laboratory tests and imaging in psychiatry

8/10/2019 Laboratory tests and imaging in Psychiatry

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LABORATORY TESTS ANDIMAGING IN

PSYCHIATRY

PRESE

DR. WA


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INTRODUCTION

Biological evolution of Psychiatry became popular since 1960s

Biological treatments (medications, stimulations, surgery) become mainstay

of Psychiatry

Usage of functional neuroimaging methods (SPECT, PET, fMRI, etc.) for

both clinical and research purposes become more common

Even, more and more evidences are found that Psychotherapies change the

brain and neurotransmitter regulations (visualized by neuroimaging)


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INTRODUCTION

But, still diagnoses in Psychiatry are based entirely on behavibiological, criteria.

Director of NIMH: 'The weakness (of DSM-5) is its lack of validity. Unlike our definitions of ische

disease, lymphoma, or AIDS, the DSM diagnoses are based on a consensus about clusters of

symptoms, not any objective laboratory measure'.

The chair of DSM-5 issued this agreement: 'In the future, we hope to be able to identify disorde

biological and genetic markers that provide precise diagnoses that can be delivered with compl

and validity'.

But they also stated: It would be great to have them, but much good diagnostic work can be d

tests and their lack is not unique to psychiatry.

(According to Psychiatric Times)


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INTRODUCTION

Laboratory tests and neuroimaging methods are currently use

To support the diagnosis

To rule out potential physical causes

To identify co morbid physical illness (4-18%)

To monitor medication level in our body system

To monitor physiological changes secondary to medications


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BASIC SCREENING TESTS

Complete blood count (CBC),

Renal function tests,

Liver function tests, and

thyroid function tests, and blood sugar


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AreALLthese routine testing enough to evaluate for medical i

ALL psychiatric patients??

The answer is NO !!

Do not forget medical history and physical examination


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NEUROENDOCRINE TESTS

1. Thyroid function test

Total thyroxine (T4), Free thyroxine (T4),Triiodothyronine (T3) uptake

serum triiodothyronine (T3), Thyroid-stimulating hormone (TSH), The thyrotr

releasing hormone (TRH) stimulation test (For suspected subclinical Hypoth

lithium-induced hypothyroidism)

Up to 10 percent of patients complaining of depression and associated fatincipient hypothyroid disease.

Other symptoms of hypothyroid; weakness, stiffness, poor appetite, constmenstrual irregularities, slowed speech, apathy, impaired memory, and ev

hallucinations and delusions

Hyperthyroid might be mistaken for mania, psychosis or anxiety.

Interpretation of thyroid function tests may be complex and is often


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2. Dexamethasone-Suppression Test

1 mg of dexamethasone by mouth at 11 pm, and the plasma cortisomeasured at 8 am, 4 pm and 11 pm. Plasma cortisol concentrations above 5

(known as non-suppression) are considered abnormal (i.e., a positive result)

help confirm a diagnostic impression of major depressive diso

False-positive and false-negative results are common, and mmedical conditions and pharmacological agents can interfere

results


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Other Endocrine Tests

Prolactin

Antipsychotics induced hyperprolactinemia

growth hormone, somatostatin, gonadotropin-releasing hormone (GnRsex steroids, luteinizing hormone (LH), follicle-stimulating hormone (F

testosterone, and oestrogen.

Anorexia nervosa

Melatonin Seasonal affective disorder

Arginine vasopressin (AVP)

Lithium induced Diabetes Insipidus


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Anorexianervosa

Low Caloricintake

Low TSH

Low Thyroidhormone

DisturbedGnRH

pulsitility

IncreasedFSH:LH

Lowoestrogen

Secondary

amenorrhoea

Stress

IncreasedCortisol

Increased GH


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COMPLETE BLOOD COUNT

Low RBC and Hb% Carbamazepine

Low Hb with high MCV Alcoholic and Folate and vitadeficiencies

Folate and vitamin B12 deficiencies are associated with dementia; delirium; psychosis, inc

paranoia; fatigue; and personality change

High WBC Lithium toxicity, Neuroleptic m$

Low WBC Clozapine, CarbamazepineWBC of less than 3,000 per mm3or neutrophil count of less than 1,500 per mm3is indicat

both clozapine and carbamazepine.

Low Platelets Cloza ine Carbamaze


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INFECTION SCREENING

HIV High risk: Mania and IVDU

Presentation: dementia, personality changes, affective symptoms of emania or depression, and psychosis

Syphilis High risk: Mania patient

Presentation: Neurosyphilis (Delusions, Hallucinations, Irritability, memdeterioration) VDRL (+), TP-PA (-) Possibly false positive due to other infection and rheum

diseases

VDRL (-), TP-PA (+) Possibly previous infection

VDRL (+), TP-PA (+) Active infection (Candidate for treatments)

Viral hepatitis (A,B,C)


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TESTS RELATED TO PSYCHOTROPIC DRUG

Benzodiazepine - Baseline LFT

Antipsychotics - CBC, LFT, RFT, Lipids, blooand ECG

Tri/tetracyclic antidepressants - ECG (quinidine-like effect)

MAOI - LFT, blood pressure

Lithium - Thyroid function tests,

Electrolyte monitoring,

CBC (WBC),

Renal function tests and

Baseline ECG


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TESTS RELATED TO PSYCHIATRIC TREATM

Carbamazepine - CBC, U&E, LFT, ECG

Valproate - CBC, LFT

Screening urine pregnancy test in women of childbearing

before administration of above mood stabilizers ( also Lamotrig

Neuroleptic Malignant Syndrome - CBC, serum electrolyBUN, Cr, and creatine kinase

myoglobin

Electroconvulsive Therapy - CBC, serum electrolyurinalysis, and liver function te

ECG, fundoscopy

MONITORING BLOOD CONCENTRATION OF


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MONITORING BLOOD CONCENTRATION OFPSYCHOTROPIC MEDICATION

Lithium - 0.6-1.2 mEq/L (Normal range)

?? 1.5-1.8 mEq/L (For acutely maniac patient)

2.0 mEq/L (Toxic concentration)

Carbamazepine - 8 to 12 ng/mL (Normal range)

>15 ng/mL (Toxic concentration)

Valproate - 45 to 50 ng/mL (Normal range)>125 ng/mL (Toxic concentration)

Clozapine - 350-500 g/L (Normal range)

Nortriptyline - 50-150 g/L (Normal range)

The blood specimen should be drawn 10 to 14 hours after the last d

usually in the morning after a bedtime dose.


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URINE TESTS FOR DRUGS OF ABUSE

Drug Length of Time Detected in Urine

Alcohol 712 hrs

Amphetamine 48 hrs

Barbiturate 24 hrs (short acting); 3 wks (long acting)Benzodiazepine 3 days

Cocaine 68 hrs (metabolites, 24 days)Codeine 48 hrs

Heroin 3672 hrsMarijuana 3672 hrs

Methadone (Dolophine) 3 days

Methaqualone 7 days

Morphine (Duramorph) 4872 hrs

Phencyclidine 8 days

Propoxyphene (Darvon) 648 hrs


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IMAGING STUDIES IN PSYCHIATRY

Magnetic Resonance Imaging (MRI)

Can detect a large variety of structural abnormalities

Provide the clinician with images of anatomical structures viewcross-sectional, coronal, or oblique perspectives

Unique in its ability to identify periventricular white matterhyperintensities

Useful in examining the patient for particular diseases, such anonmeningeal neoplasms, vascular malformations, seizure fo

demyelinating disorders, neurodegenerative disorders, and in


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IMAGING STUDIES IN PSYCHIATRY Scan parameters; T1 and T2.

T1-weighted scans provide detailed visualizations of brain anatomy.

Extracellular fluid, such as edema, looks dark. In contrast, T2-weighted

reveal a white pattern for edema. These scans are useful in examining t

for white matter disease.

The advantages of MRI include the absence of ionizing radiatthe absence of iodine-based contrast agents. Contrast agents

based on gadolinium, a rare earth metal, and usually do not p

an aller ic res onse


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Computed Tomography

Cross-sectional X-ray images of the brain

Can detect structural abnormalities in the cortical and subcortregions of the brain

Looking for evidence of a stroke, subdural hematoma, tumor,

abscess, skull fractures

May be performed with or without contrast. The purpose of coto enhance the visualization of diseases that alter the bloodb

barrier, such as tumors, strokes, abscesses, and other infectio

Allergic reactions to contrast may occur


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Indications commonly include focal findings on the neurologicexamination or abnormalities on an EEG

Slightly more controversial indications include impaired cognitthe mental status examination, the first episode of psychosis

(especially if the presentation is atypical), delirium, late-onset

years of age) personality disorders, psychosis, or affective illn

prolonged catatonia



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Positron Emission Tomography

require a PET tomograph (the scanner) and a cyclotron to crerelevant isotopes

involves the detection and measurement of emitted positron rafter the injection of a compound that has been tagged with a

positron emitting isotope

Typically, PET scans use fluorodeoxyglucose (FDG) to measuregional brain glucose metabolism

regional glucose metabolism is directly proportionate to neuroactivity

Brain FDG scans are useful in the differential diagnosis of dem


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Single Photon Emission Computed Tomography

performed using a dedicated tomographic camera to detect raemitted from a patient after the injection of radiolabeled comp

SPECT scanners to measure blood flow in dementia patients a pattern of reduced temporal-parietal blood flow is found


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Functional Magnetic Resonance Imaging

fMRI data are superimposed on conventional MRI images, res

detailed brain maps of brain structure and function. The measurement of blood flow involves the clever use of the

molecule as an endogenous contrast agent


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Magnetic Resonance Spectroscopy

Specific upgrades to the hardware and software

Signal from protons is suppressed, other conpounds to b

measured

MRS is able to measure compounds tagged with nonrad

isotopes of hydrogen, phosphorus, lithium, sodium, and fluorine

Magnetic Resonance Angiography

Method for creating three-dimensional maps of cerebral

flow

The effect of the iron atom in the haemoglobin molecule


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OTHER STUDIES IN PSYCHIATRY


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OTHER STUDIES IN PSYCHIATRY

Evoked Potential

Measurement of the EEG response to specific sensory stimul

Stimulation may be visual, auditory, or somatosensory (flashina specific tone, an electrical stimulation to an extremity)

Assist in the assessment of demyelinating disorders such as msclerosis (MS). In psychiatry.

In Psychiatry, EP testing may help in the differentiation of orgfrom functional impairments. (evaluate possible hysterical blin


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REFERENCES


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REFERENCES1. Kaplan and SadocksComprehensive Textbook of Psychiatry 8thedition

7.8, Medical Assessment and Laboratory Testing in Psychiatry

2. kaplan and SadocksConcise Textbook of Clinical Psychiatry 3rdedition3, Laboratory Tests in Psychiatry

3. Thyroid Disease and Mental Disorders;(http://www.medscape.com/viewarticle/723663_6)

4. British Journal of Clinical Pharmacology; Therapeutic drug monitoring ofpsychotropic medications

(http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2014933/)

5. American Medical Association Journal of Ethics, Diagnostic Brain ImagiPsychiatry: Current Uses and Future Prospects (http://virtualmentor.ama

assn.org/2012/06/stas1-1206.html)

6. Psychiatric Times; The Role of Biological Tests in Psychiatric Diagnosis(http://www.psychiatrictimes.com/blogs/dsm-5/role-biological-tests-psyc

diagnosis)
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2014933/http://virtualmentor.ama-assn.org/2012/06/stas1-1206.htmlhttp://virtualmentor.ama-assn.org/2012/06/stas1-1206.htmlhttp://www.psychiatrictimes.com/blogs/dsm-5/role-biological-tests-psychiatric-diagnosishttp://www.psychiatrictimes.com/blogs/dsm-5/role-biological-tests-psychiatric-diagnosishttp://www.psychiatrictimes.com/blogs/dsm-5/role-biological-tests-psychiatric-diagnosishttp://www.psychiatrictimes.com/blogs/dsm-5/role-biological-tests-psychiatric-diagnosishttp://www.psychiatrictimes.com/blogs/dsm-5/role-biological-tests-psychiatric-diagnosishttp://www.psychiatrictimes.com/blogs/dsm-5/role-biological-tests-psychiatric-diagnosishttp://www.psychiatrictimes.com/blogs/dsm-5/role-biological-tests-psychiatric-diagnosishttp://www.psychiatrictimes.com/blogs/dsm-5/role-biological-tests-psychiatric-diagnosishttp://www.psychiatrictimes.com/blogs/dsm-5/role-biological-tests-psychiatric-diagnosishttp://www.psychiatrictimes.com/blogs/dsm-5/role-biological-tests-psychiatric-diagnosishttp://www.psychiatrictimes.com/blogs/dsm-5/role-biological-tests-psychiatric-diagnosishttp://www.psychiatrictimes.com/blogs/dsm-5/role-biological-tests-psychiatric-diagnosishttp://www.psychiatrictimes.com/blogs/dsm-5/role-biological-tests-psychiatric-diagnosishttp://www.psychiatrictimes.com/blogs/dsm-5/role-biological-tests-psychiatric-diagnosishttp://virtualmentor.ama-assn.org/2012/06/stas1-1206.htmlhttp://virtualmentor.ama-assn.org/2012/06/stas1-1206.htmlhttp://virtualmentor.ama-assn.org/2012/06/stas1-1206.htmlhttp://virtualmentor.ama-assn.org/2012/06/stas1-1206.htmlhttp://virtualmentor.ama-assn.org/2012/06/stas1-1206.htmlhttp://virtualmentor.ama-assn.org/2012/06/stas1-1206.htmlhttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC2014933/http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2014933/http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2014933/http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2014933/


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laboratory tests and imaging in psychiatry

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