Differential Diagnosis

					            Differential Diagnosis
            Ken Denman ARNP, PhDc, MS, BSN, RN.
                         Psychiatry
             Armor Correctional Medical Services




8/19/2011
            The Diagnostic Problem

 DSM Diagnosis = a somewhat paradigmatic symptoms
   cluster at the syndromal level of abstraction
 However, individuals usually present clinicians with a
single symptom/small set of symptoms:
 That they find most distressing
 That they are most comfortable discussing
 Getting from a single or small number of related
symptom to a diagnosis useful for treatment is what
differential diagnosis is all about.


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                  Step #1
   Is the presenting symptom for real?
This does not imply that one should always
 mistrust what the patient says.
However there are diagnoses in which
 conscious feigning of symptoms is usual
 (Malingering and Fictitious Disorder) and one
 in which unconscious feigning of symptoms is
 usual (Conversion Disorder).


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                  Step #1 (corollaries)

1. Is this a situation in which feigning of symptoms is more
typical: ER, forensic evaluation, prison, inpatient unit?

2. Does the presentation of symptoms conform more to a
popular view of a disorder than to an actual clinical entity?

3. Do the symptoms shift significantly from one clinical encounter to
   the next?

4. Do the symptoms mimic the presentation of a role model
like a parent or another patient?

5. Is the patient unusually manipulative or suggestible?

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Step #2
• Rule out substance etiology (drugs
of abuse, medications, toxin
exposure).
1. Does the individual use any substances?

This includes dependence, abuse, recreational use, medical use, and
   environmental exposure.
This will involve a thorough history and evaluation, laboratory tests,
   and toxicology.

In an aging population with less cautious use of pharmacotherapy,
   medication use is an increasing concern.



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                   Step #2

2. What is the etiologic relationship between
substance use and psychiatric symptoms?
• a) The symptoms are a direct result of the
  effects of the substance use.
• b) The substance use is secondary to the
  psychiatric symptoms.
• c) The psychiatric symptoms and substance
  use are independent of each other.
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                             Step #2

Temporal sequence is a helpful, but not infallible, guide. If the onset
  of psychiatric symptoms clearly precedes the onset of substance
  use, it is probably a primary psychiatric disorder.

If the onset of substance use clearly precedes the psychiatric
    symptoms than the symptoms are more likely to be substance
    induced.

If the psychiatric symptoms abate in about 4 weeks after substance
    intoxication or withdrawal, the symptoms are more clearly
    substance induced.

Excepting Substance Induced Persisting Dementia or Amnesiac
   Disorder.


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                   Step #2
                  – Caveats
• Often individuals suffering from substance use
  and psychiatric symptoms are not the best
  historians of their own experience.
• Substance misuse and psychiatric disorders
  often have their onset in late adolescence
  without any causative link.
• If psychiatric symptoms are severe and pose a
  risk to self or others, waiting 4 weeks to
  determine etiology raises serious questions.

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                             Step #2

3. Is the pattern of substance use or withdrawal sufficient to account
   for the symptoms? Is the nature, amount, and duration of
   substance use consistent with the observed symptoms? Not all
   substances nor all dose levels of specific substances produce
   specific symptoms.

4. Is the pattern of substance use consistent with an attempt to
   relieve the symptoms?

5. Are there other factors like heavy genetic loading for a specific
   psychiatric problem that point to a non‐substance induced etiology?

6. In the absence of persuasive evidence in either direction, could the
    two disorders simply be co‐morbid?

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                 Step #3
 • Rule out a disorder due to a general
          medical condition?
– The clinical implication of this step are profound.

– Differential diagnosis is complicated: Symptoms of some psychiatric
   conditions and many general medical conditions can be identical.

• Sometimes the first presenting symptom of a general medical
  condition is psychiatric. The relationship between medical
  conditions and psychiatric conditions can be complicated

• Patients are often seen in mental health setting where there is low
expectation of and little familiarity with general medical conditions.


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                             Step #3

 - Just as with substance use, virtually any psychiatric presentation
  can be caused by the direct physiologic effects of a general medical
  condition (e.g. Mood Disorder due to Hypothyroidism).

 - A good diagnostic evaluation should contain a thorough history
and physical as well as tests for those medical conditions most
likely to cause the presenting symptoms ( thyroid function tests for
depression, brain imaging for late‐onset psychosis)

 In counseling work practice, involvement of a physician with good
diagnostic skills, like an Internist, in the evaluation process is very
important.



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                                     Step #3

– If a general medical condition is present, its etiologic relationship, if any, to the
     psychiatric symptoms must be established.

1. The medical condition causes the psychiatric symptom by direct
action on the CNS.

2. The general medical condition causes the psychiatric symptoms
through a indirect or psychological mechanism.

3. Medication taken for the medical condition causes the psychiatric symptoms.

4. The psychiatric symptoms adversely effect the medical condition.

5. The psychiatric symptoms and the medical condition are purely
coincidental,



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                     Step #3

There are some clues that are helpful, but not
  infallible, in making the clinical judgment
  mentioned earlier.
Temporality: do psychiatric symptoms follow the
  onset of the medical condition, vary in intensity
  with it, and disappear when it is resolved?
 Remember that psychiatric symptoms can precede,
  by some time, the onset of some medical
  problems or not occur until late stages of others.
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                                Step #3

• Atypicality: are the psychiatric symptoms atypical in pattern, age of onset,
  or course.

• – e.g. significant weight loss and severe fatigue with mildly depressed
  mood, first onset of Manic Episode in an elderly individual, severe
  disorientation accompanying psychotic symptoms.

• – Remember, manifestation of psychiatric disorders is very heterogeneous
  and atypical presentations are not unknown.

• – If you determine that a medical condition is causing the psychiatric
  symptoms, determine which DSM‐IV‐TR diagnosis of Mental Disorders Due
  to a General Medical Condition best describes the presentation.

• A decision tree or algorithm is very helpful.


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                            Step #4

• Determine the specific primary disorder(s). The arrangement of
  disorders g in the DSM‐IV‐TR into broad categories of disorders is
  done to somewhat facilitate this process:
• Disorders First Diagnosed in Infancy, Childhood, or Adolescence;
  Delirium, Dementia, Amnestic, and other Cognitive Disorders;
• Substance‐Related Disorders;
• Schizophrenia and other Psychotic Disorders;
• Mood Disorders; Anxiety Disorders; Somatoform Disorders;
• Factitious Disorders; Dissociative Disorders; Sexual and Gender
  Identity Disorders;
• Eating Disorders; Sleep Disorders;
• Impulse‐Control Disorders; Adjustment disorders;
• Personality Disorders


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 The problem is that many disorders share
           common symptoms:
                 Insomnia
•   Acute Stress Disorder
•   Cyclothymic Disorder
•   Delirium
•   Dysthymic Disorder
•   GAD
•   Hypomanic Episode
•   Major Depressive Disorder
•   Manic Episode
•   Mixed Episode

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                 Weight Loss

•   Anorexia Nervosa
•   Dysthymic Disorder
•   Hypomanic Episode
•   Major Depressive Disorder
•   Manic Episode
•   Mixed Episode
•   Substance Intoxication

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                              Irritability

•   Acute Stress Disorder
•   ASPD
•   Attentional Deficit/Hyperactivity Disorder
•   BPD
•   Conduct Disorder
•   Cyclothymic Disorder
•   Delusional Disorder
•   Dysthymic Disorder
•   GAD
•   Nightmare Disorder
•   PTSD
•   Schizoaffective Disorder
•   Schizophreniform Disorder



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                     Continued-
•   Schizophrenia
•   Substance Use/Withdrawal
•   Hypomanic Episode
•   Major Depressive Disorder
•   Manic Episode
•   Mixed Episode
•   PTSD
•   Schizoaffective Disorder
•   Schizophreniform Disorder
•   Schizophrenia
•   Substance Use/Withdrawal

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                                       Step #4

                           Dysthymic Disorder must be
                             differentiated from . . .

            In contrast to Dysthymic Disorder, the other condition . .    .
•   Major Depressive Disorder is characterized by one or more major depressive
    episodes; both can be diagnosed if the MDE occurs after the first 2 yrs. of
    Dysthymic Disorder

•   Depressive symptoms associated with chronic Psychotic Disorder occurs exclusively
    during the psychotic disturbance

•   Cyclothymic Disorder is characterized by hypomanic periods as well as depressive
    periods.

•   Nonpathological periods of sadness is characterized by short duration, few
    symptoms, an no significant impairment or distress




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                             Step #5

• If the symptom pattern or the severity of impairment or distress
  does not meet criteria for a specific diagnosis, differentiate
  adjustment disorder from not otherwise specified.

 If the clinical judgment is made that the symptoms developed from
  a maladaptive response to a psychosocial stressor, then adjustment
  disorder appropriate.

• If the judgment is that the stressor is not responsible for the
  development of the symptoms, than the relevant Not Otherwise
  Specified category can be diagnosed.

• – Given the ubiquity of stressors, the point is not whether a stressor
  is present or not but whether it is the etiology of the symptoms.


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                                Step # 6

• Establish the boundary with no mental disorder
This is an obvious but not always an easy step to take.

Many symptoms are so ubiquitous that they occur at least
briefly in the lives of most people.

At some time most individuals will experience symptoms of
anxiety, depression, difficulty sleeping, or sexual dysfunction.

• It is important not to pathologize what is really the human condition.

– The disturbance must cause “clinically significant impairment or distress in
   social, occupational, or other important areas of functioning.”



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                     Step # 6
The diagnosis of Hypoactive Sexual Desire Disorder
• should not be made in someone with low sexual
  desire,
• who is not in a current intimate relationship with
  anyone, and who is not particularly bothered by
  it.
• The problem is that what is “clinically significant”
  is greatly influenced by cultural context, the
  setting in which the individual is seen, clinician
  bias, client bias, and availability of resources.
• Unfortunately there is little solid research and no
  hard and fast rules that can guide this decision.

8/19/2011
                        Comorbidity
      • Although it is best to follow the principle of
 parsimony, it is also important to remember that most
          diagnoses are not mutually exclusive.
In an individual with delusions, hallucinations, and mood
  symptoms a decision must be made among Schizophrenia,
  Schizoaffective Disorder, and Mood Disorder with
   Psychotic Features.

In an individual with multiple unexpected panic attacks,
   significant depression, and a maladaptive perfectionistic
   and rigid personality style the diagnoses of Major
   Depressive Disorder, Panic Disorder, and Obsessive‐
   Compulsive Personality Disorder may all apply.
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                Comorbidity

• Using multiple diagnoses is neither good nor
  bad so long as the implications are
  understood.
• Do not hold the mistaken view that multiple
  descriptive diagnoses are actually
  independent:



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                Comorbidity

• Having more than one DSM‐IV‐TR diagnosis
does not mean that there is more than one
underlying pathophysiological process.
• The diagnoses are not entities but descriptive
building blocks, useful for communicating
diagnostic information and guiding therapeutic
  choices.

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                     Practice

• Consider the case of a 38 year old married male
  who is referred for evaluation after a second DUI.
  He readily admits that he is a regular and heavy
  drinker, that he has tried to stop drinking several
  times but without any sustained success, and that
  he often drinks more than he intends. He also
  complains of feelings of intense sadness,
  difficulty sleeping, weight loss, constant sense of
  fatigue, feelings of guilt and worthlessness, and
  occasional thoughts of suicide.

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                     Practice

• This is not an atypical presentation and poses a
  serious differential challenge.

• Although this is a kind of forensic evaluation, let
  us assume that there is no reason to believe that
  the individual is not being perfectly honest about
  his symptoms.

• Let us further assume that a recent history and
  physical reveals no apparent medical problem
  which might explain the symptoms.
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                 PRACTICE
The diagnostic question then is:
  Is this an individual whose Major Depressive
  Disorder is secondary to his Alcohol
  Dependence, or whose Alcohol Dependence is
  secondary to his Major Depressive Disorder, or
  who has both Major Depressive Disorder and
  Alcohol Dependence as comorbid conditions.


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                         Diagnostic tree
                            Practice
    Consider the case of a 28 year old, unmarried woman, who seeks help
    because of panic attacks. She was perfectly fine until she was in her last
    year of graduate studies in molecular biology and was attacked and
    carjacked guy in the library parking lot late one night. Her attacker forced
    her to dive, at knife point, to a deserted area where he raped, beat, and
    left her. She was so shaken by the experience that she dropped out of
    school without finishing her degree. She still has nightmares about the
    attack and takes benzodiazepines, off and on, to help her sleep. She
    eventually got a job as a technician in a medical lab and was doing better
    until the lab started running a late shift. When she works late, the thought
    of having to go to her car in a dark and deserted parking lot makes her feel
    like she is smothering. When she can convince someone to go with her to
    her car, she feels better. But several times she could not find anyone and
    her heart beat so fast and hard she was convinced she was about to die.
    She doesn’t want to loose her job but she also doesn’t want to continue to
    live as she has for the past several months.



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                    Practice

• The presenting symptom is panic attacks.
• The diagnostic question is whether this
  symptom is the result of the after effects of
  benzodiazepine use, a developing anxiety
  disorder, or trauma




8/19/2011

				
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