Constitutional syndrome symptoms, causes and treatment

Egbert Haynes
Constitutional syndrome symptoms, causes and treatment

The constitutional syndrome o syndrome of the 3 "A" is a disease characterized by 3 components: asthenia, anorexia and weight loss or significant weight loss that is involuntary. This syndrome must occur not accompanied by any symptoms or signs that guide the diagnosis of the suffering of a disease of a certain organ or system.

Constitutional syndrome constitutes a clinical challenge for professionals, as it can be difficult to diagnose and requires a thorough evaluation to detect it. In addition, it can have many causes, these being very diverse.

The constitutional syndrome can have different levels of severity, where the highest degree is cachexia, which is characterized by significant weight loss, fatigue, muscle atrophy and malnutrition; and is sometimes linked to the development of cancer.

On the other hand, it is a condition that can occur in all ages; although it is more common in advanced ages, since in these stages there is usually lack of appetite and weakness.

There are different concepts in the literature to define this condition, such as general syndrome, general affectation syndrome, cachexia-anorexia-asthenia syndrome, cachectic syndrome, etc..

Article index

  • 1 Components of the constitutional syndrome
    • 1.1 Asthenia
    • 1.2 Anorexia
    • 1.3 Slimming
  • 2 What types are there?
  • 3 Causes
    • 3.1 Non-tumor organic diseases (in 40% of patients)
    • 3.2 Tumors or neoplasms 
    • 3.3 Neurological diseases
    • 3.4 Psychiatric causes
    • 3.5 Social causes
  • 4 Diagnosis
  • 5 What is its prevalence?
  • 6 Treatment
    • 6.1 Multidisciplinary intervention
    • 6.2 Drugs
  • 7 References

Components of the constitutional syndrome


It means lack of energy or physical and mental weakness to carry out daily activities that were previously carried out normally, and is the least obvious manifestation of this syndrome.

Approximately 25% of patients who come to the consultation say they have fatigue or weakness, although it does not mean that they will present this syndrome.

If it appears in isolation, without other symptoms, it can even be functional because it gives the signal for our body to rest in the face of long periods of stress. However, in this syndrome it is accompanied by other manifestations, so it constitutes a problem to be treated.

Organic and functional asthenia differ in that they have different causes, in duration (functional lasts longer), fluctuating course, resistance to physical exercise, and other symptoms (in functional it appears imprecise, little delimited).

Faced with this situation, the professional will first try to rule out possible organic causes. 


In this case, it is defined as a significant lack of appetite not caused by other problems such as those associated with the oral cavity, loss of teeth, or lack of smell. That is, it is checked if it is due to other specific causes.

According to Suárez-Ortega et al. (2013), it ends up being developed by many processes and it is usual that little by little it ends in cachexia (severe malnutrition) or even death. Since our body needs nutrients to survive.

To find out if a person has reached cachexia, the following criteria are used:

  • Unintended weight loss of more than or equal to 5% in less than 6 months.
  • Body mass index (BMI) less than 20 in those under 65, and under 22 in those over 65.
  • Low body fat index (less than 10%).
  • Low albumin levels.
  • Elevated blood cytokines.

Lack of appetite is associated with the next component, that of weight loss or weight loss.


It involves an involuntary loss of weight, mainly of fat tissue. This begins to be considered serious when 2% of the weight is lost in a non-voluntary way in a month, in 3 months more than 5% and in 6 months, more than 10%.

This weight loss can be associated, as we said, with the previous point (lack of hunger), problems in the digestive system, poor absorption of nutrients, sitophobia or fear of eating or dementia. If it continues despite increasing caloric intake, it may be due to diabetes mellitus, hyperthyroidism or diarrhea.

In cancer, this weight loss can be due to multifactorial causes: digestive tumors that compress the organs, activation of necrosis factors, or side effects of other treatments.

In constitutional syndrome it is important to know that this loss is not due to a period of voluntary diet, diuretics or other diseases. To calculate how much weight has been lost, this formula is used (Brea Feijoo, 2011):

Percentage of body weight lost = Usual weight - Current weight x 100 / Usual weight

What types are there?

The typical classification consists of:

- Complete Constitutional Syndrome: presents the 3 components explained above.

- Incomplete Constitutional Syndrome: weight loss, which is an essential symptom, is accompanied either only by asthenia, or only by anorexia.


The main causes consist of:

Non-tumor organic diseases (in 40% of patients)

The syndrome is often due to or linked to gastrointestinal diseases, such as intestinal inflammation, ulcers, being celiac, swallowing problems, pancreatitis, etc. It can also be associated with diseases of the endocrine system such as hyper- or hypothyroidism, diabetes mellitus or, in more rare cases, pheochromocytoma or hyperparathyroidism..

On the other hand, it can arise from infections such as tuberculosis, fungemia, parasites, HIV, etc. Or be related to connective tissue, lung or kidney diseases. In the latter, the weight loss associated with hemodialysis is the situation that produces the most morbidity and mortality.

Cardiovascular alterations can be part of the etiology of the constitutional syndrome, causing the individual to lose weight for multiple reasons such as hypercatabolism (degradation or synthesis of proteins very quickly) or lack of appetite.

It is repeatedly linked to mesenteric ischemia (causing a lack of blood supply to the small intestine). On the other hand, cachexia has been associated with severe heart failure.

Curiously, a person who takes many drugs can also develop this syndrome, mainly causing weight loss in the elderly..

Tumors or neoplasms 

The constitutional syndrome can be caused by tumors (about 25% of those affected) or neoplasms, which consists of the development of new tissue in some part of the body, and can be malignant or benign.

In 50% of patients with tumors they have metastasis when diagnosed. The most common are gastrointestinal, followed by genitourinary and then oncohematological.

Neurological diseases

Neurological deterioration gradually produces visceral dysfunction and, therefore, a reduction in food intake. The most frequent associated with the syndrome are Stroke, dementia, Multiple Sclerosis or Parkinson's.

Psychiatric causes

Mental disorders, surprisingly, can also set up a cause for constitutional syndrome. For example, depression can lead to this condition in 1 in 5 affected. Mainly these disorders include eating disorder, dementia or somatization disorder.

Social causes

It is important to bear in mind that, in more disadvantaged areas of the world, especially older adults, can present this syndrome due to not being able to access adequate food.

In a study by Hernández Hernández, Matorras Galán, Riancho Moral and González-Macías (2002) highlight the importance of studying the etiology of this syndrome. 328 patients with the constitutional syndrome were analyzed and their etiology was organized by frequency, being from more to less frequent: malignant tumors, psychiatric disorders and organic diseases in the digestive tract..


To diagnose it, the criteria that we have previously exposed must be met, classifying as complete or incomplete type.

Once the professional ensures that he meets these diagnostic criteria, the patient will be asked about his personal history (illnesses, occupation, housing ...) and family (if there is a history of other diseases, cancer or mental disorders).

Data will be obtained on physical activity, or if you lead a sedentary or active life, how to eat, if you consume drugs or drugs. To know the severity of the symptoms, the duration of these and in what way it is affecting the life of the person will be questioned.

As for the physical examination, a blood test, urine test, a basic biochemical test, checking for hidden blood in the stool and abdominal ultrasound are usually performed..

If it has not been possible to reach a specific diagnosis even after exhaustive examination, the diagnosis of constitutional syndrome of unknown origin can be reached (after a minimum of 3 weeks of inpatient study). And it is recommended that a follow-up be carried out every two months at the beginning, and later, every six (Rodríguez Rostan, 2015).

What is its prevalence?

According to Suárez-Ortega et al. (2013) in the Hospital Universitario de Gran Canaria “Doctor Negrín” there is a high prevalence of the constitutional syndrome (approximately 20%).

On the other hand, in the study by Hernández Hernández, Matorras Galán, Riancho Moral and González-Macías (2002), they analyzed patients with this syndrome and found that 52% of the patients were men and 48% women. The mean age of the patients was 65.4 years, although the ages ranged from 15 to 97 years.

In addition, in 44% of those affected, at least one more concomitant disease was found, and in 24% more than one associated condition.


Obviously, the treatment of constitutional syndrome is individualized, that is, it is fully adapted to the symptoms and problems that each patient presents..

For this, in addition to taking into account the symptoms, the etiology, the phase of the disease, the therapeutic options that exist, the impact of the problem on the functioning of the person, etc..

Multidisciplinary intervention

The best way to address the constitutional syndrome is through a multidisciplinary intervention, involving several professionals: doctors, nurses, nutritionists, occupational therapists, physiotherapists, psychiatrists, etc..

In the first place, it insists on a nutritional change of the patient supervised by a professional. It is sought that the affected person increases the amount of calories they consume through a hypercaloric diet adjusted to their preferences and needs, avoiding food restriction. In some cases it may be advisable to take nutritional supplements.


In general in this syndrome, certain drugs such as megestrol acetate or low doses of corticosteroids (such as dexamethasone or prednisone) may be useful, which serve to improve symptoms of anorexia and loss of energy (asthenia). Other drugs used are cyproheptadine and metoclopramide..

However, as this syndrome can be so variable in each individual, the risks and benefits of taking these drugs should be individually assessed, since they can have adverse effects such as hypertension, insomnia, adrenal insufficiency, gastrointestinal disorders, etc..

It is also important that if there are complications that have generated the disease, they act on them. That is why it is essential to know what has caused the syndrome, because that is where the treatment will focus: if there is hyperthyroidism, neoplasms, neurological diseases, gastrointestinal problems, etc. A specific treatment will be created to act on the cause.


  1. Brea Feijoo, J. (s.f.). Constitutional syndrome. Retrieved on July 21, 2016, from
  2. Castro Alvirena, J., & Verdejo Bravo, C. (2014). Diagnostic protocol and treatment of constitutional syndrome in the elderly. Medicine, 11 (62), 3720-3724.
  3. Ramírez, F. B., Carmona, J. A., & Morales Gabardino, J. A. (2012). Initial study of the patient with constitutional syndrome in primary care. FMC. Continuing Medical Education in Primary Care, 19, 268-277.
  4. "General syndrome". (s.f.). Retrieved on July 21, 2016, from the University of Cantabria.
  5. Suárez-Ortega, S., Puente-Fernández, A., Santana-Baez, S., Godoy-Díaz, D., Serrano-Fuentes, M., & Sanz-Peláez, O. (2013). Constitutional syndrome: clinical entity or mixed bag. IMSS Medical Journal, 51(5), 532-535.

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