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
Neuroimaging indications for someone presenting with symptoms of dementia
o Onset of cognitive signs/symptoms within the past 2 years, regardless of the rate of progression
o Unexpected and unexplained decline in cognition and/or functional status in a patient already known to have dementia
o Recent and significant head trauma
o Unexplained neurological manifestations (new onset severe headache, seizures, Babinski sign etc) at onset or during evolution (this also incl. gait disturbances)
o History of cancer, in particular if at risk for brain metastases
o Risk for intracranial bleeding
o Symptoms suggestive of normal pressure hydrocephalus
o Significant vascular risk factors
o Unusual or atypical cognitive symptoms or presentation e.g. progressive aphasia
neuroimaging in someone presenting with symptoms of dementia
• MRI > CT
o Exclude other pathologies (SOL, SDH, NPL, vascular disease), establish subtype
• HMPAO SPECT
o To differentiate AD, VD, FTD if dx is in doubt
o LBD SPECT (single photon emission computed tomography) /PET – low striatal dopamine transporter uptake
o FTD SPECT/PET Frontal and/or anterior temporal hypoperfusion or hypometabolism
• FDG PET
o 2nd line ix if SPECT unavailable
• CSF examination
o Inflammatory, infective, malignant causes of dementia
o In cases where dementia is rapidly progressive, the presentation is unusual or if the person is 55 years of age, CJD
• EEG
o If dx of delirium, FTD, CJD is suspected
o Assessment of seizure disorder in people with dementia
When is brain biopsy indicated in someone presenting with symptoms of dementia?
• Brain biopsy
o In highly selected people whose dementia is thought to be due to potentially reversible condition (e.g. cerebral vasculitis) that cannot be diagnosed in another way
Delirum ix
• CAM – Confusion Assessment Method
• History
o Patient history + collateral history
o Medical + psychiatric history (acute + chronic)
Sensory impairments (hearing/vision)
Elimination patterns (urinary and bowel frequency)
o Recent surgeries
o Medication history (prescription, OTC)
o Substance use history (esp. alcohol)
o Previous cognitive functioning, ADLs, IADLs
o Hx of presenting illness
Onset + course of confusion
Hx of previous episodes of delirium (+ treatment response)
Sleep patterns
o Social hx
• Routine investigations
o FBC, U+Es, BUN/Cr, extended electrolytes (Ca, Mg, PO43-), CK, ESR, CRP
o LFTs, lipase, albumin, troponin
o Random glucose, B12, TSH, free T3/T4, O2 sats or ABGs, CXR, CT head, ECG
o Infectious aetiology work up – HIV, lactate
o Urinalysis (cultures), urine drug screen, urine/serum toxicology screen
• Baseline ECG
Anorexia nervosa ix
• Squat test
o Difficulty standing up from squatting without help
•
Screening and rating scales
• EDDS – eating disorder diagnostic scale
• The SCOFF questionnaire – PACES
o 5-question screening questionnaire for AN and BN
o 2 or more positive answers should raise your index of suspicion of a case take a more detailed history
S – do you ever make yourself sick because you feel uncomfortably full?
C – do you worry you have lost control over how much you eat?
O – have you recently lost more than one stone (14 pounds/6.4 kg) in a 3-month period?
F – do you believe yourself to be fat when others say you are too thin?
F – would you say food dominates your life?
Lab findings
• If amenorrhoea pregnancy test in women of childbearing age
• Urinalysis
o Low specific gravity – consumption of large quantities of free water
o Ketonuria - starvation
• Serum pH and ketones if DKA suspected
• FBC
o Leukopenia
o lymphocytes
o Anaemia (normocytic + normochromic)
o Thrombocytopenia
• ESR – N or low (to rule out organic cause of weight loss)
• Electrolytes are typically decreased
o Na, PO4, Mg, K, Ca, Zn
o Urea
o Self-induced vomiting – may lead to metabolic alkalosis ( serum bicarbonate, losing H+ from stomach), Cl, K
o Laxative abuse – mild metabolic acidosis (losing HCO3- through diarrhoea) , Na, K
o High urea – if dehydration
• Endocrine
o N/ T4
o T3
o rT3 (reverse T3)
o serum oestrogen levels
o serum testosterone
o GH
o cortisol
o GnRH
o leptin
• Estradiol (F), testosterone (M)
• Hypercholesterolaemia
• LFTs (ALT/AST, ALP (osteopenia))
• serum amylase
• most things low
• G’s and C’s raised: growth hormone, glucose (leading to impaired glucose tolerance), salivary glands, cortisol, cholesterol, carotinaemia
ECG
• Sinus bradycardia (common)
• Arrhythmias (rare)
• Significant prolongation of QTc (>450ms) seen in some individuals
Bone mineral density scan/DEXA scan
• After 1 year of underweight in children + young people
• After 2 years of underweight in adults
• Or earlier if bone pain or recurrent fractures
