Topic: Hyperkalemia and Rhabdomyolysis in a
10 month old infant during cleft palate repair
History: 10 month old, 10.1 kg male for cleft palate repair under general anesthesia. Past history: two other GA (pyloromyotomy and cleft lip repair) under general anesthesia without difficulty. No history of asthma or recent history of upper respiratory tract infection. Normal motor and other developmental milestones. Induction: Inhalational induction with sevoflurane, sux for intubation using 3.5 ETT uncuffed. 90 min into the case EtCo2 noted to be up to ‘71’, which had been increasing slowly. Simultaneous tachycardia occuring, followed by VT treated with lidocaine, reverted to sinus tachycardia. Temp 39.6 axillary. While attempting to remove the mouth gag used by surgeon, patients jaw found to be rigid.
(More than one correct answers possible)
- What may be the most appropriate initial steps?
- Turn off Sevoflurane, continue Nitrous Oxide
- Obtain blood gas
- Start bladder irrigation with cold normal saline.
- Cancel surgery and call ICU for transferring patient.
- A venous blood gas revealed: Ph 7.1-48-42-16, K-7.
What is your next step?
- Give dantrolene 2.5mg/kg
- Start peripheral cooling
- Place temp probe rectally
- Call for help
- Repeat blood gas: 7.10-48-192-15.3, K-8.4. What are your next interventions? CPK-20,000
- Give glucose and insulin (.1u/kg)
- Give more bicarbonate
- Immediately draw BUN and Creatinine
- Call in an urgent Nephrology consult
- What possible differential diagnosis are you considering at this point?
- Malignant Hyperthermia
- Sepsis
- Neuroleptic Malignant Syndrome
- Sux induced rhabdomyolysis
- One of your colleagues obtained an arterial line and now asks what other labs do you need? Ask for:
- Drug screen
- Blood cultures
- CPK, PT/PTT
- Serum myoglobin
Answers and Explanation:
1. a and b
There are many aspects of this infant’s presentation that point to likely Malignant Hyperthermia. Turning off “triggering agents” is a quick and easy measure and if the infant can tolerate, add intravenous opioids such as fentanyl to supplement anesthesia. The question often arises as to ‘wasting time’ in an infant with attempts to obtain blood gas before treating. This is a ‘judgment’ call. If help is available, obtaining a venous or arterial blood gas is very desirable while dantrolene is being mixed, which takes a few minutes. Cooling the patient needs to take place as well, but the immediate step in that direction is peripheral cooling with ice packs in areas of high perfusion; groin, axilla and around the head. A Foley catheter does need to be placed, to monitor urine output and it also allows one to dipstick urine to check presence of blood (could be due to myoglobin in the urine also, will need myoglobin assay to confirm).
Surgeon needs to be made aware of the situation and a combined decision needs to be made to cancel surgery, except to close any open wound that would otherwise harm the patient. Patient needs to be stabilized in the OR as the time wasted in transferring a patient such as this infant might be crucial.
2. all are correct
As you progress through the case and the blood gas results are in, you realize you may have a potential case of MH. Hyperkalemia needs immediate attention particularly as the infant had a run of V-Tach already. Initiating treatment with dantrolene is appropriate as the Hyperkalemia would respond to dantrolene if due to hypermetabolic process. Use of bicarbonate would also be appropriate.
Recognize that the management of this infant would take more than one attending Anesthesiologist and call for any available hands.
3. a and b are correct
Again Hyperkalemia needs immediate attention as well as ongoing treatment of MH, as this infant, unless proven otherwise, needs treatment for MH. A worsening Hyperkalemia can be treated by driving potassium intracellularly using insulin, in an environment of hyperglycemia. 1 ml/kg of D50% glucose can be used for this purpose followed by .1u/kg of regular insulin IV. It is important to follow glucose levels in such situation. The source of Hyperkalemia is not renal in origin and a Nephrology consult is not indicated.
4. a and d are correct
An otherwise healthy infant manifesting rhabdomyolysis and elevated temperature should be suspected of experiencing MH. Sepsis is very unlikely as this infant has no history of preoperative illnesses. Neuroleptic Malignant Syndrome is seen in patients who have been placed on phenothiazine group of drugs. Sux induced rhabdomyolysis is a consideration and should only be debated on afterwards (after the infant is treated and stable). The significant elevation of temperature in this infant favors the diagnosis of MH than rhabdomyolysis. As this is a 10 month old infant who is not old enough to exhibit signs and symptoms of muscular dystrophy (whether Duchenne Muscular Dystrophy or Becker’s Dystrophy) in view of having received Succinylcholine it is a possibility that the infant was undergoing rhabdomyolysis. However, the picture of rhabdomyolysis can mimic MH and it is difficult to differentiate between the two in an acute situation such as this. Treating MH is appropriate as delaying treatment could be fatal.
.
5. c and d are correct
To further aid in diagnosis and management of this patient, Creatinine phosphokinase (CPK) and serum and urine myoglobin are necessary. As muscle damage and disruption occurs CPK and myoglobin will start to rise
As well. Myoglobin is released faster and earlier than CPK and in a Fulminant case such as this, both will be quite high. Such elevation helps with diagnosing a case of MH as well as guide therapy with dantrolene. Dantrolene will need to be continued till CPK starts to decrease and patient had been afebrile for 24-36 hours. As DIC is the commonest cause of death in these patients, clotting studies need to be obtained as soon as possible.
Treatment with fresh frozen plasma and or cryoprecipitate might be necessary.
Mary C. Theroux, MD
The
Dept of Anesthesiology
