A confusional state, sometimes referred to as encephalopathy or delirium, is a state in which the level of consciousness is depressed, but to a lesser extent than in coma (unarousable unresponsiveness; see Chapter 3). In confusional states, responses to stimulation are at least semi-purposeful, whereas in coma, patients fail to respond to even painful stimulation or do so only in reflex fashion.Thus the difference between a confusional state and coma is largely one of degree, and the causes overlap extensively.
Evaluation of a patient with altered consciousness is aimed first at characterizing the nature of the disorder (confusional state, coma, or a more chronic condition, such as dementia) and second at determining the cause. If the patient is the only source of information, little history may be available from him or her. However, old medical charts and the patient’s clothing and other personal effects can provide diagnostic clues, and the general physical examination may be similarly helpful.
A confusional state can be most readily distinguished from dementia by the time course of the impairment: confusional states are acute or subacute in onset, typically developing over hours to days, whereas dementia is a chronic disorder that evolves over months or years.
Certain causes of confusional state must be identified urgently because they may lead rapidly to severe structural brain damage or death, and prompt treatment can prevent these complications: examples include hypoglycemia, bacterial meningitis, subarachnoid hemorrhage, traumatic intracranial hemorrhage, and Wernicke encephalopathy (Table 4-1).
Table 4-1. Most Urgent Causes of Confusional States. |Favorite Table|Download (.pdf)
Table 4-1. Most Urgent Causes of Confusional States.
|Cause||Clinical Evidence||Laboratory Confirmation||Treatment|
|Hypoglycemia||Tachycardia, sweating, and dilated pupils, sometimes progressing to mimic herniation, with or without lateralized signs||Low plasma glucose||IV glucose|
|Bacterial meningitis||Headache, fever, Brudzkinski or Kernig sign||Positive CSF Gram stain, low CSF glucose, and increased CSF protein||IV antibiotics|
|Subarachnoid hemorrhage||Headache, hypertension, retinal hemorrhages, Brudzkinski or Kernig sign||Non-clearing red blood cells in CSF; subarachnoid blood and aneurysm or other vascular malformation on CT scan||Surgical ablation of aneurysm or other vascular malformation|
|Traumatic intracranial hemorrhage||Headache, hypertension, lateralized neurologic signs||Epidural, subdural, or intracerebral hemorrhage on CT scan||Surgical evacuation of epidural or subdural (or in some cases intracerebral) hematoma|
|Wernicke encephalopathy||Ophthalmoplegia, ataxia||Macrocytic anemia may coexist||IV thiamine|
History of Present Illness
The history should establish the time course of the disorder and provide clues to its nature and cause. Confusional states are acute to subacute in onset, whereas dementias are chronic disorders. In either case, the observations of others may be the only history available. It is, therefore, useful to have access to a relative or friend who can furnish details about the patient’s previous level of functioning, the time when dysfunction became evident, and the ...