Episode 19: Bartter and Gitelman
The sun rises over the San Joaquin Valley, California, today is July 10, 2020. In case you did not notice, we did not have an episode last week. We were very busy in our residency. We started a new rotation and a new academic year. We welcomed a new group of PGY1s, along with 3rd-year medical students, and Sub-Is. We also said goodbye to our dear graduates: Greg Fernandez, Ronald Gavilan, Yunior Martinez, and Steven Saito. “Spread your wings, it’s time to fly. Make the leap. Own the sky.”(1) Good luck in your careers!
Those activities kept us busy, and, as if that wasn’t enough, we saw an increase in the incidence of COVID-19 across the nation. In Clinica Sierra Vista, we went from 270 positive cases in May to 700 positive cases in June, we also increased the total tests performed from 1200 in May to 2800 in June. Our positivity rate increased from 21% to 25%. In the county of Kern we have had 5,500 cases and 82 deaths. In California, the total of cases is 260,000 with total deaths of 6,500(2), which may have changed by the time you listen to this episode (numbers were rounded up for easy listening).
Also, on a positive note, last weekend we celebrated Independence Day. We hope you had a Happy 4th of July! Especially during these tumultuous times, may America continue to be “the land of the free and the home of the brave.”
Welcome to Rio Bravo qWeek, the podcast of the Rio Bravo Family Medicine Residency Program, recorded weekly from Bakersfield, California, the land where growing is happening everywhere.
The Rio Bravo Family Medicine Residency Program trains residents and students to prevent illnesses and bring health and hope to our community. Our mission: To Seek, Teach and Serve.
Sponsored by Clinica Sierra Vista, Providing compassionate and affordable care to patients throughout Kern and Fresno counties since 1971.
“All our dreams can come true if we have the courage to pursue them.” Walt Disney
When you want to reach a goal, dreaming is not enough. At some point, you have to start working to make that dream come true. You may need a little dose of faith, and a big dose of action. What dreams do you have? What kind of doctor do you want to become? Your training in residency is the time to prepare to live that dream. Today we have a resident who is working to reach his goals. Dr Sin is a diligent, trustworthy resident and will participate today for the first time in this podcast.
- QUESTION NUMBER 1: Who are you?
My name is Hasaney and I am a second-year resident at Rio Bravo Family Medicine residency program. I was born and raised in Long Beach, California, to parents who emigrated from Cambodia. I went to Long Beach Polytechnic High School, and continued my studies at UC Irvine majoring in Biological Sciences.
I worked in Quality Assurance for a healthcare manufacturing company for a few years, before deciding to pursue a career in Medicine. I enrolled at Ross University School of Medicine in Dominica where I received my medical degree.
I’m a pretty simple guy. I love spending time with my girlfriend, my family, and my friends. I love to go camping, especially in Mammoth, California. I love watching and rooting for the Dodgers.
- QUESTION NUMBER 2: What did you learn this week?
I had Nephrology clinic for the first time this past Wednesday and Dr. Moreno gave some little teaching points about different syndromes we may see as family physicians, a couple of them being Bartter Syndrome and Gitelman Syndrome.
Bartter Syndrome
Bartter syndrome is an autosomal recessive disorder associated with metabolic abnormalities: hypokalemia, metabolic alkalosis, hyperreninemia and hyperplasia of the juxtaglomerular apparatus, and hyperaldosteronism; There may also be associated hypomagnesemia. It is a fairly rare disease occurring 1 in 1,000,000, however the similar but milder Gitelman syndrome is more common with a prevalence rate of 1 to 10 in 40,000.
In short, Hypokalemia, metabolic alkalosis, and hyperaldosteronism.
Pathophysiology
The primary defect in both syndromes is an impairment of the sodium chloride reabsorption in the loop of Henle or distal tubule. The impaired sodium chloride reabsorption leads to volume depletion and activation of the renin-angiotensin-aldosterone system. This increased distal flow of sodium enhances potassium and hydrogen secretion at the secretory sites in the connecting tubules and collecting tubules which leads to hypokalemiaand metabolic alkalosis.
Patients generally have a lower blood pressure than the general population in Bartter syndrome but normal blood pressure in Gitelman syndrome. Bartter syndrome mimics chronic ingestion of a loop diuretic, while Gitelman syndrome mimics chronic ingestion of a thiazide diuretic.
Presentation and Types
Clinical manifestations of Bartter syndrome, besides the metabolic abnormalities we have mentioned, are growth and mental retardation, polyuria and polydipsia. There are four types of Bartter syndrome. Types 1 and 2 are usually severe disorders that cause polyhydramnios during pregnancy and prematurity. They develop hypokalemia, metabolic alkalosis, polyuria and hypocalciuria. Nephrocalcinosis is common and probably contributes to development of kidney dysfunction, sometimes end stage renal disease. Nephrocalcinosis is the deposition of calcium salts in the renal parenchyma. Nephrocalcinosis is related to, but not the same as, kidney stones (nephrolithiasis).
Bartter syndrome Type 3 is the classic form, less severe, and presents later in life with the metabolic abnormalities. Late manifestations of Bartter syndrome include proteinuria and a decline in GFR. Bartter syndrome Type 4 causes severe disease, with antenatal presentation and congenital hearing loss.
Gitelman syndrome
Clinical manifestations of Gitelman are similar to Bartter, except for having normal blood pressure. Patients may develop cramps of arms and legs due to the metabolic abnormalities, as well as fatigue. Hypertension may develop later in life.
Both syndromes are usually a diagnosis of exclusion. Patients will present with unexplained hypokalemia, metabolic alkalosis and normal to low blood pressure. Surreptitious vomiting and diuretic use must be ruled out as these could present in a similar way.
Diagnosis
Surreptitious vomiting is ruled out by measuring urine chloride excretion, with Bartter and Gitelman syndrome showing a urine chloride concentration greater than 25mEq/L, whereas vomiting would show a urine chloride concentration that is less than 25 mEq/L.
Suspicion of diuretic use would be ruled out with a urine diuretic screening. Plasma renin and aldosterone levels will be elevated; however, these are not required for diagnosis.
Treatment
Treatment requires ad lib NaCl intake with supplements of KCl and if needed magnesium salts. Most patients will require a drug that blocks distal tubule Na-K exchange such as spironolactone.
- QUESTION NUMBER 3: Why is this knowledge important?
As family physicians, we see the full spectrum of Medicine. If we see low blood pressure in a pediatric patient, with the metabolic abnormalities akin to these two syndromes an urgent nephrology referral should be placed.
- QUESTION NUMBER 4: How did you get that knowledge?
Initially, some of it was taught to me by Dr. Moreno. He did not have time to go through most of the details of each syndrome in clinic, so I decided to read a little more about it on Up to Date. Some of the details on Up to Date are very thorough, so I liked to cross reference it with Pocket Pediatrics.
- QUESTION NUMBER 5: Where did you get that knowledge?
The majority of the information were points that I thought were most important from the Up to Date article “Bartter and Gitelman syndromes”.
Speaking Medical: Nephronia
by Manpreet Kaur, MS3
Nephronia. It may sound like the sister planet of Neptune, but what exactly is it and when would you diagnose a patient with it?
Well, on the spectrum of upper UTIs, nephronia would fall at the midpoint between acute pyelonephritis and an intrarenal abscess.
It forms when a patient has an acute bacterial infection that results in a renal mass without liquefaction. We usually see this disorder in the pediatric population but there are case reports of this presentation in adults as well.
While it sounds rare, it may just be an underdiagnosed disorder. However, with advancements in noninvasive imaging, this diagnosis is being made at an increasing frequency.
Acute lobar nephronia (ALN) is similar to acute pyelonephritis (APN). ALN is similar to APN. A few differences are that acute lobar nephronia (ALN) is associated with a longer clinical course, longer fever duration even with treatment, and higher inflammatory markers like CRP and WBC count.
A CT is the most sensitive and accurate modality of making the diagnosis but risks of exposure to radiation and possible sedation have to be weighed in small children. Some studies indicate that about 25% of children with ALN can go on to develop renal abscesses and have a higher incidence of renal scarring.
Once nephronia has been diagnosed, these patients will require a minimum of 2 weeks of IV antibiotics, followed with 1 week of oral antibiotics. They will show slow improvement with fevers sometimes persisting until the end of the 1st week of treatment.
Now you know the medical word of the week: Nephronia.
Espanish Por Favor: Orina
Orina is that yellowish-colored liquid that comes out of the urethra with a characteristic smell, which in normal circumstances is sterile. Yes, you guessed it, orina is urine in Spanish. Orina can be easily turned into a verb:Orinar. Just like in English, there are several terms to refer to urine (pee, piss, pee-pee), orina can also be called meados(vulgar), orín, pis, pichi, and my favorite: pipí (pronounce pee-pee), normally used with pediatric patients. Now you know the Spanish word of this week: Orina.
For your Sanity: A wet nose
by Steven Saito
What do a puppy and a near-sighted OB doctor have in common? A wet nose.
Conclusion
Now we conclude our episode number 19, “Bartter and Gitelman”. Dr Sin briefly shared the highlights of these rare syndromes. Hypokalemia and hypotension may have a long list of differential diagnoses, but keep Bartter and Gitelman on your list. Ms Kaur explained that nephronia is not a planet, but an intermediate state between pyelonephritis and a renal abscess; and we could not leave the word urine out of this renal episode, so we learned the Spanish word orina.
This is the end of Rio Bravo qWeek. We say good bye from Bakersfield, a special place in the beautiful Central Valley of California, United States, a land where growing is happening everywhere.
If you have any feedback about this podcast, contact us by email RBresidency@clinicasierravista.org, or visit our website riobravofmrp.org/qweek. This podcast was created with educational purposes only. Visit your primary care physician for additional medical advice. Our podcast team for this episode is Hector Arreaza, Hasaney Sin, Manpreet Kaur, and Steven Saito, Audio edition: Suraj Amrutia. See you soon!
_____________________
References:
- Ms Moem, http://msmoem.com/2014/poetry-2/spread-your-wings/
- California Coronovirus Update, https://update.covid19.ca.gov/
- Emmett M, Ellison DH. Barrter and Gitelman syndromes. In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. (Accessed on July 5, 2020)
