5.2.6 Working knowledge of medicine

Working Knowledge of Medicine Including Physical Examination, Diagnosis, Investigation and Treatment of Common Conditions

Physical examination and diagnosis:

Examination of the patient’s physical state is a key part of any psychiatric assessment. A number of reasons why:

• Physical symptoms may be directly related to the psychiatric illness in question
  • Medical complications of alcohol dependency
  • Anorexia nervosa
  • Physical neglect in depression or schizophrenia
• Psychiatric medications are well known to have physical side effects
  • EPSEs from antipsychotics
  • Hypothyroidism
  • Lithium
  • Metabolic syndromes
  • Withdrawal syndromes
• Physical ailments can cause or worsen psychiatric symptoms
• Beneficial to have a physical health baseline recorded in case of future illness (or medico-legal issues)

Investigations

Clinical investigations, such as blood tests, imaging methods, and karyotyping, are less common in psychiatry than in other medical specialities. The general purpose they are carried out is to rule out of pathologies that may be part of the differential diagnosis (ie. hypothyroidism as a cause of depression and lethargy). Ideally, they should be a result of positive findings from the history of physical examination.

Basic investigations such as the FBC, LFTs, U&Es, and TFTs should be performed to assess general physical health and provide a baseline measure prior to commencing medication that can be known to have an adverse effect.

Other more invasive investigations are rarely requested. A lumbar puncture, for example, is reserved for situations where there is clear evidence to suspect a neurological disorder presenting with psychiatric symptoms e.g. meningitis, encephalitis, or multiple sclerosis. More often than not at this point, a referral will be made for medical input.

Imaging tools such as EEG, CT, MRI, SPECT, or PET require a clear rationale for their diagnostic need. It is often cited that EEG is overused by psychiatrists due to its difficulty to interpret especially since many psychotropic medications can interfere with the result. EEG may be useful upon suspicion of epilepsy, to assess atypical patterns of cognitive impairment, to investigate sleep disorders, or to aid in specific dementia diagnoses (HIV, vCJD). EEG is the gold standard for monitoring seizure activity during ECT. EEG should not be used as a screening tool. Cranial imaging adds little to primary psychiatric diagnosis unless there are suspected neurological problems such as prior head injury history, epilepsy, neurosurgery, or suspicion of a space-occupying lesion (localizing neurological signs, fluctuating consciousness level, severe headache, and marked or unexplained acute behavioural change).

The sensitivity and specificity of imaging findings for the majority of psychiatric disorders have yet to be established.

ECG and psychiatry medications:

ECG findings:	Associated medication:
Tachycardia	Clozapine TCAs MAOIs Antiparkinsonian Antipsychotics (generally the older ones)
Bradycardia	SSRIs Lithium Cholinesterase inhibitors
Heart blocks	TCAs
Repolarisation changes (ST segment & T wave changes)	Thioridazine Chlorpromazine
QTc prolongation	Wide range of antipsychotics and antidepressants
Torsades/VF	Haloperidol Thioridazine Mesoridazine Chlorpromazine

References:

(1) Semple, D. and Smyth, R. (2019). Psychiatric assessment. Oxford Handbook of Psychiatry, [online] pp.45–98. doi:10.1093/med/9780198795551.003.0002.