Diagnosis
The diagnosis of a kidney contusion is relatively easy to make with appropriate means. The main focus is to rule out more serious damage to the kidney, which in the worst case may require surgical repair. The physician first begins with the patient’s medical history.
Here, acute complaints, pain and previous events are systematically investigated. A blow in the back or on the side before the onset of symptoms can thus already point in the right direction. A clinical examination follows.
Here the doctor looks for visible signs of kidney contusion such as redness, flank swelling and bruising and the affected area is palpated. Pressure pain is almost always present in kidney contusion. In addition, a urine sample should be taken and examined for the presence of blood.
Special test strips are available to detect blood in the context of microhaematuria, which discolour even with normal-looking urine. These simple and quick methods can be supplemented by a wide range of imaging techniques if the doctor cannot reliably conclude that there is a kidney contusion or wants to rule out other concomitant injuries that cannot be detected at first glance. Ultrasound is one possibility of imaging.
It is not possible to accurately assess the severity of the trauma, but it is possible to differentiate between a contusion of the kidney and more serious injuries to the kidney. In the case of a contusion of the kidney, only the hematoma under the capsule is visible on the image. Thus, there is an apparent enlargement of the kidney.
The complex of detailed interview, history and clinical signs in combination with the ultrasound image and urine examination is sufficient for the diagnosis of a simple kidney contusion. However, if the physician is not sure whether the injury goes beyond a kidney contusion, further measures should be taken. Computer tomography can be useful for an accurate assessment of the kidneys.
It shows the whole body in detail in sectional images and allows statements to be made about the extent, areas involved and neighboring damage caused by the injury. The disadvantage of CT is the high radiation exposure. However, it can certainly rule out more serious injuries.
MRI (magnetic resonance imaging) plays a rather subordinate role and, due to the high costs, is used at most for follow-up examinations. However, MRI can be of interest in the diagnosis of children because of the lack of radiation exposure. In the case of a slight kidney contusion, both CT and MRI are rather not used.
