What Are Staghorn Kidney Stones? (Symptoms, Causes, and Treatment)

Staghorn stones are large, branching kidney stones that can wholly or partially fill the renal pelvis and calyces (Healy & Ogan, 2007). They are typically found on one side of the body and are less common in men (Diri & Diri, 2018) (Johnson et al., 1979). Staghorn stones are linked with urinary tract infections (UTIs) caused by urease-producing bacteria, leading to rocks known as struvite infection stones (Torricelli & Monga, 2020a).

There are 4 Kidney Stone Types: Calcium oxalate, Uric acid, Struvite, and Cystine.

1. Calcium Oxalate 

Calcium oxalate crystals are the most prevalent type of crystal found in urine and are a leading cause of kidney stones. When there is an excess of oxalate, it can bind with calcium to create kidney stones and crystals. These formations can inflict harm on the kidneys and impede their function. Remarkably, approximately 80% of kidney stones are comprised of calcium; of that 80%, about 80% are classified as calcium oxalate stones (Finkielstein, 2006a).

2. Uric Acid 

Hyperuricemia, a high uric acid level in the bloodstream, can be caused by an overproduction of uric acid, reduced excretion, or a combination of both factors. If left unmanaged, this condition can form urate crystals, resulting in the painful condition known as gout. Moreover, high levels of uric acid, even without crystal formation, have been associated with severe health conditions such as hypertension, atherosclerosis, insulin resistance, and diabetes (Soltani et al., 2013). Understanding these potential risks can motivate individuals to take preventive measures against hyperuricemia.

Uric acid is a byproduct of dissolved purines, natural compounds in the body and certain foods and beverages. Foods high in purine include liver, anchovies, mackerel, dried beans and peas, and beer. When these purine-rich foods are consumed, the body breaks down the purines into uric

acid, resulting in an elevated uric acid level in the bloodstream (So & Thorens, 2010).

3. Cystine

Excessive levels of cystine in the urine can result in the development of kidney stones, which have the potential to become stuck in the kidneys, bladder, or urinary tract. Individuals diagnosed with cystinuria frequently experience repeated occurrences of kidney stones (Shen et al., 2017). While the condition can be well-managed, there is currently no known cure. Cystine, a naturally occurring chemical compound, can crystallize in the urine, forming kidney stones (Moussa et al., 2020).

 4. Struvite Stones

Struvite urinary stones, also known as “infection stones” or “triple phosphate” stones, are typically caused by infections in the upper urinary tract. These complex structures form from chemicals in the urine. Once they develop, the kidney can retain or pass the stone along the urinary tract and into the ureter (Griffith, 1978).

Staghorn Kidney Stone Symptoms and Conventional Treatment 

If a staghorn calculus is present in your kidney, you may notice symptoms such as a fever, pain on the side between your ribs and hip, and blood in your urine (hematuria). These kidney stones can result in various manifestations, including pain in the abdomen, side, groin, or back and blood in the urine (Mayo Clinic, n.d.).

The treatment of staghorn calculus typically involves surgical intervention to remove the stone, including any small pieces, to prevent infection or the development of new stones. One effective method for eliminating staghorn stones is percutaneous nephrolithotomy (PCNL), the gold standard surgical treatment for staghorn renal stones, particularly those larger than 2.0cm in size (De et al., 2015) (Torricelli & Monga, 2020b).

Dietary Management and Supplementation Modification

In the 1940s, a low-phosphate and calcium diet was proposed to reduce the risk of developing staghorn stones (Shorr, 1950).
In 1968, the role of dietary advice in inhibiting staghorn stone formation was studied. Those who followed the dietary regimen reported a marked decline in stone recurrence following the nephrolithotomy procedure (Lavengood & Marshall, 1972).

1. Fluid Intake

The foundation of effective management is centred around increasing urine volume. Research suggests that this impact follows a linear trend, with a point of diminishing return observed when urine volumes exceed 2.5 litres per day. According to recommendations, consuming 2.5 to 3 litres of fluid daily is advised to achieve this goal (Finkielstein, 2006b).

2. Calcium Supplement with Meals  

When taking calcium carbonate supplements with meals, oxalate excretion in the urine is reduced, which benefits individuals at risk of developing stones. On the other hand, taking these supplements at bedtime increases the excretion of calcium in the urine. It does not significantly impact oxalate excretion (Domrongkitchaiporn et al., 2004). For those prone to stone formation (Finkielstein, 2006a), it is preferable to use calcium citrate as a supplement, as it increases urinary citrate excretion. If it is challenging to increase dietary calcium, a recommended dose of 200–400 mg is suggested.

3. Remember: Limit Foods High in Oxalate.

Oxalates are natural compounds that are present in a wide range of foods. Some familiar sources of oxalates include green leafy vegetables (such as spinach and kale), starchy vegetables (like potatoes and beets), fruits, nuts (especially almonds), cereal grains, soy, and tea (Han et al., 2015). When consumed, oxalates are processed by the body and are naturally produced as waste products. It’s essential to limit the consumption of foods high in oxalate. You can reduce their impact by consuming them with extra fluids and including dietary sources of calcium to lower oxalate absorption (Garland et al., 2020) (Finkielstein, 2006b).

4. Vitamin C (ascorbic acid)

Additionally, vitamin C can convert to oxalate, so taking vitamin C (ascorbic acid) supplements may increase oxaluria (oxalates in urine) and be linked to a higher risk of stone formation. As a result, it’s recommended to limit vitamin C supplements to less than 1000 mg per day (Curhan et al., 1996) (Finkielstein, 2006a).

5. Remember to Regulate Your Consumption of Animal-based Protein. 

A diet that includes an excessive amount of animal protein can contribute to kidney stone formation. It is advised to control the intake of animal-based protein obtained from sources such as beef, pork, poultry, or fish daily. Research indicates that a diet high in animal protein, due to purines, can produce uric acid during metabolic processes, potentially elevating the likelihood of uric acid stone development (Curhan & Taylor, 2008) (Kenny & Goldfarb, 2010).

 6. Monitor Your Sodium Intake 

Excess salt in the diet can lead to increased calcium excretion by the kidneys, raising the risk of developing kidney stones. Monitoring sodium intake can be achieved by carefully reading food labels to identify high-sodium products. Additionally, it is essential to consider adjusting calcium supplementation, as it can impact the formation of calcium oxalate stones (Chung, 2017) (Afsar et al., 2016).

7. Omega-3 (EPA) Has Some Potential Benefits 

Omega-3 fatty acids, known as PUFA, found in oily fish such as mackerel, salmon, and albacore tuna, have numerous health benefits. However, current evidence regarding their impact on kidney stones is limited. While there isn’t strong evidence from the general population about the role of PUFA in preventing kidney stone formation, studies on dietary interventions suggest that fish oil or supplemental EPA can reduce the excretion of certain substances in the urine, thus lowering the risk of stone formation. Based on these trial results, fish oil is the most effective supplement despite the wide range of conditions in which the trials were carried out. Fish oil helps reduce calcium excretion in patients who form stones, lowering the risk of further stones. It is recommended that fish oil be used as a supplement to treat these patients. This emphasizes the need for more research to define fish oil’s potential benefits in this area (Rodgers & Siener, 2020).

Conclusion 

Staghorn renal stones, or struvite stones, are large kidney stones that fill the renal pelvis and at least one renal calyx. They are typically composed of magnesium ammonium phosphate. They are associated with recurrent urinary tract infections caused by urease-producing pathogens.

In developing countries, around 10 to 15% of all urinary stones are struvite stones, and women are affected more frequently than men. However, in developed countries, the incidence of renal stones is lower due to early diagnosis and management (Flannigan et al., 2014). Staghorn renal stones carry a significant morbidity and potential mortality rate of approximately 30%, making prompt assessment and active surgical management essential (Teichman et al., 1995) (Gao et al., 2020).

Taking a holistic approach to managing staghorn renal stones involves being mindful of the foods consumed, stress levels, fluid intake, and other lifestyle factors. These include limiting green leafy vegetables, starchy vegetables, fruits, nuts, cereal grains, soy, chocolate, and tea, being cautious with calcium timing and vitamin C supplements, regulating animal-based protein and salt intake, and considering the potential benefits of omega-3 (EPA) supplementation.