Paediatrics: Chronic kidney disease

Chronic kidney disease

Most children with CKD are asymptomatic until approaching chronic renal disease stage 4 (see Table 11.7). CKD should be suspected if:

•   failure to thrive;

•   polyuria and polydipsia;

•   lethargy, lack of energy, poor school concentration;

•   other abnormalities such as rickets.

CKD: correcting common misconceptions

·  Plasma creatinine can remain normal until GFR reduced to <50%.

•   Urine flow rate may not mean a good GFR as many children with renal dysplasia have polyuria and nocturia.

•   Other urinary abnormalities such as proteinuria, glycosuria can be an indicator of tubular dysfunction.

The focus is on GFR and not plasma creatinine

•   GFR can be formally measured by the Iohexol method or alternatively by ⁵¹Cr EDTA or inulin methods clearance,

•   In ordinary clinical practice GFR (mL/min/1.73m²) may be estimated (note: less accurate in children <2yrs or >14yrs):

GFR (estimated) = 40 × height (cm)/creatinine (µmol/L).

Investigations

•   Urinalysis.

• Blood:

FBC + iron studies if anaemic;

electrolytes/Ca/PO₄/ALP/albumin;

pH/bicarbonate;

parathyroid hormone (PTH).

• Renal tract US.

• Left hand and wrist X-ray for bone age and renal osteodystrophy score.

• ECG/echocardiography for signs of left ventricular hypertrophy if hypertensive.