The renal patient seen by non-renal physicians: the kidney embedded in the 'milieu intérieur'

Abstract

Chronic kidney disease is defined as a decrease in renal function or evidence of kidney injury for >3 months. This represents an oversimplification that may confuse physicians. Thus kidney function is equated to glomerular filtration rate, which represents one of multiple kidney functions. Some potentially more important renal functions are lost earlier, such as the production for the anti-ageing factor Klotho. Overall, these changes modify the emergent properties of the body, altering the relationships between different organs and systems, in a manner that is difficult to predict the response to interventions based on normal physiology concepts, as there is a novel steady state of interorgan relations. In this regard we now discuss the impact of CKD on heart failure; osteomuscular and joint pain and bone fragility and fractures; and osteosarcopaenia as seen by a cardiologist, a rheumatologist and a geriatrician.

Keywords: bone fragility; chronic kidney disease; emergence; fracture; heart failure; network disease; osteosarcopaenia.

FIGURE 1

CKD as a network disease that disrupts the emergent properties of the body organs and systems. CKD alters the normal interactions between the kidney and different organs and systems, resulting in altered interactions between non-kidney organs. Normal signals emerging from the kidney may become fainter while novel pathological signals replace them. In the disrupted state, the results of any intervention cannot be accurately predicted by applying normal physiology concepts.

FIGURE 2

CKD patients ACHE and BREAK: the multiple challenges to manage diagnosis and treatment of pain in CKD patients (ROD).

FIGURE 3

MEDLINE survey for evaluation and treatment of pain in CKD patients: key words ‘haemodialysis/CKD/chronic renal failure’ AND ‘pain’, ‘bone’ or ‘cardio-vascular/vascular’. Dark grey bars: overall number of publications including reviews; light grey bars: number of clinical trials only.

FIGURE 4

The use of imaging for the diagnosis of skeletal pain in CKD patients. (A–D) Plain X-rays. (A) Shoulder with osteonecrosis (ON) of the humerus head. (B) Periarticular calcifications of the shoulder. (C) Massive joint bone cysts observed in a patient with amyloidosis. (D) Digital severe joint erosions in a CKD patient with severe osteoarthritis combined with microcrystals arthritis. (E–H) Patient with ON of the hip 3 years after kidney transplant failure. (E) Plain X-ray: no sign of ON. (F) Coronal T1-weighted MRI of the hip showing the necrotic quadrant in the femoral head. (G) Technetium bone scan coupled to (H) tomodensitometryshowing high technetium uptake at the hip.

FIGURE 5

Diagnosis strategy to evaluate bone fragility and underlying renal osteodystrophy in CKD patients.