There are many situations where a commercial driver has a medical condition that does not fall neatly into the “rules” regulating the medical certification of a driver pursuant to 49CFR391.41. Kidney disease is one of those conditions. Of the 13 medical standards, none address kidney disease, per se.
The standards that address cardiovascular disease, hypertension, and diabetes may come into play as these conditions contribute to end-organ damage. Certainly, kidney disease may be a result of cardiovascular disease and diabetes and may be a cause of secondary hypertension. FMCSA has convened medical expert panels to review the literature regarding the impact of certain conditions on driving and crash risk and make recommendations regarding medical conditions not otherwise addressed in the standards. Other reliable sources such as published specialty guidelines and best practices may also be used by medical examiners to help make a reasonable certification determination.
Case Examples: If a patient is a known weight lifter, drinks a large amount of protein daily along with creatine, and their urine is showing 2000++++ or higher, is it possible the protein drink is the cause if they have no other risk factors and are in their mid-30s? If that person stops protein for about one week and increases water intake, could this be reversible with a normal urine dip, or is it possible long-term drinking of the protein drinks may have caused kidney damage?
There are reports of creatine causing abnormal kidney function and kidney damage. A large amount of protein in the urine is abnormal in any event. It would be reasonable to stop supplementation but should not delay further evaluation of kidney function with a GFR calculation and/or referral to nephrology. As a medical examiner, you are responsible for further evaluation of a driver with risk factors for underlying kidney disease. Older age, family history, history of kidney problems, hypertension, and diabetes are just a few risks which may prompt the need for kidney function testing and/or imaging. Abnormal urinalysis finding of proteinuria, overly dilute urine, blood, and glucose can all indicate kidney disease. These are the four required components of the urinalysis for the commercial driver exam.
On a patient with a small amount of protein in their urine, 15(0.15) +/- and or 30 (0.3) +, are you recommending three months cert, or is this amount so small there are really no concerns with no other risk factors?
It’s examiner discretion; with no other risk factors, six months is reasonable. If the patient with 1+ proteinuria receives a three-month cert, returns, and checked again at recert and stay the same, should they be referred to PCP at this point?
Yes, if the proteinuria is persistent with risk factors, they should have at least a preliminary kidney function workup including creatinine, BUN, GFR calculation, 24h urine protein, +/- imaging if indicated, and/or nephrology referral. Again, this is at the discretion of the medical examiner. These are my opinions and cannot be taken as specific advice for any individual.
General Guidelines Concerning Chronic Kidney Disease (CKD):
- Drivers with CKD Stages 1-3 who are otherwise stable need not be restricted from driving but enhanced monitoring and further evaluation may be warranted.
- CKD Stage 4 should be certified for three to six months, depending on the severity of the disease plus cardiovascular issues and disqualified if BP is >180/110 or abnormal EKG or ECHO.
- CKD Stage 5 on dialysis is generally disqualified.
- CKD Stage 5 with a kidney transplant with a three-month waiting period can be progressively certified based on their stability over time.
Medical Examiner Discretion: Of the 13 medical standards or regulations pursuant to 49CFR391.41, four are considered “non-discretionary”. These are:
- Insulin-dependent diabetes
- Epilepsy
- Vision
- Hearing The examiner doesn’t have to use any judgment regarding these conditions. There are specific, objective criteria to determine qualification under these four standards. The driver either uses insulin or doesn’t, has epilepsy or not, meets objective vision and hearing requirements or doesn’t. All of these have federal exemption programs. The remainders are considered “discretionary”.
These all require some judgment on the part of the examiner, but some are “more discretionary” than others. For example, FMCSA has convened medical expert panels to review the literature regarding the impact of certain conditions on driving and crash risk and make recommendations regarding medical conditions not otherwise addressed in the standards.
Discretionary “BUT”: The standards that have well-accepted expert panel review and other recommendations are discretionary, but you want to follow these recognized guidelines. These include the standards for:
- Loss of a hand or foot (need an SPE)
- Impairment of hand or foot
- Cardiovascular (recommendation tables)
- Hypertension (yes, it’s discretionary!)
- Schedule 1 drugs (not really discretionary, right?)
- Alcoholism
Truly Discretionary: These require the most judgment from examiners, some more than others:
- Respiratory (COPD, Sleep apnea, PFTs in smokers, always controversial)
- Rheumatic, arthritic, orthopedic, neurological, or vascular conditions
- Mental, nervous, organic, or functional conditions Often in addition to considering the underlying condition, medications and other treatments may have side effects that interfere with the safe operation of a commercial vehicle. There are very good guidelines for sleep apnea and almost became a separate rule before it was recently derailed. I often get the question about ordering PFTs in smokers over 35 (guideline, not a rule.) Most arthritic and orthopedic conditions don’t wind up being disqualifying. There are many guidelines regarding neurologic disorders, particularly for seizures and conditions like Multiple Sclerosis and Parkinsonism. Patients with outright psychosis, schizophrenia, and severe bipolar depression are generally disqualified. Other conditions with lots of medication issues require considerable examiner judgment.
Summary: Aside from the “non-discretionary” standards that must be followed and referred to apply for a federal exemption if appropriate, the other nine standards are considered discretionary and up to the certified examiner to use their judgment to make a qualification determination. Some of those remaining standards are “more discretionary” than others. Examiners should be familiar with accepted best practices to assist in these determinations.
