Sunday, November 30, 2014

The answer is B. This patient has features of acute delirium, which can be precipitated

You are covering the night shift at a local hospital and are called acutely to the bedside of a 62-year-old man to evaluate a change in his mental status. He was admitted 36 hours previously for treatment of community-acquired pneumonia. He received treatment with levofloxacin 500 mg daily and required oxygen 2 L/min.
He has a medical history of tobacco abuse, diabetes mellitus, and hypertension. He reports alcohol intake
of 2–4 beers daily. His vital signs at 10 pm were blood pressure of 138/85 mmHg, heart rate of 92 beats/min,respiratory rate of 20 breaths/min, temperature of 37.4°C (99.3°F), and SaO2 of 92% on oxygen 2 L/min.

Currently, the patient is agitated and pacing his room. He is reporting that he needs to leave the “meeting” immediately and go home. He states that if he does not do this, someone is going to take his house and car away. He has removed his IV and oxygen tubing from his nose.

His last vital signs taken 30 minutes previously were blood pressure of 156/92 mmHg, heart rate of 118 beats/min, respiratory rate of 26 breaths/min, temperature of 38.3°C (100.9°F),and oxygen saturation of 87% on room air. He is noted to be somewhat tremulous and diaphoretic.

All of the following should be considered as part of the patient’s diagnostic workup EXCEPT:
A. Arterial blood gas testing
B. Brain imaging with MRI or head CT
C. Fingerstick glucose testing
D. More thorough review of the patient’s alcohol intake with his wife
E. Review of the recent medications received by the patient


The answer is B.  This patient has features of acute delirium, which can be precipitated 

by many causes in hospitalized patients. Broad categories of causes of delirium
include toxins, medication reactions, metabolic disorders, infections, endocrine disorders,
cerebrovascular disorders (especially hypertensive encephalopathy), autoimmune
disorders, seizures, neoplastic disorders, and hospitalization. Although the list of causes
is broad, the initial history and physical examination are important to establish potential
etiologies of delirium and guide further workup. In most patients with delirium, it is
difficult to obtain an accurate history; therefore, it is important to seek out a spouse of
family member to outline the history further. In this case, there are features that could
suggest alcohol withdrawal (hypertension, tachycardia, fevers, tremors), and one should
clarify his alcohol intake with his wife. Another primary consideration in determining
the etiology of a delirium episode is the time course over which it evolves and the current
medications. Particularly in older hospitalized individuals, common medications used as
sleep aids, such as diphenhydramine, can have a paradoxical effect with delirium and
agitation. It is estimated that as many as one-third of episodes of delirium in hospitalized
patients are the result of medications. Worsening infection also needs to be considered
because the change in the patient’s vital signs could be indicative of an infectious source,
although the elevated blood pressure is not consistent with this. Because the patient has
required oxygen during his hospitalization, it is important to check an oxygen saturation
or arterial blood gas because acute hypoxemia or hypercarbia can precipitate delirium.
Likewise, given the patient’s history of diabetes mellitus, a fingerstick glucose is necessary
because hypoglycemia could also lead to alterations in mental status with evidence
of tachycardia, tremor, and diaphoresis. Other initial tests to consider in an individual
with delirium are electrolytes and basic liver and kidney function. Although commonly
ordered, brain imaging is most often not helpful in the evaluation of delirium.


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