K 8.7 mmol/l ! You want to know what the EKG shows??

Case: 

• Women in her 60's presents with septic shock from HCAP, currently bacteremic. She was oliguric. On admission her Serum Potassium was 8.7 mmol/l. Prior to admission medications included PO Bactrim for PCP prophylaxis. 
• Focus of this article is to display the EKG changes associated with hyperkalemia in this patient. 

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EKG at 1am: 

Initial EKG with K 8.7 mmol/l showed:

1. Almost sine wave pattern
2. Wide complex tachycardia 

We treated the patient with IV calcium gluconate, Normal saline boluses, IV Furosemide, Albuterol nebulizer, Sodium bicarbonate drip, Insulin Dextrose.

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EKG at 2am: 

One hour post treatment, K was 7.1mmol/l. A repeat EKG showed:

1. 1st degree AV block
2. Prolonged QRS interval
3. QTc prolongation
4. Resolution of sine wave pattern.

We repeated the above mentioned treatments, consulted renal (just to feel safe).

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EKG at 3am: 

One hour later, K was 6 mmol/l. A repeat EKG showed:

1. Non specific ST changes. Otherwise normal EKG
2. Resolution of AV block. 
3. QRS no longer prolonged. 

Eventually her urine output improved with IV fluids and lasix. K level normalized in 6hrs. Did not need dialysis.

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Pearls:

• Hold bactrim as it can cause hyperkalemia due to blockade of the collecting tubule sodium channel by trimethoprim (an action similar to that induced by the potassium-sparing diuretic amiloride); this is most common in HIV-infected patients who are treated with high doses, but normal doses can produce a modest elevation in the plasma potassium concentration in non-HIV-infected subjects

• Not every hyperkalemia patient has tented T waves on EKG. Peaked T waves are only one of the many EKG manifestations of hyperkalemia. 

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Stuff: 

As a general rule, mentioned below are the EKG findings associated with various stages of hyperkalemia:

1. K >5.5 mmol/L is associated with repolarization abnormalities: 
1. Peaked T waves (usually the earliest sign of hyperkalaemia)
2. K >6.5 mmol/L is associated with progressive paralysis of the atria:
1. P wave widens and flattens
2. PR segment lengthens
3. P waves eventually disappear
3. K >7.0 mmol/L is associated with conduction abnormalities and bradycardia:
1. Prolonged QRS interval with bizarre QRS morphology
2. High-grade AV block with slow junctional and ventricular escape rhythms
3. Any kind of conduction block (bundle branch blocks, fascicular blocks)
4. Sinus bradycardia or slow AFDevelopment of a sine wave appearance (a pre-terminal rhythm)
4. K >9.0 mmol/L causes cardiac arrest due to:
1. Asystole
2. Ventricular fibrillation
3. PEA with bizarre, wide complex rhythm

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References: 

1. www.lifeinthefastlane.com

2. UpToDate