Where are the kidneys located?
The kidneys are located in the middle-lower back, one on each side of the spine, under and, partly, below the lower ribs (Picture 1). They lie deep in the upper abdomen, in front of the back muscles and underneath the diaphragm.
Picture 1. (View from the back): Kidney pain appears where the kidneys are located: in the middle back, on either side of the spine, at the bottom of the rib cage.
- Renal = related to kidneys
- Renal colic = sudden, severe kidney pain
- Hematuria = blood in urine
Where can you feel kidney pain?
- In the back, between the lower part of the rib cage on either side of the spine and hips (flank or loin pain)
- Deep in the upper abdomen on the left, right or both sides
- In the groin (in kidney stones in the ureter)
- In general, kidney pain is not significantly affected by the body position or exercise, while muscle, nerve, bone and joint pain are.
- Kidney pain is often accompanied by other symptoms of a kidney disease, such as frequent urination, cloudy urine and nausea.
Kidney Disease Symptoms and Signs
Kidney pain is not very specific and can be confused with side pain arising from the spleen, pancreas, liver, gallbladder, colon, abdominal aorta (an aneurysm), lungs, or lower back pain from the muscles, spine or spinal nerves.
Symptoms and signs that can speak for the kidney origin of the pain (1,3,4,7):
- Frequent urination
- Cloudy or foamy urine or blood in the urine
- Tenderness in the flank(s)
- Dull pain provoked by a slight punch by a fist in the kidney area
- Nausea, vomiting, anorexia, fever, chills
- Body swelling (edema)
- A lump in the flank(s) or upper abdomen
Most of the conditions described below can appear in both children and adults.
Sudden (Acute), Severe Kidney Pain or Renal Colic
Kidney Stone Pain
Kidney stones located in the kidneys rarely cause pain, but when they lodge in the ureter and obstruct the urine flow, they can cause the following symptoms that often start at night or in the early morning (2,4,19):
- The pain often starts as a dull flank pain and, within 30 minutes to few hours, becomes constant, sharp, severe, even extreme and typically lasts for 1-4 hours (or even longer than 12 hours). The pain can radiate to the lower abdomen, genitalia (testicles, vulva), groin or inner thighs (Picture 2). The pain can appear in the form of sudden intermittent spasms or cramps (colic pain) that can last for 5-60 minutes.
- Passing blood (pink or red urine) and, eventually, one or more stones in the urine
- Nausea, dry heaving or vomiting
- Fever is NOT a typical symptom of uncomplicated kidney stones without infection.
Picture 2. Kidney stone pain
The pain from the kidney stones can be felt in the flank,
lower abdomen and genitalia
Obstruction of the Ureteropelvic Junction (UPJ)
Obstruction of the ureteropelvic junction (UPJ) or pelvi-ureteric junction (PUJ) is the obstruction of the upper part of the ureter due to congenital disorders, surgery or infection, most commonly in children. Symptoms and signs:
- Occasional sudden flank pain, especially after drinking large amount of fluid, like alcohol or caffeinated drinks, or after taking diuretics
- Sometimes: a palpable mass in the upper abdomen due to dilated kidney (hydronephrosis) and blood in the urine
- References: (2,25,26)
Loin Pain Hematuria Syndrome (LPHS)
LPHS is a rare condition caused by infection, hormonal changes or use of oral contraceptives, mainly in young women. Symptoms:
- Persistent or recurrent severe, burning or throbbing loin pain on one or both sides, aggravated by moving or exercise
- Occasional blood in the urine, fever or nausea
- Symptoms may last from hours to months or years or can be lifelong.
- Reference: (22,23)
Other Causes of Sudden Kidney Pain
- Acute hydronephrosis–kidney enlargement caused by back pressure of urine–, mostly due to a lodged ureteral stone (7)
- Blood clots in the ureter after a kidney injury or investigation, in kidney tumors, sickle cell anemia or hemophilia (2)
- Renal papillary necrosis–partial death of the kidney tissue–due to poorly managed diabetes mellitus, liver cirrhosis or long-term analgesic abuse, mainly in women (2)
Throbbing Kidney Pain
Throbbing, pulsating pain in the kidney area can radiate up or down the back and last for several seconds to minutes.
IgA Nephropathy (Berger’s disease)
IgA nephropathy is a type of kidney inflammation (glomerulonephritis). Symptoms appear within 72 hours after the onset of a respiratory or gastrointestinal infection and may last for up to 3 days:
- Brown, cola- or tea-colored urine
- Spasms or dull pain in both flanks
- References: (10,18)
Other Causes of Throbbing Kidney Pain
- Blockage of the urine flow due to ureteropelvic junction (UPJ) obstruction, strictures (scars) after abdominal surgery or a stone in the ureter (17)
- Loin pain hematuria syndrome (LPHS) (12)
Dull Kidney Pain
Kidney Infection (Pyelonephritis)
Kidney infections are much more common in women than in men. Symptoms develop quickly–in few hours or days–and may include:
- Mild, dull ache, discomfort and tenderness in the left, right or both flanks
- Nausea, vomiting
- High fever and chills
- Cloudy and smelly urine or blood in urine
- Loss of appetite, diarrhea, stiff neck
- Symptoms of the infection of the bladder (cystitis) or urethra (urethritis): frequent urination, urge to urinate, burning pain during urination
- References: (1,2,3)
Polycystic Kidney Disease
Polycystic kidney disease is a genetic disease with multiple cysts in both kidneys. Symptoms and signs:
- Middle back or upper abdominal pain, swelling and a palpable lump in the upper abdomen on both sides
- Increased blood pressure
- Blood in urine, foamy urine
- Frequent urinary tract infections
- Reference: (13)
Other Causes of Dull Kidney Pain
- A renal abscess is a localized collection of pus in a kidney, usually as a complication of a urinary tract or systemic infection; it can present with a palpable mass in the loin, fever and chills (2).
- Fungal bezoars may develop after kidney transplantation, in diabetes or during long-term antibiotic treatment (2,8).
- IgA nephropathy (Berger’s disease)
- Chronic hydronephrosis can develop due to a blockage of the urinary tract, for example, due to ureteral strictures (scars) after ureteroscopy, radiation or kidney surgery, or due to kidney stones (5,7).
- Kidney cyst, tumor or cancer can present with a gradual development of flank pain and occasional blood in the urine (9).
- Retroperitoneal fibrosis is abnormal growth of scar tissue in the area around the kidneys, usually without a known cause. Symptoms: pain in the flank, lower abdomen, hips, buttocks or scrotum (2,11).
Bilateral Kidney Pain (in Both Flanks)
Disorders that can cause kidney pain on both sides at the same time:
Two main types of kidney inflammation are glomerulonephritis and interstitial nephritis. Causes include infections, for example, post-streptococcal glomerulonephritis after bacterial throat infection (strep throat) (28), medication side effects and autoimmune disorders, such as systemic lupus erythematosus (SLE). Symptoms may include:
- Pain in one or both flanks
- Swelling of the feet, around the eyes or generalized swelling
- Blood in urine
- Foamy urine
- Reference: (20)
Other Causes of Kidney Pain on Both Sides
- Kidney infection (pyelonephritis)
- Polycystic kidney disease
- Nephrocalcinosis refers to an accumulation of calcium in the kidney tissue in various congenital disorders, such as medullary sponge kidney and primary hyperoxaluria, etc.; symptoms are like in kidney stones (14)
- Bilateral hydronephrosis–enlarged kidneys on both sides–with lumps on both sides of the upper abdomen; causes: vesicoureteral reflux (backward flow of urine from the bladder into ureter), neurogenic bladder (after spinal cord injuries), ureteropelvic junction (UPJ) obstruction (15)
- Loin pain hematuria syndrome (LPHS) (12)
- Renal vasculitis–inflammation of the blood vessels in the kidneys–, for example, in polyarteritis nodosa, Henoch-Schönlein purpura, essential mixed cryoglobulinemia, microscopic polyangiitis, Wegener’s granulomatosis); symptoms: skin rash, low-grade fever (27)
- Anaphylactic reaction (severe allergic reaction)
- Ethylene glycol poisoning (ingestion)
- Haff disease after eating Buffalo fish
- X-ray contrast toxicity
Kidney Pain After Drinking
In urinary tract obstruction, the back pressure of urine can cause kidney pain within few hours of drinking large amounts of fluids or after taking diuretics; causes include:
- A kidney stone that has stuck in the ureter
- Ureteropelvic junction (UPJ) obstruction
- Neurogenic bladder
- Bladder outlet obstruction, for example, due to bladder cancer
- A blood clot within the urinary tract due to bleeding caused by injury or kidney cancer
Is kidney failure painful?
Usually, neither acute nor chronic kidney failure by itself is painful. Kidney failure means severe impairment of the kidney function, but, at least in the early stage, there is no severe physical damage and hence no pain. Symptoms of kidney failure may include increased or decreased urination, fatigue, nausea, unintentional weight loss, pale and itchy skin, swollen ankles and hands and shortness of breath (16). Severe acute kidney failure may cause pain in the flank(s) (6).
Common disorders that can mimic kidney pain:
- Stretched muscle (see Kidney pain vs lower back pain)
- Myofascial pain
- Serratus anterior muscle pain syndrome
- Pneumonia or inflammation of the lung membranes (pleurisy)
- Abdominal bloating (trapped wind, splenic or hepatic flexure syndrome)
- Gallstones, acute cholecystitis or other cause of gallbladder pain
- Gallbladder dyskinesia
- Sphincter of Oddi dysfunction
- Liver inflammation (hepatitis)
- Acute pancreatitis
- Enlarged spleen
- Abdominal adhesions
- Pelvic inflammatory disease
- Inflammation of the abdominal membrane (peritonitis)
- Shingles (herpes zoster)
- Rib fracture
- Vertebral fracture
- Rheumatoid arthritis
- Ankylosing spondylitis
- Kidney Infection NHS.co.uk
- Causes of Flank Pain Emedicine
- Acute Pyelonephritis, Clinical Presentation Emedicine
- Nephrolithiasis, Clinical Presentation Emedicine
- Ureteral Stricture Emedicine
- Acute kidney injury Drugs.com
- Hydronephrosis Symptoms NHS.co.uk
- Prakash PY et al, 2012, Renal fungal bezoar owing to Geotrichum candidum ScienceDirect
- Kidney cancer Mayo Clinic
- IgA nephropathy (Berger’s disease) Patient.info
- Retroperitoneal Fibrosis Emedicine
- Loin pain hematuria syndrome Rarediseases.info.nih.gov
- Polycystic kidney disease Patient.info
- Nephrocalcinosis MedlinePlus
- Bilateral hydronephrosis MedlinePlus
- Kidney failure Better Health Channel
- Chronic kidney stones and vitamin D deficiency Healthboards.com
- Questions about IgAN Igansupport.org
- Patient information: Kidney stones in adults (Beyond the Basics) UpToDate
- Inflammation diseases of the kidneys DaVita
- Renal vascular disease University of Miami Health System
- Loin pain hematuria syndrome Kidney.org.uk
- Burden RP et al, 1979, Loin pain hematuria syndrome PubMed
- Akhavan A, Ureteropelvic junction obstruction John Hopkins University
- Dignan FJ, 2003, Alcohol and the genitourinary tract PubMed Central
- Urinary tract obstruction Patient.info
- Types of vasculitis National Heart, Lung and Blood Institute
- Evaluation of Poststreptococcal Illness Americam Family Physician