Consultation-Liaison Psychiatry, Organic Psychiatry and Psychosomatic Medicine
What the exam tests
Liaison items test recognition of organic causes, delirium, catatonia, capacity and drug interactions in medically ill patients. Psychiatric symptoms are often the first sign of a physical disorder.
Core rules
- Delirium is a medical emergency; assess attention, fluctuation, drugs, infection, hypoxia, pain and metabolic status.
- Catatonia presents with stupor, rigidity, negativism, posturing or waxy flexibility; benzodiazepines and ECT are treatments.
- Capacity is decision-specific: understand, retain, weigh and communicate a choice.
- Adjust psychotropics in renal and hepatic failure; avoid anticholinergics in older adults and in delirium.
- Serotonin syndrome causes clonus, hyperreflexia, agitation, fever and diarrhoea after serotonergic drugs; stop the agent and give supportive care.
- Neuroleptic malignant syndrome causes lead-pipe rigidity, fever, autonomic instability and raised creatine kinase; stop antipsychotics and treat urgently.
Worked example
A postoperative patient on an SSRI receives tramadol and develops agitation, sweating, tremor, hyperreflexia and clonus. This is serotonin syndrome, not anxiety. The reasoning is rapid onset after adding a serotonergic drug, with neuromuscular hyperactivity. Stop the serotonergic agents, monitor, cool and treat complications; avoid antipsychotics as the first response.
Traps that cost marks
Do not attribute new confusion to 'stress' without examining for delirium. Do not miss serotonin syndrome because the patient is agitated. Do not confuse NMS with serotonin syndrome: NMS has rigidity and bradyreflexia, serotonin syndrome has clonus and hyperreflexia. Do not assume capacity from a single conversation.