Lupus urine can have a few distinct characteristics that may indicate the autoimmune disease systemic lupus erythematosus (SLE). Some of the most common urine changes seen with lupus include:
Protein in the urine (proteinuria)
One of the hallmark signs of lupus kidney involvement is protein leaking into the urine. This proteinuria occurs when the kidneys’ filters become damaged by SLE, allowing protein that should stay in the blood to pass into the urine. The amount of protein may range from trace levels to macroalbuminuria (severely increased protein).
Blood in the urine (hematuria)
Red blood cells in the urine, known as hematuria, are another potential indicator of lupus nephritis. The inflammation of SLE can cause bleeding into the kidneys’ small filtering units, allowing red blood cells to enter the urine. The color of urine with blood can range from pink, red to brown depending on how concentrated it is.
Foamy, bubbly appearance
Excess protein and cell debris due to kidney inflammation can make lupus urine appear foamy or frothy. The bubbles are formed by albumin and other proteins disturbed during urination.
Dark or tea-colored urine
In some cases, lupus urine may take on a dark honey or tea-like color. This is often due to blood, but concentrated urine and some medications can also darken the color. Lupus medications that can turn urine dark brown or black in color include azathioprine (Imuran), cyclophosphamide (Cytoxan) and methyldopa.
Increased frequency and urgency
Inflammation from lupus can make the bladder more irritated and “sensitive.” This can cause symptoms like a frequent urge to urinate, even when not much urine is passed. There can also be a feeling of pressure, discomfort or inability to wait when the urge to urinate comes on.
Urine casts
Under a microscope, lupus urine may reveal casts – clumps of cells, proteins and other debris stuck together in the shape of kidney tubules. Different types of casts like red blood cell casts, white blood cell casts and hyaline casts point to kidney inflammation.
Fatty deposits
When viewed under a microscope, lupus urine may also contain an excess of fatty lipids, which can form into oval fat bodies. This symptom is known as lipiduria and is due to inflammation damaging cell membranes.
What causes these urinary changes with lupus?
In most cases of lupus, the underlying cause of urinary abnormalities stems from inflammation in the kidneys, also called lupus nephritis. SLE triggers the immune system to attack the kidneys, damaging the intricate filtering structures that keep blood pure. As this filtration system breaks down, proteins, blood and cell debris begin leaking from the blood into the urine.
Specific urinary changes can point to different classes of lupus nephritis:
- Proteinuria – Class II, III, IV, V
- Hematuria – Class III, IV
- Casts – Class III, IV
- Fatty deposits – Class V
The most severe classes III, IV and V lupus nephritis display a full range of urinary abnormalities reflecting substantial kidney damage. Milder classes I and II may only have minimal urinary changes detected through urine tests.
When to see a doctor
It’s important to contact your rheumatologist anytime you notice possible signs of lupus kidney inflammation in your urine. A urine test and microscopic urinalysis can confirm if any suspicious findings are due to SLE.
If you already carry a lupus diagnosis, be sure your doctor monitors your urine at least every 3 to 6 months and whenever flares occur. Catching lupus nephritis early is key to preventing permanent kidney impairment down the road.
Seek prompt medical attention if you have any of the following:
- Pink, red, brown or black discoloration in urine
- Foamy or bubbly urine
- Cloudy urine
- An increased need to urinate but passing little urine
- Pain or burning during urination
- Urine that smells foul or strong
- Difficulty urinating or inability to empty the bladder
- Flank pain, lower back pain, abdominal pain
- Puffiness around eyes, leg swelling, weight gain
Reporting any odd urine changes right away allows your doctor to check for infections, kidney stones, bladder issues and monitor your kidney function. Prompt treatment helps avoid complications.
How is lupus kidney disease diagnosed?
If lupus kidney involvement is suspected based on urinalysis results, your doctor will likely order further tests to confirm the diagnosis and gauge severity, including:
- Urine protein tests – Measures amount of protein lost in a 24-hour period or excessive protein-to-creatinine ratio in random sample
- Urinalysis – Checks for blood, protein, casts, crystals, cells under microscope
- Blood tests – Monitors kidney function through levels of waste (BUN, creatinine)
- Imaging tests – CT scan, ultrasound, MRI to view kidneys’ structure
- Kidney biopsy – Examines tiny sample of kidney tissue under a microscope
These tests also identify the class of lupus nephritis based on extent of inflammation and scarring. Class I-V guides treatment approach.
Lupus nephritis treatment
Treatment focuses on relieving inflammation in the kidneys and halting further immune damage. Options may include:
- Corticosteroids – Potent anti-inflammatories like prednisone, methylprednisolone
- Immunosuppressants – Cyclophosphamide, mycophenolate, azathioprine
- Biologics – Belimumab (Benlysta), rituximab (Rituxan)
- Blood pressure medications – Keep BP under 130/80 to reduce strain on kidneys
These medications aim to drive the autoimmune response into remission and ideally prevent chronic kidney impairment. Treatment is catered to the class of lupus nephritis, with more aggressive forms requiring stronger regimens like cyclophosphamide infusions plus steroids.
Can urine appearance return to normal with treatment?
Yes, in many cases the urinary abnormalities seen with active lupus nephritis can improve and return to normal with effective treatment and immunosuppression. However, some residual damage may remain even in remission.
Getting proteinuria, hematuria and abnormal casts/deposits under control is a good sign that therapy is working to calm kidney inflammation. Follow-up urine tests help gauge treatment response and whether any lasting urinary issues persist.
The outlook depends on:
- Severity of initial flare
- The class of lupus nephritis
- How early treatment was started
- How well inflammation responds to treatment
- Presence of hypertension or other complications
Mild forms like class I and II have an excellent chance of reverting urine back to normal with therapy. More proliferative classes III/IV may still heal well, but often have some residual urinary abnormalities. Advanced class V has more scarring and is harder to stabilize.
Can kidney damage be permanent?
Unfortunately, yes – permanent kidney damage can occur in some with lupus nephritis, leading to chronic kidney disease (CKD).
This is most common with class IV disease, where extensive inflammation causes substantial scarring in the kidney’s filtering units. Significant proteinuria and hypertension also raise the risk. Over time, the accumulating changes impair the kidneys’ ability to filter blood adequately.
Ongoing kidney dysfunction may be signaled by:
- Persistently abnormal GFR (60 or below)
- Inability to reverse proteinuria into normal range
- Hypertension requiring 3 or more BP medications to control
- Fluid retention
- Foamy or dysmorphic urinary casts
If kidney damage seems irreversible, a nephrologist helps manage complications of CKD and may discuss options like dialysis or transplantation when needed.
Protecting kidney health
Some tips to help preserve kidney function with lupus include:
- Take all medications as prescribed to control SLE activity
- Have regular urine testing to catch problems early
- Follow up promptly if urinary symptoms develop
- Aim for BP below 130/80 with an ACE inhibitor or ARB
- Reduce protein intake if proteinuria is present
- Quit smoking and limit alcohol intake
- Drink plenty of fluids daily and avoid NSAIDs
- Maintain a healthy weight and stay active
What does normal urine look like?
Normal, healthy urine should be transparent yellow with a mild odor. Key features include:
- Pale to dark yellow color
- Transparent, not cloudy
- No abnormal sediment or particles
- pH around 4.5 to 8
- SG 1.003 to 1.035
- Absence of proteins, blood, excess cells
- No bacteria or casts present
The shade of yellow reflects the concentration of urine solutes. A very pale color indicates dilute or excessively hydrated urine. Dark yellow to amber hues are often seen in more concentrated morning urine after water intake has been low overnight.
Temporary changes unrelated to disease are also common, including:
- Pink to red: Beets, berries, rhubarb, food coloring
- Orange: Carrots, vitamin C
- Green: Asparagus, vitamins
- Blue to purple: Blueberries, blackberries, purple candy
- Brown: Fava beans, aloe, laxatives
- Milky or cloudy: Mucus strand, phosphates, dehydration
So while healthy urine has a rather limited range of normal color, many factors can alter its appearance transiently. Only persistent abnormal changes likely warrant medical evaluation.
When to see a doctor for abnormal urine
Some signs in urine that could signal an underlying problem and need medical assessment include:
- Blood or considerable cloudiness
- Foul or strong odor
- Any unusual color lasting more than a day or two
- Significant increased frequency or urgency
- Pain or trouble urinating
- Leaking urine or incontinence
- Foamy or frothy appearance
Having your urine tested and examined under a microscope can help identify or rule out issues like urinary tract infections, kidney stones, diabetes, bladder cancer or kidney damage.
Transient discoloration from foods or medicines is no cause for concern. But when in doubt, do not hesitate to speak with your healthcare provider.
Conclusion
Lupus kidney inflammation can cause several distinct changes in urine appearance and characteristics. Some of the hallmarks of lupus urine include excess protein, blood, foam, fatty deposits and casts under the microscope. While urine usually returns to normal with proper treatment, permanent kidney damage is possible if nephritis goes unnoticed or uncontrolled. That is why regular urine testing and prompt follow-up of any abnormalities is essential to help preserve kidney health in SLE.
