**4. Clinical features**

*Suggestions for Addressing Clinical and Non-Clinical Issues in Palliative Care*

The genesis of delirium is multifactorial. In general, all conditions that can induce a neuroinflammatory process are potential causes of delirium. Through the action of cytokines, chemokines, tumor necrosis factor-alpha, and other inflammatory agents (e.g., interleukin (IL)-1, and IL-6), a cascade of events is activated; it culminates in endothelial and microvascular damage and alterations of the blood– brain barrier. Again, disorders of neurotransmitter pathways such as the dopamine and acetylcholine systems, involving respectively dopamine excess or acetylcholine depletion, have a key role in the pathophysiology of delirium [9]. Further, in clinically ill patients, the impairment of cerebral oxidative metabolism is another

Although drugs such as opioids, anticholinergic drugs, steroids, chemotherapies and metabolic disorders such as metabolic encephalopathy, nutritional deficiencies, electrolyte disturbances, dehydration are the main inducers of delirium, many conditions can provoke delirium. These causes include constipation, infections, hematological changes, paraneoplastic syndromes, brain neoplasms, central nervous system (CNS) secondarisms, seizure disorders, hypoxia, hypo/hypercarbia, and environmental factors. Several acronyms are commonly used to memorize and recognize potential causes. Sometimes the cause of the delirium cannot be found

**3. Mechanism and causes**

(**Table 1**).

potential mechanism to be considered [10].

I WATCH DEATH Infections

DELIRIUM **D**rugs

DIMES **D**rugs

*Adapted from Bush [3].*

Withdrawal

Trauma CNS pathology Hypoxia Deficiencies Endocrinopathies Acute vascular Toxins or drugs Heavy metals

**I**nfection

**H**ypoxemia

**I**nfections **M**etabolic **E**nvironmental **S**tructural

*Acronyms used to memorize possible causes of delirium in palliative care.*

Acute metabolic causes

**E**lectrolyte disturbances **L**ack of drugs withdrawals

**R**educed sensory input **I**ntracranial infection **U**rinary/fecal retention **M**yocardial/pulmonary causes

**I**nfections **I**mmobilization **N**on-pharmacological interventions **K** or electrolyte problems

THINK **T**oxic Situations such as shock, dehydration, deliriogenic medications, organ failure

**4**

**Table 1.**

According to the type of psychomotor activity, there are three subtypes of delirium:


In palliative care, the hypoactive and mixed are the most frequent subtypes of delirium. The lack of tangible agitation and the erroneous belief that the patient is drowsy because of illness, drugs administered, or an underlying depressed habitus, make this subtype very often misunderstood. This is a serious care gap as hypoactive delirium is frequently associated with perceptual disturbances and distress [11].
