Psychiatry - Investigations Flashcards
Investigations to rule out other organic causes of depression
FBC (low levels cause fatigue) Blood glucose (DM causes fatigue) TFTs (exclude hypothyroidism) Ca levels (hyperparathyroidism can cause depression) Vitamin D+B12 (low levels cause fatigue) HIV/syphilis serology, drug screening
Imaging: CT or MRI – if presentation or examination is atypical or where there are features suspicious of an intracranial lesion e.g. unexplained headache or personality change
Cognitive assessment: where dementia/pseudodementia are differentials
Schizophrenia ix
full physical work up
to exclude organic causes (neurological system)
to pick up comorbid physical health problems (cardiovascular system incl weight + BP)
to ensure baseline tests have been done before starting an anti-psychotic
- Full physical examination and vital signs
- Collateral history
- Blood tests – FBC, U+Es, LFTs, TFTs, ESR, CRP, CBG, lipid profile, HIV testing, syphilis serology
- Urinary drug screen – can identify common illicit substances (e.g. cannabis, amphetamine) but many drugs, esp NPS can’t be detected
- Baseline ECG – ideal before starting an antipsychotic
Additional investigations if clinical presentation suggests organic pathology
• CT/MRI brain – older patients, pt w a hx of head injury or focal neurological signs
• EEG – when investigating TLE or post-ictal symptoms (can get psychosis in the post-ictal state)
• Anti-NMDA + voltage-gated potassium channel (VGKC) antibodies – if autoimmune encephalitis is suspected
• LP – for suspected encephalitis
• Social investigation – Medication free period of inpatient observation may clarify the diagnosis if someone develops psychosis while using drugs
Risk assessment
• Risk to self – suicide, self-neglect, social decline, victimisation by others
• Risk from others
• Risk to others – aggression (might be a direct response to persecutory delusions or command hallucinations).
Other factors that increase the risk of violence – substance misuse, medication non-concordance, specific threats of violence, hx of aggression
Baseline investigations before starting antipsychotics
weight waist circumference pulse, BP fasting blood glucose, HBA1c blood lipid profile prolactin levels assessment of any movement disorders assessment of nutritional status diet and level of physical activity
What should be monitored in schizophrenic patients who are on atni-psychotics?
o Response to treatment + SE o Adherence o Emergence of movement disorders o Waist circumference o BMI o Overall physical health o FBC, LFT, U&Es, lipid profile, CBG (followed by a glucose tolerance test and HbA1c if abnormal)
o Weight Weekly for 6 weeks At 12 weeks At 1 year Annually thereafter
o Pulse + BP
At 12 weeks
1 year
Annually thereafter
o some people need monitoring of
prolactin levels – if hyperprolactinaemia is suspected or likely (e.g. risperidone)
ECGs – important in older people + those on high-dose antipsychotics or clozapine – to monitor the QTc interval;
Neuroimaging in schizophrenia might show
Neuroimaging not carried out to d schizophrenia but in patients there might be:
• Increased size of lateral ventricles
• Reduced brain size (usually temporal lobes)
• Negative symptoms – correlated with decreased blood flow + other abnormalities in the frontal cortex
• EEG - decreased connections between different brain areas
Neuroleptic malignant syndrome NMS - ix + results
- Increased CK (hallmark)
- increased WCC
- Increased LFTs
- Decreased renal function
- Metabolic acidosis
GAD ix
• Rule out a medical condition
o FBC, fasting glucose, fasting lipid profiles, U+Es, LFTs, serum bilirubin, serum creatinine, urinalysis, urine toxicology, TSH
o ECG
• Screening tools:
o GAD-7
o BAI (Beck Anxiety Inventory)
PTSD ix
• As clinically indicated
• Screening and rating scales
o CAPS-5 – Clinician-Administered PTSD Scale for DSM-5
o PCL-5 – PTSD checklist for DSM-V
OCD ix
• Rating scales
o Y-BOCS – Yale-Brown Obsessive Compulsive Scale
o FOCI – Florida Obsessive Compulsive Inventory
• Anti-streptolysin O (ASO)
• anti-DNAse B titres
o Patients suspected of having a recent group A (Beta-hemolytic) streptococcus bacteria infection, from Streptococcus pyogenes.
o Should be ordered if there is an acute or dramatic onset, or exacerbation of symptoms
o Some evidence that streptococcal throat infections increase risk for mental disorders, particularly OCD + tics
Panic disorder ix
- Panic disorder severity scale
- NICE – there is insufficient evidence on which screening instrument to use in the diagnosed process – therefore consultation skills should be relied upon to elicit all necessary information
• Clinician should be alert to the common clinical situation of comorbidities
o Panic disorder with depression
o Panic disorder with substance misuse
• Cardiac, respiratory and abdominal examination should be performed according to the clinical presentation to rule out an organic cause
• Bloods
o FBC
o U&Es
o LFTs, serum bilirubin, serum creatinine
o Fasting glucose, fasting lipid profiles
o TFT
o Urinalysis, urine toxicology for substance use
• ECG
o To assess for signs of ventricular preexcitation (short PR, delta wave)
o Short or long QT interval for patient with palpitations
o Ischaemia, infarction, pericarditis in patients with chest pain
• Work-up for phaeochromocytoma o Plasma metanephrines o 24-hour urinary metanephrines o Abdominal MRI o Scintigraphy o Abdominal CT
• If panic attacks are acute, associated with cardiac symptoms + persistent vital sign changes consider PE work-up order a D-dimer
Alzheimer’s disease ix
• CSF o levels of CSF Aβ42 o Increased total tau o Increased phosphorylated tau • PET – can visualise amyloid plaques • FDG PET scans o Hypometabolism in: bilateral tempoparietal regions, posterior cingulate cortex, increased amyloid tracer retention • MRI o Atrophy with a characteristic pattern involving the medial temporal lobes, hippocampus, paralimbic and/or tempoparietal cortex
Lewy body dementia investigations
SPECT (single photon emission computed tomography) /PET – low striatal dopamine transporter uptake
MRI – generalized atrophy, sparring of the medial temporal lobes
Cognitive testing – MMSE, MoCA – deficits in attention, executive function, visual processing, spatial and perceptual difficulties occur early, memory and object naming tend to be less affected
Approach to a patient with non-rapidly progressive dementia
• Rule out delirium
o Delirium – acute onset, fluctuating course, inattention, disorganize thinking, altered level of consciousness
o UTIs in the elderly can cause delirium
o Negative culture does not mean that there is no UTI
o Asymptomatic bacteriuria should not be treated with antibiotic – adverse risks e.g. C. diff
• Rule out depression
o “pseudodmentia”
o Can cause atypical presentations – anxiety, irritability, unexplained physical complaints, worsening cognition
o Once depression is treated, the dementia symptoms go away
• Rule out substance use disorders
o UDS, HIV
• Rule out any reversible causes
o FBC (anaemia), TSH (hypo/hyperthyroidism), Cr (assess renal function and ability to clear medications), U+Es (hyponatraemia), Ca (hypercalcaemia), glucose (hyperglycemia), ferritin/iron, vitamin B12, LFTs (alcohol misuse, SDHs, alcohol related dementia, Korsakoff’s syndrome), ESR (rule out inflammatory conditions)
o Neuroimaging
o Screen for syphilis
o ECG, CXR, MSU
o Medication induced dementia
Polypharmacy
Anticholinergic medications
Other medications that could cause cognitive issues – steroid dementia syndrome related to glucocorticoid use
Other neurological disorders e.g. normal pressure hydrocephalus
• Is it dementia, mild cognitive impairment (MCI) or normal aging?
o Dementia (major neurocognitive disorder) – objective findings of cognitive loss with impairment of ADLs
o Mild cognitive impairment – objective findings of cognitive loss without impairment of ADLs
o Normal cognitive aging – no objective findings of cognitive loss
• Further tests for
AD
LBD
Frontotemporal dementia
Vascular dementia
• Further tests for
AD
o FDG-PET or perfusion SPECT (if FDG-PET is unavailable) or
o Examine CSF for
Either total tau or total tau + phosphorylated-tau 181 and
Either amyloid beta 1-42 or amyloid beta 1-42 and amyloid beta 1-40
o The older the person is, the more likely they are to get a false positive with CSF examination
LBD
o 123I-FP-CIT SPECT
o 123I-MIBG cardiac scintigraphy if first test unavailable
Frontotemporal dementia
o FDG-PET or
o Perfusion SPECT
Vascular dementia
o MRI
o CT if MRI unavailable/contraindicated
Which investigations differentiate delirium from dementia
• Delirium vs Dementia
o People in hospital with cognitive impairment of an unknow cause – consider one of th following to find out if they have delirium or delirium superimposed on dementia compared with dementia alone
Long confusion assessment method (CAM)
Observational Scale of level of arousal (OSLA)
o If it’s not possible to tell if person has delirium or dementia – treat delirium first
