Nephrology is the medical specialty concerned with the diagnosis, treatment and long-term management of kidney disease and its complications. Nephrologists care for patients with acute kidney injury, chronic kidney disease, electrolyte and acid-base disorders, hypertension linked to the kidneys, and kidney failure requiring dialysis or transplant referral. Urology, by contrast, is generally a surgical specialty focused on the urinary tract and related reproductive organs, including procedures such as stone removal or prostate surgery. The two fields overlap in conditions such as obstruction or cancer, and patients often receive care from both. Understanding this boundary helps learners know when medical management versus surgical intervention is the primary concern.
The kidneys filter blood through millions of nephrons, removing metabolic wastes such as urea and creatinine while conserving water, glucose and essential electrolytes. They regulate sodium, potassium, phosphate and acid-base balance, and they produce hormones including erythropoietin, which stimulates red blood cell production, and the active form of vitamin D that supports calcium metabolism. They also help control blood pressure through the renin-angiotensin system. When filtration declines, these functions fail together, producing fluid overload, hyperkalemia, metabolic acidosis, anemia and mineral bone disorder. Clinicians interpret this integrated physiology when assessing a patient, because a single abnormal laboratory value often reflects several interacting problems.
Glomerular filtration rate, or GFR, measures how much blood the glomeruli filter each minute and is the most widely used overall indicator of kidney function. Direct measurement is rarely practical, so clinicians use estimating equations that combine serum creatinine with factors such as age, sex and, in some formulas, race or other variables, depending on current guidance. Because creatinine is affected by muscle mass, diet and certain medications, estimates can be inaccurate in some patients, such as those with extreme body size or very low muscle mass. Staging chronic kidney disease uses GFR categories together with markers of albuminuria. This combined staging guides monitoring frequency, referral timing and treatment decisions, and current professional guidelines should be followed for the equations used locally.
Acute kidney injury is a rapid decline in kidney function, often over hours to days, that may be reversible if the cause is identified and corrected. Chronic kidney disease refers to abnormalities of kidney structure or function persisting for at least three months, usually progressive and irreversible. Common acute causes include dehydration, sepsis, nephrotoxic medications and urinary obstruction, while chronic causes include diabetes, hypertension and glomerulonephritis. Management differs substantially. Acute injury focuses on finding and treating the trigger, avoiding further insult and supporting fluid and electrolyte balance, whereas chronic disease focuses on slowing progression, controlling blood pressure and glucose, and preparing for possible kidney replacement therapy. Recognizing which pattern is present is a core clinical skill.
A thorough assessment begins with a detailed history covering symptoms such as reduced urine output, swelling, fatigue, itching, and changes in urinary appearance, along with medications, including over-the-counter analgesics and contrast exposure, and relevant conditions like diabetes, hypertension and family history of kidney disease. The physical examination looks for fluid overload, blood pressure elevation, signs of anemia and skin or joint findings. Laboratory assessment usually includes serum creatinine and estimated GFR, electrolytes, urinalysis, urine albumin measurement and imaging such as ultrasound. The clinician integrates these data to determine whether disease is acute or chronic, the likely cause and urgency. Careful initial assessment prevents missed diagnoses and ensures timely escalation when a patient is unstable.
Urinalysis examines urine appearance, specific gravity, pH, protein, blood, glucose and microscopic findings such as red cell casts, which can indicate glomerular inflammation. Urine albumin testing, often expressed as an albumin to creatinine ratio, detects small amounts of protein leakage that signal early kidney damage, particularly in diabetes and hypertension, before blood creatinine rises. Persistent albuminuria is an independent risk factor for progression and cardiovascular events. Because creatinine can remain normal while kidney damage is underway, these urine tests provide an earlier warning. In practice, a clinician might repeat the albumin test over several weeks, since transient elevation from exercise, fever or infection does not necessarily indicate chronic disease.
Hemodialysis removes waste products and excess fluid by circulating the patient's blood through an artificial filter called a dialyzer, where it passes across a semipermeable membrane. A dialysate solution containing balanced electrolytes flows on the opposite side. Solutes move down their concentration gradient through diffusion, while fluid is removed through ultrafiltration created by a pressure gradient. The system includes a blood pump, a dialysate delivery unit that prepares and monitors fluid composition, and an access route, usually a fistula, graft or catheter. Sessions typically run several hours, several times per week, though schedules vary by patient and program. Learners should understand these mechanics as the foundation for prescribing adequacy and managing complications.
The main vascular access options are the arteriovenous fistula, the arteriovenous graft and the central venous catheter. A fistula directly connects an artery to a vein, usually in the forearm, and is generally preferred because it has lower rates of infection and clotting and tends to last longer. A graft uses synthetic tubing to join an artery and vein and can be created when native veins are unsuitable, but it has higher infection and thrombosis rates than a fistula. Catheters offer immediate access and are often used temporarily, yet carry the highest risk of bloodstream infection and dysfunction. Planning access early, sometimes years before dialysis is needed, is a key quality goal, because urgent catheter placement is associated with poorer outcomes.
Peritoneal dialysis uses the peritoneum, the membrane lining the abdominal cavity, as a natural filter. A sterile dialysate solution is instilled through a surgically placed catheter, allowed to dwell for a period, and then drained, carrying waste and excess fluid with it. Exchanges can be performed manually several times daily or overnight by a cycler machine. Suitable candidates usually have adequate peritoneal membrane function, sufficient physical and cognitive ability or a supportive caregiver, a clean home environment and motivation to perform daily therapy. Patients with extensive abdominal surgery or certain hernias may be less suitable. Modality choice should be shared with the patient after an informed discussion of lifestyle, risks and preferences.
Adequacy describes whether dialysis removes enough waste to support health. The most common measure is Kt/V, which combines the clearance of urea across the dialyzer, the treatment time and the volume of body water. Many guidelines use a target value near 1.2 per session for thrice-weekly hemodialysis, although targets and measurement methods should be confirmed against current professional guidance. Clinicians also monitor interdialytic weight gain, blood pressure response, electrolyte levels and symptoms such as cramping or fatigue. Because adequacy depends on variables that change over time, including residual kidney function, body size and access flow, prescriptions are reviewed regularly. Dialysis care teams adjust time, blood flow or dialyzer characteristics as needed.
Dialysis patients are highly vulnerable to infection because they have weakened immune function, frequent vascular access manipulation and repeated exposure to blood through equipment. Catheter-related bloodstream infection is a leading cause of hospitalization and death in this population. Key prevention practices include strict hand hygiene, aseptic technique during access cannulation and connection, chlorhexidine skin antisepsis, appropriate catheter dressings, and prompt removal of unnecessary catheters. Staff must also follow standard precautions for blood-borne pathogens and maintain proper machine disinfection between sessions. Surveillance of infection rates and regular audits help units identify gaps. Clinicians working in dialysis should always follow their institution's infection control policies and current national recommendations.
Many drugs are cleared by the kidneys, so reduced function can cause them to accumulate, increasing the risk of toxicity. Examples include certain antibiotics, anticoagulants, opioids and metformin, the last of which may require discontinuation at low GFR because of the risk of lactic acidosis. Some drugs are also dialyzable, meaning doses may need timing around sessions. Clinicians consult renal dosing references, check GFR and consider dialysis status before prescribing. Pharmacists and nephrologists often collaborate on medication reconciliation, especially given the many medications patients with chronic kidney disease take. Conversely, avoiding nephrotoxic drugs such as aminoglycosides and some contrast agents, when alternatives exist, is an important safety principle.
Clinical records in nephrology should document the patient's history, examination findings, laboratory results, medication lists, dialysis prescriptions and session details, including blood pressure, fluid removal, access condition and any adverse events. Accurate, timely entries support safe handoffs between shifts and between teams. Privacy rules govern who may access these records and how they may be shared. In many jurisdictions, health information is protected by law, which requires limiting access to people with a legitimate care need, securing electronic systems and disclosing information only as permitted. Learners should be aware that specific requirements vary by country and institution, so local data protection policies and professional guidance must be followed.
Effective communication in nephrology starts with understanding what the patient already knows and what matters most to them. Clinicians should explain diagnoses in plain language, avoid unnecessary jargon, use visual aids such as diagrams of kidney function, and check comprehension with teach-back, where the patient restates key points in their own words. Discussions about dialysis or conservative management benefit from giving balanced information about options, expected burdens and outcomes, and time for questions. Involving family or caregivers, with the patient's permission, can improve understanding and adherence. Interpreters should be used when language barriers exist. Good communication builds trust and supports shared decision making, which is central to kidney care planning.
Kidney care is delivered by a team that typically includes nephrologists, specialist nurses, dialysis technicians, dietitians, pharmacists, social workers, and surgeons or interventional radiologists for access procedures. Nephrologists lead medical decisions and prescriptions. Nurses coordinate care, educate patients and monitor treatment. Technicians operate dialysis equipment and track sessions. Dietitians manage potassium, phosphate, sodium and protein intake. Social workers address financial, transport and psychological needs that influence treatment adherence. Teamwork matters because kidney disease affects many systems and requires coordinated adjustments across disciplines. Regular team meetings and shared records help prevent errors and ensure that patient goals are reflected in every intervention.
Referral is generally recommended when kidney function is persistently reduced, when albuminuria is significant, when there is an unexplained decline in GFR, when electrolyte disturbances or resistant hypertension occur, or when the patient has a hereditary or systemic cause such as glomerulonephritis or lupus. Earlier referral allows planning for access and education, which improves outcomes. Urgent escalation is needed for signs such as severe hyperkalemia, marked fluid overload with breathlessness, oliguria, confusion, uremic symptoms, or sudden kidney injury, which may require emergency dialysis. Clinicians should follow local referral criteria and established guidelines, and they should communicate clearly about why a referral is urgent.
Informed consent for dialysis should explain the diagnosis, the purpose and expected benefits of treatment, the risks such as access complications, infection, bleeding and hypotension, alternatives including conservative care and transplant, and what the patient can expect in daily life. The patient should have the capacity to understand this information and the freedom to decline. Shared decision making recognizes that patients' values, goals and circumstances shape which option is best. Decisions may change over time, so consent is an ongoing conversation rather than a single signature. Clinicians must follow legal and institutional requirements for consent documentation, and ethical practice emphasizes respect for autonomy alongside beneficence.
Conservative kidney management is a planned approach that focuses on symptom control, quality of life, and supportive care for patients who choose not to pursue dialysis or who are unlikely to benefit from it. It does not mean withholding care. It includes medication management, dietary guidance, fluid and electrolyte support, treatment of anemia and mineral disturbances where appropriate, and palliative services for symptoms such as pain, itch and breathlessness. Ethically, it reflects respect for patient autonomy and the principle that treatments should align with goals. Clinicians offering this option should document the discussion thoroughly, maintain close follow-up and ensure access to emergency care and advance care planning. Local guidance on conservative pathways should be consulted.
Nephrology practice is governed by licensing bodies, professional colleges, hospital credentialing systems and national or regional health regulations. Physicians must hold appropriate qualifications and be credentialed to prescribe and oversee dialysis. Nurses and technicians may operate equipment or deliver care only within the scope defined by their licenses, training and facility protocols. Dialysis equipment, dialyzers and solutions are regulated as medical devices or drugs, and their use follows manufacturer instructions and approved indications. Scope-of-practice limits matter when delegating tasks, such as cannulation or prescription changes. Learners should consult the regulations and professional standards that apply in their jurisdiction, since rules differ between countries and regions, and this page is educational rather than a substitute for licensed professional judgment.
Dialysis quality programs often track measures such as adequacy of dialysis, hemoglobin and anemia management, mineral and bone parameters, blood pressure control, rates of vascular access use, and infection and hospitalization rates. Some programs also monitor patient-reported outcomes, such as symptoms and quality of life, and the proportion of patients on home dialysis or transplant waitlists. These measures must be interpreted carefully. A high target achievement may reflect case mix, such as healthier patients, rather than superior care, so risk adjustment and trend analysis are important. Quality data are most useful when they prompt reflection and improvement within teams. The specific measures and target values used should follow current national or program guidance.