Underweight: Causes

Pathogenesis (development of disease)

The cause of underweight is an imbalance between energy intake and energy expenditure. The result is a negative energy balance and means weight loss and consequent secondary diseases.

Etiology (causes)

Biographic causes

• Age – increasing age; in 3-4% of men and women, BMI (body mass index/body mass index) is in the underweight range* (< 18.5) in senior age – due to deterioration of dental statuś (poorer chewing), poorer swallowing, changes in taste and smell sensation, decreased appetite, and malabsorption.

Behavioral causes

• Nutrition
  • Malnutrition and malnutrition – low fat and low calorie.
  • Raw foodists
  • Socially motivated fasting
  • Inadequate intake during pregnancy
  • Performance-related increased energy and nutrient requirements, e.g. in competitive athletes.
  • Orthorexia nervosa – unlike the eating disorders anorexia nervosa and bulimia, the focus of orthorectics is not the quantity of food, but the perceived quality. This eating disorder often leads to malnutrition and malnutrition.
• Consumption of stimulants
  • Alcohol (woman: > 40 g/day; man: > 60 g/day).
• Physical activity
  • Insufficient physical activity in old age – breakdown of metabolically active muscle tissue.
• Psycho-social situation
  • Drug addiction

Causes related to disease

Gradual weight loss without performance kink

Respiratory system (J00-J99)

• Pulmonary emphysema (pulmonary hyperinflation).

Blood, blood-forming organs – immune system (D50-D90).

• Pernicious anemia – anemia (anemia) caused by a deficiency of vitamin B12 (cobalamin).

Infectious and parasitic diseases (A00-B99).

• Infections with fungi, unspecified, rare!

Endocrine, nutritional and metabolic diseases (E00-E90).

• Malnutrition
• Food allergy
• Food intolerances (eg fructose intolerance or lactose intolerance), rare!

Liver, gallbladder and bile ducts – pancreas (pancreas) (K70-K77; K80-K87).

• Chronic pancreatitis (inflammation of the pancreas).

Musculoskeletal system and connective tissue (M00-M99).

• Diseases of the rheumatic system, unspecified.

Neoplasms – tumor diseases (C00-D48)

• Malignant neoplasms of all types
• Benign neoplasms of the gastrointestinal tract
• Pheochromocytoma – usually benign (benign) tumor (about 90% of cases), which originates mainly from the adrenal gland and can lead to hypertension crises (hypertensive crisis).

Psyche – nervous system (F00-F99; G00-G99).

• Alcohol abuse (alcohol dependence)
• Apoplexy (stroke)
• Eating disorders – anorexia nervosa (anorexia), bulimia nervosa (binge eating disorder).
• Dementia
• Depression
• Alzheimer’s disease and other dementias
• Parkinson’s disease
• Neuromuscular diseases, unspecified.

Symptoms and abnormal clinical and laboratory findings not elsewhere classified (R00-R99).

• Olfactory and gustatory disturbances

Other causes

• Elderly – e.g. due todental status, dysgeusia (taste disorder), dysphagia (swallowing disorder), chronic diseases, medications, etc.
• Poverty
• Isolation
• Heavy physical labor

Laboratory diagnoses – laboratory parameters that are considered independent risk factors.

• Fructose intolerance (fruit sugar intolerance).
• Hypercalcemia (excess calcium)
• Lacotoseintolerance (lactose intolerance).

Medication

• ACE inhibitors (antihypertensives)
• Antibiotics – drugs used to treat bacterial infections.
• Levodopa – drug used in Parkinson’s disease.
• Metformin – oral antidiabetic (drug used in diabetes mellitus).
• Non-steroidal anti-inflammatory drugs – painkillers such as ibuprofen or diclofenac.
• Serotonin reuptake inhibitors (SSRIs = Selective Serotonin Reuptake Inhibitor) – medications used primarily for depression, such as fluoxetine or citalopram.

Gradual weight loss with a drop in performance

Respiratory system (J00-J99)

• Chronic obstructive pulmonary disease (COPD).
• Pulmonary emphysema (pulmonary hyperinflation)

Blood, blood-forming organs – immune system (D50-D90).

• Pernicious anemia – form of anemia.

Endocrine, nutritional and metabolic diseases (E00-E90).

• Malnutrition
• Kwashiorkor – severe protein malnutrition, most common among children in developing countries.
• Malnutrition
• Marasmus – generalized starvation state with loss of body protein and body fat.
• Cushing’s disease/Cushing’s syndrome – disease caused by an excess of glucocorticoids.
• Malnutrition

Cardiovascular system (I00-I99)

• Chronic heart failure (heart failure) – in patients with chronic heart failure, the relatively common chronic weight loss has been known since Hippocrates as the syndrome of cardiac cachexia; weight loss in chronic heart failure is considered an isolated independent risk parameter

Infectious and parasitic diseases (A00-B99).

• Infections with fungi, unspecified, rare!
• Infections with parasites, unspecified.

Liver, gallbladder and bile ducts – Pancreas (pancreas) (K70-K77; K80-K87).

• Chronic liver disease, for example, chronic hepatitis, cirrhosis of the liver.
• Chronic pancreatitis (inflammation of the pancreas).

Mouth, esophagus (esophagus), stomach, and intestines (K00-K67; K90-K93).

• Chronic inflammatory bowel disease such as Crohn’s disease or ulcerative colitis.
• Diseases of the mouth that prevent/difficulty with food intake
• Gastric ulcers (stomach ulcers)
• Celiac disease (gluten-induced enteropathy) – chronic disease of the mucosa of the small intestine (small intestinal mucosa), which is based on hypersensitivity to the cereal protein gluten.
• Condition after surgery on the small intestine; short bowel syndrome.
• Condition after gastric resection (partial stomach removal)/gastrectomy (stomach removal).

Musculoskeletal system and connective tissue (M00-M99)

• Diseases of the rheumatic system, unspecified.
• Sarcopenia (muscle weakness or muscle wasting).

Neoplasms – tumor diseases (C00-D48)

• Malignant neoplasms of all types

Psyche – nervous system (F00-F99; G00-G99)

• Alcohol abuse (alcohol dependence)
• Apoplexy (stroke)
• Dementia – dementia patients lose about four times as much body weight annually as patients of the same age without dementia due to chronic inflammation (inflammation), secondary diseases and the sometimes increased urge to exercise
• Depression
• Alzheimer’s disease and other dementias
• Parkinson’s disease
• Orthorexia nervosa – unlike the eating disorders anorexia nervosa and bulimia, the focus of orthorectics is not the quantity of food, but the perceived quality. This eating disorder often leads to malnutrition and malnutrition.
• Neuromuscular diseases, unspecified.

Symptoms and abnormal clinical and laboratory findings not elsewhere classified (R00-R99).

• Dysphagia (dysphagia of swallowing), which occurs primarily in neurologic disease, such as apoplexy (stroke)
• Olfactory and taste disorders

Genitourinary system (kidneys, urinary tract – sex organs) (N00-N99)

• Renal insufficiency (kidney weakness).
• Pyelonephritis (inflammation of the renal pelvis), chronic.

Other causes

• Diet
  • Inadequate intake during pregnancy
  • Performance-related increased energy and nutrient requirements, e.g. in competitive athletes.
• Psycho-social situation
  • Drug addiction
• Intestinal resection, short bowel syndrome.
• Gastric resection

Laboratory diagnoses – laboratory parameters that are considered independent risk factors.

• Hypercalcemia (excess calcium).

Environmental pollution – intoxications (poisonings).

• Ingestion of radioactive substances (eg.B. Radionucleotides)

Rapid weight loss with performance kink

Endocrine, nutritional and metabolic diseases (E00-E90).

• Diabetes mellitus type 1 – due to increased catabolic metabolism (catabolism).
• Fluid deficit
• Hyperthyroidism (hyperthyroidism)
• Addison’s disease – primary adrenocortical insufficiency leading to failure of cortisol and aldosterone production.

Cardiovascular system (I00-I99).

• Endocarditis (meningitis of the heart).

Liver, gallbladder, and bile ducts-pancreas (pancreas) (K70-K77; K80-K87).

• Acute pancreatitis (inflammation of the pancreas).

Infectious and parasitic diseases (A00-B99).

• Diarrhea, acute
• HIV infection
• Whipple’s disease – a chronic recurrent disease caused by the gram-positive rod bacterium Tropheryma whippelii, which can affect the entire body (symptoms: Fever, joint pain, brain dysfunction, weight loss, diarrhea, abdominal pain and more).
• Wasting syndrome – loss of body substance, especially muscle; HIV infection as a cause.
• Tuberculosis (consumption)

Mouth, esophagus (esophagus), stomach, and intestines (K00-K67; K90-K93).

• Malabsorption – disorder of food absorption.
• Obstruction in the gastrointestinal tract as in ileus (intestinal obstruction).

Neoplasms – tumor diseases (C00-D48).

• Malignant neoplasms of all types (in the final stage).

Symptoms and abnormal clinical and laboratory findings not elsewhere classified (R00-R99)

• Uremia (occurrence of urinary substances in the blood above normal levels).

Other causes

• Condition after surgery on the small intestine