Lyrics · 完整歌詞
An acute change in attention
or cognition in an older person warrants prompt assessment for delirium
and its underlying cause.
Delirium is acute and fluctuating, and its core deficit is inattention;
consciousness drifts between drowsiness and agitation and worsens at night.
It almost always has a precipitant: infection, electrolyte disturbance, hypoxia,
drugs or alcohol withdrawal.
Dementia, by contrast, is chronic and steadily progressive,
with attention relatively spared until late.
The first task is therefore to search for the cause,
not to label.
Once a chronic course is established,
the single boundary between mild cognitive impairment
and dementia is impairment of daily activities;
language and executive scores cannot draw it.
Each dementia is a misfolded protein in a particular place.
Alzheimer disease deposits extracellular amyloid-beta plaques and intracellular hyperphosphorylated tau tangles,
so cerebrospinal fluid amyloid-beta 42 falls while phosphorylated tau rises.
Dementia with Lewy bodies combines fluctuating cognition, visual hallucinations,
spontaneous parkinsonism and REM sleep behaviour disorder.
Its striatal dopamine receptors are fragile,
so haloperidol provokes severe parkinsonism or a neuroleptic malignant-like state
and is contraindicated;
low-dose levodopa and cholinesterase inhibitors are used instead.
Normal pressure hydrocephalus impairs gait first, then continence, then cognition,
because the leg fibres beside the ventricles are compressed earliest.
Removing 30 to 50 millilitres of cerebrospinal fluid predicts shunt response.
Every new dementia is screened for B12 deficiency, hypothyroidism and syphilis,
the treatable causes.
An acute change in attention
or cognition in an older person warrants prompt assessment for delirium
and its underlying cause.
Seizure and syncope are separated by their prologue and epilogue.
Syncope follows an autonomic warning and ends in rapid, complete recovery;
a seizure bites the lateral tongue and leaves post-ictal confusion.
Absence seizures show three-hertz spike-and-wave discharges without a post-ictal phase,
and myoclonic jerks usually spare consciousness.
Temporal lobe epilepsy arises from the hippocampus and amygdala,
and bilateral hippocampal resection is forbidden because it abolishes new memory.
Status epilepticus is declared at five minutes.
A benzodiazepine, lorazepam 0.1 mg/kg intravenously or midazolam 10 mg intramuscularly,
comes first because it increases GABA-A channel opening.
Repeating it endlessly fails through respiratory depression and receptor desensitisation, so levetiracetam,
valproate or fosphenytoin follows, and anaesthesia with intubation is the third step.
Images keep their own timetable.
Diffusion-weighted imaging shows cytotoxic oedema within minutes of ischaemia,
whereas FLAIR needs six to twelve hours.
Gradient echo and susceptibility sequences detect microbleeds
and haemosiderin more sensitively than CT.
Raised intracranial pressure declares itself through the Cushing reflex of hypertension,
bradycardia and irregular breathing.
An empty delta sign after contrast marks venous sinus thrombosis in a young woman
on the pill
or in the puerperium.
Under the microscope, proteins name the disease:
alpha-synuclein for Parkinson and Lewy body disease,
TDP-43 and SOD1 rather than tau for amyotrophic lateral sclerosis,
prion protein for spongiform change.
Hypertensive haemorrhage arises deep, from Charcot-Bouchard microaneurysms of the perforating arteries,
whereas amyloid angiopathy deposits amyloid-beta in cortical vessels and bleeds lobar.
Herpes simplex encephalitis shows Cowdry type A inclusions
and haemorrhagic necrosis of the medial temporal lobes,
reached along the trigeminal and olfactory routes.
An acute change in attention
or cognition in an older person warrants prompt assessment for delirium
and its underlying cause.