Emergencies Flashcards
What is neuroleptic malignant syndrome?
Rare but potentially life threatening idiosyncratic reaction to antipsychotic drugs
Thought to be due to central D2 receptor blockade or dopamine depletion leading to impairment of homeostasis
What are the risk factors for developing NMS?
Use of neuroleptic drugs and genetic susceptibility Withdrawal of Parkinson's meds Use of high doses or depot Patient agitation/catatonia High ambient temp and dehydration Previous episode
What are the symptoms of NMS?
Dyspnoea due to hypoventilation caused by muscle rigidity
Dysphagia
Difficulty walking, development of shuffling gait
Seizures, chorea
What are the signs of NMS?
Hyperthermia above 38
Muscular rigidity - lead pipe type
Five of the following to diagnose: Changed mental status Tachycardia Hypotension/hypertension Tremor Incontinence Diaphoresis (excessive sweating) or sialorrhoea - drooling Increased creatine phosphokinase Metabolic acidosis Leukocytosis Exclusion of other illnesses
What are the differentials of NMS?
Dystonic reaction Serotonin syndrome Malignant hyperpyrexia Recreational drug toxicity Lethal catatonia - catatonia with rigidity and raised CK Organophosphate poisoning Heatstroke Encephalitis
What are the investigations for NMS?
FBC - leukocytosis U&Es - metabolic disturbance Hypocalcaemia LFTs CK elevated Coagulation studies Urinary drug screen Consider sepsis - CXR too LP to exclude diagnoses
What is the treatment for NMS?
Airway and breathing need protection
Agitated patients may need IV benzos, avoid restraint
IV fluids for dehydration
Offending drug discontinued
Overdose - activated charcoal
If rhabdomyolysis or AKI - alkalinisation of urine and dialysis
ECT if meds fail
Bromocriptine/dopaminergic agents if severe
What are the complications of NMS?
Cardiac arrest Rhabdomyolysis AKI Seizures Respiratory failure DIC Aspiration pneumonitis Hepatic failure PE
What is serotonin syndrome?
Serotonin toxicity
Drug induced - too much serotonin in the synapses of the brain
What are the most common implicated drugs of serotonin syndrome?
MAOIs
SNRIs
SSRIs
Other causes include antiemetics, recreational drugs, analgesics e.g. tramadol or pethidine
What is the presentation of serotonin syndrome?
Autonomic hyperactivity
Neuromuscular abnormality
Mental status changes
Likely only in the setting of starting or increasing the dose of a potent serotonergic drug
Symptoms usually occur within 6 hours of taking
Tremor, akathisia, diarrhoea early features
What examination signs are found in serotonin syndrome?
Autonomic disturbance - HTN, tachycardia, hyperthermia, hyperactive bowel sounds, sweating
Neuromuscular dysfunction - tremor, clonus, hypertonicity, hyperreflexia
Altered mental state - anxiety, agitation, confusion, coma
What are the differentials of serotonin syndrome?
Malignant hyperthermia NMS Anticholinergic poisoning Catatonia Dystonia Hyperthyroidism Tetanus Delirium tremens Encephalitis, meningitis
What are the investigations for serotonin syndrome?
Check U&Es, CK
Toxicology screen
FBC, blood culture, LFT
CXR, CT, LP fever/altered mental state, resp comp
What is the management of serotonin syndrome?
Likely causative drug stopped
Refer those with MAOI or SSRI and severe symptoms to hospital
Activated charcoal if overdose
Supportive measures e.g. iV fluids, benzos for agitation
What are the complications of serotonin syndrome?
Hyperthermia can lead to metabolic acidosis, rhabdomyolysis, AKI, DIC
Temp over 40.5 - paralysis, ventilation, ice bath
Seizures
Aspiration pneumonia
Respiratory failure
What is an acute dystonic reaction?
Characterised by involuntary contractions of muscles of the extremities, face, neck, abdomen, pelvis or larynx.
Leads to abnormal movements or postures.
Symptoms may be reversible or irreversible
Usually occur shortly after initiation of an offending agent
What drugs commonly cause an acute dystonic reaction?
Antipsychotics
Antiemetics
What can be the presentation of acute dystonic reactions?
Buccolingual crisis - trismus, dysarthria, dysphagia, tongue protrusion
Oculogyric - spasm of extraocular muscles
Torticolic crisis - abnormal asymmetric head or neck position
Tortipelvic - abnormal contractions of abdominal wall, hip, pelvic musculature
Laryngeal dystonia - dysphonia, stridor
Pseudomacroglossia - sensation of tongue swelling and protrusion
What is the management of acute dystonic reaction?
Balance disrupted dopaminergic-cholinergic balance in basal ganglia
Discontinue offending agent
Diphenhydramine and benztropine, IV
Supportive measures e.g. oxygen, assisted ventilation if indicated
What levels of lithium are associated with toxicity?
> 1.5, >2 may be associated with serious toxicity
Also be suspected at therapeutic levels in compromised patients with relevant symptoms
Why might lithium toxicity occur?
Intentional overdose
Chronic treatment due to reduced drug excretion - dehydration, worsening renal function, concurrent infections, drug interactions
What are some of the findings in lithium toxicity?
Anorexia, diarrhoea and vomiting.
Drowsiness, apathy, restlessness.
Dysarthria.
Dizziness, ataxia, inco-ordination, muscle twitching, coarse tremor.
What are some of the findings in severe toxicity of lithium?
Hyperreflexia, convulsions. Collapse, coma. Renal failure, dehydration, circulatory collapse (may need haemodialysis). Hypokalaemia. Death.
T wave inversion potentially
What is the treatment for toxicity?
Stop lithium, check level and refer for urgent assessment (encourage fluids, stop diuretics, monitor electrolytes and monitor renal function).
If severe, admit as emergency and whole bowel irrigation may be considered if large quantities have been ingested
What is drug induced (clozapine) agranulocytosis?
Potentially life threatening reaction, characterised by profound decrease in neutrophil count and susceptibility to infection
What defines agranulocytosis?
A neutrophil count of less than 0.5 x 10 ^ 9 / L
What monitoring is required for clozapine?
Close monitoring of FBC -weekly for 18 weeks, then fortnightly for up to a year, then monthly
What is the treatment of agranulocytosis?
Stop clozapine
Stop any other potentially marrow suppressing drugs e.g. sodium valproate
Avoid other antipsychotics for a couple of weeks where possible
Contact consultant haem as an amaergency
Avoid sources of infection, consider prophylactic broad-spectrum antibiotics
Lithium can be used to increase WCC and neutrophil count
Granulocyte colony stimulating factor can be used
What are the symptoms of agranulocytosis?
May be asymptomatic
Sudden fever, rigors, sore throat
Infection of any organ or sepsis may be rapid
