Chapter 24 | RARE CO-EXISTING DISEASES Flashcards
Most common ECG among Myotonic Dystrophy Type - 1?
Prolonged PR interval and QRS duration
this is a progressive multisystem disorder characterized by the DELAYED relaxation of skeletal muscle after voluntary contraction.
MYOTONIC DYSTROPHY
2 types
DM-1 is the more COMMON and SEVERE form, with a wide phenotype ranging from
asymptomatic to life threatening.
FEATURES of Myotonic Dystrophy Type 1:
- A trinucleotide expansion (CTG) on chromosome 19q
- Effects on virtually any organ system, but most seriously the musculoskeletal, cardiovascular, gastrointestinal, respiratory, central nervous, and endocrine systems
- dystrophic process, begins DISTALLY and
progressing proximally - The Myotonic grip often precedes weakness
A patient with Myotonic Dystrophy is at risk of aspiration due to:
Gastric ATONY and pharyngeal muscle weakness
True of False
(Myotonic Dystrophy) DM-2 commonly complain of myalgia and fatigue, and weakness is usually MILD.
True
- DM-2 is caused by a quadnucleotide expansion (CCTG) on chromosome 3q.
Overall, the clinical course of DM-2 is milder than DM-1.
Most commonly, patients present with mild proximal muscle weakness in the third decade of life or later.
TRUE or FALSE
Annual ECG are recommended among Myotonic patients?
TRUE
High yield tip | Anesthesia Technique:
Is succinylcholine indicated for Myotonic Dystrophy?
NO. Sux should be AVOIDED
Succinylcholine should be avoided, as patients have an exaggerated contracture response to succinylcholine that can potentially make ventilation and tracheal intubation difficult.
If NMB is needed, short acting NMB is preferred, and dosage of NMB should be adjusted in proportion to the degree of muscle wasting.
Is Neuromuscular monitoring reliable intraoperatively in Myotonic Dystrophy?
YES however myotonic response to stimulation can mimic sustained tetany, hence the degree of block could be UNDERESTIMATED.
- Neostigmine and Sugammadex is SAFE
TRUE or FALSE
Shorter-acting opiates and sedatives are preferred to reduce the need for postoperative ventilation.
TRUE
Disorder NOT typically associated with Malignant Hyperthermia:
A. Central core disease
B. Duchenne muscular dystrophy
C. King-Denborough Syndrome
D. Evans Myopathy
B. Duchenne muscular dystrophy
The effect of INHALATION anesthesia on patients with DMD is now thought to be a form of anesthesia-induced rhabdomyolysis
One of the following is evidently one of the earliest SIGNS of malignant hyperthermia:
A. Fever
B. Hematuria
C. Elevated ETCO2
D. Metabolic acidosis
C. Elevated ETCO2
TRUE of Malignant Hyperthermia:
A. Hypercarbia that is resistant to increases in minute ventilation.
B. After confirming adequate ventilation, hypercarbia resistant to increases in minute ventilation should prompt a suspicion of MH
C. The initial dose of dantrolene is 2.5mg/kg. Repeat as frequently as needed until there is a decrease in EtCO2 and muscle rigidity
D. All are TRUE
ALL OF THESE ARE TRUE statement
Hypercarbia that is resistant to increases in minute ventilation. After confirming adequate ventilation, hypercarbia resistant to increases in minute ventilation should prompt a suspicion of MH.
The initial dose of dantrolene is 2.5mg/kg. Repeat as frequently as needed until there is a decrease in EtCO2 and muscle rigidity
Differential diagnosis of MH includes the following EXCEPT:
A. Serotonin Syndrome
B. Fat Embolism Syndrome
C. Thyroid storm
D. Central anticholinergic syndrome
E. Hypokalemic Periodic Paralysis
E. Hypokalemic Periodic Paralysis
Which of the following findings is NOT consistent with a diagnosis of malignant hyperthermia?
a. PaCO2 150 mm Hg
b. MVO2 50 mm Hg
c. pH 6.9
d. Onset of symptoms an hour after end of operation
b. MVO2 50 mm Hg
MH reflects a hypermetabolic state. Clinical signs include tachycardia, tachypnea, arterial hypoxemia, hypercarbia, metabolic acidosis, hyperkalemia, hypotension, muscle rigidity, trismus after succinylcholine administration, and increased temperature.
- Mixed venous oxygen tension would
be very low (normal MVO2 is 30-35, so an elevated MVO2 of 50 would not be consistent with MH).
What type of channelopathy is the main culprit in Hyperkalemic periodic paralysis:
A. Na+ channel myopathy
B. K+ channel myopathy
C. Ca+ channel myopathy
D. Cl- channel myopathy
A. Na+ channel myopathy
It is an autosomal dominant channelo-pathy caused by a mutation of the sodium channel.
The muscles responsible for respiration are usually
spared
The use of potassium-wasting drugs such as thiazide diuretics or carbonic anhydrase inhibitors, along with maintaining a diet of carbohydrate-rich meals, can help prevent episodes.
What type of channelopathy is the main culprit in Hypokalemic periodic paralysis:
A. Na+ channel myopathy
B. K+ channel myopathy
C. Ca+ channel myopathy
D. Cl- channel myopathy
C. Ca+ channel myopathy
Hypokalemic periodic paralysis (hypoPP) is also autosomal dominant and is the result of mutations in both calcium ion (most common) and sodium ion channels.
Patients begin having episodes of weakness, usually in their teenage years; these episodes last hours to days and are the result of a low serum potassium concentration. Proximal muscles are most often affected, while the diaphragm and muscles supplied by the cranial nerves are spared.
Which of the following DOES not present as periodic paralysis?
A. Hyperkalemic periodic paralysis
B. Andersen–Tawil syndrome
C. Myotonia congenita
D. Thyrotoxic periodic paralysis
C. Myotonia congenita
What type of channelopathy is the main culprit in Andersen–Tawil syndrome?
A. Na+ channel myopathy
B. K+ channel myopathy
C. Ca+ channel myopathy
D. Cl- channel myopathy
B. K+ channel myopathy
Anderen–Tawil syndrome (ATS) is caused by a mtation in the potassium ion channel of skeletal muscle.
This results in a periodic flaccid paralysis
similar in presentation to hypokalemic periodic paralysis.
Unlike other channelopathies, Andersen-Tawil Syndrome affects the smooth muscle such as the cardiac muscles. May present with arrhythmia.
Andersen-Tawil syndrome (ATS) is characterized by a triad of: episodic flaccid muscle weakness (i.e., periodic paralysis); ventricular arrhythmias and prolonged QT interval; and anomalies including low-set ears, widely spaced eyes, small mandible, fifth-digit clinodactyly, syndactyly, short stature, and scoliosis.
Affected individuals present in the first or second decade with either cardiac symptoms (palpitations and/or syncope) or weakness that occurs spontaneously following prolonged rest or following rest after exertion.
Atlantoaxial subluxation is diagnosed when the distance between the:
A. anterior arch of the atlas and the odontoid process is >3mm
B. posterior arch of the atlas and the odontoid process >5mm
C. posterior arch of the axis and the odontoid process is >3mm
D. anterior arch of the axis and the odontoid process is >5mm
A. anterior arch of the atlas and the odontoid process is >3mm
Atlantoaxial subluxation is diagnosed when the distance between the anterior arch of the atlas and the odontoid process is > 3 mm
