Renal stones are a significant healthcare burden. Roughly 5-10% of population get affected at some point of time. Pain caused by renal stones generate a lot of visits to the emergency departments of hospitals and admissions. Renal stones affect the working population more in the age group between 20-60 years, and therefore causes economic losses too. Also more than half of patients treated for stone disease can form a stone again.
Therefore it important to be aware of the symptoms, diagnostic modalities, prevention and treatment options for such stones.
What are the symptoms of kidney stones?
In many cases, kidney stones do not produce symptoms. However, if a stone gets stuck in the ureter (the thin tube between the urinary bladder and the kidney), symptoms can be very severe. Often, symptoms vary depending on the stone’s location and its progress.
Kidney stone attacks tend to be most common late at night or in the early morning, possibly because of minimal urine output or constriction of the ureters during the early morning hours. Kidney stone attacks are least common during the late afternoon.
Pain usually begins abruptly on one side and then continues as intense, constant pain. In some cases it lasts for a few minutes, disappears, and then returns in few minutes. This type of pain is referred to as a Colicky pain, which is caused by string contractions in ureter as it tries to clear the stone by generating stronger contractions.
The patient cannot find a comfortable position and usually stands, sits, paces, or reclines in a failed search for a position that will bring relief.
If the stone is in the kidney or upper urinary tract, the pain usually starts in one flank area (to the side of the back near the waist). It typically moves to the groin as the stone passes down.
If the stone is too large to pass easily, the pain follows the muscle contractions in the wall of the ureter as they try to squeeze the stone along into the bladder.
Nausea and vomiting may occur.
Blood may be present in the urine, called hematuria, which can occur by damage caused to the walls of the ureter by the stones.
As the stone passes down the ureter closer to the bladder, a person may feel the need to urinate more often or a burning sensation during urination.
An infection may set in and patient may develop fever and chills. An infection cam easily set in presence of a stone. Obstruction to flow of urine causes urinary stagnation, thereby creating favourable conditions for urinary infection.
Does the size of a stone have any correlation with severity of pain?
The size of the stone does not necessarily predict the severity of the pain. A very tiny crystal with sharp edges can cause intense pain, while a larger round stone may not be as distressing. Struvite stones can often occur without symptoms.
How to confirm presence of urinary stones as cause of pain?
A careful history and physical examination are sufficient to raise the doubt of kidney or ureteric calculus. However the presence of stone needs to be proven beyond doubt, before specific therapy can be started.
Urine routine and microscopic examination is one of investigations to see red blood cells and pus cells in urine which may be suggestive of stone in urinary tract and infection in urine due to stone disease.
Ultrasound abdomen, is the most common diagnostic modality nowadays used to detect presence of stones. It is also readily available in emergency departments of most hospitals. It is an easy and quick screening method and also rules out many other problems coexisting with stone, which may mimic the pain, like gall bladder stones. However it has its own limitations as it is Operator Oriented, which means it depends on the experience of the Ultrasonologist. Small stones can be missed with this modality. Thick abdominal walls in obesity and excess bowel gas are some of its limitations to this technique.
Still it is best and most commonly available tool till date which is cost effective, non invasive and without any side effects.
Plain X-Ray KUB(Kidney Ureter Bladder)– More than 90% of kidney stones of reasonable size can be seen on plain x-ray KUB which is a simple test and cheap way of detecting kidney stones but should be avoided in pregnant females and has radiation effects on body if done very frequently.
Intravenous Pyelogram was once considered to be best investigation, but has lost its sheen in presence of CT scan, However it is still one of the best methods to detect kidney stones. It tells about anatomy and functional status of kidney but it is time consuming and requires contrast, to which sometimes patients are allergic and may need bowel preparation.
Non contrast CT scan-KUB is considered to be gold standard investigation, it is quick. No bowel preparation is required. It is highly specific and is not operator dependent but carries potential risk of radiation hazard, and therefore should be avoided during pregnancy.
CT Urography This requires injection of a contrast agent followed by CT scan of the KUB region. CT urography provides additional information about the urinary tract by outlining Kidney, Ureter & Urinary bladder and tells about functional status of kidney. This test may be required in some difficult cases where diagnostic dilemma exist.
What are the tests available to find the cause of stone occurrence?
Besides diagnosing and treating the existing stone, it is also important to find the cause of underlying problem which lead to formation of stone in the first place.
Stone analysis helps in identifying the composition of the stone. 24 hours urinary sample is also used to estimate the daily output of urinary calcium, oxalate, citrate, uric acid, sodium, creatinine and other stone forming substrates.
Disclaimer: This is for the general awareness of the patients and cannot replace expert medical advice. Patient treatments need to be individualised and that can be decided based on clinical examination and evaluation by a trained physician.
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