Common errors in the care of patients with chronic kidney disease
The paucity of specific symptoms in early chronic kidney disease (CKD)
Unfortunately, in Nigeria as in many countries around the world, there are not enough nephrologists (kidney specialists) to offer expert guidance on the care of the large number of patients with chronic kidney disease (CKD).
Therefore, the generalist physician assumes a central role in the management of CKD. Thus, it is worthwhile to highlight common errors frequently observed in the management of CKD.
Underestimating the severity of chronic kidney disease
The paucity of specific symptoms in early chronic kidney disease (CKD) necessitates vigilance to detect kidney failure.
Sixty to 70 per cent of kidney function is lost before serum creatinine becomes abnormal, so reliance on serum creatinine concentration often results in underestimation of the severity of CKD. Therefore, what is generally described as “early” or “mild” CKD, usually represents a patient with less than 30 to 40% of normal kidney function.
Failure to aggressively control hypertension
Hypertension accelerates the progression of CKD irrespective of the primary cause of CKD. Aggressive blood pressure control slows the progression of CKD and is by far the most important available tool to slow the progression of CKD.
In CKD, hypertension is often moderate to severe, worsening with disease progression due to salt and water retention.
Reducing blood pressure to the “usual” level is not good enough. A reasonable, though difficult to attain target blood pressure is 120/75 mmHg. In fact, many patients with CKD will need three to five different types of antihypertensive medications.
Use of the wrong type and insufficient doses of diuretics (water pills)
Most diuretics (water pills) need to be “filtered” by the kidneys to be effective. Resistance to the action of diuretics is a consequence of reduced kidney function, so the usual dose in persons with normal kidney function will not be effective. Furthermore, as CKD progresses there is increased salt and water retention necessitating frequent dose adjustments.
Also, in CKD patients with increased protein excretion in the urine (nephrotic syndrome), using the same doses utilized in normal kidney function is rarely enough because increased urinary protein binds the diuretic. Due to their potency, the group of diuretics referred to as “loop diuretics” such as Furosemide (Lasix) are preferred in CKD patients.
Misdiagnosis of congestive heart failure
As CKD progresses, patients are less able to excrete salt and water. Progressive fluid retention may result in severe shortness of breath, especially if the patient is not receiving enough diuretics (water pills).
The fluid retention, leg swelling and shortness of breath mimic “congestive heart failure” and many patients may be labelled as such without assessment of their heart function. Echocardiography should be performed in such patients after mobilization of excess fluid to confirm or exclude congestive heart failure.
Failure to reduce the dose of insulin or dose of oral diabetic drugs in diabetic patients with CKD
Up to 40% of daily insulin secretion is catabolized or excreted by the kidneys. So, as CKD progresses, there is impaired elimination of insulin. Failure to reduce the dose of insulin or oral diabetic drugs as CKD progresses often results in a potentially fatal drop in blood sugar.
Inadequate correction of anaemia/excessive use of blood transfusion
Anaemia is common in patients with CKD, primarily stemming from declining erythropoietin production. Erythropoietin is a hormone produced in the kidneys that stimulate the bone marrow to make red blood cells. Anaemia in CKD results in many disabling symptoms.
Recombinant erythropoietin and similar drugs called erythropoiesis-stimulating agents (ESAs) have since become available to treat anaemia in CKD, thereby significantly reducing the need for blood transfusion.
Although blood transfusions are considerably safer than in the past, a unique transfusion-related concern in CKD patients is the development of alloantibodies, which can affect a patient’s ability to receive kidney transplants.
In patients with CKD, blood transfusions should be avoided as much as possible since the resultant sensitization to HLA antigens makes kidney transplantation less successful.
Failure to avoid nephrotoxic drugs or adjust dose of medications
Minimal stress, harmless to healthy kidneys may injure failing kidneys. Accordingly, conditions that impose potential risks to the kidneys such as nephrotoxic drugs must be avoided. Each prescribed drug should be checked to discern necessary dose adjustments in CKD.
Lack of extreme care during blood drawing
Many patients require several hemodialysis vascular accesses in their lifetime. To protect arm blood vessels for future vascular access, venipuncture should be performed only when absolutely necessary and when possible, restricted to the dominant arm, or upper arm vessels of the non-dominant arm.
Discontinuing angiotensin-converting enzyme inhibitors due to a slight rise in serum creatinine
In CKD, treatment with medications called angiotensin-converting enzyme inhibitors or angiotensin receptor blockers is strongly recommended because, in addition to blood pressure reduction, they also afford benefits that are not solely dependent upon systemic blood pressure reduction.
However, a reversible rise in serum creatinine concentration occurs in many CKD patients started on these drugs. These patients need to be monitored closely and the drug not reflexively stopped as long as the serum creatinine level does not continue to rise unabated.