Causes

The kidneys are located in the flank (back of the upper abdomen at either side of the spinal column). They are deep in the abdomen and are protected by the spine, lower rib cage, and strong muscles of the back. This location protects the kidneys from many outside forces.

The kidneys are well-padded for a reason -- they have a large blood supply. Injury can lead to severe bleeding.

Kidneys may be injured by damage to the blood vessels that supply or drain them, including:

• Aneurysm
• Arterial blockage
• Arteriovenous fistula
• Renal vein thrombosis (clotting)
• Trauma

Kidney injuries may also be caused by:

• Angiomyolipoma, a noncancerous tumor
• Autoimmune disorders
• Bladder outlet obstruction
• Cancer of the kidney, pelvis, or colon
• Diabetes, high blood pressure, or other medical conditions that affect the kidneys
• Excess buildup of body waste products such as uric acid (which can occur with gout or treatment of bone marrow, lymph node, or other disorders)
• Exposure to toxic substances such as lead, cleaning products, solvents, fuels, or long-term use of high-dose pain medications (analgesic nephropathy)
• Inflammation caused by immune responses to medications, infection, or other disorders
• Medical procedures such as kidney biopsy, or nephrostomy tube placement
• Ureteropelvic junction obstruction
• Ureteral obstruction

The ureters are the tubes that carry urine from the kidneys to the bladder. Uretral injuries may be caused by:

• Complications from medical procedures
• Diseases such as retroperitoneal fibrosis, retroperitoneal sarcomas, or cancers that spread to the lymph nodes near the ureters
• Kidney stone disease
• Radiation or chemotherapy
• Trauma

Symptoms

Acute or emergency symptoms may include:

• Abdominal pain
• Abdominal swelling
• Back pain
• Blood in the urine
• Decreased alertness, including coma
• Decreased urine output
• Drowsiness
• Fever
• Flank pain, severe
• Increased heart rate
• Inability to urinate
• Nausea, vomiting
• Pale skin
• Skin cool to touch
• Sweating

Long-term (chronic) symptoms may include:

• Constipation (can occur with toxic injury or lead poisoning)
• Irritability
• Weight loss

If only one kidney is affected and the other kidney is healthy, you may not have any symptoms.

Exams and Tests

The health care provider may find the source of the injury by reviewing your:

• History of physical injury
• Exposure to toxic substances
• Recent infections or illness

A physical exam may reveal:

• Excess bleeding (hemorrhage)
• Extreme tenderness over the kidney
• Shock, including rapid heart rate or falling blood pressure
• Signs of kidney failure

Tests that may be done include:

• Abdominal CT scan
• Abdominal MRI
• Abdominal ultrasound
• Angiography of the kidney artery or vein
• Blood electrolytes
• Blood tests to look for toxic substances
• Complete blood count (CBC)
• Intravenous pyelogram (IVP)
• Retrograde pyelogram
• Kidney x-ray
• Renal scan
• Urinalysis

Treatment

The goals are to treat emergency symptoms and prevent or treat complications. You may need to stay in a hospital for close observation because of the risk of internal blood loss from an injured kidney.

Nonsurgical treatments for kidney injury may include:

• Analgesics for pain relief
• Bed rest for 1 - 2 weeks or until bleeding is reduced
• Close observation and treatment for symptoms of kidney failure
• Dietary restrictions
• Medications to treat damage caused by toxic substances or illnesses (for example, chelation therapy for lead poisoning or allopurinol to lower uric acid in the blood due to gout)
• Stopping medications or exposure to substances that may have injured the kidney
• Medications such as corticosteroids or immunosuppressants if the injury was caused by inflammation
• Treatment of acute kidney failure

Surgical treatments for kidney injury may include:

• Surgery to repair a "fractured" or torn kidney, torn blood vessels, torn ureter, or similar injury
• Surgery to remove the entire kidney (nephrectomy), drain the space around the kidney, or stop the bleeding (angioembolization)

Surgery may be needed to treat a ureter injury.

Outlook (Prognosis)

The outcome depends on the cause and extent of injury. The damage may be mild and reversible, immediately life-threatening, or long-term and causing complications.

The kidney may return to normal function, or it may go into acute or chronic failure.

Possible Complications

• Acute kidney failure, one or both kidneys
• Bleeding (may be minor or severe)
• Bruising of the kidney
• Chronic kidney failure, one or both kidneys
• Infection (peritonitis, sepsis)
• Pain
• Renal artery stenosis
• Renal hypertension
• Shock
• Urinary tract infection

When to Contact a Medical Professional

Call your health care provider if you have symptoms of an injury to the kidney or ureter, especially if you have a history of:

• Exposure to toxic substances
• Illness
• Infection
• Physical injury

Go to the emergency room or call the local emergency number (such as 911) if you have decreased urine output after a kidney injury. This may be a symptom of kidney failure.

Prevention

You can help prevent injury to the kidneys and ureter by following these precautions:

• Be aware of possible sources of lead poisoning, such as old paints, vapors from working with lead-coated metals, and alcohol distilled in recycled car radiators.
• Follow your health care provider's directions for using all medications, including over-the-counter medications.
• Follow your health care provider's instructions for treating gout and other illnesses.
• Use appropriate safety equipment during work and play.
• Use cleaning products, solvents, and fuels as directed in a well-ventilated area because the fumes may also be toxic.
• Wear seat belts and drive safely.

Alternative Names

Kidney damage; Toxic injury of the kidney; Kidney injury; Traumatic injury of the kidney; Fractured kidney; Inflammatory injury of the kidney; Bruised kidney; Ureteral injury

References

Molitoris BA. Acute kidney injury. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 121.

Updated: 4/3/2012

Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Scott Miller, MD, Urologist in private practice in Atlanta, Georgia. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.