Kidney Stones & Flying

by Dr. Bill Blank, MD
Copyright 2020. All rights reserved!
Published in Midwest Flyer Magazine (online) – December 2020/January 2021 issue

Kidney stones are particles which are formed in the kidneys. They vary in size from about the size of a grain of sand, up to almost one-half inch. Many are passed spontaneously. Some cause no symptoms. Others get hung up while the body tries to pass them, and may cause waves of extreme pain in the lower back, abdomen or groin, nausea, blood in the urine, and painful urination. In severe cases, the pain can be debilitating, something not compatible with flying. Pain management sometimes requires opioid treatment. Various surgical and non-surgical treatments are available depending upon the situation. When a stone is passed, it needs to be collected, so that it can be analyzed. This can help with choosing a preventive treatment.

Kidney stones are more common in men. The most common ones contain calcium oxalate. Others contain uric acid. Struvite stones form because of chronic urinary infection. Stones containing cysteine are the result of a hereditary disease, cystinuria. Treatment aims to reduce the level of the causative chemical in the urine. Risk factors include positive family history, high protein and high salt diets, obesity, and medical conditions, such as hyperparathyroidism and cystinuria.

How does the FAA decide to certify someone who has had or has kidney stones?

The FAA’s primary concern is decreasing the likelihood of sudden in-cockpit incapacitation. If the most recent event was more than 5 years ago, there has been no recurrence, and your kidney function is normal, your Aviation Medical Examiner (AME) can certify you. You answer yes to question 18j on form 8500-8 and describe the event, along with the date. The AME comments that you have returned to normal and don’t need any ongoing treatment. If you passed a single stone less than 5 years ago or it is in the bladder, your AME can again certify you. He will need the results of imaging studies to document that there are no retained stones.

If you have multiple or retained stones which occurred less than 5 years ago, you may be certifiable via CACI, or “Conditions the AME Can Issue.”

Isn’t this amazing? Think about how it used to be. Prior to the CACI, your exam would have needed to be deferred. You need to look up the Retained Kidney Stone(s) Worksheet. There can’t have been an increase in the number or size of the stones. If you have had surgery, recovery must be complete, and you must be off pain medications. Supportive treatments, such as hydration, medications-thiazides, allopurinol, and potassium citrate are permitted as long as there are no side effects. If you are not CACI qualified, your AME must defer you for consideration of a Special Issuance.

I hope you never experience a kidney stone. If you do, it’s nice to know there is a reasonable, sensible way to get back into the cockpit.

Happy flying!

EDITOR’S NOTE: William A. Blank is a physician in La Crosse, Wisconsin, and has been an Aviation Medical Examiner (AME) since 1978, and a Senior AME since 1985. Dr. Blank is a retired Ophthalmologist, but still gives some of the ophthalmology lectures at AME renewal seminars. Flying-wise, Dr. Blank holds an Airline Transport Pilot Certificate and has 5600 hours. He is a Certified Instrument Flight Instructor (CFII) and has given over 1200 hours of aerobatic instruction. In addition, Dr. Blank was an airshow performer through the 2014 season and held a Statement of Aerobatic Competency (SAC) since 1987.

DISCLAIMER: The information contained in this column is the expressed opinion of the author only, and readers are advised to seek the advice of others and refer to the Federal Aviation Regulations and FAA Aeronautical Information Manual for additional information and clarification.

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