Recognizing medical emergencies presenting as psychiatric problems

Roy R. Reeves, DO, PhD; Randolph H. Henderson, PA

Dr. Reeves is Chief of Psychiatry at the G. V. (Sonny) Montgomery VA Medical Center and Professor of Psychiatry and Neurology at the University of Mississippi School of Medicine, Jackson. Mr. Henderson is a physician assistant in the Mental Health Service at the G. V. (Sonny) Montgomery VA Medical Center. The authors have indicated no relationships to disclose relating to the content of this article.

Altered mental status due to physical illness is often a medical emergency. Don’t assume the cause is psychiatric, even when the patient has a known psychiatric history.

Case studies

Case 1 A 24-year-old woman was brought to the hospital with a 1-week history of increasing insomnia, irritability, pressured speech, and flight of ideas. Although she had no history of mental illness, she was thought to have mania or cocaine intoxication and was admitted to a psychiatric unit. After admission, she developed a heart rate higher than 160 beats per minute and required emergency treatment with propranolol. With further laboratory assessment she was found to have a markedly elevated T₄ level. The cause of her symptoms was thyrotoxicosis.

Case 2 A 57-year-old man with a long history of alcohol dependence was picked up by police when they found him wandering the streets in an unkempt, confused state. He was admitted to a substance abuse unit but within a few hours became lethargic and then comatose. Emergency assessment revealed him to have a finger-stick blood glucose level of 18 mg/dL. He became alert immediately following IV infusion of thiamine and glucose.

Case 3 A 20-year-old woman was admitted to a psychiatric unit because of abnormal behavior, including picking at her clothes, talking incoherently, and staring into space. After admission, she rapidly deteriorated, becoming disoriented and poorly responsive. An EEG revealed left temporal spike and wave discharges, and a lumbar puncture revealed 100 WBCs and 20 RBCs per high-power field. Treatment with acyclovir for presumptive herpes encephalitis produced some improvement, although she ultimately had residual cognitive deficits.

Case 4 A 28-year-old woman with a history of bipolar disorder was hospitalized by a psychiatrist because she was thought to be depressed and withdrawn. She was apathetic with a flat affect and did not appear to be attending to things happening around her. About an hour later, she was noted to be lethargic, hypotensive, and difficult to arouse, requiring transfer to the intensive care unit. Subsequently, it was determined that her lithium level was higher than 3.5 mEq/L and that the cause of her deteriorating status was severe lithium toxicity.

Altered mental status

Psychiatric or medical illness can cause altered mental status. As these cases illustrate, many medical emergencies can cause symptoms that appear to be primarily psychiatric. Terms used to describe the state of acutely altered mental functioning due to medical illness include delirium, organic brain syndrome, and encephalopathy. The term delirium as described in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR)¹ will be used in this discussion.

By definition, delirium is a change in mentation occurring as a direct consequence of a physiologic abnormality. It is characterized by disturbance of consciousness (reduced clarity of awareness of the environment) with reduced ability to focus, sustain, or shift attention and by a change in cognition (such as memory deficit, disorientation, or language disturbance) or the development of a perceptual disturbance. Delirium develops over a short time (hours to days) and tends to fluctuate during the course of a day. Activity levels may be increased with agitation or decreased with a quiet delirium. Three variants are described: a hypoalert-hypoactive type, a hyperalert-hyperactive type, and a mixed type. The patient with the mixed variety may fluctuate rapidly between the hypoactive and hyperactive states. Symptoms may be intermittent, and different caregivers may witness completely different behaviors within a brief time span.^2,3

Numerous disorders can cause delirium, the major ones being CNS disease, systemic disease, and either intoxication with or withdrawal from pharmacologic or toxic agents. Some common disorders that can produce delirium include head trauma, CNS infections, brain tumor, vascular disorders of the CNS, epilepsy, endocrine dysfunction, hepatic and uremic encephalopathy, hypertension, hypoxia, cardiac arrhythmias, heart failure, systemic infections and sepsis, electrolyte imbalance, poisoning or intoxication, and drug withdrawal.

Delirium is a medical emergency and must be recognized and treated as such. Delirium (an acute condition) must be distinguished from dementia (a chronic condition), as memory impairment is common to both. However, the patient with dementia is usually alert and does not have the disturbance of consciousness that is characteristic of delirium. A patient may have delirium superimposed on a preexisting dementia.⁴

Recognizing medical causes of altered mental status

Abnormalities of perception and behavior are common in patients with delirium, and the clinician can easily overlook the underlying medical problem, placing the patient at risk. However, the provider should not assume that the patient’s problem is psychiatric simply because of altered mental status, and medical causes of changes in mental status must be considered.

One key is to be systematic in the evaluation. A complete medical history (including use of prescription and nonprescription drugs) should be obtained if possible; vital signs should be taken and a thorough physical examination performed. Laboratory and imaging studies should be ordered if indicated. For example, a patient with schizophrenia who has had several previous psychiatric admissions may still develop a medical disorder that could cause confusion. The important thing is not to assume that a psychiatric patient does not have a physical illness or that a patient appearing to be mentally ill necessarily is.⁵

Performing a mental status examination that focuses on orientation, memory, attention, and concentration is an essential part of the assessment of such patients. Except for dementia, psychiatric disorders do not generally impair consciousness or significantly diminish cognitive function. Thus, a schizophrenic patient may be delusional as part of the mental illness, but if the patient is obtunded or disoriented, medical etiologies should be considered. A commonly used screening tool that has stood the test of time is the Mini-Mental State Examination, which consists of a short series of questions and may, within a few minutes, provide a gross estimate of cognitive functioning.⁶

In many cases, it may be difficult to distinguish changes in mental status secondary to medical causes from those of psychiatric etiology. Some helpful clues are shown in Table 1.⁷

Altered mentation in any person with no prior psychiatric history requires a search for an underlying medical cause. Onset of illness before age 12 years or after age 40 years suggests a nonpsychiatric diagnosis. Disorders of extremely sudden onset are more likely due to medical than to psychiatric etiologies. Abnormal vital signs do not generally occur secondary to psychiatric disorders. Focal neurologic deficits or specific abnormal physical signs are most likely attributable to a medical problem. Although a person with a psychiatric disorder may exhibit bizarre thought processes, inappropriate affect, or unusual behavior, such patients will not usually be disoriented or have significant impairment of cognition. A depressed level of consciousness does not result from primary psychiatric illness, and psychiatric patients are usually fully alert unless they have an underlying medical complication or intoxication. A patient who shows evidence of exposure to toxins or ingestion of drugs should initially be presumed to have a medical problem, even if there is a psychiatric history. Visual and tactile hallucinations are usually secondary to a medical disorder, whereas auditory hallucinations are more common in psychiatric disorders.

Conclusion

Altered mental status may be caused by many factors, both psychiatric and medical. Cases of altered mentation caused by medical etiologies are often medical emergencies and must be promptly recognized and treated. Clinicians should avoid assuming that altered mental status is due to a psychiatric problem or that it is caused by psychiatric illness when it occurs in patients with a known psychiatric history. A systematic approach to patients with delirium is necessary. A helpful resource is the guideline of the American College of Emergency Physicians for the initial approach to patients with altered mental status, which provides a comprehensive strategy for assessing and treating the patient with delirium.⁸

1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR). 4th ed. Washington, DC: American Psychiatric Assoc; 2000.

2. Rummans TA, Evans JM, Krahn LE, Fleming KC. Delirium in elderly patients: evaluation and management. Mayo Clin Proc. 1995;70:989-998.

3. Huff JS. Altered mental status and coma. In: Tintinalli JE, Kelen GD, Stapczynski JS, eds. Emergency Medicine: A Comprehensive Study Guide. 5th ed. New York, NY: McGraw-Hill; 2000:1440-1449.

4. Reeves RR, Robbins RA, Carter OS. Psychiatric presentations of medical problems. Fed Pract. 1998;15:38-50.

5. Reeves RR, Pendarvis EJ, Kimble R. Unrecognized medical emergencies admitted to psychiatric units. Am J Emerg Med. 2000;18:390-393.

6. Folstein MF, Folstein SE, McHugh PR. "Mini-mental state." A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res. 1975;12:189-198.

7. Schmidt T. An overview of psychiatric emergencies. In: Rosen P, Barkin RM, Braen CR, et al, eds. Emergency Medicine: Concepts and Clinical Practice. St Louis, Mo: Mosby Year Book; 1992:2014-2020.

8. American College of Emergency Physicians. Clinical policy for the initial approach to patients presenting with altered mental status. Ann Emerg Med. 1999;33:251-280.

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