





























anesthesia for a Patient with  
osteogenesis imPerfecta,  
achondroPlastic dwarfism and  
history of malignant hyPerthermia

AbstrAct 
A primary goal for anesthesia providers is to maintain patient 

safety. This is an even greater concern when taking care of a 
patient with a complicated medical history. This case report, 
discusses the care of a 47 year-old female patient who presented 
to a tertiary care center for an orthopedic procedure. Her 
medical history included osteogenesis imperfecta (OI), achondro-
plastic dwarfism and suspicion of malignant hyperthermia (MH). 
There were multiple anesthetic implications to ensure safety for 
this patient during the perioperative period. OI concerns include 
bone fragility and potential for multiple fractures even after 
inoffensive trauma.  Achondroplastic dwarfism concerns include 
abnormalities of the upper airway and difficulty with visual-
izing the glottic opening during direct laryngoscopy.1 Malignant 
Hyperthermia is a life threatening disorder, which places the 
patient at risk for a hypermetabolic reaction if exposed to select 
anesthetic agents.

IntroductIon: 
Patients with osteogenesis imperfect (OI) are placed at high risk 

during anesthesia for both physiological and anatomical reasons. 
Complications include osteoporosis, joint laxity, and tendon 
weakness.2 Pulmonary compromise may also occur if the patient 
displays thoracic distortion. These patients have an elevated 
basal metabolic rate that causes an increase in core body temper-
ature and can mistaken to be MH. No consistent evidence has 
shown that OI is always associated with MH.2 Achondroplastic 

Jaclyn Harvey SRNA



dwarfism is the most common form of dwarfism occurring at 
the rate of 1:30,000 live births. Airway abnormalities such as 
macroglossia, micrognathia, small oral opening and temporo-
mandibular joint immobility can make mask ventilation and 
intubation challenging for anesthesia providers. The perioperative 
period can also be complicated with managing restrictive lung 
disease patterns and cardiovascular abnormalities.1 Malignant 
hyperthermia (MH) is a hypermetabolic disorder that is triggered 
by anesthetic agents such as succinylcholine, or inhaled anes-
thetics: halothane, isoflurane, sevoflurane and desflurane. Several 
musculoskeletal disorders are coupled with MH including the 
patient’s diagnosis of osteogenesis imperfecta. Identifying suscep-
tible patients prove difficult because it is a silent disorder until 
triggered. In addition, 50% of patients who experience an MH 
crisis had previously received a triggering agent without showing 
symptoms.3 

In this case report a patient presents to a tertiary care hospital 
with all three of these conditions. Naturally, the anesthetic plan 
for this patient sparked a large amount of discussion for anes-
thetic management and concern for patient safety.

cAse rePort

A 47 year-old Caucasian female presented to a tertiary care 
center for her 55th surgery. She was 36 inches tall and weighed 
24 kg for a BMI of 28.2. The patient was an achondroplastic 
dwarf with a past medical history of OI leading to her many 
hospital admissions and surgical history. The patient was wheel-
chair bound and presented with an adduction deformity of the 
right hip. The procedural goal was palliative to remove the 
constant pressure points that caused pain between both knees. 
The patient also had a suspected history of MH due to parental 
report of “anesthetic complications” from a previous procedure. 
Medications included cephalexin, alprazolam, and oxycodone. 
She had no known allergies.

The patient was seen in the preoperative holding area by the 

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anesthesia team for the preoperative assessment. The assessment 
focused on her airway, cardiopulmonary and musculoskeletal 
status. Key airway assessment findings included a Mallampati 
class I, oral opening was greater than 4 cm, full dentition intact, 
mandibular length adequate, thyromental distance of 6 cm, 
cricothyroid membrane palpable and an atlanto-occipital exten-
sion of less than 35 degrees. The patient’s head shape and size 
was normal and her neck thin. The patient experienced constant 
pain in her left leg from pressure point contact. She preferred 
the left lateral position with a pillow between her knees to 
prevent pressure. Her chest was smaller than expected for an 
adult female and had a kyphoscoliotic shape. Lung sounds clear 
to auscultation and chest x-ray clear throughout lung fields. 
Heart rate assessed as regular with normal S1 and S2 pattern. 
Electrocardiography revealed sinus rhythm with short PR 
intervals.

With the inconclusive malignant hyperthermia history, the 
anesthesia team proceeded to follow the MH protocol. All MH 
triggers were removed from the OR with a total intravenous 
anesthetic planned. Risks and benefits of the procedure and anes-
thetic technique were discussed with the patient. She accepted 
the discussion and signed, giving informed consent. The patient’s 
number of previous surgical procedures places her at risk for 
blood loss. Blood consent was obtained with two units of packed 
red blood cells available. Preoperative intravenous access was 
obtained with a 20 gauge IV placed in the right forearm. The 
patient is a Patient Status 3.  

The anesthesia workstation was prepared in accordance with 
Malignant Hyperthermia Association of the United States 
(MHAUS) recommendations. All MH triggers needed to be 
eliminated including removing succinylcholine syringes from 
the induction drug set up and disabling the vaporizers by taping 
them to the “off” position. The carbon dioxide (CO2) absorbent 
was changed to prevent any fractionated inspired agent from 



entering the breathing circuit. The anesthesia gas machine (AGM) 
was flushed with 10L/min of oxygen for 20 minutes4 and a new 
breathing circuit was installed on the AGM. Please see Figure 1.

The patient was taken to the OR and given 1 milligram of 
midazolam and 25 micrograms of fentanyl for preoperative 
sedation and pain management. The patient was lifted to the 
OR table to prevent discomfort and then secured to the table 
with safety straps. Initial position was supine with blankets to 
support her spine. Care was taken to support her arms on padded 
arm boards bilaterally at less than a 90-degree angle. Standard 
monitors were placed and vital signs (VS) recorded. The patient 
was denitrogenated with 100% oxygen and induction of anes-
thesia began with 50 micrograms of fentanyl, 60 milligrams of 
lidocaine, and 50 milligrams of propofol. Once unconscious 
ventilation was confirmed, the patient received 20 milligrams 
of rocuronium bromide for paralysis and was intubated with a 
Macintosh 3 blade after Cormack I direct visualization of the 
cords. The patient was intubated with a pediatric cuffed 5.0 
endotracheal tube. A propofol infusion at 120 microgram/kg/
min was initiated and a right internal jugular triple lumen cath-
eter was placed. A Hotline™ (Dublin, OH) fluid warming system 
was connected to the new central line for fluid management and 
warming. An upper body forced air warming blanket was applied 
Bair Hugger® Therapy from Arizant Inc. The patient was given 
incremental fentanyl boluses (1 microgram/kilogram) throughout 
the procedure.

As requested by the surgeon, further muscle relaxation was 
withheld in order to monitor motor responses during the proce-
dure. Patient was given Zofran 4 milligrams, given to prevent the 
female predisposition to postoperative nausea and vomiting with 
general anesthesia 30 minutes prior to emergence. The patient 
regained four train of four twitches and was reversed with 2 
milligrams of neostigmine and 0.4 milligrams of glycopyrrolate. 
Upon emergence the patient awoke, opened her eyes, followed 

AEJ



commands, and was breathing spontaneously. However, she 
displayed less than 5 milliliters/kilogram tidal volumes and was 
transferred to the post anesthesia care unit with an endotracheal 
tube and on oxygen through a t-piece to protect her airway. 
Postoperative vital signs included a temperature of 37.3 degrees 
Celsius(C), 130 heart rate, blood pressure 120/80, regular respi-
ratory rate of 16 and saturations of 100% on 40% oxygen. She 
gradually gained strength and was extubated.

dIscussIon

The pathophysiology of osteogenesis imperfecta is decreased 
collagen synthesis. Ninety percent of individuals have mutations 
on the type I collagen genes, pro-a1 or pro- a2. A phenotype 
often indistinguishable from OI type II or III is a mutation of 
two of the genes responsible for encoding proteins of an enzyme 
complex LEPRE1 and cartilage-associated protein causing an 
autosomal recessive OI.1 Patients with osteogenesis imperfect 
are placed at high risk during anesthesia for both physiological 
and anatomical concerns. Physical manifestations are a large 
head, small bowed limbs, short neck, blue sclera, otosclerosis, 
and brittle teeth. Complications lend themselves to osteoporosis, 
joint laxity, and tendon weakness.2 These patients may also 
have abnormal platelet function leading to an increased risk of 
bleeding. There is a tendency for early development of athero-
sclerosis so a cardiovascular assessment that includes evaluation 
of the mitral and aortic valve function is important. Pulmonary 
compromise may also occur if the patient displays thoracic 
distortion. These patients have an elevated basal metabolic rate 
that causes an increase in core body temperature and can mistak-
enly be thought to be MH. There has been no consistent evidence 
that OI is always associated with MH.2   

Achondroplastic dwarfism is a phenotype of disproportionate 
stature. In 95%of patients the same point mutation occurs on 
the gene that encodes for fibroblast growth factor receptors, 
FGFR3.1 The anesthetic management of these patients proves a 



challenge with abnormalities of their upper airways and difficulty 
visualizing the glottic opening on direct laryngoscopy. Intubation 
is often challenged by characteristics of a short neck, protruding 
tongue, as well as enlarged tonsils and adenoids.1 Further, 
these patients may have subglottic stenosis, tracheal and bron-
chial narrowing. A thoracic dystrophy may be present causing 
the patient to have reduced lung volumes due to the restric-
tive disease pattern. Cardiac dysfunction may include acquired 
valvular disease, cor pulmonale and cardiomyopathy. It is advis-
able to preoperatively obtain a chest x-ray, echocardiogram as 
well as a physical exam to evaluate the presence and severity of 
these conditions.1 For the possibility of pulmonary and cardiac 
complications it is imperative to avoid hypoxemia and hypovo-
lemia. This can exacerbate existing pulmonary hypertension and 
worsen right ventricular function.1

Malignant hyperthermia is a hypermetabolic disorder that is 
triggered by anesthetic agents such as succinylcholine, or inhaled 
anesthetics: halothane, isoflurane, sevoflurane and desflurane. 
Several musculoskeletal disorders are associated with MH 
including osteogenesis imperfecta. Exposure to a triggering agent 
can cause a dramatic increase in skeletal muscle metabolism. The 
most common first sign of MH is a rapid increase in end tidal 
carbon dioxide (C02) as metabolism accelerates. Other early signs 
are tachycardia, tachypnea, and increased oxygen consumption, 
acidosis, muscle rigidity, and rhabdomylosis.5 Further symptoms 
are unstable blood pressure, cyanosis, mottled skin, diaphoresis, 
dysrhythmias and an increase in patient’s body temperature. 
Temperature increase can be as much as 1-2 degrees C every 5 
minutes. The mortality rate of unrecognized MH can be as high 
as 80%.6 Identifying susceptible patients is difficult because it 
is a silent disorder until triggered. In addition 50% of patients 
who experience an MH crisis had previously received a trig-
gering agent without showing symptoms.3 MH is a hypermeta-
bolic syndrome that occurs from an abnormal amount of calcium 
release by the sarcoplasmic reticulum in to the sarcoplasm. 

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Increased levels of calcium cause elevated oxygen consumption 
and anaerobic metabolism. The transportation of the calcium is 
mediated by the ryanodine receptor, isoform 1 (RYR1).3 About 
50% of known MH cases are caused by mutations on chromo-
some 19 at the RYR1 receptor. A small percentage is dihydro-
pyridine (DHP) receptor on chromosome 1.3 The most current 
dependable method to confirm diagnosis is a muscle biopsy test 
where the muscle fibers are placed in contact with caffeine and 
halothane.7 There is 95% reliability for patient susceptibility 
with a positive muscle contraction.6  

summAry

This case report presents a patient with three rare disorders 
that each has multiple anesthetic implications. The diagnosis of 
osteogenesis imperfecta predisposes the patient to brittle bones, 
joint laxity, and tendon weakness. Safety in positioning, move-
ment and transfer of the patient becomes extremely important 
for a patient with OI. Furthermore, these patients often have 
altered pulmonary or cardiovascular function. Achondroplastic 
dwarfism has additional implications that include airway abnor-
malities that make mask ventilation and direct laryngoscopy 
challenging. The presence of the difficult airway cart and avail-
ability of immediate surgical personnel are two prudent measures 
to be taken prior to induction. Additionally, this patient reported 
a possible MH exacerbation during an earlier surgical procedure. 
This mandates preparation of the anesthesia workstation and 
clarification amongst anesthesia personnel in order to ensure that 
no trigger agents reach the patient and that the team is prepared 
in the event of a hypermetabolic event. This case illustrates the 
importance of a thorough preoperative assessment, development 
of a comprehensive plan involving both anesthesia and surgical 
teams and the need for constant vigilance. Maintaining an open 
line of communication throughout the procedure is imperative in 
order to reach the ultimate goal of patient safety.



references

1. Davis PJ, Cladis FP & Motoyama EK. Smith’s Anesthesia 
for Infants and Children. 8th  ed. Philadelphia: Elsevier 
Mosby; 2011.

2. Barash PGC, Bruce F, Stoelting RK. Clinical Anesthesia. 5th 
ed. Philadelphia: Lipincott Williams & Wilkins; 2006.

3. Litman RS, Rosenberg H. Malignant hyperthermia: 
update on susceptibility testing. JAMA : the Journal of 
the American Medical Association. [Research Support, 
Non-U.S. Gov’t]. 2005 Jun 15;293(23):2918-24.

4. Malignant Hyperthermia Association of the United States.  
2011; Available from: http://www.mhaus.org/. Accessed 
June1, 2012

5. Rosenberg H, Davis M, James D, Pollock N, Stowell K. 
Malignant hyperthermia. Orphanet journal of rare diseases. 
[Review]. 2007;2:21.

6. Guideline Statement for Malignant Hyperthermia in 
the Perioperative Environment. Association of Surgical 
Technologies [serial on the Internet]. 2005; (October): 
Available from: http://www.ast.org/pdf/Standards_of_Practice/
Guideline_Malignant_Hyperthermia.pdf. Accessed January 
22, 2012

7. Rosenberg H, Antognini JF, Muldoon S. Testing for malig-
nant hyperthermia. Anesthesiology. [Research Support, 
Non-U.S. Gov’t]. 2002 Jan;96(1):232-7.

Acknowledgements
Acknowledgment is given to John M. O’Donnell DrPH, RN, 
CRNA, MSN as mentor and critiquing the case study.

AEJ



Figure 1

Photo by Jaclyn Harvey SRNA Graphic Courtesy of: Children’s 
Hospital of University of Pittsburgh Medical Center


