Neuro Flashcards
Hypo vs hyperkalemic periodic paralysis?
what is cushing reflex?
hypertension (wide pulse pressure)
bradycardia
irregular breathing
what is the scoring for gcs?
severity of TBI based on GCS?
how to treat a myasthenia gravis flare?
Treatment includes cholinesterase inhibitors, corticosteroids, immunosuppressant agents, intravenous immunoglobulin (IVIG), and plasmapheresis.
what factors increase the risk of postoperative ventilation needs in patient’s with myasthenia gravis?
Also duration of MG has the greatest influence
transcranial doppler for carotid endarterectomy..what percent flow of preclamp to avoid ischemia? mild-mod? Severe?
The mean flow velocity following clamping of the carotid artery during CEA correlates with the degree of cerebral ischemia. Ischemia is generally absent if TCD shows a mean flow velocity >40% of the preclamped value, is mild to moderate if 15-40% of the preclamped value, and is severe if < 15% of the preclamped value.
what is myotonic dystrophy?
Concerns for anesthesia?
Myotonic dystrophy is an autosomal dominant inherited disorder of the neuromuscular junction characterized by progressive muscle weakness and wasting which is most prominent in the cranial and distal limb musculature. Cranial muscle weakness presents in the facial, temporalis, masseter, sternocleidomastoid muscles, and possibly the vocal cord apparatus. These patients are at increased risk for myotonia, which is a prolonged contraction with delay of relaxation of the musculature. Myotonic dystrophy is also associated with cardiac conduction disorders, progressive myopathy, insulin resistance, neuropsychiatric impairment, and cataracts. In the perioperative period, myotonic dystrophy patients are more likely to suffer from pulmonary related complications especially when severe disease is present or they are undergoing upper abdominal procedures. Preoperative evaluation of these patients must include thorough examination of the pulmonary and cardiac systems.
Preoperative testing should include an electrocardiogram and echocardiography (A, B). If any conduction abnormality is present on electrocardiogram, a cardiology consultation should be obtained as these patients often have unpredictable and rapid progression of AV conduction disease. Pacemaker placement may be considered even if only first degree heart block is present (C). If second or third degree heart block is present, pacemaker implantation is warranted. Because of the elevated risk of cardiomyopathy and cardiac conduction defects, these patients need to have careful perioperative cardiac monitoring with the capability to provide external pacing should it be required. In addition, a chest radiograph may be obtained if the patient has acute symptoms of pulmonary disease.
Succinylcholine use may result in contractions that last several minutes, making ventilation and intubation challenging. These contractions are not antagonized by prophylactic administration of a nondepolarizing muscle relaxant, thus succinylcholine should be avoided and short acting nondepolarizing agents, or no muscle relaxants at all, should be used. These patients can be quite sensitive to anesthetic agents thus careful titration of short-acting anesthetics is recommended. Additionally, several medications (methohexital, etomidate, propofol, neostigmine), hypothermia, shivering and mechanical or electrical stimulation may induce myotonic reactions. Because of the elevated risk of cardiomyopathy and cardiac conduction defects, these patients need to have careful perioperative cardiac monitoring with the capability to provide external pacing should it be required. Also, one-third of these patients who develop AV block will not respond to atropine.
Because of the increased risk of myotonic contractions, patients with myotonic dystrophy may have findings similar to those found during a MH crisis, such as elevated metabolism and rhabdomyolysis. Avoidance of succinylcholine is advocated regardless because it increases the risk of prolonged contraction and difficulty with airway management.
what condition is commonly associated with small cell lung cancer?
This patient most likely has Lambert-Eaton myasthenic syndrome (LEMS), which is commonly associated with small cell lung cancer. The symptoms are caused by the production of IgG antibodies to the voltage gated Ca2+ channels in the presynaptic neuron of the neuromuscular junction (A). This leads to decreased release of acetylcholine and therefore weakness. The weakness, however does improve with repetition because more acetylcholine is released.
this is also called myasthenic crisis
what happens to patient with myasthenia gravis and NDMB and deploarizing NMB?
Myasthenic crisis?
Patients with myasthenic syndrome are more sensitive to both succinylcholine and non-depolarizing neuromuscular blockers. Patients with myasthenia gravis are resistant to succinylcholine and sensitive to non-depolarizing neuromuscular blockers.
