Water Retention And Its Causes
The human body contains a significant quantity of water, comprising almost up to 50 per cent of body weight in women and up to 60 per cent of body weight in men, The water is primarily present in the cells (intracellular fluid), in the blood vessels and in the tissues and other spaces (interstitial fluid). Dynamic forces govern the fluid movement across these spaces and any change in the pressures between these compartments allows fluid to diffuse across tiny cellular membranes, invariably accompanied by the electrolytes.
Another important factor in holding the water in vascular channels is the level of albumin in one’s blood. The heart, kidneys and liver are the major organs responsible for the fluid balance in the body which helps synthesize albumin. The function of these organs is also modified by the action of hormones – mainly vasopressin (AVP) and others like serum cortisol, ANP, BNP etc.
What Is Water Retention?
Water retention or oedema refers to a clinically apparent increase of fluid in the interstitial compartments, meaning in the tissues and other spaces.
The symptom is usually noticed by a swelling over certain regions of the body and the common sites where water retention is easily noticeable, includes the region around the lower legs and ankles.
In patients who are usually bedbound, the swelling is moreover the back. As the degree of fluid retention increases, the condition can lead to generalised oedema including fluid in the abdominal cavity (called ascitis) and even in the abdominal wall. Fluid can also accumulate in the free space around the lungs leading to pleural effusion and in the space surrounding the heart called pericardial effusion. Here are some of the major causes of water retention.
Causes Of Water Retention
Cardiac Or Heart Failure
Reduced pumping capacity of the heart leads to fluid accumulation in the tissues. Heart failure is usually the end result of ischemic heart disease, including myocardial infarction, valvular diseases, dilated cardiomyopathy etc. Symptoms of heart failure in addition to dependent oedema include breathlessness and fatigue. A clinical examination followed by ECG and echocardiography and subsequent evaluation helps to diagnose cardiac failure.
Renal Or Kidney Dysfunction
Structural and functional disorders of the kidney lead to fluid retention. Kidney disorders cause an increased exertion of proteins in the urine, resulting in low albumin levels and fluid retention commonly in the legs and around the eyes. The kidneys may be affected by systemic disorders like diabetes mellitus – one of the common causes of kidney failure, hypertension and connective tissue disorders. Also, primary kidney dysfunction including nephritic syndrome and chronic kidney disease – renal failure causes significant oedema.
A simple urine test showing proteinuria, investigations for anaemia, serum creatinine, electrolytes and an ultrasound of the abdomen may confirm kidney dysfunction in a patient with oedema and associated hypertension.
Hepatic Or Liver Disorders
This can cause fluid retention, mainly in the lower limbs and abdomen too, It is related to liver cell dysfunction, reduced production of albumin by the liver and portal hypertension in chronic liver disorders. Tests including blood counts, liver function tests, ultrasonography of the abdomen and tests for hepatitis help in the diagnosis of chronic liver disorder.
Chronic Lung Disease
This condition may cause fluid retention secondary to the effect of pulmonary hypertension and right sided heart failure. It leads to an impairment of backflow to the heart and accumulation of fluid in the peripheries. This is diagnosed clinically as ‘cor pulmonale’ in patients with long-standing COPD and restrictive lung disease presenting with oedema in the legs and abdomen.
Hypothyroidism
This refers to a diminished thyroid hormone output causing fluid retention, mainly in the myxomatous tissues leading to swelling of the limbs and facial puffiness. A simple thyroid function test can identify the condition.
Deep Venous Thrombosis
It refers to thrombosis or clotting in the veins of the extremities. It impairs the flow of blood backwards and leads to swelling of the particular limb associated with significant pain. A Doppler test of the affected limbs can identify the problem, which needs to be treated immediately.
Water retention is only a symptom of an underlying condition and timely evaluation and treatment will definitely reduce the problem
Lymphoedema
This refers to accumulation of lymphs in the tissues, secondary to damage to the lymphatic channels in conditions like filariasis, following surgery, radiation etc.
Hormonal Related Issues
Most commonly seen in the premenstrual phase, when women tend to develop water retention related to the effect of the hormones which usually reverses after their cycle is over.
Usage Of Drugs
Certain drugs usage can lead to fluid retention. These include BP-lowering drugs like amlodipine and other calcium channel blockers, NSAIDS, steroids, oral contraceptive pills amongst others.
The management of fluid retention involves identifying and treating the specific condition. In addition, restriction of fluid intake and reducing salt intake helps in controlling oedema. Diuretics too help to control the problem, but needs to be used judiciously. Water retention is only a symptom of an underlying condition and timely evaluation and treatment will definitely reduce the problem.