Epidemiology, pathophysiology, clinical characteristics and management of childhood cardiorenal syndrome

Table 1 Some clinical and non-clinical features of cardiorenal syndrome

Heart failure	Renal failure
Difficulty in breathing; grunting respiration	Reduced daily urine output
Prolonged feeding time in infants	Facial puffiness
Tiredness	Acidotic breathing
Tachypnea	Drowsiness due to uremia
Tachycardia	Ascites/pitting bipedal edema
Raised jugular venous pressure	Pallor
Displaced apex beat	Hypertension when fluid overloaded or renal failure is due to either acute glomerulonephritis, Burkitt’s lymphoma nephropathy or CKD
Heart murmurs	Bleeding diathesis
Galloping cardiac rhythm	Seizures
Bilateral basal crepitations	Failure-to-thrive in CKD
Tender hepatomegaly	Hyponatremia, hyperkalemia, metabolic acidosis, hypocalcemia, hyperhosphatemia, hyperuricemia, azotemia, hypercreatinemia, high fractional sodium excretion, reduced GFR; Ca × PO4-3 product is elevated in late CKD stages and in those receiving calcium and vitamin D3 supplements and regular dialysis
Pitting bipedal edema in older children with chronic heart failure; usually a late manifestation	Dyslipidemia and proteinuria especially in CKD; reduced plasma level of vitamin D3; elevated parathyroid hormone. Low circulating level of erythropoietin
Increased cardiothoracic ratio on chest X-ray (> 60% in under fives and > 55% in older children)	Kidneys may be slightly enlarged in AKI or grossly enlarged in infantile polycystic kidney disease on ultrasound or shrunken in size in other forms of CKD. Radiological evidence of vascular calcification may be present
Electrocardiographical evidence of left ventricular hypertrophy	Biomarkers of kidney injury Plasma NGAL, plasma cystatin C, urine NGAL, urine interleukin-18, urine kidney injury molecule-1 and urine liver fatty acid-binding protein (rises within 4 h of injury) levels are elevated few hours after kidney injury
Echocardiographical evidence of heart failure like increased left ventricular mass index (> 38 g/m2.7), reduced ejection fraction (normal: 64%-83%) and reduced shortening fraction (normal: > 30%)
Biomarkers of cardiac injury Troponin, creatine kinase myocardial band and natriuretic peptides are elevated

NGAL: Neutrophil gelatinase-associated lipocalin; CKD: Chronic kidney disease; GFR: Glomerular filtration rate; AKI: Acute kidney injury.