Thread by @amyaimei

The Tale of the Low Chloride

Once there was 34 year old man who used marijuana and was 🤮nauseous, vomitting, and confused. The resident 📞calls and says, "All the electrolytes are abnormal!! Can you help?"

renalfellow.org/2019/12/16/ske…

@TheSkeletonKG #FOAMED #medtwitter #tweetorial

You say of course and see the patient. 🥼🩺His BP was 131/87 mmHg with a HR of 142 bpm. He was fatigued, but AOx3. Moist mucous membranes, normal skin turgor, and no LE edema.

💉Labs are shown and reveal a serum osmolality of 263 with ALL normal labs 3 months prior.

Loving Nephrology🤓, you ask, "What about the urine?!"

He is making urine with a urine Cl of < 20.

(💭Learn more about FeK and Urine K/Cr ratio with our previous case! renalfellow.org/2019/11/14/the… @hotsaltrocks )

In this case, which 🩸electrolyte abnormality the most concerning to be life threatening?☠️

I would worry about his hypokalemia!

Look at this #Uwave! #ECGplease

Our patient has a 🌟Cl depleted metabolic alkalosis based on labs and results from ⬇️HCl loss from gastric secretions.🤮

For more on the #pathophysiology, read our post! renalfellow.org/2019/12/16/ske…

Figure courtesy of @kidney_boy

🧐But notice something missing?

📌There's only 5-10% of K in gastric acid, so why the hypokalemia?

Source: ncbi.nlm.nih.gov/pubmed/14919895

Potassium is lost through the urine via 3⃣ mechanisms

1⃣Secondary hyperaldosteronism in response to hypovolemia and low distal sensing of UrCl

Source: cjasn.asnjournals.org/content/10/2/3…

2⃣Filtered bicarbonate exceeding the reabsorptive capacity of bicarbonate. This leads to increased sodium bicarbonate delivery to the distal tubule.

Source: jasn.asnjournals.org/content/17/9/2…

3⃣Hypochloremia opens voltage gated K channels in the collecting duct resulting in K efflux.

Source: ncbi.nlm.nih.gov/pubmed/21270092

But hypokalemia can maintain the alkalosis through activation of H/K ATPase and intracellular shifting.

For more alkalosis initiating (ie increase HCO3 concentration) and maintaining (ie poor HCO3 excretion) mechanisms, read the post! @renal_padawan

renalfellow.org/2019/12/16/ske…

With a total of 360 mEq of KCl, our patient's Na and K normalized per our correction goals of Na change of 6-8mEq/L/24 hours.

For more and a discussion of Cl salts and the influence correction of hypokalemia has on hyponatremia, read the post!

renalfellow.org/2019/12/16/ske…

For more about the case and a discussion of Cl salts and the influence correction of hypokalemia has on hyponatremia⚖️, read the post!

renalfellow.org/2019/12/16/ske…

ERRATA: GIF updated. Thanks @NephroMD

Key Points
⚡️Where did all the K go? Out the urine!
⚡️Alkalosis worsens hypokalemia, which can perpetuate the alkalosis...and worsen the hypokalemia...
⚡️Cl depletion needs Cl repletion
⚡️Repleting low K can rapidly correct low Na

@TheSkeletonKG @eljosemenap @SaynaNorouzi

@NephroMD Thanks, Dr. Rondon.