Delirium occurs at any age, but it occurs more commonly in patients who are elderly and have compromised mental status. Delirium is extremely common among nursing home residents and in medical and surgical inpatients (10-20%). Prevalence of delirium in ICU patients may reach as high as 50-75%, reason for which delirium was also referred to as “ICU psychosis”. In Nigeria, of the 77 in-patients referred to Ibadan, 68 % of those referred had definite mental disorders, most commonly psychosis (50.7%), and delirium (29.9%). Infectious disease, notably Salmonella typhi, were most predominant etiologies.

1. Predisposers: Visual impairment, Underlying brain pathology, Chronic Major medical illness, Recent major surgery, Extremes of age (very old and very young), Previous history of delirium, History of head injury, Surgical procedure, and post-operative period (especially cardiac), Hip fracture, burn victims, alcohol and benzodiapine-dependent.
2. Precipitants: Dehydration, drug abuse, Metabolic abnormalities, Anemia, Pain, Shock, Polypharmacy, Sensory deprivation, Sensory over-stimulation, Infections.

1. Neurotransmitter imbalance: in the reticular activating system
2. Neuroinflammatory: Inflammatory response with increased Cytokines- IL-1, IL-2,6; TNF; IF.
3. Neuroimaging: white matter lesions including cerebral atrophy, and ventricular enlargement,
4. Neurophysiology: slowing of resting state EEG rhythms with abnormally decreased alpha
5. Neuroendocrinology: Increased activity of the hypothalamic-pituitary-adrenal axis.

1. Hypoactive or hypoalert: The most common type (65.6%). The patient appears to be napping on and off throughout the day, lethargic and may have psychomotor retardation. This may be misdiagnosed as dementia or depression
2. Hyperactive or hyperalert/agitated: Accounts for 21.9%. The patient is hyperactive, combative, and uncooperative. There are presence of hallucinations, delusion or inappropriate behavior. Frequently, they come to attention because they are difficult to care for.
3. Mixed Delirium: Is a mixture of both hypoactive and hyperactive delirium together (12.1%).

1. Discriminating: Waxing and waning awareness; Clouding of consciousness, Acute onset.
2. Consistent features: Disorientation (time), distractibility, Recent Memory impairment.
3. Psychomotor disturbances: in the form of agitation, hyperactivity (related to disorientation or confusion), hypoactivity (apathy, withdrawal). Disturbance of the sleep-wake cycle; Diurnal variation with worsening of symptoms in the evening and night (sundowning effect).

Diagnosis of delirium is mainly clinical but is often missed as the possibility is overlooked in the medical and surgical setting. Delirium is diagnosed at bedside, first the diagnosis of delirium itself, and second, the diagnosis of the cause. Information from other informants can be very important but bedside clinical testing is the mainstay.

ICD-10 diagnosis includes (1) Impairment of consciousness and attention : from clouding to coma, reduced ability to direct, focus, sustain and shift attention; (2) Global disturbance of cognition : Perceptual distortions, impairment of abstract thinking and comprehension, impairment of immediate recall and of recent memory, disorientation; (3) Psychomotor disturbances : Hypoactivity or hyperactivity, increased or decreased flow of speech; enhanced startle reaction; (4) Disturbance of sleep-wake cycle : Insomnia, reversal of the sleep-wake cycle; daytime drowsiness; nocturnal worsening of symptoms; disturbing dreams or nightmares; and (5) Emotional disturbances : Depression, anxiety, fear, irritability, euphoria, apathy  or perplexity.

The onset is usually rapid and the course diurnally fluctuating and total duration of the condition much less than 6 months. The above clinical picture is so characteristic that a confident diagnosis of delirium can be made even if the underlying cause is not clearly established.

1. Neurologic: Complex partial seizures, Traumatic Brain Injury, Beclouded Dementia.
2. Psychiatric: Mood disorders, Acute and transient psychotic disorders, Dissociative disorders
3. Physical: Thyrotoxicosis, Severe pain.

History: time course of mental status changes, association with other events (i.e. medications, illness). Also, evaluation for recent medical illness and interventions.  Screen for history of substance dependence to determine the risk of withdrawal.

MSE - Especially motor activity (for purposeless aggressive behaviour), Cognition (for fluctuating level of consciousness),

Physical examination: can give a clue to the cause of delirium while Investigation will depend on the suspected causes and the clinical situations. Chart notes with particular attention to level of consciousness, behaviour and level of cooperativeness. Look at the overall time course. Vital signs: normal range of BP, HR, SpO2, Temperature, and hydration.

Biological: FBC, ESR, Urinalysis, Blood glucose, Blood urea, Serum electrolytes, LFT, RFT, TFT, CSF analysis, Serum B12 folate levels, VDRL, HIV testing, Urine toxicology, CXR, Skull Xray, CT scan, MRI, EEG in delirious patients characteristically shows generalised slowing of activity. It may sometimes show focal areas of hyperactivity.

Psychological testing: Confusion Assessment Method (CAM), Delirium Rating scale (DRS).

Non-pharmacologic treatments: These are the first measures in delirium unless there is severe agitation that places the person at risk of harming oneself and others. Identification and treatment of the underlying acute physical cause; the search should be thorough, as in the diagnosis and treatment of any other organ system failure. Optimising conditions of the brain: ensuring the patient has adequate oxygenation, hydration, nutrition, normal levels of metabolite, control fever if present, pain treatment and stopping non-essential medications. A 40% decrease in the incidence of delirium was achieved in adults using a multicomponent approach, which included repeated reorientation, early mobilization, noise reduction, and a non-pharmacological sleep management.

Pharmacological: Medication should not be used merely because the patient has delirium, as drugs themselves will tend to make the patient drowsy and therefore mitigate against recovery. However, it may be necessary if patient is distressed (e.g if a patient in the ICU is removing endotracheal tube, arterial lines) agitated or in danger of injuring self or others, and mainly to control psychosis and insomnia. High potency antipsychotic (haloperidol) is the most used usually in low doses. Second generation antipsychotics may be used e.g risperidone olanzapine, quetiapine, cloxapine, aripriprazole e.t.c. However, at times of severe life-threatening agitation, sedation at nearly any cost becomes necessary, and benzodiazepines e.g.  Bromazepam or Lorazepam are used.

Prodromal symptoms may occur a few days prior to the full development of symptoms. The symptoms will continue to progress/fluctuate until the underlying cause is treated. Delirium 6will continue if the primary ailment remains untreated and subside following treatment. The older the patient is, the longer the period of delirium takes to resolve. Recent studies showed that many patients still meet the criteria for delirium for a prolonged period after hospital discharge with 21% showing persistent delirium 6 months after discharge. Mortality is high – About 25% mortality in 3 months, but can be reduced by rapid diagnosis, identification of cause and treatment.

Episodes of delirium can be prevented by identifying hospitalised people at risk of the condition: those over 65, those with known cognitive impairment, hip fracture, and severe illness. Close observation for early signs is recommended in those people. Also, systematically addressing contributing factors (such as constipation, dehydration, and polypharmacy), as well as providing adequate lighting ways to tell time and signage, may prevent delirium. You can improve delirium with such simple measures as Glasses, hearing aids, Fluids and nutrition, reducing noise, Early mobility, and Familiar faces.

Delirium is a neuropsychiatric syndrome common among the medically ill and is often misdiagnosed as a psychiatric illness, which can result in the delay of appropriate medical intervention. It has multiple causes and multiple ways of presentation, and it is potentially preventable. It is associated with an increased cost of medical care and increased morbidity and mortality, so the identification patients at risk, prompt diagnosis, and early treatment are crucial.