Your Questions about Kidney Stones Answered by Dr Odion Aire
Nephrolithiasis or kidney stones is one of the most common diseases in modern times, it is estimated that more than half a million people go to emergency rooms for kidney stone problems, each year. Recurrence rates are high, and prevalence worldwide is increasing due to diet and lifestyle changes.
We chatted with Dr Odion Aire, Specialist Urologist at the Urology Hospital in Pretoria to answer all your burning questions about this disease.
What are kidney stones?
Kidney stones are hard, pebble-like masses developing within the collecting system of the kidney due to the precipitation (substances changing from solution to solute/solid) of certain chemicals found in the urine. There are 4 broad groups of renal stones, depending on their chemical constituents but the calcium containing stones make up the majority (>70%)
When do you need to call a urologist?
It is important to see a doctor when you have severe pains, particularly if you have had previous history of kidney stones before. The doctor/urologist is then able to decide which clinical situation deserves urgent intervention, admission or alternatively conservative management with medical expulsive therapy. Any pre-existing urological abnormality, whether congenital or acquired, should be mentioned because it has a possible role in decision to intervene. For example, in individuals with only one kidney, there is no role for conservative management, even for small calculi.
What are the symptoms and diagnosis?
Symptoms really depend on the size, position of the kidney stone at the time.
The typical clinical presentation of renal calculi (kidney stones) is called renal colic - this is the severe, sudden feeling of pain on the flank or back and it happens when the stone which was formed in the kidney enters the ureter and gets lodged there, causing back-pressure of urine and inflammation; the pain may be on-and-off or persistent. As the stone progresses from the kidney down the length of the ureter, the position of the pain characteristically changes in a 'loin-to-groin' direction.
Small kidney stones may, however, be present in the kidney without any symptoms at all. In addition, large 'staghorn calculi' occupying the whole of the collecting system are surprisingly asymptomatic, sometimes only picked up incidentally.
Kidney stones are diagnosed using imaging on a patient who presents with the symptoms described above. The gold-standard for imaging is a non-contrast CT scan which has the ability to pick out even small stones against the backdrop of the viscera in a human being. It is also able to assess the density of the stone, which may make prediction of the type/constituent of the stone possible. An ultrasound is an alternative imaging tool to identify the effect of the obstructing calculus on the kidney collecting system. X-ray is able to identify calcium-containing stones although its sensitivity is rather poor.
What are the treatment options?
The choice of treatment depends on a number of factors: the stone location, stone size, presence of infection. In addition, medical conditions and renal issues dictate the need to intervene, and also the type of intervention needed.
- medical expulsive therapy: usually for small (<5mm) kidney stones which are located in the ureter, this involves the use of oral medication to relax the ureter while using fluid to flush the stone down towards the bladder. In addition, the use of anti-inflammatories like NSAIDS concurrently completes the concept of MET.
- JJ-stent insertion: this is a commonly used and virtually indispensable initial part of the management of acute renal colic. It involves the placement of a plastic pipe from the bladder up to the kidney. This effectively bypasses the stone and decreases the pressure in the kidney, evacuates infection where it is present, and dilates the ureter for future surgical intervention.
- Percutaneous Cutaneous Nephro Lithotripsy (PCNL): this is a relatively invasive option for managing kidney stones. It involves the percutaneous insertion of a drilling tool to fragment and expel large size (>2cm) stones from the kidneys. It is the best option for dealing with staghorn calculi.
- Extracorporeal Shockwave Lithotripsy: ESWL is a non-invasive method of breaking stones in the kidney and upper ureter. It involves use of a specialised machine with a particular method of shockwave creation which is transmitted through the body of the patient to impact on the stone and fragment it. Ideally this would be a perfect tool for management for stones, however it has a number of limitations such as the bulky equipment size, accessibility to such specialised technology, low stone-free rate in comparison to other options, contraindication with pregnancy, UTI, abnormal body habitus, bleeding issues etc.
- Ureterorenoscopy: this is a versatile camera system that is designed to go through the bladder, through the ureteric os, into the kidney, where lasers and baskets can be used to break and remove stones present in the ureter or the kidneys. It is presently the most commonly used modality for calculus management due to its versatility and relative minimal-invasiveness. Its introduction in the late 80s was a major landmark in stone management, without which a majority of stones would otherwise have been managed with excessive, traumatic open surgeries to achieve the same outcome. This advantage becomes more relevant in the context of high stone recurrence in the same patients.
Where these technical options are unavailable, open surgery may be done to remove the stones from the ureter or the kidney (ureterolithotomy and nephrolithotomy respectively). The option of laparoscopic management is available to achieve the same thing. Finally, where the kidney has been damaged by the long-term effects of the stone, removal of the kidney would be the most reasonable option.
When is ureteroscopy recommended as treatment?
Ureteroscopy is relatively invasive and is recommended when visualisation of the kidney is necessary, for example in the assessment of possible kidney and ureter malignancies.
With regard to stone management, as stated above, it has become the most commonly used modality of stone management. This is because of its ability to access virtually any part of the renal collecting system and enable introduction of laser fibres through its length to break the stones in any of these areas. This tool also enables the use of the stone basket which allows the removal of the fragment s- these can then be sent for analysis, thus providing important information towards preventing future stone occurrence.
Ureteroscopy is recommended as treatment for stones which have failed conservative therapy, are impacted, or are located in anatomically abnormal renal tracts.
What are the risks of ureteroscopy?
Ureteroscopy risks include: injury to the wall of the ureter, from punctate tears to a full disconnection of the ureter off the kidney (requiring major surgical reconstruction as an emergency). Ureteric strictures are commonly the long-term outcome of these injuries
Persistent bleeding intrarenally and intra-ureterally
Stone migration during manipulation of the ureteroscope
Urosepsis due to infection
Injury to surrounding structures, e.g. blood vessels nearby to ureters and renal pelvis
How to prepare before surgery?
The preparation for a patient for ureterorenoscopy is not much different from the basic pre-operative preparation.
The primary site of surgery is the ureter which is located in the retroperitoneum. The best way of facilitating ureteroscopy is by stenting the patient beforehand. This causes a much more accessible tract than a case of a 'virgin' ureter which also translates to far less risk of ureter injury during the procedure.
Another recognised option for aiding ureter access is the use of alpha blockers for a short duration before the procedure.
Confirmation of the urine being free of infection is a safe preoperative practice to prevent urosepsis.
Review of the CT imaging to confirm the stone burden, position and prepare the necessary equipment pre-operatively. (need for flexible or semi-rigid ureteroscopy)
What to expect after surgery?
Post-operatively, after a ureteroscopy, the recovery and symptomatology depend on the surgery. The application of excessively high ureteroscopy irrigation pressures commonly ends up with significant post operative flank and back pains, almost worse than the colic of the stone itself.
Intra-operative ureteric injuries, from lasers to the stone during delivery can present with urine leak, bleeding and severe pains.
Residual fragments of the stones, when passing through the inflamed, swollen ureteric wall, are able to re-obstruct the system, causing a repeat of the primary issue.
Commonly, this post operative pain is associated with degree of nausea and vomiting.
Most of these post operative issues can be avoided with post-operative stenting.
What is a ureteral stent?
The JJ stent is a hollow tube about 25 to 30cm long, usually made of polyurethane and meant to traverse the length of the ureter in order to achieve its objective of bypassing an obstructive stone. It decompresses the kidney by passing the urine on the outside of the stent. As mentioned above, it's role in stone management is indispensable.
Advice for aftercare / recovery?
After stone management, the patient can expect an 'uneventful' recovery, hopefully.
Where a stent was inserted, he/she may experience stent-related irritation which manifests as irritative symptoms like frequency to void, nocturia, painful urination or even lower abdominal pains. In a few cases, blood in the urine is observed. These irritative symptoms can be managed with alpha blockers given on discharge.
The immediate/post-op flank pain after stone manipulation usually subsides over 24 to 48 hours and the patient can be assisted by use of NSAIDS or opioids where necessary.
Post operatively, in most cases in my practice, the patient is discharged with prophylactic antibiotics.
Where, however, the patient presents with febrile symptoms 48 hours after discharge, urinalysis and antibiotic commencement is prudent.
Treatment for nausea and vomiting is also beneficial.
Follow up visits – what do you want patients to know?
It is very important that the patient presents on the appointed date for stent removal and stone manipulation- losing a patient to follow-up is dangerous because of the risk of stent-encrustation, a situation where the stent gets crystalised, hardened, attached to the kidney and ureter, and become friable. In the worst-case scenario of this preventable outcome, a nephrectomy may become necessary.
The patient must be aware that the stone manipulation might require a repeat stent insertion and must not be discouraged when this happens.
On the follow-up visits, the discussion of stone analysis is made and this has bearing on preventive actions for stone recurrence. Where the patient had a metabolic workup, this is the opportunity to discuss the results.
What lifestyle changes would you recommend?
In general, increase in fluid intake is beneficial to decrease stone formation - HOWEVER, in my experience it is common for patients to take this advice too far. For an average sized individual, 2L of fluids is adequate.
The popularly-held idea that citrosoda is able to prevent all stones is wrong. In fact, it could worsen the situation for certain types of stones like calcium phosphate or struvite stones. Please follow the advice of your urologist who will advise you based on the type of stone you are diagnosed with.
Calcium intake should NOT be stopped or dramatically decreased- this can lead to increase in stone formation instead. It should rather be limited in the diet.
Animal protein should be decreased- it has been shown to increase stone formation, particularly uric acid calculi.Decrease in weight- obesity has been shown to be associated with increased stone disease.
Although there is a racial distribution in the prevalence of kidney stone disease in South Africa (Indian>White>Black), it must be made clear that kidney stones can occur in everyone and interestingly, the incidence is rising globally. The trends are also shifting.
The patient must be aware of the ever-present possibility of recurrence despite preventive measures adopted; within 5 years there is a 50% incidence of recurrence globally.
To book an appointment with Dr Aire, visit https://urology.co.za/doctors/dr-oo-aire/