The symptoms of postoperative psychosis are many and varied, and as noted above may be mistaken for symptoms of other psychiatric disorders. The condition, especially when associated with cognitive decline, may be responsible for increased morbidity and prolonged hospital stay. Recognizing the symptoms and treating them early may reduce the impact of this condition. Carers and relatives may find the symptoms very alarming and should be advised as to the likely course of the disorder.
Three types of postoperative neurobehavioural disturbance are recognized by Sanders et al. They suggest they may be usefully divided into distinct forms: emergence delirium, postoperative delirium, and postoperative cognitive decline.
These same authors usefully define the terminology they employ and give approximate time-spans for each:
“Delirium is defined by the presence of disturbed consciousness (reduced clarity of awareness of the environment with reduced ability to focus, sustain, or shift attention) and a change in cognition (such as memory deficit, disorientation, or language disturbance) or the development of a perceptual disturbance that is not better accounted for by a pre-existing, established, or evolving dementia. Emergence delirium occurs on emergence from anaesthesia and sedation, with no lucid interval, and lasts approximately 30 minutes. Postoperative delirium lasts hours or longer, with or without lucid intervals. Postoperative cognitive decline refers to a more subtle cognitive impairment noted on neuropsychological tests that typically assess attention and memory.”
They regard postoperative delirium as the most severe. They describe the phenomenon as “brain failure” and draw an analogy with failure of any major organ – e.g. kidney or liver.
There is no universally accepted mechanism thought to be responsible for the development of postoperative delirium. Very often there is a period of normality, followed by a dramatic change. Patients may become very lethargic and uncooperative or exceedingly agitated, aggressive and violent. They are at risk of lethal self-harm at this stage. In our view this is a medical emergency and help is required immediately. Signs include fluctuating levels of consciousness, inattention, disorganised thinking, and perceptual disturbances such as hallucinations and delusions.
Some factors are thought to predispose to the development of postoperative delirium. In one prospective study of the incidence of post operative delirium in an intensive care unit preoperative benzodiazepines, breast and abdominal surgery and surgery of long duration were found to be risk factors for emergence delirium. Thankfully in this study the incidence was uncommon. Sixty -four (4.7%) patients developed delirium in the PACU. Other prospective studies have found a higher incidence (20% +-). Other authors report incidence rates in medical inpatients as high as 42%. Other studies have failed to demonstrate benefit from identifying high-risk patients preoperatively. Introducing the delirium prevention protocol did not reduce delirium incidence although it was good at identifying those at greater risk. In this same study, the use of prophylactic medication (haloperidol) in high-risk patients failed to reduce the incidence of delirium prevention protocol did not reduce delirium incidence although it was good at identifying those at greater risk. In this same study, the use of prophylactic medication (haloperidol) in high-risk patients failed to reduce the incidence of delirium.
Symptoms of delirium
- Sudden onset of impairment in cognition (patient is less sharp, slurred speech, sleepy all the time)
- Problems with orientation in time and/or place and/or person
- Impairment of memory (repeating the same story to the same person in a short period of time)
- Impairment in ability to plan or organise
- Changes in sleep-wake cycle
- Altered affect, often with emotional lability (mood swings, emotional dysregulation, alternating tearfulness and laughter, out or proportion to events)
- Altered perception of external stimuli (derealisation)
- Visual, sensory or auditory hallucinations – often vivid (seeing, feeling or hearing things or sounds others are unaware of)
- Agitation or change in activity levels
Due to the nature of the presenting symptoms, post-operative psychosis and acute confusional states may commonly be mistaken for other conditions with graver long term consequences:
- Dementia
- Depression
- Psychotic illness or bipolar disorder
The doctors and nurses may not know your relative as well as you will, or may not even have met them before (new shift). You may have noticed some of these initial signs or changes in your relative before anyone else. It is important to bring your observations to the attention of the nurses or doctors.
Assessing the level of disorientation
When staff respond to your observation that you believe your relative’s personality has changed, the initial assessment of an apparently confused patient would require some or all of the following measures.
Where possible, a new history should be taken. If the patient has periods of lucidity and insight then the history may be obtained from the patient themselves but very often the next of kin, relatives or accompanying person are the best source of information. This information should include discrete questions about drugs, alcohol use, other illnesses especially diabetes, head injury and previous mental state. It is likely that these lines of personal medical history will not have been explored previously if, for example, a patient’s initial purpose for admission to hospital had been for a joint replacement in the knee. Do not be offended by these questions, some of which may be very personal.
If the patient is disoriented then the degree of disorientation needs to be assessed. This is commonly achieved by means of standardized protocols. Examples are either the Confusion Assessment Method (CAM) 2, 3 or the Abbreviated Mental Test (AMT). Information that is collected includes asking the patient their:
- Age
- Date of birth
- The time to the nearest hour
- Year
- Name of institution
- Are they able to recognise two people (e.g. can they recognise the job of the person asking the questions and that of the nurse)
- Year of the first world war (or some other major event for younger people)
- Name of the monarch/president/prime minister
- To count backwards from 20 to 1
A score of less than 6 suggests impaired cognition. Having diagnosed impaired cognition it is important to identify the cause and start appropriate treatment. Depending on the cause the period required to recover once treatment is started may vary between hours to months.
Examination and investigations
There are additional means of assessing patients with POND you might expect the doctor to use when attempting to find the cause of the disturbance. They may include some or all the following. They would:
- Look for any obvious causes e.g. head injury (fallen out of bed), hypothermia (inadequate cover, for example have they been found wandering about the hospital unobserved without warm clothing), dehydration (confusion prevents feelings of thirst) and undiagnosed hip fracture. They should look for evidence of a cerebrovascular accident CVA (stroke), a urinary retention (place a hand on the lower belly or use a bladder ultrasound, plus tests for infection in the urine)
- They should check the body temperature, pulse, oxygen saturation (SPo2), blood pressure (BP) and central venous pressure (JVP – jugular venous pressure) – distended neck veins
- Look for sources of infection e.g. listen to the chest to detect chest infection. They should inspect the entire body including the operation site, for evidence of deep skin infection – cellulitis
- Perform and record a urine “Dip test” for blood, protein and sugar
- Check venous blood for hypoglycaemia (low blood sugar)
- Perform a full blood count (FBC), looking for raised white cell count (implying infection) or anaemia. A low haemaglobin levels may lead to relative hypoxia. Red blood cells that are present do carry the correct amount of oxygen but there are not enough red blood cells)
- Measure blood urea and electrolytes (U+Es or BUNs) looking for electrolyte imbalance and dehydration (Postoperative hyponatraemia – low sodium, is very common especially in the elderly undergoing joint surgery. A severely low postoperative serum sodium may allow water to accumulate on the brain causing swelling and impairing function)
- Serum Calcium- hypercalcaemia (high calcium) may result in confusion
- Perform an arterial blood gas to measure oxygen content and acidity of the blood
- They may examine the legs, especially the calves to find evidence of a deep vein thrombosis that has given rise to a pulmonary embolism. This may require a venous ultrasound to confirm or refute the diagnosis
- Possibly request a chest x-ray, (CXR) even if there are no clinical signs of pneumonia
- Perform an abdominal ultrasound to determine the state of the bowels. There may be few signs even severe infection within the abdomen in the elderly.
- Inspect the surgical wound for signs of infection
- Take venous blood for blood cultures
By the end of these standard, quick and inexpensive set of tests and investigations the cause of most impairment will have been identified. Most patients respond very quickly to correction in electrolyte imbalance or administration of antibiotics when infection is the precipitating factor. Occasionally no cause is found but even before any intervention or treatment is started a patient may quickly get better. A spontaneous or treatable recovery is not always the outcome.
Remember however, a good doctor will not be offended by a request for a second opinion or referral to a specialist experienced in general or internal medicine. You always have the right to ask.
References
- Sanders RD, Pandharipande PP, Davidson AJ, Ma D, Maze M. Anticipating and managing postoperative delirium and cognitive decline in adults. BMJ 2011;343:d4331
- Lepousé C, Lautner CA, Liu, L Gomis P and Leon A. Emergence delirium in adults in the post-anaesthesia care unit Br. J. Anaesth. (2006) 96 (6): 747-753.
- Yu, DH (Yu, Daihua); Chai, W (Chai, Wei); Sun, XD (Sun, Xude); Yao, LN (Yao, Linong)
- Emergence agitation in adults: risk factors in 2,000 patients. Canadian Journal Of Anesthesia-Journal Canadien D Anesthesie. Volume: 57. Issue: 9. Pages: 843-848
- Siddiqi, N., House, A. O. & Holmes, J. D. (2006) Occurrence and outcome of delirium in medical in-patients: a systematic literature review. Age and Ageing, 35, 350–364.
- Vochteloo AJH, Moerman S, van der Burg BLS, de Boo M, de Vries MR, Niesten DD, Tuinebreijer WE, Nelissen R, and Pilot P. Delirium risk screening and haloperidol prophylaxis program in hip fracture patients is a helpful tool in identifying high-risk patients, but does not reduce the incidence of delirium BMC Geriatr. 2011; 11: 39.