Izben C. Williams, MD, MPH Instructor

BIOLOCICAL ASSESSMENT OF PATIENTS WITH PSYCHIATRIC SYMPTOMS

Laboratory Examinations OVERVIEW 1: With psychiatrists’ increasing use of certain psychotropic medications (eg, lithium, antidepressants, anticonvulsants), there has been a growing awareness of the usefulness of monitoring blood levels of these medications and their metabolites to guide therapy and to minimize adverse reactions or other complications.

Laboratory Examinations OVERVIEW 2: With the current illicit substance abuse epidemic there is also increasing need for psychiatric clinicians to be able to detect those patients whose psychiatric conditions might be affected by drug abuse.

Laboratory Examinations OVERVIEW 3: Laboratory tests are often therefore, essential diagnostic resource to psychiatrists At the same time it should be appreciated that indiscriminate ordering of tests……. Is costly May short-circuit traditional clinical practice procedures and guidelines It can undermine patient-physician relationship

Laboratory Examinations OVERVIEW 4: The request for diagnostic tests by should therefore derive from, and should be dictated by, findings in the: History MSE and Review of systems Physical examination

Laboratory Examinations OVERVIEW 3:. It should however be emphasized that negative test results do not always constitute proof that organic disease is not present Thus, test results should always be viewed as part of the larger clinical picture

Laboratory Examinations Monitoring patients for complications of pharmacotherapy: The mood stabilizer Carbamazapine and the antipsychotic Clozaril may cause blood dyscrasias such as agranulocytosis Mood stabilizers carbamazapine and valproic acid may cause abnormal LFTs

Laboratory Examinations Monitoring patients for complications of pharmacotherapy -2: Thyroid function and renal function tests should be carried out for patients receiving the mood stabilizer Lithium as this drug can cause thyroid hypo or hyper activity Because serum Lithium has a narrow therapeutic range this is additional reason for regularly monitoring its level

Laboratory Examinations Tests for Endocrine Function: Hypothyroidism can mimic depression Hyperthyroidism an mimic anxiety Therefore it may be important to rule out thyroid disease as a differential for these disorders

Laboratory Examinations Other endocrine abnormalities: Reduced levels of gonadotropins are seen in schizophrenia Depression may also present with abnormalities in growth hormone and melatonin (pineal gland), and a reduced response to a challenge with thyrotropin-releasing hormone

Laboratory Examinations Other endocrine abnormalities: As with thyroid disease, adrenal dysfunction may be associated with a wide range of psychiatric disturbances. Adrenal’s, you will, recall produce: Catecholamines (eg epinephrine) Glucocorticoids, mineralocorticoids, and adrenal androgens (precursors of sex hormones)

Laboratory Examinations Other endocrine abnormalities: Addison’s disease and Cushing’s syndrome, two mojor adrenal disorders, may present with psychiatric symptoms because of the biogenic amines production and other metabolic derangements which accompany these disorders Reduced levels of gonadotropins are also seen in schizophrenia

Laboratory Examinations Dexamethasone suppression test (DST)-1: Dexamethasone is a type of steroidal medication It has anti-inflamatory and immunosuppressive effects It is 25 times more potent than cortisol in its glucocorticoid effect The DST measures whether adrenocorticotropic hormone (ACTH) secretion by the pituitary can be suppressed

Laboratory Examinations Dexamethasone suppression test (DST)-2: In a person with normal hypothalamic-adrenal- pituitary axis, dexamethasone suppresses the secretion of cortisol In only 50% of persons with major depressive disorder will this suppression occur in the other 50% it is limited or absent Hence DST has limited clinical usefulness, as non suppression is also seen in other mental conditions including schizophrenia and dementia

Dexamethasone suppression

Laboratory Examinations Dexamethasone suppression test (DST)-2: Plasma cortisol detects abnormalities in cortical secretion from the adrenal gland. In principle low plasma cortisol suggests Addison’s disease Elevated plasma cortisol suggests Cushing’s disease

Other diagnostic tests used in Psychiatry It cannot be over emphasized that: Request for laboratory or other diagnostic tests should derive from the Hist, ROS & PE Negative test results do not constitute proof that organic disease is not present The range of tests may include: Anatomic (eg CT scan) Functional (eg EEG, DST) Diagnostic (eg VDRL)

Other diagnostic tests used in Psychiatry Case # 1: Let us take the case of a patient presenting with Delirium- an acute confusional state Toxicology screen indicated (cultural bias) Heavy metals Hallucinogens Atropine substances Stimulants CNS depressants Anxiolitics Pain medication, etc

Other diagnostic tests used in Psychiatry Case # 2: Let us take the case of a patient presenting with Dementia – decline in mental ability enough to interfere with daily life List of tests to be considered: Blood plasma or serum values Antigen and antibody tests CXR EKG EEG CT scan MRI Lumbar puncture Positron emission tomography