Proteinuria
Evaluation of excess protein in the urine to identify and manage the underlying kidney condition
What is proteinuria?
Protein in the urine is a finding and not a diagnosis. The filters in the kidney are built to hold protein back while letting water and waste through, so protein appearing in the urine means that barrier is leaking, and the work is then to establish why.
Some causes are harmless. A fever, heavy exercise, dehydration or standing for long periods can all push a little protein through temporarily, and it disappears on a repeat sample. In some young people protein appears only while upright and vanishes overnight, which is benign and needs nothing but reassurance.
The rest fall into two groups. Damage to the filters themselves, from diabetes, from long-standing high blood pressure or from the several diseases that inflame the filtering units, is the common and important group, and the leak is typically steady and grows over time. Damage to the tubes downstream lets through smaller amounts of a different kind of protein.
How much protein is leaking is what sorts these out, and a single positive strip test proves nothing on its own. A measured quantity on a repeat sample is what your doctor is working from.
What you might notice
- Passing much less urine than usual
- Urine the colour of cola or strong tea
- Frothy urine
- A face that is puffy on waking, with swollen legs
- You have been told you will need dialysis
How it is diagnosed
The first job is confirming the finding is real and persistent, so a repeat sample is taken, usually a first-morning one, and the protein is measured against the creatinine in the same sample to give a proper quantity.
The consultation is then a search for the cause. Your doctor asks about diabetes, blood pressure, swelling, recent infections, joint pains, rashes, medicines including painkillers and traditional remedies, and kidney disease in the family. The examination is deliberately wide: blood pressure carefully measured, the face and ankles pressed for fluid, the chest listened to, the skin and joints examined for signs of a disease affecting the whole body, and the abdomen felt.
They are separating three situations. A small leak in somebody with long-standing diabetes or high blood pressure usually needs no further hunt. A large leak, particularly with swelling and a low blood albumin, is a different and more urgent problem. And a leak with blood in the urine points towards inflammation of the filters, which is investigated promptly, sometimes by examining a small sample of kidney tissue, since several of these causes respond well to treatment when caught early.
Recovery
How long this takes depends entirely on the cause, and the treatable inflammatory causes are the ones where the picture can change substantially.
Where the leak comes from diabetes or from long-standing high pressure, the aim is to reduce it and hold it down. Medicines that lower the pressure inside the filters usually reduce the protein within four to eight weeks, and your nephrologist will keep adjusting until the figure stops falling. This is a long-term treatment and stopping it lets the leak return.
Where an inflammatory cause is found and treated, response is measured over three to six months, and treatment often continues for a year or longer. Some of these settle completely.
Expect the protein measurement to be repeated at every visit; it is the number that tells your doctor whether the treatment is working, and it responds long before the filtration rate does. Blood pressure and kidney function are checked one to two weeks after any change of medicine. Keep salt low, since a high-salt diet blunts the effect of the very drugs being used to reduce the leak.
If it is left untreated
A small, stable leak with normal blood pressure and normal kidney function in an otherwise well person may reasonably be watched with periodic checks, and some of these never progress.
A persistent leak that is left alone is a different matter, because protein passing through the kidney is itself damaging to the tubes it flows past. The leak accelerates the scarring, the scarring worsens the leak, and kidney function falls over years. The amount of protein in the urine is one of the strongest available predictors of how fast that happens, and reducing it measurably slows the decline.
Where the loss is heavy, the level of albumin in the blood falls, and fluid then moves out of the circulation into the tissues, so the face becomes puffy in the mornings and the legs swell by evening. Cholesterol rises, and the blood becomes more likely to clot, which carries a real risk of clots in the legs and the lungs. Protein loss on this scale needs a specialist assessment without delay.
Breathlessness, chest pain or a swollen, painful calf needs emergency attention.
Questions about proteinuria
Is protein in my urine serious?
It depends entirely on how much, whether it persists, and what is causing it. A trace on a strip test after a fever, heavy exercise or dehydration is often temporary and disappears on a repeat sample, and in some young people protein appears only while standing and is harmless. A persistent, measured leak matters, both as a sign of kidney damage and because the protein itself damages the kidney as it passes through. Heavy loss with swelling of the face and legs needs specialist assessment without delay. The next step is a repeat first-morning sample with the protein properly measured.
Can I see or feel it?
Usually not, and that is why it is almost always found on a test done for another reason. Where the leak is heavy, urine can look persistently frothy or bubbly in the toilet, and that is worth reporting, though froth alone proves nothing. What you would notice with heavy loss is swelling: puffiness around the eyes in the morning, and legs and ankles that swell through the day and leave a dent when pressed. Weight rising by a few kilograms in a week is fluid and not fat. Anything at that level should be seen promptly instead of watched.
Will the protein ever go away?
Sometimes completely, and often it can at least be reduced substantially. Temporary causes resolve on their own. Several of the inflammatory conditions that damage the filters settle fully with treatment, and a good number of patients end with clear urine. Where the cause is diabetes or long-standing high blood pressure, the realistic aim is reduction and control: medicines that lower the pressure inside the filters typically cut the leak within weeks, and keeping it low is what protects your kidney function over the following years. That treatment is long-term, and the protein returns if it is stopped.
Other nephrology treatments
A specialised surgeon operates to place a healthy donor kidney, while the nephrologist manages your medical care before and after the procedure
InpatientMonitoring and treatment of kidney damage related to diabetes
Day CareTalk to a care coordinator about proteinuria
Leave a number and a care coordinator calls you back with what the treatment involves and which hospital it would be at. They book a consult only if you want one