out of immediate danger is the primary goal of severe anorexia treatment, but the next step is to start the recovery journey. Each person's road to recovery is different but typically includes a combination of therapy and nutrition counseling. During recovery, the individual will take care of the physical self and treat mental and emotional complications such as depression, anxiety, and intrusive thoughts. 

The experts at Within Health understand the complexity of eating disorders, including severe anorexia. Within Health offers evidence-based treatment personalized to each individual's unique case. Call our team today to start the recovery.

Disclaimer about "overeating": Within Health hesitatingly uses the word "overeating" because it is the term currently associated with this condition in society, however, we believe it inherently overlooks the various psychological aspects of this condition which are often interconnected with internalized diet culture, and a restrictive mindset about food. For the remainder of this piece, we will therefore be putting "overeating" in quotations to recognize that the diagnosis itself pathologizes behavior that is potentially hardwired and adaptive to a restrictive mindset.


  1. DeNoon, D. J. (2011, July 12). Deadliest Psychiatric Disorder: Anorexia. WebMD. https://www.webmd.com/mental-health/eating-disorders/anorexia-nervosa/news/20110711/deadliest-psychiatric-disorder-anorexia.
  2. Gibson, D., Waters, A., Cost, J., Mascolo, M., & Mehler, P. S. (2020). Extreme anorexia nervosa: medical findings, outcomes, and inferences from a retrospective cohort. Journal of Eating Disorders. https://jeatdisord.biomedcentral.com/track/pdf/10.1186/s40337-020-00303-6.
  3. Cost, J., Krantz, M. J., & Mehler, P. S. (2020). Medical complications of anorexia nervosa. Cleveland Clinic Journal of Medicine, 87(6), 361–366. https://doi.org/10.3949/ccjm.87a.19084
  4. Santilli, V., Paoloni, M., Mangone, M., & Bernetti, A. (2014). Clinical definition of sarcopenia. US National Library of Medicine National Institutes of Health.
  5. Vandergriendt, C. (2020, January 6). Everything you should know about refeeding syndrome. Healthline. Retrieved January 26, 2022, from https://www.healthline.com/health/refeeding-syndrome


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