Myoglobinuria (myoglobin bodies in the urine)
Myoglobinuria is the appearance of myoglobin in the urine. Myoglobin is a pigment-protein in muscle cells. It is considered a primitive respiratory pigment that acts as a short-term oxygen reserve in muscles and is part of the oxygen transport system within cells. Myoglobinuria is preceded by myoglobinemia.
Myoglobin is excreted in the urine when its concentration in the blood reaches 9-12 μmol / L. Urine becomes red, then after 2-3 hours it becomes brown, urine pH is sharply acidic, proteinuria is detected, and there may be cylindruria.
Types of myoglobinuria
The following types of myoglobinuria were identified:
- idiopathic myoglobinuria
- paroxysmal myoglobinuria
- paralytic myoglobinuria
- traumatic myoglobinuria, including after electrical injury
- myoglobinuria after a snakebite, wasp
- myoglobinuria due to ischemia of muscle tissue (heart attack, thrombosis, embolism)
- toxic myoglobinuria (alcohol, chemical poisoning)
- myoglobinuria in muscular dystrophy
- march myoglobinuria, etc.
Massive myoglobinuria causes damage to the renal nephrons, leading to anuria and the development of acute renal failure.
Myoglobin and hemoglobin are the most closely related chromoproteins. Therefore, chemical reactions for hemoglobin give a positive result for myoglobin.
Differential diagnosis of myoglobinuria
Criteria for the differential diagnosis of myoglobinuria and hemoglobinuria:
- with hemoglobinuria, plasma is colored, with myoglobinuria - no
- myoglobin in urine appears faster, hemoglobin - later
- myoglobin in urine quickly turns into metamioglobin and urine becomes brownish-brown; with hemoglobinuria, the urine remains cherry-red for a long time (the color of "meat slops")
- with myoglobinuria, there are no corpuscular elements in the urine sediment on the first day; with hemoglobinuria from the first day, hemosiderin, erythrocytes, pigment casts may appear in the urine sediment
- with myoglobinuria, in contrast to hemoglobinuria, hemosiderin is not detected