The flank is the area of the back located between the bottom of the rib cage and the top of the hip. A number of different diseases and conditions can cause pain in the left flank. Depending on the cause, left flank pain can be mild and nagging or severe enough to incapacitate the patient. Left flank pain may sometimes be accompanied by fever, nausea and vomiting.
Urinary Tract Disorders
Urinary tract disorders, such as a urinary tract infection or an obstruction of the ureter, can cause left flank pain. The ureters are tubes that carry urine from the kidney to the bladder. The pain from a urinary tract infection will generally also be accompanied by frequency of urination, low-grade fever and pain while urinating. The pain from a ureteral obstruction (often with a ureteral stone) will generally be more severe. A ureteral stone that is lodged in the ureter can cause pain in either the left or the right flank and is the most common cause of flank pain.
Left flank pain can be caused by any of a number of disorders of the left kidney. The potential causes include renal inflammation or infection, a renal cyst, a renal infarction, trauma to the kidney, a kidney stone and a urinary tract infection that has migrated to the kidney. Although kidney cancer can cause left flank pain, it generally does not come on suddenly and is usually accompanied by other symptoms like hematuria, which is blood in the urine.
Diverticulitis occurs when bacteria get trapped inside small pouches that have formed in the wall of the colon, causing inflammation and infection. The typical symptoms of diverticulitis include abdominal pain, fever, bloating, diarrhoea or constipation, nausea and vomiting and a lack of appetite. Diverticulitis can also be a cause of left flank pain, although it will usually be accompanied by the other usual symptoms of the disease.
Left flank pain can also be caused by a number of other gastrointestinal diseases. Ulcers, aneurysms, abscesses, irritable bowel syndrome, viruses and food poisoning can all cause left flank pain. These diseases and conditions will generally present together with more typical gastrointestinal symptoms, however, and are more apt to cause abdominal discomfort or bilateral flank pain rather than pain that is localised at the left flank.
Other Causes of Left Flank Pain
Other causes of left flank pain include chest disease, shingles and pancreatitis. Diseases of the chest, such as heart disease or a pulmonary embolism, can cause pain that radiates down to the left flank. Shingles can also cause left flank pain that is accompanied by a blistering rash. Pancreatitis can cause left flank pain that usually occurs in conjunction with fever, a tender abdomen and a rapid pulse.