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5.7 Medical Assessment and Laboratory Testing in Psychiatry

NMS. Dystonic reactions from neuroleptic administration may also result in elevated levels of CK.

(due to the pituitary or hypothalamus) or nephrogenic. Nephrogenic DI may be acquired or due to an inherited X-linked condition. Lithium- induced DI is an example of an acquired form of DI. Lithium has been shown to decrease the sensitivity of renal tubules to AVP. Patients with central DI respond to the administration of vasopressin with a decrease in urine output. Secondary central DI may develop in response to head trauma that produces damage in the pituitary or hypothalamus. About one-fifth of patients taking lithium develop polyuria, and a larger amount may have some degree of impairment in concentrating urine. Chronic treatment with lithium is a common cause of nephro- genic DI. However, there are other causes of polyuria in lithium-treated patients in addition to nephrogenic DI. Primary polydipsia is common and is often associated with the dry mouth associated with many psychi- atric medications. Central diabetes has also been associated with lithium treatment. Excessive secretion of AVP results in increased retention of fluid in the body. This condition is called SIADH. Water retention in SIADH causes hyponatremia. SIADH may develop in response to injury to the brain or from medication administration (including phenothiazines, butyrophenones, carbamazepine, and oxcarbazepine).The hyponatremia associated with this condition may produce delirium. Human Chorionic Gonadotropin Human chorionic gonadotropin (hCG) can be assessed in the urine and blood. The urine test for hCG is the basis for the commonly used urine pregnancy test. This immunometric test is able to detect pregnancy approximately 2 weeks after an expected menstrual period has passed. Routine tests are most accurate when performed 1 to 2 weeks after a missed period and are not reliably accurate until the 2-week period has passed. However, there are ultrasensitive urine hCG tests that can accu- rately detect pregnancy 7 days after fertilization. Pregnancy tests often are obtained before initiating certain psychotropic medications, such as lithium, carbamazepine, and valproate, which are associated with con- genital anomalies. Parathormone Parathormone (parathyroid hormone) modulates serum concentra- tions of calcium and phosphorus. Dysregulation in this hormone and the resulting production of abnormalities in calcium and phosphorus may produce depression or delirium. Prolactin Prolactin levels may become elevated in response to the administra- tion of antipsychotic agents. Elevations in serum prolactin result from the blockade of dopamine receptors in the pituitary. This blockade pro- duces an increase in prolactin synthesis and release. Cerebral MRI is not usually performed if the patient is taking an antipsychotic drug known to cause hyperprolactinemia, and the magni- tude of the prolactin elevation is consistent with drug-induced causes. Prolactin levels may briefly rise after a seizure. For this reason, prompt measurement of a prolactin level after possible seizure activity may assist in differentiating a seizure from a pseudoseizure. Thyroid Hormone Disease of the thyroid is associated with many psychiatric manifes- tations. Thyroid disease is most commonly associated with depression and anxiety but may also give rise to symptoms of panic, dementia, and psychosis. Thyroid disease may mimic depression. It is difficult to achieve euthymia if a patient is not euthyroid.

Electroconvulsive Therapy Electroconvulsive therapy (ECT) is usually reserved for patients with the most treatment-resistant depression. Typical laboratory tests obtained before the administration of ECT include a CBC, serum electrolytes, urinalysis, and liver function tests. However, no specific laboratory tests are required in the pre-ECT evalu- ation. Usually, an ECG is also obtained. A spinal X-ray series is no longer considered routinely indicated because of the low risk of spinal injury associated with modern administration techniques that use paralyzing agents. A comprehensive medi- cal history and physical examination are useful screening tools to identify possible conditions that could complicate treatment. Endocrine Evaluations Endocrine disease is of great relevance to psychiatry. Manage- ment of psychiatric illness is complicated by comorbid endo- crine disease. Endocrine illness frequently has psychiatric manifestations. For these reasons, screening for endocrine dis- ease is often of relevance to the psychiatrist. Adrenal Disease Adrenal disease may have psychiatric manifestations, including depression, anxiety, mania, dementia, psychosis, and delirium. How- ever, patients with adrenal disease rarely come to the attention of psy- chiatrists. Assessment and management of these patients are best done in conjunction with specialists. Low plasma levels of cortisol are found in Addison’s disease. These patients may have symptoms that are also common in psychiatric condi- tions including fatigue, anorexia, weight loss, and malaise. Patients may also have memory impairment, confusion, or delirium. Depression or psychosis with hallucinations and delusions may occur. Elevated levels of cortisol are seen in Cushing’s syndrome. About half of all patients with Cushing’s syndrome develop psychiatric symp- toms. These symptoms may include lability, irritability, anxiety, panic attacks, depressed mood, euphoria, mania, or paranoia. Cognitive dys- functions may include cognitive slowing and poor short-term memory. Symptoms usually improve when cortisol normalizes. If not, or if symp- toms are severe, psychiatric treatment may be necessary. Cortisol levels have not been found to be useful in the assessment or management of primary psychiatric disease. In particular, the dexam- ethasone-suppression test (DST) remains a research tool in psychiatry that is not used in routine clinical care. Anabolic Steroid Use Use of anabolic steroids has been associated with irritability, aggres- sion, depression, and psychosis. Athletes and bodybuilders are common abusers of anabolic steroids. Urine specimens can be used to screen for these agents. Because so many compounds have been synthesized, a variety of tests may be required to confirm the diagnosis, depending on the compound that has been used. Consultation with a specialist is advised. Generally, androgens other than testosterone can be detected by gas chromatography and mass spectroscopy. Antidiuretic Hormone Arginine vasopressin (AVP), also called antidiuretic hormone (ADH), is decreased in central diabetes insipidus (DI). DI may be central