Psychiatric Emergencies

Question 1

What is the aetiology of NMS?

Answer 1

NMS is commonly due to antipsychotic medications, particularly FGA (e.g haloperidol).

Symptoms arise due to blockage of D2 receptors in the nigrostriatal pathway and hypothalamus.

Question 2

Clinical symptoms of NMS?

Answer 2

F - fever
A - autonomic dysfunction (eg. labile BP, tachycardia)
L - leukocytosis
T - tremour and ataxia
E - elevated enzymes (CK and transaminases)
R - rigours

Symptoms usually develop 10-14 days after commencement of medication.

Question 3

Investigations for NMS.

Answer 3

• urine toxicology screen
• blood glucose levels
• FBC
• Inflammatory markers
• UECs
• LFTs
• CK
• ECG
• ABG

Question 4

Management of NMS.

Answer 4

1. Primary survey —> ABCDE
2. Cessation of offending agent
3. Supportive measures (eg. ice packs, cooling agents)
4. Pharmacotherapy:
   - daltrolene —> inhibits release of Ca++ from sarcoplasmic reticulum, thus preventing rigours and muscle contraction / spasticity
   - bromocriptime —> D2 receptor agonist

Question 5

What is the aetiology of SEROTONIN SYNDROME?

Answer 5

Serotonin syndrome is often caused by concurrent use of multiple serotonergic medications. This includes:

• SSRIs
• SNRIs
• TCAs
• MAO inhibitors

It can also occur when there is a change in medication without appropriate tapering.

Question 6

Clinical symptoms of serotonin syndrome?

Answer 6

H - hyperthermia
A - autonomic instability
R - raised blood pressure
M - myoclonus + rigidity + increased reflexes

SS typically comes on within 24 hours (much more acute compared to NMS).

Question 7

Investigations for SS?

Answer 7

Investigation findings for SS will be non-specific.

Investigations may include:

• FBC
• Inflammatory markers
• UECs
• LFTs
• CK
• ECG
• ABG

Question 8

Management for SS?

Answer 8

1. Primary survey —> ABCDE
2. Cessation of offending agent
3. Supportive measures (eg. ice packs, cooling agents)
4. Pharmacotherapy:
   - cyproheptadine —> anti histamine with anti-serotonin properties at high doses

Question 9

PARACETAMOL OVERDOSE

• maximum dose
• clinical presentation
• key investigations
• management

Answer 9

MAXIMUM DOSE - 4g / day (note that 10g / day is considered the “overdose” amount)

CLINICAL PRESENTATION:
Day 0-1 —> asymptomatic, non-specific N+V
Day 1-2 —> RUQ pain, jaundice, N+V
Day 3-4 —> fulminant hepatic failure (encephalopathy, coagulopathy, bruising)

NB LFTs should return to normal within 3 months.

KEY INVESTIGATIONS 
✔️ serum paracetamol levels at presentation and four hours
✔️ FBC and WCC
✔️ inflammatory markers
✔️ UECs
✔️ LFTs
✔️ coags
✔️ urine toxicology screen

ANTIDOTE - N-acetyl-cystine (NAC)
✔️ give if plasma paractamol levels > 153 mg / L at any time or if serum levels are above normal at 4 hours

Question 10

OPIOID OVERDOSE

• maximum dose
• clinical presentation
• key investigations
• management

Answer 10

MAXIMUM DOSE - variable; depends on previous exposure, body mass, drug interactions etc.

PRESENTATION - clinical triad of

1. reduced GCS
2. respiratory depression
3. pinpoint pupils

KEY INVESTIGATIONS
✔️ vital signs (particularly respiratory rate and O2 %)
✔️ FBC and WCC
✔️ UECs and LFTs
✔️ coags
✔️ urine + blood toxicology screen

ANTIDOTE - naloxone IM or IV (acts as a complete opioid receptor antagonist)

Question 11

TRICYCLIC ANTIDEPRESSANT OVERDOSE

• maximum dose
• clinical presentation
• key investigations
• management

Answer 11

MAXIMUM DOSE - 10mg / kg per day is potentially life-threatening
✔️ >30mg / kg per day can cause severe cardio toxicity and coma for > 24 hours

CLINICAL PRESENTATION
1. Anticholinergic effects
✔️ blurred vision
✔️ dilated pupils
✔️ urinary and feacal retention
✔️ dry mouth
✔️ myoclonic jerks

2. Reduced catecholamine uptake
   ✔️ postural hypotension
   ✔️ tachycardia
3. Inhibition of fast Na+ channels
   ✔️ arrythmia
   ✔️ widening of QRS complexes
   ✔️ broad complex tachycardia

4 CNS side effects
✔️ sedation and coma
✔️ seizure
✔️ delirium

KEY INVESTIGATIONS
✔️ FBC and WCC
✔️ inflammatory markers
✔️ UECs and LFTs
✔️ lipids
✔️ coags
✔️ TFTs
✔️ lipase + amylase

MANAGEMENT

• If presentation is within 60 mins –> gastric leverage and charcoal
• If presentation is < 60 mins –> give IV sodium bicarbonate to maintain pH > 7.5