Lab Tests

LABORATORY TESTS IN PSYCHIATRY Ramon S. Javier, MD University of Santo Tomas Faculty of Medicine & Surgery Deparment of Neurology and Psychiatry

• 1. To complete a general medical

workup of the sort done routinely for any hospital admission

• 2. To rule out non-psychiatric causes of the presenting symptoms

• 3. To conduct a specific work-up

appropriate for a specific treatment that has been planned

• 4. To obtain information that will assist

in making a differential diagnosis among several different mental illnesses

• 5. To assist in determining

pathophysiology, estimating prognosis, and formulating a treatment plan.

I. GENERAL MEDICAL WORKUP

• standards vary in different hospital

settings • CBC, FBS, BUN, Creatinine, liver enzymes, serum electrolytes • Chest X-ray, ECG

II. TO RULE OUT . . . . . ‘organic’ vs ‘functional’

Conditions Considered in the Differential Diagnosis of Major Mental Illnesses

• • • • • • •

Multi-infarct Dementia Subdural Hematoma Normal-Pressure Hydrocephalus Tumors HIV-related Dementia Temporal Lobe Epilepsy Endocrine/Metabolic Disorders

Multi-infarct Dementia

Subdural Hematoma

Normal-Pressure Hydrocephalus

Tumors

HIV-related Dementia

Temporal Lobe Epilepsy

Endocrine/Metabolic Disorders

Conditions Considered in the Differential Diagnosis of Major Mental Illnesses

• Exposure to Toxins • Vitamin Deficiency Syndromes (eg

pernicious anemia) • Other CNS infections (TBM, syphilis)

Conditions Considered in the Differential Diagnosis of Major Mental Illnesses

• Substance-induced Symptoms • Neuropsychiatric effects of medical

treatment (eg K depletion from diuretics, fatigue from propranolol, digitalis toxicity, Phenytoin toxicity)

III. PERTAINING TO A SPECIFIC TYPE OF TREATMENT

• to determine & document the pt’s physical condition before the tx • to rule out conditions that might be adversely affected by the treatment • to establish baseline values for the pt before instituting treatment

ECT • routine chemistries, urinalysis • ECG – baseline cardiac status • if with questionable signs of dementia -> further workup

LITHIUM Therapy • BUN, serum creatinine, serum electrolytes, urinalysis • T3, T4 levels • ? ECG (age) • serum lithium levels

ANTIPSYCHOTIC Therapy • no special work-up prior to therapy • if poor response -> blood levels (haloperidol, clozapine, CBZ, VPA) • clozapine & blood dyscrasias

ANTIPSYCHOTIC Therapy • clozapine, olanzapine & weight gain • genetic subtyping for cytochrome P450

allele • SPECT, PET – visualize & measure density of D2 receptors

ANTIDEPRESSANT Therapy • no special work-up prior to therapy • tricyclics – ECG • poor response – blood levels – no imaging techniques available yet

IV/ V. TO ASSIST IN PSYCHIATRIC DIFFERENTIAL DIAGNOSIS and TREATMENT

PLANNING • Various neuroimaging and psychological tests

• Determines the overall integrity of brain

function, the presence of structural abnormalities, or the presence of generalized intellectual deficits or specific learning disabilities

Abnormalities Commonly Seen in Schizophrenia • Ven tri cula r enl ar ge ment • • • • •

Prominent cortical sulci Decreased cerebral size Decreased frontal / temporal /thalamic / etc size Increased caudate/putamen size Midline developmental abnormalities

Indications for CT Scan or MRI • Confusion and/or dementia of unknown cause • First episode of a psychotic disorder of unknown • •

etiology First episode of a major mood disorder after age 50 years Marked personality change after age 50 years

Indications for CT Scan or MRI • History of recent head trauma • Anorexia nervosa with marked weight loss • Alcoholism or other substance abuse disorder with signs and symptoms of cognitive deterioration

Some clues suggestive of organic mental disorder 1. 2.

Psychiatric symptoms after age 40 Psychiatric symptoms a. during a major medical illness b. while taking drugs that can cause mental symptoms 3. History of a. alcohol or drug abuse b. physical illness impairing organ function c. taking multiple prescribed or over-the-counter drugs 4. Family history of a. degenerative or inheritable brain disease b. inherited metabolic disease (eg, diabetes, pernicious anemia, porphyria)

5. Mental signs including a. altered level of consciousness b. fluctuating mental status c. cognitive impairment d. episodic, recurrent, or cyclic course e. visual, tactile, or olfactory hallucinations 6. Physical signs including a. signs of organ malfunction that can affect the brain b. focal neurologic deficits c. diffuse subcortical dysfunction ( slowed speech / mentation / movement, ataxia, incoordination, tremor, chorea, asterixis, dysarthria) 7. Cortical dysfunction ( dysphasia, apraxias, agnosias, visuospatial deficits, or defective cortical sensation)

Provocative tests for Panic Disorder Intravenous lactate infusions – reported to induce panic attacks (+) in 70 % – 90 % of pts with panic disorder (+) in 0 – 30 % of control subjects Other substances: CO2, isoproterenol, betacarboline, yohimbine, & caffeine

the future • •

Genetic markers Biochemical markers – examination of potentially relevant

compounds found in blood, urine, CSF, skin Body fluid markers – molecular compounds, eg., DA, 5HT, NE & their metabolites ( HVA, 5-HIAA, MHPG), various neuropeptides (endorphins, enkephalins) & biological compounds (IgM, plasma melatonin) Peripheral tissue markers: blood – NT receptors, enzymes platelets – MAO, alpha1-adrenergic receptors, serotonin reuptake sites, H-labeled-imipramine binding sites RBC – lithium transport mechanism, COMT skin – fibroblasts – NT receptors, important transport systems

THANK YOU