Pathophysiology
Kidney stones are basically minerals that have accumulated inside the kidney. When these minerals are present in large concentrations in the body they began to deposit inside the kidney, and after a while become crystals. These crystals continue to stick together until a large formation is produced. These crystals may dislodge and migrate to other organs, potentially damaging these organs and obstructing the flow of urine (Thakore and Liang, 2020).
Aetiology
Urolithiasis is caused by the presence of high amounts of certain minerals. Based on their aetiology, kidney stones are classified into the following categories:
Calcium stones
Calcium stones are the most common types of kidney stones. About 80% of kidney stones are composed of calcium, 70% of which are calcium phosphate stones and the rest of the 10% are stones of calcium oxalate.
The consumption of oxalate-rich food and low calcium intake increases the risk of oxalate stone formation.
Uric acid stones
Uric acid stones are the deposition of uric acid crystals in the kidney. When the pH levels of urine decrease and the concentration of urine increases, uric acid deposition also enhances.
Struvite stones
Struvite stones are infectious stones that are composed of ammonium phosphate. When urea is broken down in the kidney it yields by-products that increase the pH levels of urine. The formation of struvite stones is accelerated in the presence of high urinary pH levels.
Cystine stones
Cystine stones are a rare form of urolithiasis and are genetic in nature. In this condition stones made from cysteine amino acids develop and patients may form kidney failure (Thakore and Liang, 2020).
Aetiology
Urolithiasis is caused by the presence of high amounts of certain minerals. Based on their aetiology, kidney stones are classified into the following categories:
Calcium stones
Calcium stones are the most common types of kidney stones. About 80% of kidney stones are composed of calcium, 70% of which are calcium phosphate stones and the rest of the 10% are stones of calcium oxalate.
The consumption of oxalate-rich food and low calcium intake increases the risk of oxalate stone formation.
Uric acid stones
Uric acid stones are the deposition of uric acid crystals in the kidney. When the pH levels of urine decrease and the concentration of urine increases, uric acid deposition also enhances.
Struvite stones
Struvite stones are infectious stones that are composed of ammonium phosphate. When urea is broken down in the kidney it yields by-products that increase the pH levels of urine. The formation of struvite stones is accelerated in the presence of high urinary pH levels.
Cystine stones
Cystine stones are a rare form of urolithiasis and are genetic in nature. In this condition stones made from cysteine amino acids develop and patients may form kidney failure (Thakore and Liang, 2020).
Risk Factors
The formation of kidney stones is an anomaly, occurring under specific circumstances evoked by the poor quality of life. A few risk factors that enhance stone formation are discussed below:
Gender
The epidemiologic studies have observed the influence of gender in the occurrence of kidney stones. The men-to-women ratio for the development of kidney stones is 2:1.
Low prevalence of kidney stones in women is due to the protective effect of estrogen on renal tissues (Peerapen and Thongboonkerd, 2019).
Ethnicity
Urolithiasis is more common in Caucasians than in the rest of the population. The study of the distribution of kidney stones reported the development of kidney stones in 21% of African-American men against 79% of white men. This study revealed that urolithiasis is secondary to other complications in African-Americans, and was more common in individuals with higher body mass index (BMI) (Akoudad et al., 2010).
Medical History
Medical history of a patient increases the vulnerability of that individual towards the formation of kidney stones. Some of these factors include
- Previous history of urolithiasis
- Family history of kidney stone
- Hypertension
- Gastric bypass
Dietary factors
The formation of kidney stones largely depends on the dietary intake of a patient. Urolithiasis is more common in patients that drink less than the recommended amount of fluid per day. Low fluid intake concentrates the urine and decreases its production, enhancing the chances of accumulation of minerals inside the urinary system (NHS.UK, 2018).
Another contributing factor to the formation of urinary stones is the high-protein diet especially if it is low in dietary fibre. A high protein and low carbohydrate diet is used for weight loss but can be harmful to renal health as it increases the acid load, and decreases the excretion of oxalate, elevating the risk of kidney stone formation (Gottlieb, 2002).
Low calcium intake is also associated with an increased risk of urolithiasis. This is attributed to the competition between oxalate and calcium in the gut. When oxalate-rich food is consumed, calcium is excreted out of the body and the risk of deposition of oxalate crystals increases (Borghi et al., 2002).
High sodium intake is associated with elevated levels of serum calcium levels which contributes to the risk of calcium stones. Several researchers have highlighted the importance of restricting sodium consumption and even recommended the DASH diet (Dietary Approaches to Stop Hypertension) for declining deposition rates in urolithiasis (Ferraro et al., 2020).
Drug Usage
Certain medications are also responsible for enhancing the rate of stone deposition in the kidney. Researchers have estimated that 1-2% of total kidney stones are induced by drug usage. HIV patients are treated with a class of drugs called protease inhibitors (PIs). PIs are notorious for kidney stones that are not susceptible to lithotripsy and cause urinary obstruction (Izzedine, Lescure and Bonnet, 2014).
Signs and Symptoms
The patients of urolithiasis show a variety of different symptoms ranging from symptomless to severe pain. Usually, urolithiasis symptoms appear if the stones move inside the kidney or try to pass through the ureters (tubes connecting the kidney to the urinary bladder). A few of the symptoms used to determine the presence of kidney stones are as follows:
- Pain in the lower back or below ribs the intensity of which fluctuates from dull to severe pain
- Painful urination
- Pink, red, or brown urine, often due to the presence of blood
- Frequent urination
- Cloudy, foul-smelling urine, especially if an infection is present
- Nausea and vomiting
Kidney stones are difficult to diagnose as they are often symptomless or they have general symptoms that are associated with other issues of urinary systems.
Urolithiasis Treatment
The treatment of kidney stones is mostly dependent on the symptoms of the patients. In symptomless cases, the patients are asked to wait for the stone to pass through the urinary system. Depending on the severity of the pain, oral or intravenous painkillers are administered to the patients.
If nausea or vomiting persists, patients are given anti-emetics to ease these symptoms. In case of persistent vomiting, IV fluids are given to prevent the risk of dehydration.
The diagnosis of urolithiasis depends on endoscopy, an invasive procedure in which a tube with a camera is inserted into the body to determine the presence of kidney stones. The presence of larger stones or complications may require more intense medical attention (Thakore and Liang, 2020). In some cases, surgical methods may be required to operate on kidney stones.
Shock-wave lithotripsy
This is the least invasive method for removing stones from the kidneys, ureter, and even gall bladder. It uses high-energy shock waves that break down the stones into small pieces so they can be easily excreted out of the body.
Ureteroscopy
Ureteroscopy is an endoscopic procedure of the urinary system in which a ureteroscope is inserted through the ureter. This procedure breaks down the kidney stones either manually or through a laser.
Percutaneous Nephrolithotomy
Percutaneous nephrolithotomy is done for the removal of the stones that are present with complications. This procedure involves an incision in the skin to create an opening, and a catheter or tube is inserted into the tube to break down the kidney stones.
Treatment of Urolithiasis in Unani Medicine
Unani medicine has been used as a potent anti-urolithiasis for centuries. The success of Unani practices for renal health is attributed to the great perception of Unani scholars as they incorporated lifestyle interventions in their treatments instead of targeting kidney stones.
Without proper management, urolithiasis is recurring and requires interventions to improve life quality.
Fluid Intake
Fluid intake is the best anti-urolithiasis agent as it can prevent, delay, and treat kidney stones in patients. Unani practitioners put special emphasis on the consumption of fluid and recommend at least three litres of fluid every day to prevent the deposition of minerals. It is interesting to highlight that guidelines use the word ‘fluid’ and not water. Fluids include all beverages like water, fruit and vegetable juices, tea, and coffee (NHS.UK, 2017).
Another important fluid in the prevention of kidney stones is vinegar. Daily consumption of vinegar protects patients from recurring kidney stones by increasing the urinary excretion of citrate (Zhu et al., 2019).
Dietary Interventions
Depending on the diet of the patients, Unani practitioners also recommend changes in the diet that can decline the rate of kidney stone deposition. A few interventions on the basis of the diet of the patients are discussed below:
Low Sodium Intake
Unani experts believe that consuming a diet low in salt is the best possible treatment for urolithiasis. The presence of sodium increases the urinary excretion of calcium leading to a high risk of oxalate deposition.
For the general population, a sodium intake of 2300mg per day is recommended, which translates to 6g of salt. A lower intake of 1500mg sodium (⅔ tsp of salt) per day is for the population suffering from diseases secondary to high salt intake (Pendick, 2013).
A few guidelines have been recommended to manage the intake of salt in everyday diet:
- Do not use salt shakers as sprinkling salt increases the intake of sodium
- Avoid canned or frozen foods as they have higher sodium content
- Read the nutrition label, and determine the sodium content of the food before buying
High Calcium Intake
Calcium intake reduces the risk of kidney stones by decreasing the availability of oxalate in the intestine and increasing the urinary excretion of oxalate. This effect was only seen when calcium is consumed with oxalate otherwise the intended effect on oxalate may not be observed (Bargagli et al., 2021).
Some commonly used calcium sources are as follows:
- Dairy products (milk, yoghurt, cheese, butter)
- Nuts (almonds)
- Calcium-fortified juices or cereals
- Leafy green vegetables (spinach, kale, mustard)
Lean Protein Diet
Higher intake of animal protein is associated with a higher risk of kidney stones. Animal protein has a higher percentage of saturated fats in the body which can increase the risk of comorbidities in the body.
Protein intake also increases the renal load and pH levels of urine which can be harmful to kidney health in the long term (Ferraro et al., 2020).
Higher intake of lean protein especially from plant sources can help achieve the daily protein goal while minimising the effect on kidneys.
Vitamin C
A Swedish study found that about 2% of the men that took vitamin C supplements over a long period developed kidney stones (Thomas et al., 2013). Vitamin C has a large variety of health benefits that includes improving immune function, decreasing oxidant stress, and delaying ageing. Vitamin C is naturally present in many foods and should be obtained from these sources as supplementation of vitamin C increases the risk of renal insufficiency.
Some of the sources of vitamin C are mentioned below
- Citrus fruits (orange, lemon, lime, grapefruit)
- Cruciferous vegetables (broccoli, cabbage, cauliflower)
Low intake of oxalate
Oxalates are the naturally occurring compounds present in different food sources. Oxalates combine with calcium and form the most common type of kidney stones. Unani practitioners recommend a diet that is low in oxalate sources to prevent the onset of urolithiasis.
The richest source of oxalate is tomato seeds. When recommending dietary prevention of kidney stones, Unani scholars encourage patients to remove the seeds of tomatoes before using them in food.
Some other sources of oxalates that should be restricted if a high risk of kidney stones is present are:
- Cruciferous vegetables (spinach, kale, rhubarb)
- Nuts (cashews and almonds)
- Potatoes (sweet potatoes, baked potatoes with skin, french fries)
Best Diet
From the above discussion, it is quite evident that Unani experts believe kidney stones can be prevented and managed with the help of diet. A natural, low-fat, moderate-protein diet, which is also low in salt can work wonders for susceptible populations.
Unani Medicine
Perhaps the most effective treatment for urolithiasis is the medicines prescribed by Unani practices. These medicines have successfully been used for centuries and are very effective for removing stones without invasive procedures.
A few herbal medicines used in Unani practices were tested on the animal model to determine their efficacy as anti-urolithic agents. The results of these trials showed a decrease in urinary calcium oxalate crystals, and the levels of serum calcium, urea, phosphorus, and creatinine were also reduced (Parveen et al., 2021).
Bhumi Amla
Bhumi Amla (Phyllanthus niruri) is an ayurvedic herb, used as a treatment for kidney stones. The efficacy of Amla is evident by its name “Stone Breaker”. Due to its fame, modern researchers have shown quite a lot of interest in this herb.
Research has shown that Bhumi Amla has shown the same efficacy as that of procedures like lithotripsy and ureteroscopy (Dhawan and Olweny, 2020).
Another study has revealed that the use of Bhumi Amla significantly reduces the rate of stone formation. The recurrence rate in the patients using this herb was also lower as compared to the control group (Micali et al., 2006). These results are evident that Amla has significant efficiency as an anti-urolithic agent.
Zakhme Hayat
Zakhme Hayat (Bergenia cilita) is an Unani herb and a potent antioxidant that can prevent lipid peroxidation, and reduce the oxidative load. The use of Zakhame Hayat has also been shown to decrease the urinary levels of calcium, phosphate, and oxalate levels (Saha, Shrivastav and Verma, 2014).
This herb can also dissolve calcium-phosphate and oxalate stones, but greater dissolution rates were seen in oxalate crystals (Byahatti, Pai and D’Souza, 2010).
Kalonji
Kalonji (Nigella sativa) is a spice commonly added to food as a flavour enhancer. The positive effect of Kalonji is due to its biologically active compound thymoquinone which is antioxidant and anti-inflammatory in nature (Hayatdavoudi et al., 2016).
In research, half of the participants using Kalonji have reduced sizes of kidney stones, and about 45% of the patients were able to excrete the stone completely (Ardakani Movaghati et al., 2019).
Khar-e-Khasak-khurd
Khar-e-Khasak-khurd (Tribulus terrestris) is another popular ayurvedic medicine. A unique quality of this herb is its anti-oxidant property which protects the kidney against free radicals, restores the renal structure, and improves kidney function (Kaushik et al., 2019).
Although higher doses had no significant adverse effects, moderate doses were more efficient against urolithiasis (Kaushik et al., 2019).
Ajmal Treatments for kidney stones
These medicines are produced after tactfully considering dosages, adverse effects, and intended use. Some of the herbs produced for the development of herbs are given as follows:
Dawa-i-Pathri Ajmali
It is composed of Sang-e-Surbhi (silicate of lime), and is used for dissolving stones in the kidney and urinary bladder.
Qurs Hajrul-Yahud
It is a mineral supplement used for the treatment of problems associated with the urinary system including urinary tract infections (UTI), and renal calculi.
Qurs Hasat Ajmali
It is another ingredient used to dissolve and excrete kidney stones.
- Sorokin, I., Mamoulakis, C., Miyazawa, K., Rodgers, A., Talati, J. and Lotan, Y. (2017). Epidemiology of stone disease across the world. World journal of urology, [online] 35(9), pp.1301–1320. doi:https://doi.org/10.1007/s00345-017-2008-6.
- Thakore, P. and Liang, T.H. (2020). Urolithiasis. [online] PubMed. Available at: https://www.ncbi.nlm.nih.gov/books/NBK559101/.
- Peerapen, P. and Thongboonkerd, V. (2019). Protective Cellular Mechanism of Estrogen Against Kidney Stone Formation: A Proteomics Approach and Functional Validation. PROTEOMICS, 19(19), p.1900095. doi:https://doi.org/10.1002/pmic.201900095.
- Akoudad, S., Szklo, M., McAdams, M.A., Fulop, T., Anderson, C.A.M., Coresh, J. and Köttgen, A. (2010). Correlates of kidney stone disease differ by race in a multi-ethnic middle-aged population: The ARIC study. Preventive Medicine, 51(5), pp.416–420. doi:https://doi.org/10.1016/j.ypmed.2010.08.011.
- nhs.uk. (2018). Kidney stones – Causes. [online] Available at: https://www.nhs.uk/conditions/kidney-stones/causes/.
- Gottlieb, S. (2002). High protein diet brings risk of kidney stones. BMJ : British Medical Journal, [online] 325(7361), p.408. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1169452/.
- Borghi, L., Schianchi, T., Meschi, T., Guerra, A., Allegri, F., Maggiore, U. and Novarini, A. (2002). Comparison of Two Diets for the Prevention of Recurrent Stones in Idiopathic Hypercalciuria. New England Journal of Medicine, 346(2), pp.77–84. doi:https://doi.org/10.1056/nejmoa010369.
- Ferraro, P.M., Bargagli, M., Trinchieri, A. and Gambaro, G. (2020). Risk of Kidney Stones: Influence of Dietary Factors, Dietary Patterns, and Vegetarian–Vegan Diets. Nutrients, 12(3), p.779. doi:https://doi.org/10.3390/nu12030779.
- Izzedine, H., Lescure, F.X. and Bonnet, F. (2014). HIV medication-based urolithiasis. Clinical Kidney Journal, 7(2), pp.121–126. doi:https://doi.org/10.1093/ckj/sfu008.
- nhs.uk. (2017). Kidney stones – Prevention. [online] Available at: https://www.nhs.uk/conditions/kidney-stones/prevention/#:~:text=The%20best%20way%20to%20prevent.
- Zhu, W., Liu, Y., Lan, Y., Li, X., Luo, L., Duan, X., Lei, M., Liu, G., Yang, Z., Mai, X., Sun, Y., Wang, L., Lu, S., Ou, L., Wu, W., Mai, Z., Zhong, D., Cai, C., Zhao, Z. and Zhong, W. (2019). Dietary vinegar prevents kidney stone recurrence via epigenetic regulations. EBioMedicine, 45, pp.231–250. doi:https://doi.org/10.1016/j.ebiom.2019.06.004.
- Pendick, D. (2013). 5 steps for preventing kidney stones. [online] Harvard Health. Available at: https://www.health.harvard.edu/blog/5-steps-for-preventing-kidney-stones-201310046721#:~:text=So%2C%20a%20low%2Dsodium%20diet [Accessed 7 Feb. 2023].
- Bargagli, M., Ferraro, P.M., Vittori, M., Lombardi, G., Gambaro, G. and Somani, B. (2021). Calcium and Vitamin D Supplementation and Their Association with Kidney Stone Disease: A Narrative Review. Nutrients, 13(12), p.4363. doi:https://doi.org/10.3390/nu13124363.