Acute kidney injury, CKD, glomerulonephritis, renal transplant, electrolyte disorders, and dialysis — essential renal medicine topics.
Disturbances in blood pH resulting from imbalances in acid production, acid excretion, or bicarbonate handling. Classified as metabolic acidosis, metabolic alkalosis, respiratory acidosis, or respiratory alkalosis. Arterial blood gas analysis is essential for diagnosis and management.
Rapid decline in kidney function over hours to days, defined by KDIGO criteria as a rise in serum creatinine of ≥26.5 µmol/L within 48 hours or ≥1.5× baseline within 7 days, or urine output <0.5 mL/kg/hr for 6 hours. Common causes include sepsis, hypovolaemia, nephrotoxins, and obstruction.
Hereditary nephritis caused by mutations in type IV collagen genes (COL4A3/4/5), resulting in progressive glomerulonephritis, sensorineural hearing loss, and ocular abnormalities. X-linked inheritance (COL4A5) accounts for 80% of cases.
Group of small-vessel vasculitides characterised by necrotising inflammation and association with anti-neutrophil cytoplasmic antibodies (ANCA). Includes granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). Renal involvement manifests as pauci-immune crescentic glomerulonephritis.
Rare autoimmune disease caused by antibodies against the alpha-3 chain of type IV collagen in the glomerular and alveolar basement membranes. When both kidneys and lungs are affected, it is termed Goodpasture syndrome. It presents as rapidly progressive glomerulonephritis with or without pulmonary haemorrhage and requires emergency treatment with plasma exchange and immunosuppression.
Progressive, irreversible decline in kidney function defined as eGFR <60 mL/min/1.73m² or markers of kidney damage persisting for >3 months. Leading causes in the UK include diabetes mellitus and hypertension. Managed per NICE NG203 with a focus on cardiovascular risk reduction and slowing progression.
Acute kidney injury occurring within 48-72 hours of intravascular iodinated contrast administration, defined as a rise in serum creatinine of ≥25% or ≥44 µmol/L from baseline. Risk is highest in patients with pre-existing CKD and diabetes. Prevention with IV hydration is the cornerstone of management.
Progressive kidney disease caused by long-standing diabetes mellitus, characterised by increasing albuminuria, declining GFR, and hypertension. It is the single most common cause of end-stage renal disease in the UK.
Renal replacement therapy that removes waste products, excess fluid, and electrolytes from the blood when native kidney function is insufficient. The two main modalities are haemodialysis (HD) and peritoneal dialysis (PD). In the UK, approximately 30,000 patients are on dialysis, with haemodialysis being the most common modality.
Generalised dysfunction of the proximal renal tubule leading to impaired reabsorption of glucose, amino acids, phosphate, urate, bicarbonate, and small proteins. Causes include cystinosis (children), myeloma, drugs (tenofovir, ifosfamide), and Wilson disease.
Histological pattern of glomerular injury characterised by segmental sclerosis affecting some (focal) glomeruli. It is the most common cause of primary nephrotic syndrome in adults of African descent and has a significant risk of progression to ESRD.
Thrombotic microangiopathy characterised by the triad of microangiopathic haemolytic anaemia (MAHA), thrombocytopenia, and acute kidney injury. Typical (Shiga toxin-associated) HUS is most common in children following E. coli O157:H7 gastroenteritis. Atypical HUS is complement-mediated and requires eculizumab.
Functional renal failure occurring in patients with advanced liver disease (usually decompensated cirrhosis), caused by extreme renal vasoconstriction in the setting of splanchnic vasodilation. It is a diagnosis of exclusion with no structural renal abnormality.
Chronic kidney disease resulting from long-standing hypertension causing progressive nephrosclerosis. It is the second most common cause of end-stage renal disease in the UK after diabetic nephropathy.
Pattern of glomerular injury characterised by mesangial cell proliferation, GBM thickening with double contour formation, and lobular appearance. Now reclassified by immunopathogenesis into immune complex-mediated and complement-mediated (C3 glomerulopathy) forms.
Immune-mediated glomerulonephritis characterised by subepithelial immune complex deposition and glomerular basement membrane thickening. It is the most common cause of primary nephrotic syndrome in Caucasian adults.
Most common cause of nephrotic syndrome in children, characterised by diffuse podocyte foot process effacement on electron microscopy with normal light microscopy. Highly steroid-responsive with an excellent overall prognosis.
Acute glomerular inflammation presenting with haematuria (often with red cell casts), proteinuria (usually <3.5g/day), oliguria, hypertension, and oedema. The classical post-streptococcal form occurs 1-3 weeks after pharyngitis or skin infection and is usually self-limiting in children.
Clinical syndrome characterised by heavy proteinuria (>3.5 g/day or uPCR >350 mg/mmol), hypoalbuminaemia (<25 g/L), peripheral oedema, and hyperlipidaemia. In children, minimal change disease is the most common cause; in adults, membranous nephropathy and FSGS predominate.
Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited renal disease, caused by mutations in PKD1 (85%) or PKD2 (15%) genes. Characterised by progressive bilateral renal cyst development leading to ESRD by median age 54 (PKD1) or 74 (PKD2).
Acute bacterial infection of the renal parenchyma and collecting system, usually caused by ascending infection from the lower urinary tract. E. coli is responsible for 70-80% of cases. Presents with fever, loin pain, and systemic upset. Can lead to sepsis, renal abscess, or chronic scarring.
Medical emergency characterised by rapid decline in renal function over days to weeks with crescent formation on renal biopsy in ≥50% of glomeruli. Requires urgent diagnosis and treatment with immunosuppression and often plasma exchange to prevent irreversible renal failure.
Narrowing of one or both renal arteries, most commonly due to atherosclerosis (90%) or fibromuscular dysplasia (10%). Can cause renovascular hypertension and ischaemic nephropathy. Diagnosis is by duplex USS or MR angiography.
Most common primary renal malignancy in adults, accounting for 85-90% of kidney cancers. Clear cell carcinoma is the predominant subtype (70-80%). Presents with the classic triad of haematuria, loin pain, and palpable mass in <10% of cases; most are now found incidentally on imaging.
Nephrolithiasis is a common condition affecting 10-15% of the UK population, characterised by formation of calculi within the urinary tract. Most stones are calcium oxalate (70-80%). Presents with acute ureteric colic. Managed per NICE NG118 with analgesia, hydration, and intervention for large or complicated stones.
Gold standard treatment for end-stage renal disease, offering superior survival and quality of life compared to dialysis. Living donor transplants have the best outcomes. Requires lifelong immunosuppression with associated risks of infection, malignancy, and cardiovascular disease.
Group of disorders characterised by normal anion gap (hyperchloraemic) metabolic acidosis due to impaired renal acid-base handling. Type 1 (distal) and type 2 (proximal) affect acid secretion and bicarbonate reabsorption respectively; type 4 (hyperkalaemic) is the most common form and results from aldosterone deficiency or resistance.
Syndrome of skeletal muscle breakdown with release of intracellular contents (myoglobin, CK, potassium, phosphate) into the circulation. A major cause of AKI due to myoglobin-induced tubular obstruction and toxicity. Requires aggressive IV fluid resuscitation.
Inability to voluntarily void urine. Acute retention is a urological emergency presenting with sudden painful inability to pass urine. Chronic retention is painless and associated with a large bladder residual. Most common cause in men is benign prostatic hyperplasia.
Common infection of the urinary tract, classified as lower (cystitis) or upper (pyelonephritis). Most frequently caused by E. coli (70-80%). Women are affected far more commonly than men. Management is guided by NICE NG109 and local antimicrobial guidelines.