CRACKCast E017 – Confusion

In CRACKCast, Podcast by Chris Lipp1 Comment

This episode of CRACKCast cover’s Rosen’s Chapter 017, Confusion. Confusion can mean many things, arise in a number of situations, from a variety of causes.

Shownotes – PDF Link

Rosen’s in Perspective

Confusion means many different things, but we are particularly interested in processes impacting:

  • Memory
  • Attention
  • Awareness

Remember, confusion is a symptom, not a diagnosis – it reflects recent change in behaviour. Do no overlook subtle confusion in the elderly, as it is an independent risk factor for increased mortality. Confusion is a spectrum, ranging from:

  • Mild impairment of short-term memory
  • Delirium – a global inability to relate to environment and process sensory input:
Hyperactive DeliriumHypoactive Delirium

Acute confusional state with triad of:

  • Increased alertness
  • Increased psychomotor activity
  • Disorientation +/- hallucinations

Acute confusional state with:

  • Decreased alertness
  • Decreased behaviour

Varied Terminology for Confusion:

  • Altered mentation
  • Change in mental status
  • Altered mental status
  • Change from baseline
  • “Different”


Again as discussed in chapter 16, Consciousness in made up of arousal and content, which are controlled by the ARAS and cerebral cortex respectively. With confusion, we are really talking about issues with content, or cortical disruption.

Three major categories can impact and disrupt normal cortical function:

  1. Substrate deficiency
    1. Hypoxia
    2. Hypoglycemia
  2. Neurotransmitter dysfunction
    1. Endocrine disease
    2. Hepatic failure
    3. CNS sedatives
    4. EtOH
    5. Poisons
  3. Circulatory dysfunction
    1. Shock

1. List the Major Categories for the differential diagnosis of Confusion:

  • 17-1

    Box 17-1 – Major Categories: Differential Consideration.  From Rosen’s.

    Again, we can go back to the “DIMS” (DIMES see episode 16) approach or use the categories that Rosen’s uses:

  • I like to use the DIMS approach – it’s simple and I can use this memory aid for MANY presenting complaints (seizures, AMS, confusion, syncope, etc).
  • The key is to use BROAD categories

2. Differentiate between organic and functional confusion.

  • A more classical Rosen’s question would probably ask you to contrast organic vs. functional confusion (psychiatric) by listing 6-10 features.
  • Break it down like Rosen’s does based on:
  1. History
    1. Sudden onset (hrs to days) vs. gradual

      Box 17-2 – Findings That May Help Differentiate between Organic and Functional Causes of Confusion. From Rosen’s.

    2. Age – vs. middle aged
  2. Mental status exam
    1. Fluctuating LOC vs. alertness
    2. Disorientation vs. oriented
    3. Inattention vs. agitation/anxiety
    4. Visual hallucinations vs. auditory
    5. Cognitive difficulties vs. delusions/illusions
  3. Physical exam
    1. ABNORMAL VITAL SIGNS vs. normal VS
    2. Nystagmus vs. NO nystagmus
    3. Focal neurological signs vs. purposeful behaviour
    4. Signs of trauma vs. no signs of trauma
  • A little pearl here for you: KNOW this list well.
  • When you’re seeing any patient and especially one triaged to the psychiatric Emergency Area you should be looking for and documenting these pertinent positive and negative findings in your exam section!

3. List the Critical and Emergent causes of Confusion

  • Critical:

    Box 17-3 – Critical and Emergent Diagnoses. From Rosen’s.

    • Shock and hypoxia
    • Hypoglycemia
    • Head infections
    • Hypertensive encephalopathy
    • Head exploding
  • Emergent:
    • Anemia leading to diffuse cerebral ischemia
    • Metabolic diseases
    • Electrolytes
    • Endocrine
    • Hepatic encephalopathy/failure
    • Nutrition
    • Sepsis
    • Drugs and poisons
    • Intracranial
      • Trauma
      • Infection
      • Stroke
      • SAH
      • Tumour
      • Seizures
  • Remember the 4 H’s or the phrase “the Hyper Hippo’s Head”
    • Hyper (hypertensive encephalopathy)
    • Hypoglycemia
    • Hypoxia
    • Hypotension
    • Head
    • Tumour, Stroke, SAH, Seizure, etc.
  • All that being said there is a lot of overlap with this in the last chapter – if there’s truly something big bad and ugly going on – the patient will exhibit altered mental status, rather than just confusion.

Wise Cracks

  • So you have the confused patient: you have collected a history with GOOD collateral information, now it’s time for your head to toe exam.
  • Describe a quick assessment tool for screening for confusion


  • Don’t forget: almost everyone with confusion should be getting the veterinary workup:
    • Full set of vitals
    • Glucose
    • CBC, lytes, liver panel, kidney function
    • ECG (MI)
    • Urine
    • CXR
    • CT head (maybe) and LP (maybe)

This post was copyedited and uploaded by Michael Bravo (@bravbro).

Chris Lipp is one of the founding Fathers for CrackCast. He currently divides his time as an EM Physician in Calgary (SHC/FMC) and in Sports Medicine (Innovative Sport Medicine Calgary). His interests are in paediatrics, endurance sports, exercise as medicine, and wilderness medical education. When he isn’t outdoors with his family, he's brewing a coffee or dreaming up an adventure…..

Tristan Jones

Tristan Jones is a resident by day, early 90s style hacker by night. We had to give this Emergency Medicine Resident from UBC a job, or else he would shut down our website faster than Anonymous taking down Donald Trump.