Red flag symptoms
- Periorbital oedema in a child
- Change in medication
- Accompanying breathlessness
- Pain, hyperpigmentation, absent leg pulse
- Signs of sepsis
- High blood pressure
An adult male weighing 70kg typically has about 12 litres of interstitial fluid and would need to have an increase of about 2 litres (15%) before this becomes visibly apparent as clinical oedema.
As a result of gravity this would be noticed most easily over the ankles, when mobile, or over the sacrum, if bed bound.
Several physiological states can increase the chance of oedema occuring, such as dehydration, immobility, pregnancy, timing in the menstrual cycle, or obesity.
Pitting oedema can also be a sign of dysfunction in a range of organs or organ systems.
Decreased oncotic pressure in the liver, kidneys or gastrointestinal tract is often triggered by protein loss somewhere, such as in liver cirrhosis, nephrotic syndrome, malabsorption, starvation, inflammatory bowel disease, allergies or tumours.
Oedema in children is most commonly caused by nephrotic syndrome and usually presents with periorbital oedema.
Two-thirds of patients with a deep vein thrombosis (DVT) may end up with a late complication of post-thrombotic syndrome, which can increase oedema, pain, hyperpigmentation and even skin ulcerations.
Rapid onset of new pitting oedema is more likely related to (new) medication, commonly NSAIDs, calcium antagonists, steroids or insulin. If there are systemic symptoms, such as breathlessness, then an acute cardiac cause is among the most likely reasons – until proven otherwise.
Consider local infection, inflammation or trauma if pitting oedema is more localised and perhaps unilateral. Idiopathic pitting oedema is a diagnosis of exclusion.
Non-pitting oedema can develop in cases of hypothyroidism – through mucopolysaccharide deposition – or lymphoedema (often traumatic; after injury, radiation, surgery, malignant infiltration, infection, and so on).
- Compression (varicose veins, compartment syndrome, tumours)
- Chronic venous insufficiency
- Congestive cardiac failure
- Cor pulmonale
- Liver cirrhosis
- (Acute) renal failure, nephrotic syndrome
- Compression (pelvic, intra-abdominal)
Establish whether there are any signs to suggest an acute process or emergency. Check the legs for pulses, skin changes, differences in circumference and redness. In cases of suspected cardiac oedema, check (bilateral) blood pressure, jugular venous pressure, oxygen saturation and pulse. Do not miss possible ascites during abdominal examination.
Do a urine dipstick. Blood tests include FBC, U&E, LFT and gamma-glutamyl transferase. Consider inflammation markers, TFT, urate, BNP as needed.
Consider a chest X-ray, ECG and an abdominal ultrasound or a duplex doppler scan or arterio-venous pressure measurement. In suspected DVT, refer acutely for confirmation of diagnosis and initial management.
Review current medication. Consider any contributing factors including diet (protein) and fluid intake/loss and advise accordingly. Establish whether the oedema needs any medical treatment and, if so, how urgently. Involve specialists as required, particularly for oedema in children.
Empirical treatment with diuretics is usually inappropriate, especially if the diagnosis is not yet clear and if there are no other symptoms.
- This article was originally writted by Dr Anna Cumisky a GP in Bath and was updated in 2019 by Dr Tillmann Jacobi, a GP in York