Chronic kidney disease and progression: Case

This boy has chronic kidney disease from posterior urethral valves with associated reflux and dysplasia, and he is progressing with established complications. His estimated GFR by the bedside Schwartz equation is 0.413 multiplied by 128 divided by 1.36, which is about 39 mL per minute per 1.73 square metres, placing him in GFR category G3b. His albumin-to-creatinine ratio of 85 mg per g is category A2 (moderately increased), and albuminuria is the modifiable target most closely linked to his rate of decline. [3]

Clinical findings

The pattern is one of progressive CKD with multisystem complications. His growth has crossed centile lines downward, a cardinal feature of significant CKD in childhood driven by poor appetite, chronic acidosis, anaemia, mineral-bone disease and growth-hormone resistance. His blood pressure of 118 over 78 in a 7-year-old is above the 50th percentile and likely elevated, and ambulatory monitoring is needed to confirm whether his 24-hour mean exceeds the target that the ESCAPE trial showed slows progression. His albuminuria of 85 mg per g confirms significant protein leak that both reflects and drives glomerular damage. [2]

His biochemical disturbance shows the predictable complications of declining function. The bicarbonate of 18 mmol per litre reflects chronic metabolic acidosis, which dissolves bone and worsens growth failure. The haemoglobin of 96 g per litre reflects the anaemia of CKD from reduced erythropoietin production and relative iron deficiency. His parathyroid hormone at three times the upper limit of normal, with a phosphate of 1.7 mmol per litre, indicates secondary hyperparathyroidism as part of chronic kidney disease mineral and bone disorder. Each of these is treatable, and treating each one is central to letting him grow and reach transplantation in good condition. [1]

Investigations and staging

The diagnosis of CKD is established, and the task is staging and surveillance. His estimated GFR of 39 mL per minute per 1.73 square metres places him in G3b, and his albuminuria category A2 places him in a higher-risk cell of the KDIGO grid. I would confirm his blood-pressure status with 24-hour ambulatory monitoring, repeat the albumin-to-creatinine ratio on a first-morning sample to confirm significance, and obtain a renal ultrasound to document size, scarring and any residual obstruction or bladder-wall thickening. A DMSA scan would quantify differential function and scarring, and urodynamic studies would assess his valve bladder. I would survey his complications fully with iron studies, 25-hydroxyvitamin D, alkaline phosphatase, lipids and an echocardiogram for left-ventricular hypertrophy. [1]

The progression mechanism is the hyperfiltration vicious cycle: his nephron loss from dysplasia and scarring forces the surviving nephrons to overwork, angiotensin two raises intraglomerular pressure, and the resulting sclerosis and proteinuria destroy the compensating nephrons. This mechanism is the rationale for renin-angiotensin blockade and strict blood-pressure control, the two evidence-based interventions that slow his decline. [4]

Management and outcome

My nephroprotective plan has three pillars. First, rigorous blood-pressure control targeting a 24-hour mean arterial pressure below the 50th percentile for his age, sex and height, confirmed on ambulatory monitoring, on the strength of the ESCAPE trial. Second, an angiotensin-converting enzyme inhibitor such as enalapril, starting at 0.1 mg per kg per day and titrated, for his proteinuric CKD, with monitoring of creatinine and potassium and the understanding that a small rise on initiation is expected and acceptable. Third, elimination of reversible insults: prompt treatment of urinary tract infections, urological management of his valve bladder, and withdrawal of nephrotoxins. [2]

I would control his complications in a defined order. For his acidosis I would give oral sodium bicarbonate, 1 to 3 mmol per kg per day, to maintain his bicarbonate at 22 mmol per litre or above. For his anaemia I would give oral elemental iron at 2 to 3 mg per kg per day and add an erythropoiesis-stimulating agent if his haemoglobin remains below 100 g per litre despite adequate iron, targeting 100 to 120 g per litre. For his mineral-bone disease I would correct his 25-hydroxyvitamin D with cholecalciferol, apply phosphate restriction and a binder, and add an active vitamin D analogue to suppress parathyroid hormone toward the target range. Only after these reversible drivers are corrected would I consider recombinant growth hormone at 28 IU per square metre per week (about 0.05 mg per kg per day) subcutaneously, given his marked growth failure. [1]

Looking ahead, his trajectory is toward end-stage kidney disease, and I would begin transplant work-up and living-donor evaluation well before he reaches stage G5. Pre-emptive kidney transplantation, ideally before dialysis is started, offers him the best survival, growth, neurodevelopment and quality of life, and it is the destination the entire management ladder is engineered to reach. As he approaches adolescence, I would institute a structured transition programme to adult nephrology, because poorly managed transition is a recognised period of graft loss and disengagement. [1]