Part 1: pathophysiology, causes and types, by Sharon Edwards, appeared in the September issue. There are links between the development and formation of oedema and some of the common conditions observed in clinical practice. In-depth knowledge of oedema formation helps us to understand our practice better, and the interventions, management, prevention, and specialist care these types of patients require.
Oedema is the abnormal collection of fluid in the tissues, which can occur in the interstitial or intracellular spaces Edwards, It can be the result of two processes:. The balance between filtration and absorption can be altered as a result of everyday occurrences or as part of a disease process. The former is the movement of fluid from the capillaries into the interstitial space, while the latter is the movement of fluid into capillaries from the interstitial space Germann and Stanfield, Oedema forms when there is an increase in hydrostatic pressure either at the arterial end of the capillary or at the venous end.
This raises the pressure of blood in the capillary and causes an increase in the rate of filtration Edwards, This will occur, for example, if hydrostatic pressure increases by 5mmHg - from 38mmHg to 43mmHg in the arterial end and from 16mmHg to 21mmHg in the venous end - but when oncotic pressure remains the same at 25mmHg. This leaves a deficit pressure of 12mmHg which is the result of adding 17 to -5 , leading to an increase in filtration and a reduction in absorption.
As the lymphatic system drains only a certain amount of fluid, large amounts of fluid will collect in the interstitial space and cause the formation of interstitial oedema Figure 1. Immobility - When a person stands up, capillary hydrostatic pressure increases in the lower parts of the body because the column of blood raises hydrostatic pressure in the lower arteries and veins.
When someone stands very still the problem is exacerbated because the inactivity minimises the action of the skeletal muscle pump, causing pressure in the lower veins to rise further, owing to venous pooling, in turn augmenting an increase in capillary hydrostatic pressure.
Hypertension - When blood pressure increases, the individual is at risk of developing oedema, as the increase in blood pressure is reflected through the circulatory system at the capillaries as the hydrostatic pressure. As such, this increases filtration and reduces absorption processes. Peripheral vascular disease - When the pressure increases in the legs as a result of PVD, the principles outlined above will apply, leading to oedema and serious swelling of the legs. An increase in swelling can lead to hypoxic cell damage or stimulation of the inflammatory response see below.
Heart failure - The pressure can rise in either the systemic veins or pulmonary veins, depending on which side of the heart is affected Carelock and Clark, Failure of the left ventricle will cause pressure to rise in the pulmonary veins and can lead to oedema formation in the lungs, known as pulmonary oedema. Right-sided heart failure complete heart failure is characterised by an increase in hydrostatic pressure in the vena cava and other systemic veins.
This tends to cause oedema in systemic tissues, and oedema will form in areas such as the wrists and ankles. Renal failure - Certain types of damage to the kidneys will interfere with their ability to eliminate excess water and solutes into urine, resulting in accumulation of excess fluid in the body Edelstein et al, Blood volume increases and blood pressure rises throughout the cardiovascular system.
The increase in pressure raises capillary hydrostatic pressure, in turn increasing filtration and reducing absorption processes, leading to oedema. Oedema also forms when there is a reduction in plasma proteins in the extracellular fluid. So any condition that leads to a reduction in plasma proteins will promote changes in capillary absorption.
For example, if the oncotic pressure on the arterial side were to fall by 5mmHg from 25mmHg to 20mmHg - and the same level is reflected at the venous end - changes will occur. The hydrostatic pressure in the extracellular fluid capillary is 38mmHg and in the interstitial fluid is 1mmHg.
The liver manufactures plasma proteins. Liver damage can cause plasma protein concentration to decrease, lowering plasma oncotic pressure. This can lead to formation of ascites. Kidney damage can increase elimination of plasma proteins in the urine - nephrotic syndrome. This loss of protein triggers a reduction in capillary absorption because of the drop in plasma oncotic pressure.
Malnutrition causes insufficient amounts of proteins to be digested through the gastrointestinal tract Edwards, If the malnourished state is allowed to continue, the proteins stored in the body are broken down by the liver and used as a source of energy to maintain cellular and organ function. This leaves inadequate amounts of protein in the plasma to produce effective plasma oncotic pressure. Oedema that occurs with issue injury and infection differs.
The tissue damage leads to cellular changes, which cause a severe inflammatory response that ends with repair to damaged cells and tissue Huddleston, Following damage, the injured endothelium releases mediators and stimulates the clotting cascade.
The mediators of inflammation are histamine, kinins, prostaglandins, complement and the cytokines. Type 1 diabetes can affect anyone of any age, but is more common in people under 30 years.
Henoch-Schonlein purpura causes a purple spotted skin rash which lasts around one to four weeks, and is often marked by relapses. Content on this website is provided for information purposes only. Information about a therapy, service, product or treatment does not in any way endorse or support such therapy, service, product or treatment and is not intended to replace advice from your doctor or other registered health professional.
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The State of Victoria and the Department of Health shall not bear any liability for reliance by any user on the materials contained on this website. Skip to main content. Conditions and Treatments. Home Conditions and Treatments. Fluid retention oedema. Actions for this page Listen Print. Summary Read the full fact sheet. On this page. Symptoms of fluid retention Causes of fluid retention Medical conditions that may cause fluid retention Diagnosis of fluid retention Treatment for fluid retention Self-care options for fluid retention Where to get help.
Symptoms of fluid retention Symptoms of fluid retention can include: swelling of affected body parts feet, ankles and hands are commonly affected aching of affected body parts stiff joints rapid weight gain over a few days or weeks unexplained weight fluctuations when pressed, the skin may hold the indent for a few seconds pitting oedema in other cases, the skin may not hold an indent when pressed non-pitting oedema.
The skin retains fluid and swells in response to burn injuries menstrual cycle — some women experience oedema in the two weeks prior to menstruation pregnancy — hormones encourage the body to hold onto excess fluid the pill — oral contraceptives that include oestrogen can trigger fluid retention dietary deficiency — such as insufficient protein or vitamin B1 thiamine in the diet medications — certain drugs, including high blood pressure medication antihypertensives , corticosteroids and nonsteroidal anti-inflammatory drugs NSAIDs are known to cause fluid retention chronic venous insufficiency — weakened valves in the veins of the legs fail to efficiently return blood to the heart.
The pooling of blood can result in varicose veins. Edema itself is not a disease, but a symptom. Less severe forms of edema can result from lifestyle and general health factors such as:. If left unchecked, peripheral and general edema can result in the overlying skin becoming stretched, developing infections or ulcerating. Also, decreased blood circulation can lead to blood clots in the deep veins of the body, also known as deep vein thrombosis.
Depending on diagnosis, the following precautions may help minimize the risk of developing edema in at-risk patients and to minimize complications in patients already exhibiting symptoms:. Treating edema should always begin with diagnosing and treating the underlying cause.
Depending on the cause, diuretics may be prescribed to increase water output from the kidneys and combining these with a low-sodium diet can help to decrease fluid retention. Other medications and treatments may be prescribed as well. Peripheral edema can also be treated by wearing prescribed compression stockings or garments, which apply more pressure to the affected area and can help force fluid to be reabsorbed into the intravascular compartment.
Cleveland Clinic. Accessed April 25, Cunha JP. MedicineNet, Inc. Klabunde RE. Cardiovascular Physiology Concepts. Updated July 11, Mayo Foundation for Medical Education and Research. Mayo Clinic. Published October 11, MediLexicon International Ltd. What Is Edema? What Causes Edema? Medical News Today.
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