RED HERRINGS AND RED URINE: IS IT MH OR NOT? IF NOT, WHY NOT?
30 year old, 75 KG male presented to the emergency department with severe shortness of breath. His medical history is unremarkable. His social history is remarkable for polysubstance abuse. His employment history is significant for work as an anesthesia technician with a history of home diversion of sevoflurane.
Upon presentation, the patient had peripheral oxygen saturation between 70 and 80%, temperature of 38 degrees orally, HR 152, BP 135/77 and respiratory rate of 42. The remainder of the physical examination was normal. Chest x-ray was positive for extensive bilateral infiltrates. EKG was interpreted as a sinus tachycardia with prolonged PR interval; beside ECHO cardiogram demonstrated an EF 50% and considered normal by local criteria. There was no evidence of cardiac tamponade or ventricular dysfunction. CT scan of the chest was negative for pulmonary embolus. Laboratory values of note: Creatinine 1.1, Potassium 3.5, CPK 176, Bicarb 26, WBC 2.6 with increased bands. Serum toxicology tests were negative for benzodiazepines, opiates, amphetamines, modified amphetamines, marijuana and alcohol.
The emergency medicine staff was unable to correct the patient’s tachypnea and hypoxia with spontaneous ventilation using a non-rebreathing mask with a FiO2 of 100%. Consequently, the patient was intubated help improve oxygenation and ventilation. Endotracheal intubation was facilitated with etomidate 30 mg and succinylcholine 150 mg. Intubation of the trachea was uneventful and the patient was transitioned to an institutional ARDS ventilation protocol in the intensive care unit. Immediate ABG after intubation of the trachea was 7.08/86.5/65/ 25.7 with a base deficit of minus 7 and oxygen saturation of 81%. The patient required low TV, FiO2 100%, PEEP 15. Based upon the criteria of ARDS, the patient had all of the clinical signs for ARDS including shortness of breath, negative left heart failure via echocardiography examination, diffuse bilateral infiltrates on chest x-ray, and a PaO2/FiO2 ratio of less than 200. The patient’s ratio was 65.
During this period in the emergency department, family members and friends volunteered that the patient had been abusing sevoflurane at home by sniffing sevoflurane containing rags over a period of months prior to the admission including the preceding hours prior to admission to the hospital. (By patient own admission, the estimated number of events was 8-10 over 3-4 months ascertained when the patient made a full recovery.)
Within 18 hours of admission, poor progress immediately mandated the patient to transition to rotation bed. At this time, the patient’s temperature rose precipitously to 41 degrees, CPK of 10,083 and a urine myoglobin of 21,600. MH clinical grading score of 58 was achieved and presumptive diagnosis of malignant hyperthermia was made. The anesthesiology department was contacted and dantrolene was started with and IV bolus of 2.5 mg via central IV access since no peripheral access was available. During the bolus administration, the patient suffered a cardiac arrest. Aggressive CPR was started including the administration of norepinephrine and vasopressin to reverse refractory hypotension. The patient spontaneously recovered cardiac activity with adequate perfusion. Dantrolene was continued via infusion. Due to the rising temperature, ALSIUS™ Femoral cooling catheter was inserted and continued in situ until the patient’s temperature normalized over the next several days. The dantrolene infusion continued as well over several days as the patient’s temperature and CPK levels normalized. With the patient’s and family permission, genetic testing was sent for assay and was negative for RYR 1.
The patient made a sufficient recovery to be discharged within several weeks to a rehabilitation facility and following complete recovery, the patient was discharged to home. The patient required general anesthesia 6 months after the initial event for closure a decubitus that developed during the patient’s stay in the critical care unit. A non-triggering anesthetic was administered uneventfully. At the time of the follow-up procedure, the family was considering halothane-contracture testing for the patient and first-degree relatives.
Was this MH presenting as ARDS? Was this SIRS? Was this a direct due to repeated exposure to sevoflurane? Should we have done anything differently?
1- The patient had all of the following possible diagnoses except?
A- MH
B- ARDS
C- Fulminate aspiration pneumonia
D- CHF
E- Direct myotoxic affects of sevoflurane
2- What recommendations would you make to the patient and his first degree relatives regarding subsequent anesthetic in the absence of a halothane-contracture test and other negative history for triggering anesthetics?
A- Proceed with a triggering anesthetics since the genetic testing was negative
B- Proceed with a non-triggering anesthetic
C- Obtain a MedicAlert bracelet and label oneself as MHS until more definitive information is available
D- No recommendations until halothane-caffeine contracture test is performed
3- The patient is physically and emotionally ready to return to work.. What recommendations would you make to their manager concerning occupational exposure to volatile agents?
A- The patient should not return to work due to the fear that the patient may trigger MH from ambient exposure to volatile agents
B- The patient may return to work with full duties since there are no report incidents of occupational triggering of MH
C- Defer decision until a halothane-caffeine contracture test is performed and the result are known
ANSWERS
1. D - The patient had a normal echocardiogram?
2. B+C
3. B
