Flashcards in 14. Neuromuscular Disease Deck (40)
damage or disease involving fibers of the nervous system. may affect sensation, movement, gland or organ function.
a muscular disease in which the muscle fibers do not function for any one of many reasons, resulting in muscular weakness.
connects the nervous system to the muscular system via synapses between efferent nerve fibers and muscle fibers, also known as muscle cells.
"dying back" neuropathy
neuropathy affecting distal neurons first; toxins or metabolic deficiencies can affect longest nerve fibers first because longer nerve fibers require more energy to maintain functin, and because there is a greater opportunity to injure a longer nerver fiber
a process that results when a nerve fiber is cut or crushed, in which the part of the axon separated from the neuron's cell body degenerates distal to the injury
The epineurium is the outermost layer of dense irregular connective tissue surrounding a peripheral nerve. It usually surrounds multiple nerve fascicles as well as blood vessels which supply the nerve. Smaller branches of these blood vessels penetrate into the perineurium.
In the peripheral nervous system, nerve fibers are each wrapped in a protective sheath known as the endoneurium. These are bundled together into groups known as fascicles, each surrounded by a protective sheath known as the perineurium
The endoneurium is a layer of delicate connective tissue made up of endoneurial cells that encloses the myelin sheath of a spinal cord nerve fiber.
glial cells of the PNS
compression of a nerve resulting in myelin disruption. could be due to mechanical abnormalities or swelling of tissues
where is a common site for an entrapment neuropathy?
lateral femoral cutaneous neuropathy
aka meralgia paresthetica, entrapment between ilium and inguinal ligament.
other sites of compression neuropathies?
ulnar passing behind the epicondyle, deep branch of the ulnar passing wrist, radial nerve at spiral groove of upper arm, peroneal nerve at head of fibula, lateral femoral cutaneous.
what nerves make up the lateral femoral cutaneous?
what is a result of lateral femoral cutaneous entrapment?
numbness, burning pain on lateral thigh.
Polyneuropathy is a serious, unpredictable, occasionally progressive, and life threatening neurological disorder that occurs when many nerves throughout the body malfunction simultaneously.
Charcot Marie Tooth disease
Charcot–Marie–Tooth disease (CMT), also known as Charcot–Marie–Tooth neuropathy, is a genetically and clinically heterogeneous group of inherited disorders of the peripheral nervous system characterised by progressive loss of muscle tissue and touch sensation across various parts of the body.
Lambert-Eaton myasthenic syndrome: cause?
due to antibodies against the VG calcium channels in the terminals of motor nerves. Ca entry into these terminals is needed for release of Ach. produces weakness, diminished reflexes and autonomic dysfunction
associated with cancer. consequence of cancer being in body but not directly related to local cancer cells.
example of a paraneoplastic sx?
autoimmune sx in which antibodies exist against the Ach receptor. means that nerve is unable to activate the muscle.
nerve conduction studies do what?
evaluate the speed of nerve conduction and amount of nerve signal that gets through. can test both sensory and motor.
assesses electrical activity of muscle fibers, evaluates health of muscles, can detect muscle fibers that have been denervated.
large peripheral nerve fibers convey what?
localized touch, pressure, vibration, joint pressure sense
small nerve fibers convey what?
pain, touch, temp, autonomic
what are a few causes of polyneuropathy?
infection, diabetes, nutritional prob, alcohol, toxins, meds, hereditary, inflammatory
what is a hereditary cause of polyneuropathy
with polyneuropathy, what reflex is detected early
ankle jerk reflex
what is a common pattern of polyneuropathy?
distal, symmetrical sensory loss (stocking/glove)
a few causes of myopathies?
metabolic, infectious, inflammatory, genetic, drug, toxin
myopathies usually result in what?
proximal and symmetrical weakness (hip, shoulder) and then move on to more distal muscles
reflexes in myopathies?
reflexes are preseved until very late in disease
sensation in myopathies?
no sensory loss. muscles may be tender/cramp
myasthenia gravis: most commonly what population?
young females, old males
fatigued muscles, due to damage to Ach receptors by antibody
myasthenia: how affect resp?
may affect diaphragm, other resp muscles
AchE inhibitors, immunosuppressives
Lambert-Eaton: weakness where?
hip girdle muscles, decr patellar reflexes
sometimes small cell cancer, can also be idiopathic