Musculoskeletal Diseases Flashcards
What is myasthenia Gravis?
Autoimmune disease ~ igG antibodies destroy post-junctional, nicotinic, acetylcholine receptors at the neuromuscular junction
What is a key feature of Myasthenia Gravis?
Skeletal weakness that becomes worse later in the day (periods of rest allow for muscular recovery)
What are some S&S of Myasthenia Gravis?
Diplopia, ptosis (EARLIEST sign)
Bulbar muscle weakness (muscles of the throat and mouth)
Dyspnea with exertion
What are some things that make myasthenia Gravis worse?
Pregnancy
Infection
Electrolyte imbalances
Stress
Aminoglycoside abx
What is the treatment for myasthenia Gravis?
Oral pyridostigmine (anticholinesterase inhibitor) is first line treatment
How can you tell if a patient with myasthenia crisis is having a cholinergic crisis (they are on anticholineresterases) or if they are having myasthenia crisis?
Tensilon test!
Diagnose with edrophonium (1-2 mg IV)
If muscle weakness worsens ~pt is with cholinergic crisis
If muscle weakness improves ~ myasthenia crisis
What type of surgery can a patient with myasthenia Gravis have that may relieve symptoms?
Thymectomy
What can provide temporary relief during myasthenia crisis or before thymectomy?
Plasmapharesis
A patient with myasthenia Gravis has what reaction to NMB?
Increased sensitivity to non-depolarizing NMBs (ROC)
Decreased sensitivity to depolarizing NMBs (SUX)
Patients with myasthenia Gravis who may need postoperative ventilation include:
Disease duration > 6 years
Daily pyridostigmine > 750 mg/day
Vital capacity < 2.9
COPD
Surgical approach ~ median sternotomy > transcervical thymectomy
What is Eaton-Lambert Syndrome associated with?
Destruction of presynaptic voltage gated calcium channels
Increased sensitivity to succinylcholine
Small lung carcinoma
In Eaton-Lambert Syndrome, when are symptoms the worst?
Worse in the morning and get better throughout the day.
What is the treatment for eaton-Lambert Syndrome?
3,4-diaminopyridine (DAP) ~ increases Ach release from presynaptic terminal
**anticholinesterases are NOT helpful
How does a patient with Eaton-Lambert Syndrome response to NMB?
Sensitive to BOTH! Doses should be reduced.
They are a high risk for postoperative ventilatory failure
What is the most common cause of acute, generalized paralysis?
Guillian-Barre syndrome
What is Guillian Barre?
Acute idiopathic polyneuritis ~ immunologic assault on myelin in the peripheral nerves
How does Gillian barre present?
Flu-like symptoms 1-3 weeks before
Most common etiologies are campylobacter jejuni bacteria, Epstein-barr, and cytomegalovirus
What are the S&S of Gillian Barre?
Flaccid paralysis that begins in distal extremities and ascends bilaterally towards the proximal extremities
What is the treatment for Gillian Barre?
Plasmapheresis and IV IgG
How does patients with Guillian Bare react to NMB?
Sensitive to BOTH! Avoid Sux.
What is familial Periodic Paralysis?
Characterized by acute episodes of skeletal muscle weakness accompanied by changes in K+ concentration.
Two variants: hypokalemic vs. hyperkalemic
Hypokalemic periodic paralysis is associated with what?
Calcium channelopathy
Hyperkalemic periodic paralysis is associated with what?
Sodium channelopathy
What do you know if a patient has hypokalemic periodic paralysis?
Patient gets weak following a glucose-insulin infusion ~ becomes weak after the serum K+ decreases
How do you know if a patient has hyperkalemic periodic paralysis?
Patient becomes weak following oral potassium administration ~ weakness following a rise in serum K
What is the treatment for both hypokalemic AND hyperkalemic periodic paralysis?
Acetazolamide
What are TWO major anesthetic considerations?
HYPOTHERMIA must be avoided
Serial K+ monitoring is recommended
What is safe to administer for HYPOkalemic periodic paralysis? What is not safe!?
Safe: acetazolamide and Nondepolarizers
Not safe: glucose containing solutions, potassium wasting diuretics, beta 2 agonists, Sux
What is safe to administer for HYPERkalemic periodic paralysis? What is not safe!?
Safe: glucose containing solutions, potassium wasting diuretics, beta-2 agonists, nondepolarizers, acetazolamide
Not safe: sux and potassium containing solutions (LR)
What is MH?
Inherited disease of skeletal muscle that is characterized by disordered calcium homeostasis.
What two drugs stimulate MH?
Halogenated agents
Succinylcholine
what is the pathophysiology of MH?
T-tubule depolarized > Ca influx > activation of RyR1 receptor > increase in Ca (can’t be “turned off”) > SERCA2 tried to help but it take a LOT of ATP > increase O2 consumption > breakdown in sarcolemma > K+ and myoglobin leak
What are the only three co-existing diseases with MH?
King-Denborough
Central core
Multiminicore
What are early signs of Malignant hyperthermia?
Tachycardia, increased EtCO2, and masseter spasm, tachypnea, warm soda lime
What are late signs of MH?
Hyperthermia, cola-colored urine, and DIC, muscle rigidity
What is the most sensitive indicator of MH?
EtCO2 the rises out of proportion to minute ventilation
What is the different b/t trismus and masseter spasm?
Trismus: tight jaw that CAN still be opened
(Normal response to sux)
Masseter spasm: tight jaw the CANNOT be opened
(If patient experiences this, assume MH until proven otherwise)
What is the gold standard for diagnosing MH?
Caffeine-halothane contracture test (requires a LIVE muscular biopsy sample)
What are some differential diagnoses for MH?
Pheochromocytoma
Thyroid storm
Malignant neuroleptic syndrome
Serotonergic syndrome
Heatstroke
Cocaine intoxication
What medications are contraindicated in the treatment of MH?
Calcium channel blockers
(Life-threatening hyperkalemia may result when a CCB is co-administered with dantrolene)
How should a provide prep for a patient with MH?
Anesthesia gas machine must be flushed with high-flow oxygen ~ (can be for 20-100 minutes)
All external parts should be removed
Vaporizers should be physically removed from the machine
Patient should be monitored for 1-4 hours in PACU.
As an alternative to purging guideline for MH, what can you use?
Charcoal filter
How much fluid does each vial of dantrolene need to be reconstituted with?
60 mL of FREE WATER (not NS)
What is the order in which you treat MH?
- Discontinue triggering agent
- Call for help
- Hyperventilate with 100% FiO2 at FGF of 10L/min
- Administer Dantrolene or Ryanodex (2.5 mg/kg)
- Cool the patient
- Correct lactic acidosis (bicarb 1-2 mEq)
- Treat hyperkalemia (Ca-DI ~ calcium, Dextrose, insulin)
- Protect dysrhythmias (lido/procainamide)
- Maintain urine output (>2 mL/kg/hr)
- DIC is a baaaad sign ~ impending demise
What is the most common skeletal muscle myopathy?
Duchenne muscular dystrophy
What is Duchenne muscular dystrophy?
X-linked recessive disease that results from the absence of the dystrophin protein
What is dystrophin?
Structural component of the cytoskeleton of skeletal and cardiac cells. ~ helps anchor actin and myosin to the cell membrane
Why does Succinylcholine carry a black box warning?
Risk of cardiac arrest and sudden death secondary to hyperkalemia in children with undiagnosed skeletal muscle myopathy
What are some resp considerations for Duchenne?
Kyphoscoliosis (restrictive lung disease) > decreases FRC (decreased reserve) > increased secretions and risk of pneumonia.
What are some cardiac considerations for Duchenne’s?
Degeneration of cardiac muscle > reduced contractility, papillary musc dysfunction, mitral regurge and CHF
(These pts may have resting tachycardia, JVD, S3/S4 gallop)
**must have cardiac work up before surgery (EKG, ECHO, MRI)
What are some EKG changes you may see with Duchenne’s?
Sinus tach with short PR
Due to scarring, LV manifests as increased R wave amplitude in lead I and deep Q waves
What are some GI considerations for Duchenne’s?
Impaired airway reflexes and GI hypomotility ~ increased risk for aspiration
What is the Cobb angle?
Describes the magnitude of spinal curvature in a patient with scoliosis
What does a Cobb angle of 40-50 indicate?
Surgery
What does a Cobb angle of 60 indicate?
Decreased pulmonary reserve
What does a Cobb angle of 70 indicate?
Pulmonary symptoms present
What does a Cobb angle of 100 indicate?
Gas exchange impairment. Very high risk of post-operative pulmonary complications.
What are some early resp complications with scoliosis?
Restrictive vent defect
FEV1 and FRC are decreased
FEV1/FVC ration = normal
Decreased lung volumes
And decreased chest wall compliance
What are some late resp complications of scoliosis?
V/Q mismatch
Hypoxemia
Hypercarbia
Pulmonary HTN
Cor Pulmonale
What are some cardiovascular changes due to scoliosis?
RV hypertrophy (d/t PHTN)
A vital capacity of what correlates with the requirements for post-op ventilation?
VC < 40%!
What is a “wake up” test?
Method of assessing neurological integrity during complex spine surgery
**turn off agent and allow patient to wake up.
( Risks of wake up include: pain, awareness, air embolism, tracheal extubation, damage to surgical instrumentation, line removal)
What three areas does Rheumatoid Arthritis affect the airway?
Temporomandibular joint (limited mouth opening)
Cricoarytenoid Joints (decrease glottic opening)
Cervical spine (limited neck extension)
What is the most common airway complication of RA?
Atlantoaxial subluxation and separation ~ this ultimately allows the atlanto-odontoid process to compress the spinal cord at the level of the foramen magnum
What is Rheumatoid Arthritis?
Autoimmune disease that targets the synovial joints. In addition, there is infiltration of immune complexes in the small and medium arteries leading to vasculitis.
What is the hallmark of RA?
Stiffness in the morning that generally improves with activity
Primarily affects proximal interphalangeal and metacaepophalangeal joints.
How does RA affect the pulmonary system?
Pleural effusion
Interstitial fibrosis ~ limited chest wall expansion and restrictive vent pattern
how does RA affect the cardiac system?
Pericardial effusion/tamponade
Aortic regurge
Vascular fibrosis
Coronary artery arteritis
How does RA affect the hematological system?
Anemia
Platelet dysfunction (d/t asa)
What labs are increased in RA?
C-reactive cells protein
Erythrocyte sedimentation rate.
(Both labs test for inflammation)
What is the treatment for RA?
Antirheumatics (think methotrexate)
Glucocorticoids
NSAIDS
How does RA affect the renal system?
Insufficiency d/t vasculitis and NSAIDs
How does RA affect the CNS?
Peripheral neuropathy
What is Systemic Lupus Erythematosus?
Autoimmune disease characterized by the proliferation of antinuclear antibodies
Antibody induced vasculitis and tissue destruction
Who does Lupus primarily target?
Young women
How does lupus affect the airway?
Cricoarytenoiditis ~ airway obstruction, stridor, and hoarseness
How does Lupus affect the Nervous system?
Stroke
Psychosis
Neuropathies
How does Lupus affect the kidneys?
Nephritis with proteinuria
How does Lupus affect the pulmonary system?
Restrictive dx process
PHTN
Interstitial lung disease
Pleural effusion
**Recurrent PE
How does Lupus affect your heart?!
Pericarditis
Raynaud’s disease
HTN
Conduction defects
Endocarditis
How does Lupus affect your Hematologic system?
Antiphospholipid antibodies
Hypercoagulability
Anemia
Thrombocytopenia
Leukopenia
What are some things that can exacerbate Lupus symptoms? Think of the mnemonic
PISSED CHIMP
P: pregnancy
I: infection
S: surgery
S: stress
E: enalapril
D: d-penicillamine
C: captopril
H: hydralazine
I: isoniazid
M: methyldopa
P: procainamide
What is the medical treatment for Lupus? Similar to RA
Corticosteroids
NSAIDs
Immunosuppressants (methotrexate, cyclophosphamide)
Antimalarials
Which immunosuppressant increases the duration of succinylcholine? This immunosuppressant is used for both RA and Lupus.
Clycophosphamide
What is the defining characteristic of Marfan’s disease?
Aortic insufficiency
(Also remember AAA)
What is the definitely characteristic of Ehler’s Danlos syndrome?
Bleeding into joints
(Result of poor vessel integrity)
What is the definitely characteristic of osteogenesis imperfecta?
Blue sclera
(Also think weak bones ~ fx can occur from BP or Sux)
What is Multiple Sclerosis?
Demyelination disease of the CNS (can cause sensory, motor and autonomic instability)
Can be exacerbated by stress and hyperthermia
NO sux
What is myotonic dystrophy?
Prolonged contracture following voluntary contracture ~dysfunction in calcium sequestration
What are 3 things that increase the risk of contractures in myotonic dystrophy?
Sux
NMB reversal with anticholinesterases
Hypothermia
What is Scleroderma?
Excessive fibrosis in the skin and organs ~ particularly the microvascular.
What is CREST syndrome?
Type of scleroderma
C: calcinosis
R: Raynaud’s phenomenon
E: esophageal hypomotility
S: sclerodactyly
T: telangiectasia (spider veins)
What is Paget’s disease?
Excessive osteoblastic and osteoclastic activity that causes abnormally thick, but weak, bone deposits
What is Paget’s disease caused by?
Excessive parathyroid hormone or calcitonin deficiency
Pain and fx are the most common problems.
How does scleroderma complicate airway management?
Ski fibrosis > limits mouth opening
Telangiectasis > increases the risk for mucosal bleeding
