Clinical Case 113: Feeding Me Softly

Today’s case comes from Dr Trent Little – chronic Broome JMO and now my right-hand man in the Education Department (  i.e.. we share a desk ;-]  ).  This is a great Kimberely case – all the usual mix of third and first world medicine that just doesn’t happen much in the city.  Lets jump right in:

Solomon is a 44 y.o. man, he presents to the ED with a painful finger.

On examination he has a gangrenous looking right index finger. He is febrile, but not particularly looking that unwell. He also incidentally complains of having an increasing productive cough over the last week.

He is however well known to our department here and has a long medical history.
Previous TB
Chronic pancreatitis
Malnourished and ETOH abuse
Chronic normocytic anaemia
CKD stage 2
Smoker

He reluctantly agrees to admission and is brought into hospital with presumed osteomyelitis and commenced on IV piperacillin / tazobactam tds to cover his chest and finger.

Some clever doctor thought we best do a full blood work up given his history which showed:
Hb =98
Na = 124 (134-146)
K = 2.4 (3.4-5.0)
Cl = 86 (98-108)

Urea = 8.4 (3.0  – 8.0)

Creat = 183 (about double upper range of normal for US readers.)

Phosp = 0.92 (0.8-1.50)
Mag = 0.38 (0.7-1.10)
Cal = 2.20 (2.15-2.60)
Alb = 37 (35-50)
CRP = 220  [Ed: we do not encourage the use of CRP around here, but if you must….]
Lipase = 220 (ever so slightly elevated)

His electrolyte abnormalities were thought to be largely due to malnutrition and chronic disease.

In addition to his anti-microbial cover he his given initially IV K + Mag and then high oral doses. 2g oral Mag tds and 1200mg BD slow K.
His K rises slowly as planned, but despite the high doses oral Mag his serum Mag concentration does not reach >0.4.

On the third day of his admission he absconds from the ward for a few hours to have a couple of cigarettes. On return he his tachycardic with a rate of 110. He is completely asymptomatic and he gets and ECG.

ECG shows:

ECG 1 113

new ST elevation in V3 V4 and perhaps V5. What do you think may be going on here? Would you treat for STEMI/ACS?

Advice from the remote cardiologist is sought.  Solomon is given

-aspirin,

– enoxaparin  1mg/kg bid

– bisoprolol (bisoprolol was thought to be a better B-blocker option given his respiratory history).

The next morning his ECG had returned to normal and his high sensitivity Troponins were all negative at 6 & 12 hours

Now we are confused. What other investigations?

His bloods were revisited that morning.
Na = 126
K  = 4.2
Cl = 90
Cr  = 186
Urea= 8.4
Cal = 2.12
Phosp = 0.44
Mag = 0.38
Lipase 979
CRP is now 10  [Ed: wooohooo! Cured, discharge – hurrah for us…  sorry I just really don’t like CRP as a test. CP]

So, what was all that about then?  Whats the diagnosis ??

He was diagnosed with refeeding syndrome. Our ICU friends thought that the ECG changes were presumed myocardial dysfunction secondary to refeeding syndrome.

How do we manage refeeding sydnrome?  We would be interested to hear anyones opinion who has experience in this area.

What patients are at risk of Refeeding syndrome?

The best way of preventing re-feeding syndrome is identifying those who are at high risk. This BMJ article gives a nice summary.

Anyone not feeding for more than >5 days is at theoretical risk of refeeding syndrome. Our common high risk groups patients groups include:

Anorexia nervosa
Chronic Alcoholism
Postoperative (particularly GI surgery)
Oncology patients
Patients with uncontrolled diabetes
Malabsorptive syndromes such IBD, CF and chronic pancreatitis
Some patients who we would be less likely to consider, but who are also at risk include long term antacid users (Mag and aluminium salt binding phosphate) and long term diuretic users (loss of electrolytes).

It is largely a clinical diagnosis with a few characteristic biochemical abnormalities. Here is a nifty flow diagram from the BMJ review of the NICE guidelines for managing referring syndrome

refeed mx

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