Lab Tests

NEUROPSYCHIATRY (September 2008) UST Faculty of Medicine and Surgery LABORATORY TESTS IN PSYCHIATRY Lecturer: Dr. Ramon S. Javier Objectives 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, electrolytes • Chest X-ray, ECG

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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 • Exposure to Toxins • Vitamin Deficiency Syndromes (eg pernicious anemia) • Other CNS infections (TBM, syphilis) • 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 • clozapine, olanzapine & weight gain • genetic subtyping for cytochrome P450 allele • SPECT, PET – visualize & measure density of D2 receptors

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 • 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. Psychiatric symptoms after age 40 2. 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, beta-carboline, yohimbine, & Caffeine The Future 1. Genetic markers 2. 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

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