Lyrics · 完整歌詞
Weakness, seizures and altered consciousness describe clinical presentations rather than diagnoses;
anatomical localisation helps narrow the mechanisms that could account for them.
Synapse, muscle, peripheral or central myelin, meninges,
parenchyma and the immature brain each fail in their own way,
and the level decides name, treatment and prognosis.
Neuromuscular transmission has two steps:
calcium enters through presynaptic P/Q-type channels to release acetylcholine,
which then opens postsynaptic nicotinic receptors.
Myasthenia gravis attacks the postsynaptic receptor,
so each burst of acetylcholine finds too few targets
and strength fatigues with use.
It associates with thymoma,
decrements on low-frequency stimulation and responds to pyridostigmine and thymectomy.
Lambert-Eaton syndrome attacks the presynaptic calcium channel,
so release is scant at rest but calcium accumulates with repetition
and strength improves with use.
Reflexes return after exercise, high-frequency stimulation increments,
and small-cell lung cancer is the usual companion.
Weakness, seizures and altered consciousness describe clinical presentations rather than diagnoses;
anatomical localisation helps narrow the mechanisms that could account for them.
Muscle itself fails in Duchenne dystrophy,
an X-linked loss of dystrophin with calf pseudohypertrophy
and a very high creatine kinase;
myotonic dystrophy is dominant, distal and facial.
Guillain-Barré syndrome arises one to three weeks after Campylobacter
or a respiratory infection,
when antibodies raised against microbial lipo-oligosaccharide cross-react with gangliosides on peripheral myelin.
Weakness ascends symmetrically and reflexes vanish.
Vital capacity is measured serially,
because diaphragmatic failure is the main cause of death.
Immunoglobulin or plasma exchange treats it; corticosteroids alone do not.
Multiple sclerosis is central demyelination in which T
and B cells cross the blood-brain barrier to attack oligodendrocytes.
Optic neuritis is a common first attack,
and heat worsens symptoms in Uhthoff's phenomenon.
Periventricular ovoid plaques,
oligoclonal bands and dissemination in time and space satisfy the McDonald criteria.
A relapse takes intravenous methylprednisolone, disease-modifying therapy reduces relapses,
and cognitive impairment affects around half of patients.
Cerebrospinal fluid separates the infections of the meninges and brain.
Bacterial meningitis gives neutrophils, low glucose and high protein.
After blood cultures, vancomycin with a third-generation cephalosporin follows at once,
with ampicillin for Listeria after fifty and dexamethasone alongside.
Viral meningitis gives lymphocytes with normal glucose,
tuberculous meningitis lymphocytes with very low glucose and very high protein.
Herpes simplex encephalitis attacks the medial temporal lobes with fever,
seizures and personality change, and aciclovir starts before the PCR returns,
because each hour of delay worsens outcome.
A brain abscess enhances in a ring like glioblastoma,
but its pus restricts diffusion,
so the centre is bright rather than dark on diffusion imaging.
Weakness, seizures and altered consciousness describe clinical presentations rather than diagnoses;
anatomical localisation helps narrow the mechanisms that could account for them.