Kidney Boy Returns! Compare the types of dialysis, learn how nephrologists approach medication management in ESRD, and avoid the most common mistakes non-nephrologists make in patients on dialysis! Kashlak Chief of Nephrology Dr. Joel Topf, @kidney_boy, walks us through what you need to know to take care of a patient on dialysis and gives us an idea of how nephrologists think through mineral bone disease (calcium, phosphorus and vitamin D), anemia, iron repletion, and hypertension. We answer all your questions about co-managing patients on dialysis!
Producer: Hannah R. Abrams
Written and produced by: Hannah R. Abrams
Cover Art and Infographic by: Hannah R. Abrams
Hosts: Hannah R. Abrams, Matthew Watto MD, FACP; Paul Williams MD, FACP
Editor: Matthew Watto MD, FACP (written materials), Clair Morgan of Nodderly.com (audio)
Guest: Joel Topf MD
ACP’s Internal Medicine Meeting 2020 April 23-25th in Los Angeles, CA at the LA Convention Center. Early bird rates are available through January 31, 2020. Don’t forget to use the code: IMCURB20
“Nephrologists are just internists that like diffusion”-Joel Topf MD, @kidney_boy
When counseling patients approaching dialysis, use the Tangri Kidney Failure Risk Calculator to give them more appropriate expectations of the timeline and probability of dialysis; they may be further from dialysis than you think!
There are several options for treatment of kidney failure. Transplant is best, but if your patient is going to need dialysis, Dr. Topf urges you to be a ‘cheerleader’ for peritoneal dialysis. It allows more independence and longer maintenance of residual renal function!
The Nephrology team will manage volume status, anemia, and mineral bone disease (i.e. calcium, phosphorus, vitamin D, PTH); hypertension management is an opportunity for primary care physicians to add helpful clinical data.
Medications to avoid: As a general rule, any drug that is neuroactive (i.e. baclofen, gabapentin) will have greater toxicity in dialysis patients, so avoid these drugs. Also avoid sodium phosphate (FleetⓇ) enemas. NSAIDS can be used with caution if patient has no residual renal function, but cardiac, GI risks remain a concern.
How to differentiate an AVG from an AVF on exam. An AVF is soft and appears tortuous when matured. An AVG is synthetic. It feels firm and is less compressible.
Dr. Topf describes the four key categories of treatment for kidney failure, how to counsel patients about the likelihood that they will need renal replacement therapy, and how he as a nephrologist approaches the decision to initiate dialysis.
For patients who are transplant candidates, kidney transplantation has a survival advantage and should be preferred; patients should be referred for transplant evaluation while GFR is in the low 20’s. (Sakhuja, 2014)
Of dialysis options, peritoneal dialysis (PD) has the advantages of improved patient independence and preservation of residual renal function; barriers to implementation include patient and practitioner discomfort. (Saxena, 2006)
Peritoneal dialysis catheters can usually be used 2 weeks after insertion (Sakhuja, 2014), though Dr. Topf notes that with some emergent-use protocols, timing should not be considered a barrier to initiation of PD.
Dr. Topf interprets the early survival benefit for PD as associated with preservation of residual renal function (USRDS, 2018), and will make medication changes to protect renal function for PD patients making >400 ml of urine daily. Ask the patient, “can you fill a beer can?” -Dr Topf.
Hemodialysis (HD) is the most commonly used type of dialysis in the United States. (Kaplan, 2017) HD requires vascular access, which can be accomplished by tunneled catheter (TDC), arteriovenous graft (AVG), or arteriovenous fistula (AVF).
An AVF is the most preferred option for HD access. It is a surgically-created fistula that requires 1-3 months to “mature” prior to use for HD. However, there is a high rate of surgical failure (~60%) and alternate forms of access often must be used. (Dember, 2008, Sakhuja, 2014) For patients in whom AVF is an option, Dr. Topf recommends early referral for vein mapping.
An AVG is a synthetic tube connecting an artery and vein. It can be used in patients without suitable vessels for AVF or in whom AVF has failed; its maturation time is approximately 2 weeks. (Sakhuja, 2014) Like AVF, AVG has a high rate of failure, with limited evidence of benefit of antiplatelet benefit in maintaining patency (Dixon, 2009). Kashlak Pearl: How to differentiate an AVG from an AVF on exam. An AVF is soft and appears tortuous when matured. An AVG is synthetic. It feels firm and is less compressible.
A TDC represents the least preferred choice for HD access. It is a line placed in a large central vein, most commonly the internal jugular vein, and has a high risk of infection and thrombosis. It can be used immediately and is most commonly used for situations in which urgent HD is required. (Sakhuja, 2014)
Dr. Topf uses the metaphor of a game of JengaTM for elderly patients with several comorbidities who are approaching kidney failure: the hemodynamic and logistical stresses of dialysis are like shaking the table. He includes medication management of electrolytes, hypertension, and uremic symptoms in his definition of conservative care.
A key area on which to counsel patients on this decision is functional status. In nursing home residents with kidney failure, initiating dialysis was associated with a significant decrease in functional status at 1 year and still had a high mortality rate. (Kurella Tamura, 2009)
Many clinicians overestimate their patients’ risk and timeline for initiating dialysis (Potok, 2019). He recommends using the Tangri Kidney Failure Risk Calculator to determine the risk of kidney failure at two and five years. His practice is to begin discussing dialysis with patients who have >20% risk of kidney failure in that time.
The IDEAL trial found no difference in survival or clinical outcomes in patients initiating dialysis at a GFR 10-14 ml/min (early start) or the point of symptom development or GFR 5-7 ml/min (late start.) (Cooper, 2010) Dr. Topf considers loss of appetite, weight loss, nausea, pruritus, difficulty with blood pressure control, electrolyte abnormalities, and refractory volume overload when he is deciding to initiate dialysis.
For some dialysis patients, one way to conceptualize co-management is to think of the nephrologist as the patient’s main source of primary care and the primary care provider as a consultant. (Sakhuja, 2014)
Dr. Topf notes that hemodialysis patients will receive protocol-based management for mineral bone disease, anemia, volume status, and influenza vaccination at the dialysis center. He considers hypertension and non-CKD related primary care key areas in which primary care providers can contribute.
Hypertension is a key opportunity for primary care to add valuable information for the care of a dialysis patient. During dialysis, avoiding hypotension is prioritized, and thus non-dialysis day blood pressures may be more indicative of the patient’s baseline. Dr. Topf recommends communicating with the patient’s nephrologist if the patient’s BP is uncommonly high or low on their non-dialysis day visit.
Dr. Topf notes that restarting an ACEi/ARB or spironolactone that was stopped prior to dialysis to preserve residual renal function may be appropriate for patients who are anuric. He prefers not to use minoxidil or hydralazine in these patients because of the risk of pericarditis.
Limited evidence exists regarding the value of cancer screening for patients on dialysis. Non-invasive colorectal cancer screening methods may result in a high false positive rate due to mucosal GI bleeding in these patients. (Collins, 2019) Dr. Topf does not recommend routine cancer screening for the majority of patients on dialysis; however, this should be considered on a case-by-case basis.
Mixed evidence exists on the benefit of statins for patients with CKD on dialysis. (Sakhuja, 2014) Dr. Topf’s practice is to continue statins for those patients for whom they were initiated prior to dialysis, but he does not initiate statins in patients already on dialysis.
Dialysis does not clear phosphorus as effectively as other electrolytes; phosphorus binders keep phosphorus from being absorbed. Common phosphorus binding agents include calcium acetate (or carbonate), sevelamer, lanthanum carbonate, and iron citrate.
Dr. Topf explains that mineral bone disease, phosphorus, and PTH are usually managed by protocol by the patient’s dialysis physician. However, he explains his approach: there is no compelling evidence for calcium vs. non-calcium based phosphorus binders, and no clear clinical outcomes benefit for clinical lowering PTH. (EVOLVE, 2012) He uses the KDIGO guidelines of a phosphorus (serum phosphate) target in normal range and intact PTH between 2-9 times the upper limit of assay. (KDIGO, 2017)
Reasons for anemia in ESRD include decreased hepcidin clearance, GI mucosal bleeding, and blood loss during hemodialysis. Following the results of the PIVOTAL trial, many centers are using a proactive high-dose IV iron protocol. (Collister, 2019)
Sodium Phosphate (FleetⓇ ) enemas: The high phosphorus load of these enemas can precipitate severe hyperphosphatemia and subsequent hypocalcemia, resulting in coma, cardiac arrest, and death. (See Dr. Topf’s post on the topic at his blog pbfluids.com)
High dose gabapentin: Do not exceed doses of 300 mg per day in patients on dialysis. Gabapentin is renally cleared and at high doses can cause significant altered mental status; coadministration with opioids is associated with significant increase in opioid-related death. (Gomes, 2017)
Non-synthetic opioids: Morphine and codeine both are cleared by the kidney and have active metabolites that can have a long duration of CNS effects; synthetic- and semisynthetic- opioids (e.g. hydromorphone) are less likely to accumulate.
Baclofen: Baclofen is renally cleared and can lead to severe neurotoxicity, including coma, in patients with kidney failure.
NSAIDs: While kidney injury is not applicable to patients without residual renal function, Dr. Topf cautions that NSAIDs still carry risk for cardiac events and GI bleeding.
Warfarin: Limited evidence for treatment of dialysis patients with Afib exists. However, Dr. Topf points out the risk for calciphylaxis, so proceed with caution.
Dialysis works! Avoid checking a post-dialysis BMP and reflexively repleting the potassium; it is expected for patients to be hypokalemic after dialysis.
Protect potential vascular access sites: be extremely cautious with PICC lines in patients with advanced CKD or on dialysis; these lines may compromise future fistula placement sites.
Listeners will comprehend the role of the general internist in caring for the patient on or approaching dialysis.
After listening to this episode listeners will…
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Dr Topf lists the following disclosures on his website: “I have an ownership stake in a few Davita run dialysis clinics and a vascular access center. Takeda Oncology made a donation to MM4MM the program that is taking me to Mount Everest in 2018”. The Curbsiders report no relevant financial disclosures.
Topf, J, Abrams, HR, Williams PN, Watto MF. “#192 Dialysis for the Internist with Joel Topf MD”. The Curbsiders Internal Medicine Podcast. http://thecurbsiders.com/episode-list. January 27, 2020.
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