AUG
03

Mothballs, Crowbars, and Blue People in Kentucky

In 1960, Madison Cawein III was a freshly graduated Hematologist. He was displaced from the hallways and coffee shops of Lexington into the rural hills of moonshine country. He was no longer a doctor in a lab or clinic, he was an investigator chasing a legend. Through small talk amongst his colleagues over meals or in casual get togethers he had heard rumors of a unique family living in Eastern Kentucky. This family dwelling in the hills were your average rural family with one definitive exception; they all had dark blue skin. 

 

I was caught off guard to say the least. What little fluid drained into the bag at the end of the catheter was a dark and rusty brown color.

What had struck me immediately as I first encountered my patient was how cyanotic she was. Her nose, lips, ears and hands were tinged deep purple. Her work of breathing was increased, her shoulders heaving and the muscles around her clavicles tugged with every struggling breath. The smell of vomit lingered in the air and a small quantity of green bile lined the porcelain in the toilet. It had started as a headache, then nausea, then vomiting and abdominal pain. Though she had not noticed, her urine output plummeted. Dehydration, and possibly something more sinister was slowing her kidney function. She called 911 when she couldn’t breath. Now, around 24 hours after her first headache, she was lying on a hospital bed in a rural emergency department. 

A ventilator hissed in the corner and an IV pump with two bags of fluid or medication dripped regularly into a green capped catheter in her left arm. The nurse had placed a foley and I had watched the dark fluid run slowly into a foley bag. Labs had been drawn and sent to the lab. No other crews were out on calls so we spent some time in the ED watching and assisting in her care. My curiosity was there and I wanted to know what had driven a healthy 30 year old woman to a ventilator in 24 hours. She had no medical history. Her husband, quiet but visibly scared gave an uneventful history of her health that aside from some minor dental surgery was completely empty. 

The doctor walked in moments later. He scratched his forehead and looked at the sedated patient.

“She has methemoglobinemia”. He said looking back down at his pen and paper. 

“Oh okay cool”, I responded. ”whats methemoglobinemia?”

Truthfully, I knew that methemoglobinemia was a disease. I had heard a few rare stories regarding pediatric cases and knew it was related to teething medicine. And…well yeah that’s it. So coffee in hand and computer open I ventured forward…and called Tyler to ask him what methemoglobinemia is. 

Methemoglobinemia is the condition of having an abnormal percentage of methemoglobin in your total hemoglobin. Why does this matter? Hemoglobin carries oxygen, methemoglobin does not. 

Picture yourself standing in line at a lazy river. As people exit the tubes upstream, the line files into the river as empty float tubes pass by and are snatched up by the people in line. Oxygen binds in a similar fashion to hemoglobin. The opposite charges of the oxygen molecule and the iron molecule attract each other and bind together. Now you have oxyhemoglobin. Your oxygen is on its way to the bodies tissues. 

Illustration by Austin Quillet @QuilletAustin

But now imagine the lifeguard steps into the river and begins placing fence posts into the seats of some of tubes. Now no one can sit in those tubes. So they float unoccupied for another cycle. Meanwhile, people who already have tubes are scared to give there tube up in case they can’t get another one the next go around.  Methemoglobin, its iron heme blocked by two hydrogen ions, cannot host an oxygen molecule, reducing its carrying capacity and causing the remaining 3 hemes to aggressively protect their oxygen binding. 

Methemoglobin occurs naturally in the blood stream. Between 1-2% of hemoglobin at any time. Thats not a big deal! You’re still working with over 90% of your hemoglobin at full carrying capacity. But what happens when more and more hemoglobin begins to take on hydrogen ions and convert to methemoglobin? Your oxygen carrying capacity begins to fall…

When Dr. Cawein arrived in Hazard, Kentucky his saving grace was Ruth Pendergrass. She not only had heard the rumors, but had confirmed them herself. She was a nurse at a small clinic and had treated a woman with blue skin.  What stood out to Ruth was that despite her profoundly cyanotic appearance she had no symptoms of illness or oxygen desaturation. She had only come to the clinic for a routine check. Dr. Cawein had a suspicion that these individuals were suffering from methemoglobinemia. But without bloodwork it couldn’t be confirmed. He needed to find a patient. 

Why did my patient have methemoglobinemia? She was a healthy woman in her thirties who took no medication and seemed to live an active lifestyle. 

I don’t know. Writing this article today, I still don’t. I tried to follow up with the hospital system. I know she lived but I don’t know why she got sick in the first place. But there are a few reasons why people develop this rare disease. 

Medication reaction is the most common. Pain medications utilizing topical anesthetic (benzocaine, lidocaine etc) are a risk factor and are the most common cause in the pediatric population. Certain antibiotics, nitrate containing medications and even Reglan have caused it in adult populations. Naphtalene poisoning from mothball ingestion has been a cause multiple times in suicide attempts and accidental ingestion.  The exact pathophysiology behind this is complex. The point being that these medications and causes although rare have caused incidences of methemoglobinemia. 

The second cause…genetics. 

Madison and Ruth had no luck in locating an individual willing to talk about their blue skin. They made treks into the local community but were either ignored or denied a conversation, no less a full assessment. Stunningly though, a husband and wife presented to the clinic for a routine check up. They were blue, very blue. This middle aged couple ended up being the key. They were open to assessment and research and honest when answering questions although skeptical that a medication called methylene blue would make them turn pink. Although not dangerously inbred, there was some distant relations in that valley between the families that inhabited it. Both sides carried a recessive gene that predisposed this family to methemoglobinemia. Due to the chronic nature of this, they were naturally polycythemic and compensated for the higher levels of the altered hemoglobin. Over time, with occasional treatment with methylene blue, the blue people of Kentucky became a thing of the past. 

I wrote this because I found this entire history fascinating. But I was also highly intrigued by my patient and the disease process. Sometimes there is no initial reason why they develop it…that we can ascertain. These patients need oxygen support. Its basic, but unless you have methylene blue on your ambulance that is your best place to start. Get them to a facility that has access to methylene blue. If the cause is environmental remove the environmental and toxic cause. Simple stuff, and rarely used…maybe it will save a patient’s life. 

 

 

0
JUL
10

Euglycemic DKA (Urine and Ureout)

Screen-Shot-2020-07-10-at-9.25.08-A_20200710-143102_1
In the classical FOAMed style, let’s start with a case.
 

You’re dispatched for a sick person. You walk into a ground level walk-up apartment and meet your patient. He is 38 years old, he looks generally ill but not in any acute distress. He reports 4 days of excessive thirst, hunger, and urination. He is a type 2 diabetic. He managed his diabetes with metformin for years but recently added empagliflozin (Jardiance).

 

You obtain the following vital signs on the monitor: 

 

PC: Chris Kroboth with iSimulate (@capno_medic)

 

Now the moment of truth. We all know where this is headed. You watch the glucometer county down as you await the final piece of the puzzle. As you prepare to pat yourself on the back---- 

 



So now we have information that does not fit with the diagnostic picture we painted in our heads. 

 

So you give the patient a monitor and transport, maybe some fluids. If you were thinking atypical ACS that’s a great thought- but the 12 lead is clean. 

 

You come to find out that he was ultimately diagnosed with DKA. 

 

But the sugar was normal?

 

Luckily for you this paragraph is not a detailed review of the pathophysiology of DKA. There are far better explanations on the internet than I can provide here. If you want a really good explanation of DKA FlightBridgeEd did a good nightmare series case on a DKA patient.

 

The big thing to remember about DKA is that the hyperglycemia is a symptom of the underlying pathology. It’s not the problem itself. The glucose accumulates in the blood because of the insulin resistance at the cellular level. Insulin resistance is the primary disorder. 

So now you secretly google the name of that long drug and see it classified as a "Sodium-glucose Contransporter-2 (SGLT-2)... this doesnt help. 

 

In 2013 the FDA approved a new class of medications called Sodium-glucose Contransporter-2 (SGLT-2) inhibitors. The three medications in this class on the market are:

 
  • Canagliflozen sold as Invokana (sounds like the name of a woman in James bond)
 
  • Gapagliflozen sold as Farxiga 
 
  • Empagliflozen sold as Jardiance
 

Note the “gliflozen” suffix.

 

The main action of these drugs is the excretion of glucose through the kidneys. It does this by inhibiting a protein (SGLT) that facilitates reabsorbtion of glucose in the kidney.

This is very different from the other common therapies for diabetes. Other therapies target the cell’s insulin sensitivity and aid with transport into the cell. Think about it:

 

Insulin - directly transports glucose into the cell

 

Metformin - lowers cellular insulin resistance

 

Sulfonylureas - stimulate insulin production in the presence of glucose

 

Under conventional therapy: 

 


 

As the serum glucose goes so goes insulin. With all of the above therapies the serum glucose will decrease because the cells are able to metabolize the glucose. 

 

If the glucose is simply being excreted via the kidneys two things happen that we do not see with the older therapies:

 

1.The pancreas sees less glucose so it releases less insulin

 

2. The cells are not able to metabolize more glucose since insulin resistance is unaffected

With SGLT-2 therapy:

 

So to recap the cells are still breaking down fatty acids generating ketone bodies, driving the pH down. On top of that - the body is able to lose glucose in the urine.

 

The effect is a patient in DKA with normal blood glucose. The literature refers to this as Euglycemic Diabetic Ketoacidosis. The causes of ketoacidosis in these patients are the same as those seen in a hyperglycemic DKA patient.

 

I’ll wrap this up with the “so what” part. What we had with our case is a set of symptoms that points us in one direction but the centerpiece of the diagnosis didn’t match up. When you have the picture we talked about ETCO2 can give you the last piece of the puzzle. If the ETCO2 is greater than 29mmHg, they are most likely not in DKA. Check out this explanation in ACEP.

 

I used to put ETCO2 on my hyperglycemic patients to try and tease out DKA vs HHNS. Then one day it dawned on me - in the 911 setting it really doesn’t matter. The prehospital treatment for DKA and HHNK is the same. The two key treatments are:

 

1. Fluid resuscitation since these patients run very dry- sometimes liters. 

A note on fluid loading- we only have lactated ringers (LR) at my shop but given the choice I would (as usual) steer clear of normal saline. LR is closer to a neutral pH which is where the patient needs to be corrected to eventually. One step better would be one of the “balanced” solutions such as Plasmalyte. PulmCrit gives a great explanation here: https://emcrit.org/pulmcrit/four-dka-pearls/

 

2. Resisting the urge to do something just to do something (Sodium Bicarbonate, intubation, etc…)

For a great podcast on when sodium bicarb is effective, check out this podcast.

https://foamfrat.libsyn.com/podcast-74-bicarb-or-bye-carb

 

As far at the potassium in these fluids remember that it is a physiologic amount of potassium. You are adding potassium and volume so there is no net difference. On top of that they are probably going to get potassium repletion anyway.

 

This one is a bit of a needle in the haystack, but it’s out there. Please let us know if you have seen this in the field. Did you know it at the time or did you come across it after and piece it together? 

 

Thank you all! 

1
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