Myoglobinuria is a condition where myoglobin, a muscle protein, is found in the urine. This usually indicates that the muscles have been damaged in some way and are essentially leaking myoglobin into the blood. Signs and symptoms of myoglobinuria may include painful and swollen muscles, fever, nausea, and dark, reddish urine. In certain types of myoglobinuria, individuals with the condition are often asymptomatic until episodes are triggered, most often by intense exercise or an infection. When this happens, the muscle becomes damaged and releases myoglobin into the circulation and eventually to be filtered by the kidney. In the familial type of myoglobinuria, the attacks may be triggered by upper respiratory infections and other illnesses. If only a small amount of myoglobin is excreted in the urine, there are often no serious concerns, but if too much myoglobin is released in the urine, it can cause kidney damage and indicate a larger problem.
In the familial type of the condition, myoglobinuria is linked to mutations (changes) in the LPIN1 gene. We inherit our genes in pairs, one from each parent typically. Familial myoglobinuria is inherited in an autosomal recessive manner. Autosomal recessive means that an individual must have two copies of the changed gene that causes the condition. A person with one changed gene would be a carrier of the condition but usually will not have any symptoms. If both parents are carriers of the condition, each child has a one-in-four chance (25%) of having the disease.
Diagnosis for myoglobinuria can be made by testing the urine for myoglobin and by looking at the urine color. This condition can be treated in the hospital with supportive care and hydration, with medication, or in other ways.
Description Last Updated: Sep 03, 2018