Kidney stones (nephrolithiasis) are hard deposits composed of crystallized minerals and salts that form inside the kidneys. These solid masses begin when urine contains high levels of substances like calcium, oxalate, or uric acid, and not enough fluid to dissolve them. Stones form on the inner surfaces of the kidney and can grow large enough to obstruct the flow of urine, causing severe pain and requiring medical attention.
Specific Risk Factors for Women
Although kidney stones were historically more prevalent in men, the incidence rate in women has been rising significantly due to distinct physiological and anatomical factors. A major factor is the higher lifetime incidence of urinary tract infections (UTIs). The shorter female urethra allows bacteria easier access, and persistent infections can lead to the formation of struvite stones, which are composed of magnesium ammonium phosphate and linked to bacterial activity.
Hormonal fluctuations also alter body chemistry and stone risk. Changes in estrogen levels, particularly during and after menopause, are associated with shifts in bone mineral density and calcium metabolism. Lower estrogen levels increase calcium excretion in the urine, favoring calcium-based stone formation. Pregnancy presents another specific risk, including physiological hydronephrosis (dilation of the urinary system) due to hormonal effects and compression from the growing uterus.
Reduced ureteral peristalsis and increased urinary calcium excretion during pregnancy promote stone development. While the overall risk of forming a stone during pregnancy is similar to that of non-pregnant women, the composition differs; pregnant women have a higher rate of calcium phosphate stones compared to the more common calcium oxalate stones. Women with a history of kidney stones may also face increased risks for complications during pregnancy, such as gestational diabetes and preeclampsia. Obesity, a general risk factor for kidney stones, appears to be a stronger risk factor for stone formation in women than in men.
Identifying Symptoms in Female Patients
The symptoms of a kidney stone, known as renal colic, are characterized by sudden, intense, cramping pain that comes in waves. This pain typically starts in the flank or side, below the ribs, and radiates toward the lower abdomen and groin area as the stone moves through the ureter. For women, this presentation often overlaps with symptoms of other conditions, leading to potential misdiagnosis.
The pain can be confused with gynecological issues, such as a ruptured ovarian cyst, endometriosis, or pelvic inflammatory disease. Both kidney stone pain and ovarian cyst pain can manifest as severe discomfort on one side of the lower abdomen. A key difference is that stone pain is often sudden and rapidly intensifying, whereas pain from a cyst may be more constant or cyclical, sometimes coinciding with the menstrual cycle.
Other symptoms, like a burning sensation during urination (dysuria) and a frequent, urgent need to urinate, can mimic a urinary tract infection (UTI). This similarity often causes women to delay seeking care, believing they have a simple UTI. Nausea and vomiting are also common due to shared nerve pathways between the kidneys and the stomach. Accurate diagnosis relies on imaging tests like a CT scan, which definitively locate the stone and rule out other causes of abdominal or pelvic pain.
Management and The Process of Passing a Stone
Management depends on the stone’s size, location, and symptom severity. Small stones, typically less than 5 millimeters, are often managed with watchful waiting, allowing the stone to pass naturally. Patients are encouraged to increase fluid intake, aiming to produce at least 2.5 liters of urine daily, which helps flush the stone through the urinary system.
Pain management during passage involves over-the-counter or prescription-strength medications for the intense renal colic. Physicians may also prescribe alpha-blocker medications, such as tamsulosin, which relax the smooth muscles in the ureter walls. This relaxation widens the passageway, making it easier for the stone to travel and reducing pain. The actual passage involves the stone moving from the kidney, down the ureter, into the bladder, and out through the urethra.
If a stone is too large (greater than 10 millimeters), causes a complete blockage, or is accompanied by an infection, medical intervention is necessary. Common procedures include:
Extracorporeal Shock Wave Lithotripsy (ESWL)
This uses targeted sound waves to break the stone into smaller fragments that can be passed.
Ureteroscopy
This involves inserting a thin, lighted scope through the urethra and bladder to either retrieve the stone with a basket or use a laser to break it up directly.
Once the stone exits the body, patients typically experience immediate relief from the severe cramping pain.