Mohammed T. Abou-Saleh

128 PRINCIPLES AND PRACTICE OF GERIATRIC PSYCHIATRYwherever possible, mainly to establish the patient’s normal mentaland physical state and the timing of any change, making use of‘‘landmarks’’ (such as Christmas) to focus the memory. Thepatient’s current mental state should then be assessed in the lightof this information.Diagnosis and AssessmentWhen assessing an elderly person with a potential delirium, it isuseful to bear in mind the common causes for precipitatingdelirium, which include infections, biochemical and metabolicderangements, organ failure and drugs. There is frequently morethan one potential cause and thus assessment should becontinued, even after one ‘‘cause’’ has been identified.The approach and manner of the clinician towards the patientare of great importance. The aim is to provide a stable and, ifpossible, familiar sensory environment, so assessment should takeplace in a well-lit room with a minimum of distracting andmisinterpretable stimuli. Physical examination starts with assessmentof general hygiene, nutritional state, hydration andsuperficial signs of injury.Body temperature must be measured with care: significantinfections usually cause fever at any age 25 , although it is oftenmissed in elderly patients, where oral or axillary temperature maytake longer to equilibrate with core temperature 26 . Suspectedhypothermia must be checked by measuring rectal temperature.The relationship between peripheral and core temperaturedepends mainly on the state of the circulation: cool peripheriesare just as likely to indicate arterial shut-down, due to low cardiacoutput or hypovolaemia, as hypothermia. Other important signsof dehydration or blood loss are a low jugular venous pressure(venous pulsation not visible at the root of the neck with thepatient lying at 208 or less to the horizontal) or posturalhypotension (a fall of over 20 mmHg systolic and/or 10 mmHgdiastolic on sitting or standing up). The latter may, of course, bedue to the effect of drugs or autonomic failure, in which case thefall in blood pressure may not be accompanied by reflextachycardia. High blood pressure has little diagnostic value andshould normally be left alone in the acute situation.Abnormalities of heart rate or rhythm can also seriouslyaffect cardiac output and cerebral perfusion. Heart rate shouldbe assessed by both feeling the pulse and listening over theprecordium, where murmurs can also be detected. An electrocardiogramis an essential extension of clinical examinationand, as well as documenting heart rhythm, may also showclinically undetectable signs of myocardial infarction. Signs ofcardiac failure should be sought, including the presence of agallop rhythm, fine inspiratory crepitations in the chest andperipheral oedema. The peripheral pulses should be felt. Bruitsin the neck are useful, although non-specific, markers of arterialdisease.Abnormalities of respiratory rate or pattern must be noted, aswell as the presence of central or peripheral cyanosis. In adelirious patient with cyanosis, warm peripheries and boundingpulses, the characteristic flapping tremor of CO 2 retention shouldbe sought. Focal signs in the chest are useful but non-specific, anda chest X-ray is nearly always required. Any sputum must beexamined at the bedside as well as sent for microscopy andculture. Arterial blood gasses are sometimes useful, but bothpersistent and transient hypoxaemia can be detected noninvasivelywith a pulse oximeter, although in the presence ofsigns of hypercapnia measurement of arterial blood gases ispreferable.Examination of the alimentary system begins with nutritionalassessment and inspection of the mouth, looking for evidence ofsepsis or neoplasm. The abdomen must be carefully examined, asvirtually any surgical emergency can present as a change in mentalstate without apparent abdominal symptoms. Abdominal signsmay be far from obvious and many a strangulated hernia in anelderly patient has been missed by the unwary.Urinary retention and faecal impaction are often detectable perabdomen but a rectal examination should also be done whereverpossible. Whether constipation can cause delirium by itself is stilla subject of vigorous debate, but most geriatricians and generalsurgeons are familiar with the elderly patient whose mental andphysical state improves dramatically with rehydration andenemas. Examination of the perineum includes inspection ofclothing for evidence of incontinence or precautions against it.Incontinence is a frequent finding in patients with delirium 21 ;whether as a consequence of the underlying cause or as a directresult of the mental disturbance is not clear.In the locomotor system, trauma and acute inflammation areimportant causes of delirium and swelling, warmth, tendernessand pain on movement of any joint should give rise to suspicion.The feet should be carefully examined for signs of ischaemia orsores, and the gait observed.The most important part of neurological examination is theassessment of conscious level and higher mental function. In adelirious patient this is as much the province of the physician asthe psychiatrist and it is important that both terminology andassessment should be standardized. The hard-pressed housephysician confronted with an acutely disturbed patient in themiddle of the night is unlikely to turn to the Diagnostic andStatistical Manual of Mental Disorders of the AmericanPsychiatric Association for immediate guidance, but she mightfind a simple standardized assessment of attention, orientationand memory, such as the 10-question Abbreviated Mental TestScore 28 or the Mini-Mental State Examination 13 useful. Such testsare often criticized because they are prone to misuse, a low scorebeing taken as evidence of dementia, but their main value lies inrepeated use, when dramatic changes often seen in acute medicalpatients clearly point 29 to delirium rather than dementia as thecause of poor performance. The routine use of such tests remindsthe busy junior doctor to consider the possibility of delirium, andmay prompt a search for the underlying cause in those whohave a low score. Moreover, routine use of cognitive screeningtests can avoid the clinician being fooled by an apparentlycognitively intact older person who, in fact, has a significantcognitive deficit but a good ‘‘social front’’, can act as a baselineshould the mental status change. It is important to be aware,however, that these tests are merely screening tests, and thescores are influenced by numerous factors other than thecurrent mental disturbance. Including sensory impairments,educational level, social class and language. When applyingstandardized criteria to patients admitted to a geriatricassessment unit, 18% satisfied DSM-III-R criteria for deliriumon admission 29 and the mean duration of the delirium by the samecriteria was 7 days. Some deficits persisted longer, however,notably memory impairment, with a mean duration of 28 days.The use of standardized scales will not replace clinical judgementbut will undoubtedly lead to greater clarity of thought anddiscussion, and is essential for progress in research.Many clinicians place great emphasis on careful neurologicalexamination, looking for focal signs which, if found are usuallyattributed to cerebrovascular disease. This assumption may oftenbe correct, although the evidence is scant, but it is a mistake toblame everything on acute stroke, since the metabolic disturbancecausing delirium may simply be highlighting areas of brainischaemia. Thus, focal signs may be related to previous strokedamage, where neurological function has largely recoveredalthough perfusion has remained impaired. If this is notappreciated, then the real culprit, which might be a treatableinfection, may be missed.