September Case Of The Month

SCLERODERMA OR MH?

A patient with SEVERE SCLERODERMA and obesity is in Radiology undergoing esophageal dilatation with sedation by the Radiologist, which included Versed 7 mg and Dilaudid 5mg. About 45 minutes into the case, Radiologists noted she was not breathing and called a Code. CRNA in house came to suite, noted that CPR was in progress and mask ventilation was extremely difficult. Attempt at intubation failed secondary to total body rigidity and inability to open mouth. Mask ventilation continued with four hand techniques, SpO2 from ear probe, 94-98, HR 140s, sinus tach. Anesthesiologist called in from home, decision to proceed with fiberoptic intubation in OR. After move to OR, ETCO2 60-70 from mask, BP140-160s, HR 140-170, temp 37.5°C by nasal and esophageal probes. A single attempt at laryngoscopy using a Miller 3 blade after Etomidate 14mg and Succinylcholine 140mg was given IV. They were able to get the laryngoscope into mouth but were not able to achieve visualization of the larynx. They were unable to get a Glidescope in, so next 45 min spent doing a difficult, but successful FOI. Pink froth noted at this time coming out of trachea and Dx of APE assumed, and treatment with Lasix and Mannitol begun.

Initial ABG (FIO2, 1.0): 7.0/92/103/90%/HCO3 22/BE-6.0

After intubation, Anesthesiologist began to go through chart and noted an entry that patient's brother said that she is never to have a GA because she is MHS. Anesthesiologist decides that with MHS dx and his having given Sux, this might be MH and gives dantrolene 220 mg IVP. After dantrolene, things start improving, easier hyperventilation and ETCO2 begins to decrease and temp decreases somewhat.

Questions:

What is you diagnosis?

Succinylcholine-induced MH
Hypoventilation induced Respiratory acidosis and
Dilaudid induced body rigidity
Hypoperfusion induced metabolic acidosis
b and d
a and c

What is the source of the body rigidity?

Narcotics
Succinylcholine
Scleroderma
Pulmonary edema
Tension

Why did the dantrolene help?

Dantrolene is a general skeletal muscle relaxant
Dantrolene is an anti-pyretic
Dantrolene is an anxiolytic
a and b
a and c

ANSWERS

1. e - The patient probably suffered an unrecognized hypoventilation-induced respiratory arrest as a result of over sedation by the endoscopist(s) in the endoscopy suite, which subsequently led to cardiac arrest. The former caused a severe respiratory acidosis, the latter the metabolic acidosis.

2. c - The most likely answer is the pre-existing scleroderma, rather than succinylcholine, since there was no evidence of any increase in body rigidity or change in autonomic parameters (blood pressure or heart rate) after giving the drug. Furthermore, it is prudent to first attribute a medical problem to an existing diagnosis (Scleroderma) that explains the phenomena being observed before invoking a rare disease (MH) as an explanation.

3. d - Dantrolene is an intracellularly acting, skeletal muscle relaxant, and has anti-pyretic properties aside from its activity in MH. Therefore, fevers that respond to dantrolene are not necessarily the result of MH, and one cannot conclude ipso facto that if dantrolene improves patient outcome/parameters, that the inciting factor was MH. One still needs the constellation of clinical parameters that constitute likely or almost certain MH that were described by Larach et al. (1994) to assist in making the diagnosis.¹ Ultimately, a positive genetic test and/or a Caffeine-Halothane Contracture test is required to confirm the diagnosis.

¹Larach, M.G., Localio, A.R., Allen, G.C. et al. (1994) A clinical grading scale to predict malignant hyperthermia susceptibility. Anesthesiology 80:771-779.

Jerome Parness, MD
Children's Hospital of Pittsburgh
Pittsburgh, PA