In many serious chronic diseases, especially in their later stages, it is common to find that the patient is very emaciated. It barely conserves muscle and fat, it is found in the bones and has no strength.
Originally this was considered a symptom of any serious illness, however, it seems that, although it accompanies the main illness, these symptoms would be, in themselves, another illness: cachexia
Below we will discover what this disease is, in what other medical conditions it can appear, what are its causes, diagnosis and treatment.
Cachexia (from Greek “kakos” and “hexis” “bad constitution, bad condition”) is a state of extreme malnutrition, fatigue and general weakness It is a metabolic disorder that is thought to affect around nine million people worldwide, including 80% of people diagnosed with an advanced oncological disease. It involves an extreme loss of weight and muscle mass, making it extremely difficult to carry out daily tasks and being more prone to accidents and being sedentary.
Contrary to what you may think, cachexia cannot be reversed with a high-calorie diet (surplus diet) or a high protein and fat diet (ketogenic diet). The person loses muscle mass and fat due to metabolic problems, not due to malnutrition caused by not being able to consume all the nutrients you need. Likewise, it is not unusual to find relatives and friends of the cachectic person who think that by forcing them to eat they will reverse or slow down the course of the disease.
History of the condition
Although it has been in the last two decades that deserved attention has been paid to this metabolic disorder, the truth is that it is believed that Hippocrates himself described the disease in the 4th century BC. C. Still, cachexia It has been considered a medical condition and not a mere symptom since 2000 when medical research gave it this name and began to study and define it formally.
Currently Cachexia is considered to occur when a person has lost about 5% or more of their body weight over a 12-month period, accompanied by a significant reduction in muscle strength. Clinically, it remains poorly recognized by oncologists, and there are still no standard guidelines to treat it, focusing more on treating the main disease it accompanies, be it cancer, infection, inflammation or autoimmune disorder.
Causes
Cachexia can be seen in the later stages of almost all serious chronic diseases, such as cancer, HIV-AIDS, and infectious diseases such as tuberculosis Between 16 and 42% of people with heart failure, 30% of patients with chronic obstructive pulmonary disease, and 60% of people with kidney disease have cachexia. Normally, this condition tends to go unnoticed among doctors because more attention is paid to the main disease for which the patient is being treated.
Cachexia is physically debilitating. The patient reaches such a state of deterioration that he has very reduced mobility. He has no strength because of his extreme thinness, asthenia and anemia The response to treatments to reverse these symptoms is usually low, so the person will barely recover muscle and fat mass.
Pathophysiology
Cachexia has special physiological characteristics, although it has traditionally gone largely unnoticed or has simply been considered another symptom of the serious illness with which it was accompanied. It is currently considered a metabolic disorder and different hypotheses have been proposed to explain it hypotheses which have served to create drugs with the intention of reversing the effects of this medical condition.
According to the most recent research, what would happen in cachexia is that white adipose tissue or white fat is replaced by brown or brown fat, in which there is an increase in energy expenditure. This phenomenon of browning of white fat occurs before muscle atrophy, a very characteristic symptom in advanced cachexia, and would be due to the action of different mediators of the inflammatory process and the cytokine interleukin-6 (IL-6).
In studies with mice, a relationship has been observed with genes encoding E3 ubiquitin ligase enzymes These enzymes are responsible for labeling proteins to generate cell destruction. Mice that did not have these enzymes were more resistant to muscle loss. It seems that when muscle cells receive a signal from an inflammatory process, tumor or immune cell, these cells begin to produce more E3 ubiquitin ligase enzymes, which would explain their relationship with cancer, autoimmune diseases and inflammation.
A molecular link has also been found with the browning of white fat, which is the increase in UCP1 protein expression This molecule is responsible for uncoupling mitochondrial respiration towards the production of heat or thermogenesis instead of towards the synthesis of ATP, which implies an increase in the mobilization of lipids and an increase in energy expenditure.
Diagnosis
Despite the prevalence of cachexia, diagnostic criteria have been proposed relatively recently, and are still provisional and awaiting standardization. Even so, it is agreed that cachexia should be diagnosed when there is a progressive loss of muscle mass and fat, reduced food intake, problems in carbohydrate, lipid and protein metabolism, reduced quality of life and physical deterioration.
Although until relatively recently the loss of 10% of the individual’s original weight was considered a diagnostic criterion, this criterion alone has been considered too limited to even diagnose a case of malnutrition. Yes, a 5% weight loss in the last 12 months is considered an indicator, but tests and analyzes of nutrient levels are considered more reliable and decisive indicators in the diagnosis of this medical condition.
With the intention of being able to classify the level of severity of cachexia, different evaluation systems have been proposed. Among them we find “Cachexia Staging Score” (CSS) and the “Cachexia Score” (CASCO):
The CSS takes into account weight loss, in addition to the patient’s perceived muscle function, their degree of performance of different physical tasks, loss of appetite and biochemical changes. This scale allows the case to be categorized into four types: non-cachexia, pre-cachexia, cachexia and refractory cachexia The CASCO evaluates whether weight loss, changes in body composition, inflammation, metabolic alterations, immunosuppression, physical performance, anorexia and changes in quality of life.
The treatment of cachexia depends on the underlying disease with which it is accompanied, the general prognosis and the needs of the affected person. The main therapeutic route for cachexia is treat the disease that causes it For example, if we were talking about a person with cachexia associated with AIDS, active antiretroviral therapy would be applied. In any case, it is common to not be able to reverse cachexia, since it usually appears in advanced diseases.
Despite this, there are different therapeutic options to reverse a little or, at least, slow down the progress of cachexia.
1. Exercise
In therapy, physical exercise is usually recommended, since activates and strengthens skeletal muscles People who suffer from cachexia usually report that they exercise little and few follow a routine, either due to lack of motivation or because they believe that exercise can worsen their symptoms or even harm them.
2. Medication
As one of the symptoms of cachexia is loss of appetite, drugs that stimulate it are usually used as a therapeutic route. In any case, appetite stimulants do not stop muscle loss and can have side effects that further deteriorate the patient’s condition. Among these drugs we find glucocorticoids, cannabinoids and progestins Antiemetics such as 5-HT3 antagonists are also used if nausea is a common symptom.
3. Nutrition
Among the diets that seem to be able to reduce the loss of muscle mass, we have those that have a high amount of calories and proteins, although this is not a guarantee that the patient will at some point recover the lost muscle mass.
