Altered mental status

Altered mental status due to psychiatric causes is discussed in the first of two columns on the topic.


Altered mental status is commonly encountered among inpatients. It is defined as change in intellectual, emotional, psychological, and personality functioning, typically accompanied by behavioral changes, and in hospitalized patients it is almost always acute. Altered mental status is not a diagnosis but rather a group of variable, nonspecific neurologic symptoms requiring further specification of the cause. It may be classified using three broad clinical areas: psychiatric, encephalopathic, or disease processes confined to the intracranial contents.

Photo by Thinkstock
Photo by Thinkstock

Psychiatric mental disorders that may cause altered mental status include schizophrenia and other psychoses, mania primarily due to bipolar disorders, severely decompensated major depression, and rapid progression of dementia. Acute encephalopathy causes altered mental status due to generalized brain dysfunction resulting from reversible systemic metabolic or toxic processes. Intracranial processes such as stroke, hemorrhage, or neoplasm may cause altered mental status due to their local or generalized effects on the brain.

Patients presenting with altered mental status can be classified as hyperactive or hypoactive. Manifestations of the hyperactive state may include increased psychomotor activity, agitation, labile mood, and behavioral disturbances. Hypoactive changes may include decreased psychomotor activity, altered level of consciousness, depressive affect, or withdrawal.

An altered level of consciousness (including changes in both arousal and responsiveness) is a very important clinical and documentation consideration that requires careful assessment and precise, specific terminology. It can range from lethargy to stupor and obtundation to deep coma, sometimes with complete absence of responsiveness.

These changes are assessed using the Glasgow Coma Scale (GCS). A score of 3 to 8 (severe) is clearly consistent with the diagnosis of coma, a score of 9 to 12 (moderate) indicates stupor or obtundation, and a score of 13 to 15 (minor) is lethargy or drowsiness. These descriptive terms should always be used to document the patient's condition. It is crucial that the GCS be calculated whenever a patient has an altered level of consciousness, regardless of its cause.

To classify and document the causes of altered mental status for precise diagnosis and correct coding, the concept of delirium must be clearly understood from a broad clinical perspective. Delirium is not a disease process but rather an acute clinical syndrome with an underlying cause. Characteristics may include confusion, disorientation, agitation, inattention, and disorganized behavior. Patients may even develop psychotic symptoms of hallucinations and delusions. Delirium may be associated with psychiatric, encephalopathic, or intracranial causes of altered mental status.

The American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), indicates that delirium is an acute disturbance in attention, awareness (reduced orientation to the environment), and cognition, affecting such faculties as memory, orientation, language, perception, and visuospatial ability, not associated with severely reduced level of consciousness and not a manifestation of another underlying neurocognitive disorder. When an underlying neurocognitive disorder is causing the symptoms of delirium, delirium should not be separately diagnosed.

According to the DSM-5, delirium is a manifestation of an underlying medical condition, the effects of medication or nonmedicinal drugs and toxins, or multiple factors. Delirium is therefore almost always caused by either intracranial pathology or a metabolic or toxic encephalopathy resulting from extracranial medical conditions, drugs, or toxins. The DSM-5 also states that the underlying cause should be documented and coded along with delirium and gives the example of delirium due to hepatic encephalopathy.

Psychoses are defined by disordered thought and behavior, including loss of contact with reality. Manifestations include delusions, hallucinations, disorganized speech, and abnormal behavior. Schizophrenia is by far the most commonly encountered form, but psychotic symptoms may occur with delirium, severe manic episodes of bipolar disorder, and even severe depression. When delirium occurs in a patient with schizophrenia (or another form of psychosis), delirium should not be separately diagnosed.

Mania is a state of abnormally elevated arousal and energy level together with labile mood. The most common cause is decompensated bipolar disorder. It is characterized by euphoric or irritable mood, psychomotor hyperactivity, racing thoughts (“flight of ideas”), and pressured speech. Patients are not confused or disoriented unless their mania progresses to psychotic manifestations.

Major depression, or major depressive disorder (MDD), can sometimes become so severe that patients may have, or appear to have, an altered mental status. Hypoactive manifestations of severe MDD may include withdrawal, inattention, memory loss, hypersomnia, or inability to perform activities of daily living. Patients may even become catatonic with stupor, mutism, and bizarre body movements or posturing. On the other hand, some patients may develop psychotic features with delusions and/or hallucinations. Clinicians must always consider whether extreme hyperactivity actually represents a manic episode of bipolar disorder, which may have been previously undiagnosed.

A common clinical scenario among hospitalized patients is an apparent acute mental status alteration in a patient with preexisting dementia. However, an acute mental status change due to rapid progression of dementia alone is extremely unusual. A truly acute change almost always has another underlying cause, usually a metabolic or toxic encephalopathic process or an acute intracranial condition.

On the other hand, it is not unusual for a family to bring a demented family member to the hospital reporting an acute mental status change when there really hasn't been an acute change in baseline mental status. It is always important to determine such patients' true baseline, and observing no improvement is clear evidence that nothing acute has happened. Family members may not have noticed slowly progressive changes that at some point appear acute to them. Sometimes, a family may have become exhausted by trying to care for a loved one with progressive dementia and will claim there has been an acute change.

In summary, altered mental status is not a diagnosis but rather a group of variable, nonspecific neurologic symptoms with psychiatric, encephalopathic, and intracranial pathologic causes that should always be precisely documented and coded. A clear understanding of the clinical syndromes of delirium and altered consciousness are necessary for diagnostic classification, documentation, and coding purposes.

Next month we will address the encephalopathic and intracranial causes of acute alteration in mental status, as well as the importance of specific documentation for correct coding that will accurately reflect their severity.