Costovertebral angle (CVA) tenderness is a finding from a physical examination where a patient experiences pain in a specific area of the back upon touch or percussion. This tenderness is a clinical sign, not a final diagnosis, that points toward an underlying medical problem located deep within the flank region. It is a common indicator used by healthcare providers to narrow down the possible causes of pain in the upper back or side. The presence of this pain suggests irritation or inflammation, requiring further investigation.
Locating the Costovertebral Angle
The Costovertebral Angle (CVA) is an anatomical landmark on the back, formed by the intersection of the lowest rib and the vertebral column. Specifically, it is the acute angle created by the twelfth rib and the spinal column, or the transverse processes of the lumbar vertebrae. This area is located on both the left and right sides of the body, just below the rib cage and above the waistline.
The CVA is medically significant because the kidneys are positioned directly beneath this region. The kidneys are situated in the retroperitoneal space, meaning they lie behind the abdominal cavity organs. Because of this anatomical relationship, inflammation or swelling of a kidney often manifests as pain localized to the corresponding CVA.
How Healthcare Providers Assess CVA Tenderness
Medical professionals use a specific maneuver, sometimes called “fist percussion” or the “kidney punch test,” to assess for CVA tenderness. The patient is typically asked to sit upright or lie prone to allow the provider clear access to the back. The technique begins with the examiner placing the palm of one hand flat over the patient’s costovertebral angle.
The provider then uses the closed fist of their other hand to deliver a firm, gentle strike to the back of the hand placed on the patient’s back. The force of this percussion transmits a jarring action through the muscles and tissues to the underlying kidney. A positive result is noted if the patient experiences a sudden, sharp pain in response to this action, indicating that an inflamed structure is being disturbed by the transmitted vibration.
What Causes Tenderness in This Region
The primary reason CVA tenderness occurs is the sudden stretching or inflammation of the renal capsule, the fibrous layer surrounding the kidney. This capsule contains sensitive nerve fibers that transmit pain signals when compressed or distended. Therefore, conditions that cause the kidney to swell or become acutely inflamed are the most frequent causes of a positive CVA tenderness finding.
Acute pyelonephritis, a severe bacterial infection of the kidney, is the classic condition associated with marked CVA tenderness. The bacterial invasion causes significant inflammation and edema within the kidney tissue, leading to rapid swelling and distension of the renal capsule. This internal pressure triggers the sharp pain when the area is percussed during the physical exam.
Another common cause is the passage of kidney stones (nephrolithiasis). A stone lodged in the ureter can obstruct the flow of urine. This obstruction causes a buildup of pressure and fluid (hydronephrosis), which stretches the renal pelvis and capsule, resulting in intense flank pain and CVA tenderness. Less frequently, CVA tenderness can indicate a perinephric abscess or non-renal issues like musculoskeletal strain.
Confirming the Diagnosis and Treatment Approach
Once CVA tenderness is noted, the next steps involve diagnostic testing to pinpoint the exact underlying cause. Initial laboratory work includes a urinalysis and a urine culture to check for signs of infection, such as bacteria or white blood cells. Blood tests are also ordered to assess kidney function and measure inflammatory markers. Imaging studies are often necessary to visualize the internal structures of the urinary tract.
A renal ultrasound is frequently the first-line imaging modality, as it can detect swelling, fluid buildup, or large obstructions like stones. Depending on the clinical picture, a Computed Tomography (CT) scan may be performed for a more detailed view. CT scans are particularly effective for precisely locating kidney stones or identifying an abscess.
Treatment is entirely dependent on the confirmed diagnosis. If pyelonephritis is diagnosed, the patient will be started on a course of antibiotics, which may be given intravenously in severe cases. For pain caused by kidney stones, initial management focuses on pain control and promoting the stone’s passage. Larger stones or those causing complete obstruction may require procedural intervention, such as lithotripsy or ureteroscopy, to break up or remove the stone.