What Causes Dark Brown or "Soy Sauce" Colored Urine?

Normally, the color of urine is light yellow or transparent, but some people's urine is colored like soy sauce. In this case, it is necessary to consider whether it is a kidney disease or hemolysis and bleeding issues. Additionally, hematuria may also lead to soy sauce-colored urine, so attention should be paid to the treatment based on the causes. Here are some possible reasons:

1. Hemorrhage or Hemolysis

Soy sauce-colored urine may be due to hemolysis or hemorrhage, such as kidney damage, nephrotic syndrome, hemolysis, etc. When red blood cells are destroyed in a large number within the blood vessels, which is intravascular hemolysis, the hemoglobin originally in the red blood cells will become free, causing a large amount of free hemoglobin to appear in the plasma and be excreted from the kidneys as hemoglobinuria, whose color is similar to red wine or soy sauce.

2. Nephropathy Caused by Malaria

Nephropathy caused by malaria can also lead to soy sauce-colored urine. The main clinical manifestations are hypertension, urinary protein, albuminuria, hematuria, and edema. Patients with acute renal failure caused by malaria may have high fever, excessive sweating, and insufficient water intake, leading to a decrease in effective blood volume. Subsequently, compensatory sympathetic nerve activity increases, catecholamine secretion increases, and renal blood vessels contract strongly, resulting in a significant reduction in renal blood flow, which can cause or worsen renal insufficiency. Malaria can also cause chronic progressive renal damage.

3. Hematuria

The appearance of soy sauce-colored urine does not exclude the possibility of hematuria. If it is venous bleeding with a large amount, the color of the urine may be dark red, close to black. Further investigation is needed to determine the cause of hematuria. The causes of hematuria can be both urological and non-urological.