Metabolic Emergencies

 Laurl at ONS 

Welcome to the ONS Hot Topic Chats! Today’s expert is Brenda Shelton, who will be talking with us about any and all questions you have regarding neurologic emergencies. Welcome Brenda!

 sheltbr 

Welcome to all this bright and early time. Send your burning questions!

 Laurl at ONS 

To get us going, I have heard that the new approach to TLS is NOT to alkalinize the urine, but we have always maintained this practice.

 ghrn2004 

I'm a little new. What is TLS please?

 smhazen 

Hi Lisa. :)

 Laurl at ONS 

Tumor lysis syndrome

 ghrn2004 

oh, duh

 Laurl at ONS 

It's early!!

 ghrn2004 

lol

 sheltbr 

It has always been the standard to administer D5W with bicarb with the goal to alkalinize, but the latest standards now say that while decreasing affects of uric acid on the kidneys, it worsens the calcium- phosphate byproduct damage. More..

 sheltbr 

Now we should give normal saline hydration and monitor uric acid. Since it is considered reversible, rapid pathway to dialysis when appropriate should be encouraged. There are good national guidelines published about 2006.

 sheltbr 

TLS occurs with rapid proliferating cancers that respond rapidly to chemo and all substances inside cells dump into serum. more..

 sheltbr 

 TLS happens in leukemia, lymphoma, small cell lung, testicular- 24-48 hr after start chemo. Results are high uric acid, high phos, high potassium, low calcium and acidosis.

 sheltbr 

Have some of you had patients with TLS? What did you do for them?

 ghrn2004 

allopurinol, hydration with D5 and bicarb

 lkrioux 

Our typical protocol is to hydrate and allopurinol.

 ghrn2004 

Typically sent to ICU for monitoring

 sheltbr 

Allopurinol is still indicated if uric acid less than 9, but if higher, allopurinol stops making uric acid but does not get rid of what is there. There is a new drug rasburicase that may be used. Has anyone given this?

 ghrn2004 

yes

 lkrioux 

I have seen rasburicase ordered, but less than allopurinol

 sheltbr 

Can you share your experience with this drug- did it work? Are there special techniques when using?

 lkrioux 

I have no personal experience with rasburicase. Please share

 sheltbr 

Rasburicase is expensive and can cause hemolytic anemia as well as antibodies making it not work again in future. Also all uA levels must be sent on ice. Was initially only used in kids.

 ghrn2004 

I have only used it once, and I seem to remember being concerned about anaphylaxis.

 sheltbr 

There are hypersensitiy reactions, though seldom. We screen all African American, mediterranean pts for GPD deficiency that increases hemolytic anemia risk.

 ghrn2004 

GPD?

 sheltbr 

GPD deficiency is an often undiagnosed hematology disorder of metabolism. Increases risk of hemolytic anemia even with out this drug

 emjm19072 

Would it help prevent thls if we hydrate well during the rituxan chop, etc?

 sheltbr 

Always!!! Hydration of 200-500mL/hr is considered he mainstay of prevention. Of course also monitor electrolytes every 6-8 hours, sometimes every 4 hr is in TLS

 ghrn2004 

hydrate with 0.9/?

 sheltbr 

Yes- no longer hydrate with D5 with bicarb

 Laurl at ONS 

Why do we not use a common diuretic like hydrochlorthiazide to treat hypercalcemia?

 sheltbr 

HCTZ actually decreases calcium excretion and the purpose of a diuretic in hypercalcemia is to enhance calcium excretion. Again, use 0.9 NS and loop diuretic like lasix. More….

 smhazen 

We are creating cheat sheets for the OEs for new nursing staff...what would be a short way to explain SIADH?

 sheltbr 

The additional benefit of loop diuretic is that it enhances renal tubular dilation, increasing flow and electrolyte excretion.

 sheltbr 

SIADH- inappropriate ADH in context of plasma osmolarity.. translated: normally the blood viscosity (lyte concentration) causes us to turn off ADH. In patients with excess ADH it does not turn off properly. This is also why we treat with fluid restrictions. More…

 sheltbr 

Restricting fluid makes blood viscosity even higher and hopefully with turn off ADH message. no ADH, no fluid retention and dilution of lytes, esp sodium. Most sxms due to low Na

 sheltbr 

Keep the questions coming

 emjm19072 

Then low sodium is diagnostic?

 emjm19072 

Or should I say, first sign..?

 sheltbr 

The low sodium is the strongest clue, but we also test plasma osmolarity (it is low) and test urine for Na and osmo. The na and osmo is high. Spot urine lytes and osmo is considered diagnostic with low sodium and risk factor. Who gets this?

 lkrioux 

Are there specific chemo regimens that promote the development of SIADH or is it mostly disease related?

 smhazen 

Not I, said the oncology nurse!

 sheltbr 

Maybe you are taking cytoxan for autoimmune, or anti-TB drugs!! Ha!! More…

 sheltbr 

There are cancers that make ectopic ADH- pancreatic, nonsmall cell lung, gastric. These are most common causes...More….

 sheltbr 

Though patients with brain or lung conditions can get this because ADH receptors are in lungs and brain and when stimulated with injury (e.g. like pneumonia), excess ADH can occur.

 Laurl at ONS 

When giving saline to treat SIADH, why are the doctors concerned about the exact volume and rate- they said something about not correcting the sodium quickly, but I don’t understand this concern.

 sheltbr 

I forgot to mention if SIADH is not corrected with fluid restrictions, we may give hypertonic saline- usually in step down or ICU. 2% or 3% saline corrects NA. More…

 sheltbr 

There is a formula of how fast to give it to make sure you do not correct the sodium more than .5 meq/ hr.- too fast sodium correction can lead to bleeding in pons and midbrain.

 ghrn2004 

Are you aware of the formula?

 ghrn2004 

Our dr won't share lol

 sheltbr 

I don't have it memorized, but I have used a great website for all kinds of formulas -Will post on transcript

 lkrioux 

Please explain the mechanism of bleeding if sodium corrected too quickly.

 ghrn2004 

thanks

 sheltbr 

RE: bleeding: I don't know reason, but have always just accepted fact... sorry.

 ghrn2004 

Can you expand on "ectopic" ADH

 sheltbr 

Some tumors create their own ADH- like substance just like some tumors make a parathormone-like substance to cause hypercalcemia. The effects are same as if you triggered ADH in the brain.

 ghrn2004 

Like a neoplastic syndrome? thanks!

 sheltbr 

Yep- good point!

 smhazen 

Adminstering the 3% saline is restricted to the stepdown/ ICU areas for monitoring in my facility and now I can explain why to the Onc nurses :) We knew rate and amt was particularly important, but...this helps.

 sheltbr 

Yea- sometimes they don't look so sick and it is hard to part with our patients, huh?

 Laurl at ONS 

Could you review the symptoms (early, later) of hypercalcemia?

 sheltbr 

First the risk factors are important- the number one is bone mets, although also neoplastic, renal dysfunction. So, know the high risk patients. Most present with mental status changes- confusion, somnolence, combativeness. More…

 sheltbr 

Some get directly admitted to an ICU because they present with bradycardia or heart block. It worsens because polyuria make scalcium concentration even more. Constipation also common.

 sheltbr 

Don't forget that calcium may not look as bad as it is because it needs to be corrected up for low albumins (like all of our pts). Do any of you know the correction formula?

 ghrn2004 

It is in my palm pilot, but out lab has told us that corrected calcium is not very accurate.

 sheltbr 

Not exact, but helps us realize that calcium is higher than we think. Calcium binds to albumin and if albumin low, there is more calcium than reported by lab. More…

 sheltbr 

You subtract patient’s albumin from low normal albumin, and then multiply X 0.8, then add that number to reported calcium.

 sheltbr 

E.g. Reported calcium 12, albumin 2

 sheltbr 

Low normal albumin 3.5 - 2.0 = 1.5 X 0.8 = 1.2. Add 12 + 1.2 = 13.2 calcium. ALWAYS on OCN exam!!

 ghrn2004 

So I can't use my palm pilot lol!

 sheltbr 

I guess if you must... but not on that exam!!!

 lkrioux 

Can you explain resorption and reabsorption as it pertains to calcium levels in the bone?

 sheltbr 

Ouch!!! Resorption is letting go and reabsorption is hanging on to it. So in hypercalcemia there is bone resorption to put more calcium in blood and more kidney reabsorption to retain in the blood. Does this help?

 lkrioux 

yes, thank you

 Laurl at ONS 

Brenda, can you explain hemolytic uremic syndrome?

 emjm19072 

Wish i could stay, gotta go to work....great site....thank you.....

 lkrioux 

Sorry to change the subject...I know that leucovorin can be given as a potentiator of 5FU but also as a protectant with MTX. Can you explain the difference and how it works differently?

 sheltbr 

HUS ( hemolytic uremic syndrome) is a syndrome of hemolytic anemia and renal failure from the hemolysis. It occurs in lymphoma, BMT, but is a rare disorder. Very difficult to diagnose- we check bilirubin- indirect I think is hemolysis. Renal failure often requires dialysis.

 smhazen 

Also leaving. Thanks to all!

 Laurl at ONS 

As Brenda is answering, we have about 5 more minutes - please continue to ask your questions! Also, at the end of today’s chat, please take a moment to cut and paste this URL into your browser and take our very brief survey -we’d love to hear what you think of these chats! The URL is: http://research.zarca.com/k/RsTUTRsRYVsVXVSVsPsP
  Thank you!

 sheltbr 

RE Leukovorin. Methotrexate is an antimetabolite that acts by blocking folate metabolism and leucovorin "reverses" effects of methotrexate still hanging around after anti-neoplastic effects are done. More…

 sheltbr 

This same drug for unknown reasons enhances cellular absorption and therefore efficacy of the folate antagonist 5-FU. I am sure there is a better explanation for 5 FU but I have never found it and I have written biotherapy drug book chapters. Do any of you know it?

 ghrn2004 

Sorry, no I didn't know what TLS stood for

 lkrioux 

LOL!

 sheltbr 

Really good thinking questions- you all are really challenging my brain.

 ghrn2004 

Thank you for your answers! i found it all very informative!

 lkrioux 

same

 sheltbr 

Any last minute questions?

 ghrn2004 

no thanks

 lkrioux 

Not from me...thank you for your time and expertise. I enjoy this venue for learning how my/our practice differs from others.

 sheltbr 

Great! This has been a packed session. I like the format too- sitting here in my PJs.

 Laurl at ONS 

Hello, I'm so sorry, but we are just ending. If you have a specific question, feel free to ask now. The transcript from today's chat will be posted on Monday.

 ghrn2004 

How do we get to the transcript?

 Laurl at ONS 

Go to the Hot Topics pages (you can get there from the main ONS page) and click on past speakers and transcripts. They are all there.

 ghrn2004 

Thanks, and thanks again shetbr, and Laurl!

 Laurl at ONS 

Have a great day everyone!