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Feature Presentation Delirium Dementia Mania Depression Schizophrenia Anxiety states Personality disorder Onset Abrupt Chronic Can be acute Subacute Insidious Chronic or acute in context of major stressor Chronic with acute exacerbation of symptoms and/or decompensation in context of stressors Delusions Persecutory; fleeting, changeable, poorly formed; first-rank symptoms uncommon Delusions can develop, generally late-stage, simple and persecutory Grandiose, ‘mood congruent’ Nihilistic or persecutory ‘mood congruent’ Fixed, false system of beliefs with complex logical structure; ‘first-rank symptoms’ Absent Although can have ‘overvalued ideas’, true delusions absent Hallucinations Predominantly visual Both auditory and visual can occur in later disease (visual common in Lewy body dementia) If present, generally auditory and ‘mood congruent’ If present, generally auditory, ‘mood congruent’ Auditory hallucination core feature, especially ‘third person’ Absent Not true hallucinations; ‘pseudohallucinations’ Attention and/or working memory Impaired Relatively normal until advanced stages Distractible, but attentional impairment less pronounced than delirium Minimal impairment, although poor motivation can result in poor performance on assessment Relatively intact Intact Intact Arousal Abnormal: hypoalert or hyperalert Relatively normal Hyperalert May be hypoalert Relatively normal or mildly hyperalert Relatively normal or hyperalert in panic Normal or mildly hyperalert Orientation Generally disorientated to time and often place Disorientated in advanced cases Orientated Orientated Orientated Orientated Orientated Episodic memory Impaired Impaired, temporal gradient to memory loss Relatively intact Selective or patchy impairment, might complain about memory impairment Relatively intact Intact Intact Motor activity Increased or decreased Varies, often normal Increased Generally decreased Generally fairly normal, although might be apathetic and can be catatonic Often increased Normal unless acutely agitated Affect Labile, although might be fearful or seem depressed Variable Elevated mood, although might be irritable and labile Sustained low mood Perplexed Anxious Anger Speech Slow and/or rapid, incoherent Word finding difficulty but reasonably coherent until late stage Pressured, ‘flight of ideas’ Slowed, monotonous Disjointed, ‘loosening of association’ Relatively normal, might be slightly pressured Normal Sleep–wake cycle Very disturbed, cycle can be reversed Some fragmentation Reduced sleep without sleepiness Disturbed, often early-morning wakening Relatively normal, although sleep-phase disorders common (especially delayed) Initial insomnia characteristic Relatively normal Course Fluctuating, lucid intervals can mislead Stable from day to day Alternate between elation and irritability Diurnal variation in mood, worst in morning Stable once established with deterioration generally consequent to medication non-compliance Stable with potential episodes of panic Stable ↵aLewy body dementia poses particular difficulties in distinguishing from delirium given that visual hallucinations are prominent, the course is fluctuating and consciousness can be impaired.
Insult Presentation How to detect Modest insults in context of vulnerable brain Hypoactive, hyperactive or mixed delirium Core features of delirium; presence of vulnerability factors (eg dementia, brain injury) Non-convulsive status Episodic confusion with sudden onset EEG; history of epilepsy; vigilance to motor symptoms Alcohol withdrawal/delirium tremens Hyperactive delirium; sympathetic activation (tachycardia, sweating etc); visual hallucinations Alcohol history; abnormal LFTs/MCV Wernicke’s encephalopathy Can occur in absence of alcohol withdrawal; ophthalmoplegia or ataxia might be present Characteristic MRI changes (diencephalic hyperintensities on T2-weighted MRI) specific but not sensitive; response to Pabrinex® Benzodiazepine or other sedative withdrawal Similar to alcohol withdrawal History of sedative abuse Medication adverse effects Very common precipitant. Can present as sedated, but delirium can take various forms. Visual hallucinations can be particularly common with anticholinergic drugs Be particularly vigilant for medications with anticholinergic effects and opiates Recreational drug intoxication Depends on actions of drug: nystagmus common, stimulants likely associated with sympathomimetic effects and hyperactive delirium Drug screen, but will not detect novel psychoactive substances; collateral history Constipation and/or faecal impaction May be no overt symptoms; abdominal pain Nursing records of bowel movements; abdominal and PR examination; abdominal X-ray Sleep deprivation History of sleep disorder (eg sleep apnoea) History of disturbed sleep; polysomnography (sleep study) EEG = electroencephalography; LFTs = liver function tests; MCV = mean corpuscular volume; MRI = magnetic resonance imaging; PR = per rectal
- Table 3.
Situations in which brain imaging is mandatory, with magnetic resonance imaging generally being preferred modality
Symptom or sign Why imaging mandatory Localising signs on neurological exam Identify focal pathology and/or exclude space-occupying lesion New-onset seizures Identify focal pathology and/or exclude space-occupying lesion Cognitive impairment excessive and/or atypical for psychiatric condition (and not explained by delirium, intoxication, etc) Assist in identification of potential neurological or degenerative cause Possible encephalitis (eg pyrexia, headache, seizures, cognitive impairment) Visualise inflammation, assist in exclusion of other potential causes of symptoms Possible fall, cognitive impairment, vulnerability factors such as anticoagulation or alcoholism Exclude subdural haematoma Indication Investigation Rationale Routine screening for first psychiatric presentations Full blood count, urea and electrolytes, calcium, phosphate, liver function tests (including GGT), thyroid function tests, ESR, glucose, urine dipstick, drug screen, chest X-ray if respiratory symptoms; BP, pulse, temperature Exclude obvious causes of delirium, increase chances of detection of relevant general medical condition B 12 and folate levels Reversible causes of dementia; B 12 deficiency can present with psychosis Localising signs Imaging (CT or MRI) Exclude space-occupying lesion or parenchymal brain damage Cognitive impairment prominent or psychiatric presentation has atypical features (eg age of onset of psychosis, very changeable and/or fluctuating presentation etc); overt neurological symptoms such as movement disorder or seizures 4-h temperature readings Assist detection of infection, especially HSV or other viral encephalitis c Imaging, likely MRI Exclude space-occupying lesion, identify generalised or localised atrophy, vascular damage, oedema and/or inflammation etc HIV and syphilis serology Exclude these infectious agents (part of routine screen in some centres) Consider EEG Identify seizure activity, could help to identify delirium ANA; if justified clinically also RF, anti-SSA, anti-SSB, p-ANCA and c-ANCA Detection of CNS vasculitis (ESR can be normal) Consider LP and CSF analysis, testing for HSV etc If justified on basis of possible of infective or autoimmune encephalitis Serum (and ideally CSF) autoantibodies associated with autoimmune encephalitis: most commonly associated with ‘psychiatric’ presentation are Ab to NMDA receptor, VGKC receptor complex proteins (LGI1 and CAsPR2), GABAB receptor and AMPA receptord Autoimmune encephalitis can present without fever, but psychiatric symptoms can be associated with confusion, memory impairment, movement disorder and/or seizures Catatonia: stupor potentially accompanied by negativism, echopraxia, posturing or flexibilitas care (waxy flexibility; a tendency to remain in an immobile posture) MRI Identify focal pathology (especially brainstem, diencephalon) or hydrocephalus Possibly EEG Non-convulsive status CPK NMS Ensure metabolic disturbance excluded and consider autoantibody testing etc Cognitive impairment, deranged LFTs, movement disorder and grimacing Caeruloplasmin; examine for Kayser–Fleischer rings Detection of Wilson’s disease Clumsiness, weakness, visual changes, speech difficulty and behavioural changes Establish if immunocompromised (eg organ transplant, corticosteroids, natalizumab) Progressive multifocal encephalopathy MRI MRI has characteristic changes CSF testing for JC virus DNA Cognitive impairment, apathy, agitation, change in gait and incontinence; occasionally suspiciousness and visual hallucinations Examination of optic fundi for papilloedema; CT or MRI; CSF tap test (if not contraindicated because of concerns about raised intracranial pressure) Consider hydrocephalus Late-onset psychosis (after 3rd decade) with personality change, disinhibition, executive deficits, semantic memory loss, parkinsonian features or possibly motor weakness Cognitive assessment Characteristic deficits of frontotemporal or sematic dementia MRI Identify regional atrophy in frontal or temporal regions in keeping with bvFTD or SD Genetic testing for C9orf72 and potentially other genetic mutations associated with FTD and/or MND Will require discussion with neurologist and/or geneticist and possibly genetic counselling Visual hallucinations, parkinsonian features Dopamine transporter scan Exclude Parkinson’s disease and/or Lewy body dementia Although classically cognitive decline, seizures and stroke-like episodes, there are case reports of presenting as psychosis Thyroid peroxidise Ab Consider Hashimoto’s encephalopathy; exquisitely steroid responsive encephalopathy Personality change, possibly with psychotic symptoms; restlessness and incoordination evolving into jerky choreiform movements Family history; genetic testing Exclude Huntington’s disease Fatigue, anxiety, depression, possibly psychosis; weight loss, muscle weakness, light-headedness and hyperpigmentation Synacthen test Exclude Addison’s disease Episodic, highly stereotyped symptoms or behaviours with sudden onset and termination Collateral history: dysphasia, paresis and motor symptoms Ictal phenomena Episodic confusion without obvious cause EEG Non-convulsive status epilepticus Cluster of seizures followed by lucid interval and then florid psychosis, often with grandiosity and religious preoccupations Establish diagnosis of epilepsy; EEG to exclude ongoing seizure activity Post-ictal psychosis Episodic delusions, hallucinations, mood disturbance, agitation and/or restlessness; abdominal pain, urinary symptoms, peripheral neuropathy and seizures Family history; urinary testing for porphobilinogen; genetic testing Intermittent porphyria Episodes of daytime sleep associated with visual hallucinations Multiple sleep latency test; HLA typing; CSF hypocretin levels Exclude narcolepsy ↵aThis list of investigations is neither exhaustive nor mandatory; it is intended as loose guidance and to prompt consideration of rarer conditions if suggested by the totality of the presentation.
↵bMore-specialist or invasive investigation (eg EEG, LP or genetic testing) will normally be undertaken after discussion with neurologists or other relevant specialists.
↵cApyrexial cases of HSV encephalitis are recognised.
↵dCertain limbic encephalitides are particularly likely to have ‘psychiatric’ presentations. Classic presentations are as follows: (i) NMDA receptor antibody: female predominance; irritability and insomnia progressing to paranoia, delusions and hallucinations, followed by speech dysfunction, dyskinesias, memory deficits, autonomic instability, and a decrease in the level of consciousness. Seizures can occur at any time during the disease, but tend to occur earlier in males; and (ii) Anti-LGI1 encephalitis (voltage-gated potassium channel antibody group): amnesia and confusion, seizures, movement disorders, sleep disorders; Hyponatraemia and faciobrachial dystonic seizures are particularly associated with both these antibodies. The decision to treat will generally need to be made before antibody test results are available. Autoimmune encephalitis is suggested by subacute onset of memory deficits, psychiatric symptoms or altered consciousness and at least one of new focal CNS findings, seizures not explained by a previously known seizure disorder, CSF pleocytosis (white blood cell count of more than five cells per mm³), or MRI features suggestive of encephalitis.12 Ab = antibody; ANA = antinuclear antibody; p/c-ANCA = perinuclear/cytoplasmic antineutrophil cytoplasmic autoantibodies; BP = blood pressure; bvFTD = behavioural variant frontotemporal dementia; CNS = central nervous system; CPK = creatine phosphokinase; CSF = cerebrospinal fluid; CT = computed tomography; EEG = electroencephalography; ESR = erythrocyte sedimentation rate; FTD = frontotemporal dementia; GGT = Gamma-glutamyltransferase; HLA = human leukocyte antigen; HSV = herpes simplex virus; LP = lumbar puncture; LFT = liver function test; MND = motor neurone disease; MRI = magnetic resonance imaging; NMS = neuroleptic malignant syndrome; RF = rheumatoid factor; SSA/B = anti-Sjögren’s syndrome A/B
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