The physical examination and investigations relevant to psychiatry

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CHAPTER 2 The physical examination and investigations relevant to psychiatry

Darryl Bassett, David J. Castle

This chapter provides a brief overview of the physical examination in psychiatry, as well as pointing to special investigations that might be pertinent in the psychiatric setting. Of course the extent of special investigations depends upon the clinical presentation and findings on psychical examination, but as a general guide those investigations shown in Box 2.1 are recommended in most cases.

Why a physical examination?

Many psychological disorders are provoked, amplified or complicated by general physical illness. In addition, some patients present with psychological symptoms due entirely to general physical illness (see Ch 4). It is appropriate to ensure that a comprehensive history and physical examination is included in the management of most patients presenting with psychological disorders. Exceptions to this include patients whose medical history is well known already or who choose to decline such examination (the potential consequences must be explained to the patient and documented).

Sometimes, the examination will need to be postponed until the patient is capable of informed consent. For example, capacity for consent may be impaired by psychosis associated with fear of contact or a history of sexual abuse may provoke anxiety about an examination.

Who performs the physical examination?

A physical examination is a vital component of any psychiatric examination, whoever performs this examination. While psychiatrists should remain competent in physical examination skills, some patients may prefer that someone other than a psychiatrist has physical contact with them and this requires sensitive negotiation.

Context of the physical examination

A thorough mental state examination (see Ch 1) will help focus the physical examination, but a brief review of all systems is essential. A good motto is ‘when in doubt, think organic’ and review all physical findings, as some general medical disorders may present with psychological symptoms (see Ch 4).

Elements of the physical examination

The physical examination should follow the usual clinical principles, but certain elements are particularly important in the psychiatric context.

Observation

Observation includes noting:

facial expression (e.g. tearfulness, injected conjunctivae from substance abuse, dystonia and dyskinesia with medications, fixed gaze or grimacing in schizophrenia)

posture (e.g. bizarre posturing in schizophrenia), unusual movements (e.g. tremor, dystonia, dyskinesia, choreoathetosis or stereotypy), and

bruising, needle marks, mutilation (e.g. lacerations, scratching or burns) and unusual hair loss (e.g. trichotillomania or hypothyroidism).

Palpation

Palpation includes:

altered tone (e.g. medication effects)

enlarged thyroid gland (e.g. hypothyroidism)

enlarged and/or tender liver (e.g. alcohol abuse), and

pulse examination (e.g. anxiety disorders).

Mensuration

Blood pressure should be measured (e.g. medication effects).

Waist circumference

Waist circumference should be measured to determine the risk of cardiovascular disease and/or diabetes mellitus (type 2). For males, a waist circumference equal to or greater than 94 cm represents a moderate risk, while a waist circumference greater than 102 cm represents a high risk. For females, a waist circumference equal to or greater than 80 cm represents a moderate risk, while a waist circumference greater than 88 cm represents a high risk.

Body weight and height measurement

Body mass index (BMI) is calculated as follows:

A BMI over 25 = overweight, while a BMI over 30 = obese.

Other neurological features

pupillary changes

fundal examination

occulomotor functions

visual fields to confrontation, and

primitive reflexes.

Blood and urine tests

The focus is upon those of particular psychiatric importance. Baseline measures are invaluable with all relevant investigations and the frequency of certain tests thereafter will vary with clinical variables such as medication use, substance abuse and the progression of illness.

Complete blood examination

White cell counts are particularly important with medications such as clozapine. Platelet counts are relevant particularly with medications such as sodium valproate and carbamazepine. Note that macrocytosis can be associated with alcohol abuse.

Electrolytes

These include serum sodium, potassium, chloride and bicarbonate estimations. Note that lithium levels are altered by fluctuations in sodium levels, and several medications (e.g. selective serotonin reuptake inhibitors (SSRIs) and serotonergic and noradrenergic reuptake inhibitors (SNRIs)) can provoke hyponatraemia, particularly in the elderly.

Renal function

This includes serum urea, creatinine and calculated glomerular filtration rate (GFR) estimations. It should be noted that several medications (e.g. lithium, amisulpride) are predominantly or significantly excreted through the kidneys and renal dysfunction can significantly alter their blood levels. Lithium can cause kidney damage and, rarely, renal failure.

Liver function

This includes serum bilirubin, alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), alanine aminotransferase (ALT), aspartate aminotransferase (AST), total protein, albumin and globulin estimations. Most psychotropic medications are metabolised in the liver, and liver dysfunction can significantly alter the blood levels of these medications. Alcohol and several psychotropic medications can cause liver damage (e.g. chlorpromazine and sodium valproate) and monitoring can be invaluable. Intravenous substance use may provoke significant liver dysfunction.

Endocrine functions

Thyroid function tests (includes serum thyroid-stimulating hormone (TSH), T4 and T3) are particularly important in a variety of psychological disorders (e.g. anxiety disorders, depressive disorders and cognitive disorders). Thyroid monitoring is particularly important in the use of lithium, which can cause thyroid damage: annual monitoring is usually sufficient unless clinical factors suggest a higher risk.

Fasting blood glucose (after 3 months and then 6-monthly unless particularly high-risk patient) is particularly important with some antipsychotic medications (e.g. clozapine, olanzapine, quetiapine, risperidone) and sometimes with other medications which are associated with weight gain (e.g. lithium, mirtazapine). There should be concurrent monitoring of waist circumference and body weight (with BMI) at each visit.

Calcium (adjusted for albumin levels) and phosphate levels may be important in depressive disorders or as a consequence of treatment with lithium.

Prolactin levels are relevant for medications which promote increased release of prolactin, such as amisulpride, risperidone and paliperidone.

Oestrogen and gonadotrophin levels may be relevant if a perimenopausal state is clinically significant (e.g. depressive disorders).

Testosterone levels may be useful in males with mid-life depressive symptoms and prominent amotivation, although gonadotrophin, luteinising hormone and testosterone levels tend to fall during depressive disorders and recover with treatment. They may also be relevant in females with persistent loss of libido.

Other endocrine tests are usually reserved for less common clinical situations (e.g. 24-hour urinary cortisol for adrenocortical disorders, noradrenaline and serotonin levels in adrenomedullary disorders).

Lipids

Fasting cholesterol and triglyceride levels are very important when prescribing several antipsychotic medications (e.g. clozapine, olanzapine, quetiapine, risperidone). Monitoring after 3 months of commencement of the agent, and thereafter every 6–12 months (depending on levels and risk profile), is recommended.

Medication blood levels

The low therapeutic index of lithium makes close monitoring of blood levels very important. Blood should be taken between 10 and 12 hours after ingestion of lithium, close to the expected end of the ‘distribution phase’, to allow meaningful comparison with other patients. Persistent monitoring should be performed every 3 months and at times of suspected toxicity (note that toxicity can occur even when the blood level is within the accepted range).

Levels of other medications such as antidepressants, anticonvulsants and antipsychotic medications can be appropriate in certain clinical situations.

Blood should be sampled at the expected ‘trough’ level of the medication.

Serology

Hepatitis B and hepatitis C are relevant if there is a history of risk behaviours such as intravenous substance use.

Human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) are seen in excess in a number of psychiatric disorders, and infection has many psychological presentations. It is ethically appropriate to ask the patient’s permission for these tests and to be attentive to appropriate counselling.

Syphilis serology may be performed, as the illness can imitate a number of psychiatric and neuropsychiatric disorders.

Vitamin assays

These are performed mostly in depressive disorders, delirium and dementias, and in the setting of chronic substance use and/or malnutrition. They include assays of vitamin B12, red cell folate, thiamine and vitamin D.

Urine drug screens

Screening for substance use is particularly useful for patients with a history of substance abuse, those with psychosis and those in whom substance use might contribute to complications in treatment. Dilution of urine, for example by drinking copious water or directly adding water, may lead to false negative results. The urine creatinine level is measured and reported to allow recognition of this. Optimally, the urine sampling should be supervised.

Initial urine screening is usually performed using radioimmunoassay techniques. High pressure gas liquid chromatography is used to establish the precise nature of a substance detected by initial screening.

Electroencephalography (EEG)

EEG examinations are particularly useful in psychiatric disorders as a screening examination for ‘organic’ brain disorders such as encephalopathies, epilepsy and a range of other neurological disorders. Indications include clinical presentations suggestive of epilepsy or other neurological disorders, which might be evident on EEG (e.g. encephalopathies), unusual psychotic symptoms or signs, and recent significant changes in behaviour or personality.

Neuroimaging

Computerised tomography (CT)

This is a very useful investigation to exclude major brain pathology and the indications are similar to those for an EEG, but should be used as a screening investigation prior to electroconvulsive therapy (ECT) as well.

Magnetic resonance spectroscopy

This is useful to exclude major neurological pathology which might be suspected. Subtle signs such as subcortical hyperintensities can be relevant in mood disorders.

Single photon emission computerised tomography (SPECT)

SPECT is an imaging technique which uses a single photon source injected into the bloodstream to provide scans indicating metabolic activity (and hence blood flow) throughout the brain. It is predominantly a research tool in psychiatry, but can be useful to detect relevant cerebrovascular disease, early degenerative diseases (e.g. dementias in younger patients) or sometimes to offer possible options in psychopathology. While ‘false negative’ findings are common in clinical practice, the presence of significant alterations in function (see Chs 6 and 7) can help support the presence of major mood disorders, schizophrenia and major anxiety disorders.

Positron emission tomography (PET)

PET is an imaging technique similar to SPECT. It uses a dual photon source (at 180° to each other) and provides a higher level of resolution than SPECT. This remains only a research tool in psychiatry, but it may have clinical applications in the future.

References and further reading

Hurley R Taber K, editor. Windows to the brain. Washington DC: American Psychiatric Publishing, 2008.

Levenson J., Lyketsos C., Trzepacz P., editors. Psychiatry in the medically ill. Psychiatric Clinics of North America, Vol. 25, No.1. Philadelphia: WB Saunders, 2002.

Sadock B., Sadock V., editors. Kaplan and Sadock’s concise textbook of clinical psychiatry. Philadelphia: Lippincott Williams and Wilkins, 2008.

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