Renal Medicine

What is Renal Medicine?

Renal medicine, also known as nephrology, is the medical specialty concerned with the diagnosis, treatment, and long-term management of diseases affecting the kidneys. Nephrologists are medical doctors with specialist training in kidney function, blood pressure control, and the balance of fluids, salts, and minerals in the body. They care for patients across a wide spectrum, from those with early, silent kidney damage to those whose kidneys have failed and who need dialysis or a transplant.

Kidney disease often develops slowly and quietly. Many people have no symptoms until a large part of their kidney function has already been lost, which is why early detection and steady, ongoing care matter so much. With the right monitoring and treatment, kidney damage can often be slowed, complications can be prevented, and patients can continue to live full and active lives.

Understanding How the Kidneys Work

The kidneys are two bean-shaped organs, each about the size of a fist, located on either side of the spine in the abdomen. Every day they filter many litres of blood through millions of tiny filtering units called nephrons, removing waste products and excess fluid while carefully retaining the substances the body needs, such as glucose and electrolytes. Beyond filtration, the kidneys perform several other essential roles:

• Waste removal: Filtering waste products, such as urea and creatinine, out of the blood and passing them out of the body in urine.
• Fluid and electrolyte balance: Regulating the body’s water content and levels of sodium, potassium, and calcium, which are vital for the normal working of the heart, muscles, and nerves.
• Blood pressure control: Managing fluid volume and releasing hormones that help keep blood pressure within a healthy range.
• Red blood cell production: Producing erythropoietin, a hormone that signals the bone marrow to make red blood cells.
• Bone and mineral health: Activating vitamin D and helping to balance calcium and phosphate, which keeps bones strong.
• Acid-base balance: Maintaining the right level of acidity in the blood so that the body’s cells and organs can function properly.

When kidney function declines, each of these roles can be affected, which is why kidney disease can have effects throughout the body.

Kidney Health in Singapore

Kidney disease is a significant and growing health concern in Singapore. Around six people in Singapore are diagnosed with kidney failure every day, and more than 9,000 people are currently on dialysis. Survey data shows that about 15 in every 100 Singapore residents have some degree of chronic kidney disease, and many of them may not know it.

Singapore also has one of the highest rates of diabetes-related kidney failure in the world. Diabetes is the leading cause of kidney failure here, followed by high blood pressure. Because both conditions are common, and can go unnoticed for years, regular health screening and good control of blood sugar and blood pressure are among the most effective ways to protect the kidneys. National initiatives such as Healthier SG encourage residents to build a long-term relationship with a family doctor, who can monitor kidney function as part of routine chronic disease care and refer patients to a nephrologist when needed.

Common Conditions Treated in Renal Medicine

Nephrologists diagnose and manage a broad range of conditions affecting the kidneys and the body’s fluid and chemical balance, including:

• Acute Kidney Injury (AKI): A sudden decline in kidney function over hours to days, often caused by dehydration, severe infection, or certain medications. It can often be reversed when the cause is treated promptly, but severe cases may need temporary dialysis.
• Chronic Kidney Disease (CKD): A gradual, long-term loss of kidney function, most often associated with diabetes, high blood pressure, or other underlying conditions. It is staged from 1 to 5 according to how well the kidneys are filtering.
• Diabetic Kidney Disease: Kidney damage caused by long-standing high blood sugar, which gradually harms the kidneys’ filtering units. It is the most common cause of kidney failure in Singapore.
• Hypertensive Kidney Disease: Damage to the small blood vessels of the kidneys caused by sustained high blood pressure. Kidney disease can in turn worsen blood pressure, creating a cycle that needs careful control.
• Glomerulonephritis: Inflammation of the glomeruli, the kidney’s filtering units, which may be caused by autoimmune conditions or infection. It can lead to blood or protein in the urine, swelling, and declining kidney function.
• Polycystic Kidney Disease (PKD): An inherited disorder in which clusters of fluid-filled cysts grow in the kidneys, gradually enlarging them and reducing their function over time.
• Kidney Stones: Hard deposits of minerals and salts that form in the kidneys, causing pain and, in some cases, blocking the flow of urine.
• Kidney Cancer: The uncontrolled growth of abnormal cells in the kidney. Renal cell carcinoma is the most common type.
• Electrolyte and Acid-Base Disorders: Imbalances in sodium, potassium, calcium, or the acidity of the blood, which can affect the heart, muscles, and brain if left untreated.

Recognising the Signs of Kidney Disease

Early kidney disease frequently causes no symptoms at all, so routine screening is important for anyone at higher risk. As kidney function declines, or when a sudden problem occurs, signs that may warrant medical review include:

• Swelling of the feet, ankles, legs, or face: Can occur when the kidneys are unable to remove excess fluid and salt from the body.
• Foamy urine or blood in the urine: Foamy urine can indicate protein leaking through damaged filters, while red, pink, or cola-coloured urine should always be assessed promptly.
• Changes in urination: Passing noticeably more or less urine than usual, needing to urinate frequently at night, or difficulty passing urine.
• Persistent tiredness, nausea, or loss of appetite: Can result from a build-up of waste products in the blood and from anaemia linked to kidney disease.
• Itchy skin, muscle cramps, or difficulty sleeping: Common in more advanced kidney disease as waste products and minerals accumulate.
• High blood pressure that is difficult to control: Can be both a cause and a consequence of kidney disease.
• Severe pain in the side or back: Particularly when it comes in waves or is accompanied by fever, vomiting, or blood in the urine, can point to a kidney stone or infection and requires urgent attention.

Risk Factors for Kidney Disease

• Diabetes: The leading cause of kidney failure in Singapore. Long-standing or poorly controlled blood sugar progressively damages the kidneys’ filters.
• High blood pressure: Sustained high pressure scars and narrows the small blood vessels in the kidneys.
• Age: Kidney function naturally declines with age, and the risk of chronic kidney disease rises steadily in older adults.
• Family history: A family history of kidney failure, polycystic kidney disease, or other inherited kidney conditions increases personal risk.
• Excess weight and smoking: Both are linked to faster decline in kidney function and to higher rates of diabetes, high blood pressure, and heart disease.
• Heart disease: The heart and kidneys are closely connected, and problems with one often affect the other.
• Long-term use of certain medicines: Regular use of over-the-counter anti-inflammatory painkillers (NSAIDs), or of unregulated herbal and traditional remedies, can harm the kidneys. Patients should always tell their doctor about everything they take.
• Recurrent kidney stones, urinary tract infections, or urinary obstruction: Repeated or untreated problems can cause lasting damage to the kidneys.
• Previous acute kidney injury: An episode of sudden kidney injury increases the likelihood of chronic kidney disease later on.

How Kidney Conditions Are Diagnosed

Diagnosis usually begins with a detailed medical history and examination, followed by tests that measure how well the kidneys are working and look for signs of damage.

• Blood tests: Measure creatinine, urea, and electrolytes. Creatinine is used to calculate the estimated glomerular filtration rate (eGFR), the main measure of how well the kidneys are filtering blood.
• Urine tests: Detect blood, protein, infection, or crystals in the urine. The urine albumin-to-creatinine ratio (UACR) can reveal kidney damage at a very early stage, often before the eGFR changes.
• Blood pressure monitoring: Regular measurements, sometimes supported by home or 24-hour monitoring, help assess how blood pressure and kidney health are affecting one another.
• Imaging: Ultrasound is commonly used to assess the size and shape of the kidneys and to look for stones, cysts, or obstruction. CT or MRI scans may be used for more detailed assessment.
• Kidney biopsy: In selected cases, a very small sample of kidney tissue is taken and examined under a microscope to identify the exact cause of kidney damage and guide treatment.

Treatment and Management of Kidney Conditions

Treatment depends on the underlying cause, the stage of kidney disease, and each patient’s overall health and personal goals. For many patients, the aim is to protect the kidney function that remains and to prevent complications.

• Controlling the underlying cause: Careful management of blood sugar and blood pressure is the foundation of kidney protection for most patients.
• Kidney-protective medication: Medicines that lower blood pressure, reduce protein leakage in the urine, and protect the kidneys may be prescribed, together with treatments for anaemia, bone and mineral problems, and fluid retention.
• Treatment of inflammatory kidney disease: Glomerulonephritis and autoimmune kidney conditions may be treated with medicines that calm the immune system, guided by biopsy results.
• Management of kidney stones: Small stones may pass naturally with adequate fluids and pain relief. Larger stones may need procedures such as shock wave lithotripsy (SWL), ureteroscopy, or percutaneous nephrolithotomy (PCNL), carried out in coordination with our urology colleagues.
• Dialysis: When the kidneys can no longer keep up, dialysis takes over the work of filtering waste and excess fluid from the blood.
• Kidney transplantation: For suitable patients, a transplant can offer the best long-term outcome for kidney failure.
• Conservative kidney management: For some patients, particularly those who are elderly or have several other serious illnesses, focusing on symptom control and quality of life without dialysis may be the choice that best reflects their wishes.

Kidney Replacement Options

When kidney function falls to the point where it can no longer sustain health, usually at stage 5 chronic kidney disease, patients and their families will need to consider their options. Our nephrologists take time to explain each one, so that the decision is an informed one that fits the patient’s medical condition, lifestyle, and values.

• Haemodialysis: Blood is passed through a filter outside the body, cleaned, and returned. It is usually carried out three times a week at a dialysis centre. Farrer Park Hospital’s Dialysis Centre on Level 10 offers haemodialysis and other forms of extracorporeal therapy with extended operating hours.
• Peritoneal dialysis: The lining of the abdomen is used as a natural filter, with a cleansing fluid placed in and drained from the abdominal cavity. It can be done at home and may suit patients who prefer more flexibility. National efforts are under way in Singapore to encourage wider use of home-based peritoneal dialysis for suitable patients.
• Kidney transplantation: A healthy kidney from a living or deceased donor is surgically placed in the recipient. Transplantation is regulated in Singapore under the Human Organ Transplant Act, and suitability is assessed carefully for both recipients and living donors.
• Conservative care: Ongoing medical treatment and support aimed at comfort and quality of life, without dialysis or transplant.

Diet and Lifestyle for Healthy Kidneys

Everyday habits have a real effect on kidney health, both in preventing kidney disease and in slowing its progress. General principles include:

• Keep blood sugar and blood pressure under control: Take medications as prescribed, attend regular reviews, and monitor readings at home where advised.
• Reduce salt: Many popular local dishes and condiments, including soups, gravies, sauces, preserved foods, and processed foods, are high in sodium. Choosing lighter, less salty options and asking for gravy or sauce on the side can help.
• Limit sugary drinks: Sweetened beverages, including sweetened coffee and tea, contribute to weight gain and diabetes, which in turn raise kidney risk.
• Drink enough water: Staying well hydrated lowers the risk of kidney stones and supports healthy kidneys, unless a doctor has advised a fluid restriction.
• Be careful with painkillers and supplements: Avoid regular use of anti-inflammatory painkillers, and check with a doctor or pharmacist before taking herbal remedies or supplements.
• Stay active and avoid smoking: Regular physical activity and a healthy weight support heart and kidney health.
• Get screened: People with diabetes, high blood pressure, heart disease, or a family history of kidney disease should have their kidney function checked regularly.

A diagnosis of kidney disease can feel overwhelming, but it does not mean life has to stop. With early detection, good control of related conditions, healthy habits, and timely specialist care, many people live well with kidney disease for years, and those who need dialysis or a transplant can still work, travel, and enjoy time with family.

Close, ongoing communication between patients, their families, and their nephrology team plays an important role in achieving the best possible outcome. If you have diabetes, high blood pressure, a family history of kidney disease, or any of the warning signs described above, we encourage you to speak with a doctor about having your kidneys checked.

Our dedicated teams of experienced multidisciplinary specialists and healthcare professionals work together to provide treatment plans tailored to the needs of our patients on their recovery journey.

Speak to our Specialists today.