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د. ضياء الليلة

عدد الاوراق (4)

13/11/2012

Unintentional weight loss

Definition
The involuntary decline in total body weight over time
Clinically important weight loss:
1. loss of more than 5 percent of usual body weight over six months.
2. Involuntary weight loss exceeding 20 percent of usual weight is often associated with:
Severe protein-energy malnutrition
Nutritional deficiencies
Multiorgan dysfunction


Mechanisms
In general, wt.loss may be the result of:
Inadequate food intake
Inadequate absorption
Inadequate retention
Or
Increased utilization

Causes

1. Weight loss with increased appetite
2. Weight loss with decreased appetite

Major causes of weight loss

Involuntary weight loss with increased appetite
Hyperthyroidism
Uncontrolled diabetes mellitus
Malabsorption syndromes
Marked increase in physical activity

Involuntary weight loss with decreased appetite

a. Medical disorders
Malignancy (particularly gastrointestinal, lung, lymphoma, renal, and prostate cancers)
Gastrointestinal diseases (including peptic ulcer disease, malabsorption, diabetic enteropathy, dysphagia, inflammatory bowel disease, hepatitis, Zenker's diverticulum, paraesophageal hernia)
Endocrine diseases (hyperthyroidism, diabetes, adrenal insufficiency)
Infectious diseases (HIV, viral hepatitis, tuberculosis, chronic fungal or bacterial disease, chronic helminth infection, lung abscess)


Severe heart, lung, or kidney disease (cardiac cachexia from heart failure; pulmonary cachexia from severe obstructive or restrictive lung disease; renal failure, nephrotic sydrome, chronic glomerulonephritis)
Neurological diseases (stroke, dementia, dysphagia, Parkinson disease, amyotrophic lateral sclerosis)
Noninfectious chronic inflammatory diseases (sarcoidosis, severe rheumatoid arthritis, giant cell vasculitis)

b. Psychiatric disorders

Affective disorders (depression, bipolar disorder, generalized anxiety disorder)
Food-related delusional manifestations of other psychiatric disorders

c. Drugs

Alcohol
Opiates
Amphetamines and cocaine
Drug withdrawal syndromes (withdrawal after chronic high-dose psychotropic medications or cannabis)
Adverse effects of prescription drugs (topiramate, zIs, levodopa, digoxin, metformin, exenatide, liraglutide, NSAIDS, and anticancer and antiretroviral drugs)onisamide, SSR
Herbal and other nonprescription drugs (5-hydroxytryptophan, aloe, caffeine, cascara, chitosan, chromium, dandelion, ephedra, garcinia, glucomannan, guarana, guar gum, herbal diuretics, nicotine, pyruvate, St. John's wort)

Other causes

Change of surroundings
Irregularity of meals
Over-long hours of work
Taking a new occupation
Any disease which produces sleeplessness or persistent pain may lead to serious loss of weight.


Idiopathic
Up to one-quarter of all cases have no identifiable cause, despite extensive investigation.
People with no known cause of weight loss generally have a better prognosis than people with known causes

EVALUATION

There is no single diagnostic approach for all patients
The work-up should be individualized, based on findings from the patient's history and physical examination
If no abnormality is identified after initial evaluation, the patient should be reassessed in one to six months

History

Important points:
1. Documenting weight loss
2. Determine the duration and pattern of weight loss, including past fluctuations in weight and whether weight loss is progressive or stabilized
3. Rapidity of weight loss:
The more rapid the wt.loss, the more likely it is due to organic disease.
4. Intention to lose weight.
5. Changes in appetite.
6. Caloric intake .
7. Physical activity.
7. Medical
8. Psychological and functional factors.
9. Drugs.
The nine D's associated with weight loss may help elicit these factors, particularly in the elderly :


The nine D's
Dentition
Dysgeusia
Dysphagia
Diarrhea
Depression
Dementia
Disease
Dysfunction
Drugs

How to document weight loss

a. Measure weight directly
b. Change in clothing size
c. Corroboration of weight loss by a relative or friend
d. Numerical estimate of weight loss provided by the patient are suggestive enough of true weight loss

Physical examination

The clinician should assess :
The overall appearance
Affect
Skin changes (eg, melanoma or spider angiomata)
Presence of lymphadenopathy
Cardiopulmonary status
Hepatosplenomegaly
Abdominal mass
Breast/prostate abnormalities
Rectal examination with stool hemoccult
Neurologic deficit
Two physical signs commonly associated with serious causes of wt. loss:
Anemia
Fever
These must be specifically excluded both clinically and by appropriate investigations.


Diagnostic testing
1. Laboratory testing
Complete blood count with differential
Chemistries (electrolytes, glucose, calcium)
Renal functions
Hepatic functions
Urinalysis
TSH
Serology for HIV infection
ESR or C-reactive protein (CRP).
Imaging study
- Chest radiograph
- Others include:
USG , CT, MRI

Predictors of malignancy among patients with unexplained involuntary weight loss



Hyperthyroidism

Due primarily to increased catabolism
Other causes include:
Increased intestinal motility
Malabsorption.
Most patients have hyperphagia.
In older patients, however, hyperthyroidism often causes anorexia with accelerated weight loss.


Diabetes mellitus
Uncontrolled diabetes mellitus is a common cause of weight loss with increased appetite, particularly with new-onset type 1 diabetes mellitus.
There is a loss in lean body mass as well as loss of extracellular and cellular water due to the osmotic diuresis from glucosuria
The etiology of weight loss in uncontrolled diabetes is likely multifactorial, a combination of anorexia, depression, pain, malabsorption, gastroparesis, and enteropathy

Type 2 diabetes

- Weight gain is much more common
- Some patients with type 2 diabetes can occasionally present with:
Diabetic neuropathic cachexia:
An unusual and poorly understood syndrome characterized by:
Profound weight loss (as much as 60 percent of body weight).
Severe neuropathic pain of the anterior thighs
There is no strong relationship between glucose control and resolution of weight loss, which usually happens spontaneously after months or years.

Chronic primary adrenal insufficiency

Often presents with significant weight loss.
Other associated signs and symptoms are more prominent: dehydration, anorexia, lassitude, fatigue, and weakness.
Adrenal insufficiency that is acute or due to hypothalamic or pituitary dysfunction is usually not associated with weight loss.

Malabsorption
May cause weight loss with increased or normal appetite.
However, celiac disease, one of the more common causes of malabsorption, usually does not present with weight loss or diarrhea in adults.
More commonly, adult patients with celiac disease present with iron deficiency or other manifestations of nutritional malabsorption.


Malignancy (cancer cachexia)
- Anorexia and weight loss are present in over 50% of cancer patients at the time of diagnosis
Cancer cachexia involves complex metabolic abnormalities that decrease muscle mass.
Mediated, at least in part, by tumor necrosis factor alpha and interleukins 1 and 6.

HIV
Weight loss is usually episodic
Common causes:
- Secondary infections.
- Gastrointestinal diseases.

Anorexia nervosa

- Wasting is a prominent symptom.
- It affect young women.
- Remarkable loss of appetite
- The patient remain surprisingly well and active.
- Other features: amenorrhea,subnormal temperature
- Low basal metabolic rate
- Sever constipation

Alcohol effect

Variable depend on food intake:
Beer drinker tend to become obese and pot-bellied
Heavy spirit drinkers tend to lose weight
When alcoholism leads to peripheral neuropathy , there is often rapid and extreme wt,loss.


Why Elderly are more prone?
Age-associated physiologic changes:
Declining chemosensory function (smell and taste),
Reduced efficiency of chewing
Slowed gastric emptying
Alterations to the neuroendocrine axis (including changes in levels of leptin, cholecystokinin.
Elderly people are less able to adapt to periods of over- and undereating and less likely to return to their usual body weight after such periods which makes them more susceptible to weight change.
Medications : many elderly people take medications, mostly for chronic conditions

Management

Depends on the specific underlying cause.











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