Vanderbilt University School of Medicine
VC3 – Vanderbilt Core Clinical Curriculum

Altered Mental Status

 

Because the etiologies and corresponding treatment strategies for patients with altered mental status are so varied, distinguishing among the causes of altered mental status is an important training problem for third-year medical students.

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Prerequisites

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Describe and discuss:

  • basic physiology
  • basic pathology
  • basic neuroanatomy

Demonstrate:

  • ability to take a medical history
  • ability to perform a physical exam
  • ability to perform a mental status exam

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Apply Medical Knowledge in the Clinical Encounter

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1.     Describe the criteria used to distinguish delirium from dementia. 

2.     Describe the pathophysiology, signs, and symptoms of the most common and serious causes of altered mental status: 

  • metabolic causes
    • hyper/hyponatremia
    • hyper/hypoglycemia
    • hypercalcemia
    • hyper/hypothyroidism
    • hypoxia/hypercapnea
    • hepatic encephalopathy
    • uremic encephalopathy
    • drug intoxication/withdrawal
    • Wernicke encephalopathy
  • structural lesions (primary or metastatic tumor, intracranial hemorrhage, infection)
  • cerebrovascular accident
  • transient ischemic attack
  • meningitis
  • encephalitis
  • seizures
  • postictal state
  • hypertensive encephalopathy
  • vasculitis
  • arrhythmias
  • heart failure
  • endocarditis  

3.     Describe the signs and symptoms associated with the most common causes of altered mental status that help to differentiate one etiology from another.

4.     Describe the key diagnostic criteria of altered mental status.

5.     Describe the differences in clinical presentation and pathophysiology for each etiology.

6.     Describe how diagnostic tests would help in the evaluation of altered mental status, including their indications and contraindication, limitations, and cost:

  • lumbar puncture
  • CT scan
  • MRI scan
  • EEG
  • drug screen
  • CBC with differential
  • electrolytes
  • serum chemzyme screen (glucose, renal/hepatic function tests)
  • VDRL
  • arterial blood gas
  • vitamin B12 and thiamine
  • thyroid function tests

7.     Describe the principles of management of common causes of altered mental status. 

8.     Describe the steps in a critical pathway for altered mental status.

 

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Diagnose

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1.     Obtain, document and present an age-appropriate medical history, that differentiates among etiologies of disease, including eliciting appropriate information from patients with altered mental status, and/or their families, including the onset, progression, associated symptoms, potential causes (including medications), and level of physical and mental disability.

2.     Perform a physical exam, including a mental status exam, to establish the diagnosis and severity of disease:

  • appearance
  • level of alertness
  • speech
  • behavior
  • awareness of environment
  • mood
  • affect
  • thought process
  • thought content
  • memory
  • ability to perform calculations
  • judgment
  • higher cortical functioning and reasoning

3.     Generate a prioritized differential diagnosis that recognizes specific history and physical exam findings that distinguish innocent from abnormal altered mental status and confirms or rejects a specific diagnosis. 

4.     Recommend when to order diagnostic, laboratory tests, and clinical tests both prior to and after initiating treatment, based on the differential diagnosis. Justify ordering of tests and include consideration of test cost and performance characteristics as well as patient preferences. Interpret the results (with consultation):

  • lumbar puncture
  • CT scan
  • MRI scan
  • EEG
  • drug screen
  • CBC with differential
  • electrolytes
  • serum chemzyme screen (glucose, renal/hepatic function tests)
  • VDRL
  • arterial blood gas
  • vitamin B12 and thiamine
  • thyroid function tests

5.      Perform selected basic and advanced procedures:

  • perform a venipuncture for collection of blood specimens
  • insert a peripheral venous catheter
  • obtain an arterial blood gas
  • assist in performing a lumbar puncture after explaining the procedure to the patient

6.     Record, present, research, critique, and manage clinical information.

 

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Develop a Management Plan

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1.     Describe and discuss indications, mechanism of action, side effects, adverse reactions, and significant interactions of medications that could be prescribed for patients with altered mental status.

2.     Design an approach to treatment for the patient with altered mental status based on the diagnosis, evidence about treatment options, patient characteristics, and patient preferences:

  • write appropriate fluid orders for the treatment of hyper/hyponatremia, hyper/hypoglycemia, and hypercalcemia
  • write appropriate insulin and glucose orders for the treatment of hyper/hypoglycemia
  • write appropriate antibiotic orders for the treatment of meningitis, encephalitis, and endocarditis
  • determine when to involve a neurosurgeon in the management of patients with altered mental status

3.     Formulate a prognosis for the patient with altered mental status based on diagnosis, treatment plan, and patient characteristics.

4.     Communicate the diagnosis, treatment plan, and prognosis of the disease to patients and their families in a caring and compassionate manner, taking into consideration the patient's knowledge and ability to comprehend new information and reflecting an understanding of the emotional impact of a diagnosis of altered mental status and its potential effect on lifestyle (work performance, sexual functioning, etc.).

5.     Provide education for the patient about his or her treatment plan.

6.     Provide counseling to patients when indicated about issues related to prevention.

7.     Refer for psychological support if indicated.

8.     Access and utilize appropriate information systems to ascertain information about health system and community resources.

9.     Plan for follow-up.

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Differential Diagnosis

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Substance-Induced Psychosis

  • Brief Psychotic Episode
  • Schizophrenia
  • Delusional disorders
  • Mood Disorder with Psychotic Features
  • Factitious Disorder or Malingering

 Metabolic Causes

  • hyper/hyponatremia
  • hyper/hypoglycemia
  • hypercalcemia
  • hyper/hypothyroidism
  • hypoxia/hypercapnea
  • hepatic encephalopathy
  • uremic encephalopathy
  • drug intoxication/withdrawal
  • Wernicke encephalopathy

Other Causes

  • structural lesions (primary or metastatic tumor, intracranial hemorrhage, infection)
  • cerebrovascular accident
  • transient ischemic attack
  • infectious (meningitis, encephalitis)
  • seizures
  • post-ictal state
  • hypertensive encephalopathy
  • vasculitis
  • arrhythmias
  • heart failure
  • endocarditis