Delirium Flashcards
MOA of aciclovir
An antiviral (guanine analogue). Guanine analogues inhibit viral DNA polymerase and DNA synthesis.
Aciclovir indications
Treatment and prevention of HSV infections, shingles, acute chickenpox.
Aciclovir adverse effects
Encephalopathy, hallucinations, headache, injection site reactions, nephrotoxicity
MOA of levetiracetam (keppra)
Exact mechanism unknown. May modulate neurotransmission by binding to synaptic vesicle protein 2A.
Levetiracetam is only covered by PBS if used:
as a second-line treatment
Adverse effects of levetiracetam
Behavioural changes, drowsiness, weakness, vertigo, insomnia
Major causes of delirium (MNEMONIC)
I WATCH DEATH
Infection
Withdrawal
Acute metabolic disorder
Trauma
CNS pathology
Hypoxia
Deficiencies
Endocrine
Acute vascular
Toxins/drugs
Heavy metals
Drugs/toxins that are associated with delirium include:
Anticholinergics
Benzodiazepines
Antihistamines (in older patients)
Opioids
Recreational drugs
Alcohol use disorder
Heavy metals
Metabolic causes of delirium include:
Liver or renal failure
Diabetic ketoacidosis
Hyper/hypothyroidism
Electrolyte abnormalities
Vitamin deficiencies (B12, folic acid, thiamine)
Delirium features of onset
Sudden. Prodromal phase may proceed.
Delirium time course
Rapid and fluctuating. Hours to days.
Delirium level of consciousness
Impaired (fluctuating)
Delirium effect on attention
Impaired (fluctuating)
Memory changes in delirium
Recent memory loss
Delirium effects on thought process
Disorganised
Delirium and hallucinations
Present - often visual or tactile.
Delirium and psychomotor activity
Psychomotor activity is altered (increased or decreased)
Delirium reversibility
Delirium is a reversible condition.
Delirium definition
Acute, reversible alteration in the level of awareness and attention.
Concerning intracranial features of a patient with delirium
History of trauma
Focal neurological symptoms
Seizure
Fever with headache or meningismus
Diagnostic studies for delirium of a suspected intracranial aetiology
Neuroimaging (CT/MRI head)
EEG (shows diffuse slowing of background activity in patients with delirium
Lumbar puncture and CSF analysis
Concerning pulmonary features in a patient with delirium
Fever with cough or shortness of breath
Risk factors for aspiration pneumonia
Diagnostic studies for delirium of a suspected pulmonary aetiology
CXR
Concerning cardiovascular features in a patient with delirium
Abnormal haemodynamics
Chest pain
Worsening peripheral oedema and/or shortness of breath
Diagnostic studies for delirium of a suspected cardiovascular aetiology
ECG
Echocardiogram
Concerning features in a patient with delirium suggestive of a nutritional aetiology include:
Hx of heavy drinking
Malabsorptive disorders
Malnutrition
Diagnostic studies for delirium of a suspected nutritional aetiology
Vit. B12, folate and thiamine levels
Concerning features in a patient with delirium suggestive of a toxic aetiology include:
Hx of alcohol or recreational drug use
Suspicion of CO poisoning
Diagnostic studies for delirium of a suspected toxic aetiology
Consider urine toxicology or serum drug levels
Concerning features in a patient with delirium suggestive of an infectious aetiology include:
Fever
RFs for blood borne diseases or STIs
Diagnostic studies for delirium of a suspected infectious aetiology
Bacterial cultures (urine, blood)
Serum lactate
HIV, syphilis serology
First-line investigations in the diagnosis of delirium include:
CBE
Serum glucose
Electrolytes
Urinalysis
The most common causative pathogens in encephalitis are:
- Herpes simplex virus
- Varicella zoster virus
All patients with suspected encephalitis should undergo the following investigations:
Neuroimaging (MRI brain with contrast)
Lumbar puncture with CSF analysis
EEG
What is the pathognomonic sign of HSV encephalitis?
Bilateral temporal lobe involvement on imaging.
CSF analysis in the setting of encephalitis includes:
PCR, gram stain and cultures
The gold-standard diagnostic test for HSV encephalitis is:
CSF PCR for HSV-1 and HSV-2 (allows for early detection of pathogen and targeted treatment)
CSF findings in HSV encephalitis
Increased lymphocytes (lymphocytic pleocytosis)
Normal or increased opening pressure
Normal to mildly increased lactate
Mild protein elevation
Normal glucose
Common focal neurological deficits for encephalopathy affecting the medial temporal lobe include:
Altered sense of smell
Loss of vision
Aphasia
Memory loss
Hemiparesis
Ataxia
Hyperreflexia
The most common strain of HSV implicated in adult viral encephalitis is:
HSV-1
Patients with suspected viral encephalitis should begin empiric therapy immediately with:
aciclovir
When administering IV aciclovir patients should be monitored for:
Nephrotoxicity. Manage with adequate hydration and adjust doses for renal function.
Prognosis of HSV encephalitis
Fatal in up to 70% of cases if left untreated.
Examination features of viral encephalitis
Fever
Vesicular rash
Focal neurological deficits
Meningismus (neck stiffness, Kernig’s sign, Brudzinski’s sign)
Electrolyte disturbances associated with delirium include:
Hypernatraemia
Hyponatraemia
Hypercalcaemia
Anticholinergics mechanism of action
Block the neurotransmitter Ach in the central and peripheral nervous system. Most anticholinergics are muscarinic antagonists which inhibit the effect of Ach on muscarinic receptors.
Side effects of anticholinergics
Mydriasis
Delirium
Flushing
Hyperthermia
Decreased secretions/dry skin
Urinary retention
Paralytic ileus
Tachycardia
MNEMONIC: BLIND as a bat (mydriasis), MAD as a hatter (delirium), RED as a beet (flushing), HOT as a hare (hyperthermia), DRY as a bone (decreased secretions), the bowel and bladder lose their TONE (urinary retention/paralytic ileus) and the heart runs ALONE (tachycardia)
The mainstay of delirium treatment is:
Treatment of the underlying condition and supportive care. Consider discontinuing causative medications e.g. anticholinergics.
Maintain adequate hydration.
Indications for pharmacological management of delirium
Patient is in significant distress or considered to be a threat to themselves/others.
The following drugs can be used in the pharmacological management of delirium (as a last resort)
Haloperidol
Olanzapine
Risperidone
