Obsessive-compulsive disorder, a primary psychiatric disorder, is included here because of its close relation to Tourette's syndrome, where more than half of affected individuals meet criteria for obsessive-compulsive disorder (see Table 59).
Description of Idiopathic Normal Pressure Hydrocephalus Classification: Probable, Possible, and Unlikely Categories
The diagnosis of probable INPH is based on clinical history, brain imaging, physical findings, and physiological criteria. I. History
Reported symptoms should be corroborated by an informant familiar with the patient's premorbid and current condition, and must include the following:
a. Insidious onset (versus acute).
b. Origin after age 40 years.
c. A minimum duration of at least 3 to 6 months.
d. No evidence of an antecedent event, such as head trauma, intracerebral hemorrhage, meningitis, or other known causes of secondary hydrocephalus.
e. Progression over time.
f. No other neurological, psychiatric, or general medical conditions that sufficiently explain the presenting symptoms.
II. Brain imaging
A brain imaging study (CT or MRI) performed after onset of symptoms must show evidence of the following:
a. Ventricular enlargement not entirely attributable to cerebral atrophy or congenital enlargement (Evan's index > 0.3 or comparable measure).
b. No macroscopic obstruction to CSF flow.
c. At least one of the following supportive features:
i. Enlargement of the temporal horns of the lateral ventricles not entirely attributable to hippocampus atrophy.
ii. Callosal angle of 40° or more.
iii. Evidence of altered brain water content, including periventricular signal changes on CT and MRI not attributable to microvascular ischemic changes or demyelination.
iv. An aqueductal or fourth ventricular flow void on MRI.
Other brain imaging findings, such as the following, may be supportive of an INPH diagnosis but are not required for a "probable" designation:
a. A brain imaging study performed before onset of symptoms showing smaller ventricular size or without evidence of hydrocephalus.
b. Radionuclide cisternogram showing delayed clearance of radiotracer over the cerebral convexities after 48-72 hours.
c. Cine MRI study or other technique showing increased ventricular flow rate.
d. A SPECT-acetazolamide challenge showing decreased periventricular perfusion that is not altered by acetazolamide.
By classic definitions, findings of gait/balance disturbance must be present, plus at least one other area of impairment in cognition, urinary symptoms, or both. With respect to gait/balance, at least two of the following should be present and not be entirely attributable to other conditions:
a. Decreased step height.
b. Decreased step length.
c. Decreased cadence (speed of walking).
d. Increased trunk sway during walking.
e. Widened standing base.
f. Toes turned outward on walking.
g. Retropulsion (spontaneous or provoked).
h. En bloc turning (turning requiring three or more steps for 180°).
i. Impaired walking balance, as evidenced by two or more corrections out of eight steps on tandem gait testing.
With respect to cognition, there must be documented impairment (adjusted for age and educational attainment) and/or decrease in performance on a cognitive screening instrument (such as the Mini-Mental State Examination), or evidence of at least two of the following on examination that are not fully attributable to other conditions:
Table 58 (Continued)
a. Psychomotor slowing (increased response latency).
b. Decreased fine motor speed.
c. Decreased fine motor accuracy.
d. Difficulty dividing or maintaining attention.
e. Impaired recall, especially for recent events.
f. Executive dysfunction, such as impairment in multistep procedures, working memory, formulation of abstractions/similarities, insight.
g. Behavioral or personality changes.
To document symptoms in the domain of urinary continence, either one of the following should be present:
a. Episodic or persistent urinary incontinence not attributable to primary urological disorders.
b. Persistent urinary incontinence.
c. Urinary and fecal incontinence.
OR any two of the following should be present:
a. Urinary urgency, as defined by frequent perception of a pressing need to void.
b. Urinary frequency, as defined by more than six voiding episodes in an average 12-hour period despite normal fluid intake.
c. Nocturia, as defined by the need to urinate more than twice in an average night. IV. Physiological
CSF opening pressure in the range of 5-18 mmHg (or 70-245 mmH2O), as determined by a lumbar puncture or a comparable procedure. Appropriately measured pressures that are significantly higher or lower than this range are not consistent with a probable NPH diagnosis.
A diagnosis of "possible INPH" is based on historical, brain imaging, and clinical and physiological criteria I. History
Reported symptoms may:
a. Have a subacute or indeterminate mode of onset.
b. Begin at any age after childhood.
c. Last less than 3 months or indeterminate duration.
d. Follow events, such as mild head trauma, remote history of intracerebral hemorrhage, or childhood and adolescent meningitis or other conditions, that, in the judgment of the clinician, are not likely to be causally related.
e. Coexist with other neurological, psychiatric, or general medical disorders but, in the judgment of the clinician, may not be entirely attributable to these conditions.
f. Be nonprogressive or not clearly progressive.
II. Brain imaging
Ventricular enlargement consistent with hydrocephalus but associated with any of the following:
a. Evidence of cerebral atrophy of sufficient severity to potentially explain ventricular size.
b. Structural lesions that may influence ventricular size.
Symptoms of either of the following:
a. Incontinence and/or cognitive impairment in the absence of an observable gait or balance disturbance.
b. Gait disturbance or dementia alone.
Opening pressure measurement not available or pressure outside the range required for probable INPH. Unlikely INPH
a. No evidence of ventriculomegaly.
b. Signs of increased intracranial pressure, such as papilledema.
c. No component of the clinical triad of INPH is present.
d. Symptoms explained by other causes (e.g., spinal stenosis).
INPH, idiopathic normal-pressure hydrocephalus; CT, computed tomography; MRI, magnetic resonance imaging; CSF, cerebrospinal fluid; SPECT, single-photon emission computed tomography.
(Adapted from Relkin N, Marmarou A, Klinge P, Bergsneider M, Black, Peter McL. Diagnosing idiopathic normal-pressure hydrocephalus. Guidelines for the diagnosis and management of idiopathic normal-pressure hydrocephalus. Neurosurgery 2005;57:S2-4-S2-16.)
DSM-IV Diagnostic Criteria for Obsessive-Compulsive Disorder
A. Either obsessions or compulsions: Obsessions as defined by the following:
1. Recurrent and persistent thoughts, impulses, or images that are intrusive and inappropriate and that cause marked anxiety or distress.
2. The thoughts, impulses, or images are not simply excessive worries about real-life problems.
3. The person attempts to ignore or suppress such thoughts, impulses, or images, or to neutralize them with some other thought or action.
4. The person recognizes that the obsessive thoughts, impulses, or images are a product of his or her own mind (not imposed from without as in thought insertion).
Compulsions as defined by:
1. Repetitive behaviors (e.g., hand washing, ordering, checking) or mental acts (e.g., praying, counting, repeating words silently) that the person feels driven to perform in response to an obsession, or according to rigidly applied rules.
2. The behaviors or mental acts are aimed at preventing or reducing distress or preventing some dreaded event or situation; however, these behaviors or mental acts either are not connected in a realistic way with what they are designed to neutralize or prevent or are clearly excessive.
B. At some point during the course of the disorder, the person has recognized that the obsessions or compulsions are excessive or unreasonable. (Note: This does not apply to children.)
C. The obsessions or compulsions cause marked distress, are time-consuming (take more than 1 hour a day), or significantly interfere with the person's normal routine, occupational (or academic) functioning, or usual social activities or relationships.
D. If another DSM-defined Axis I disorder is present, the content of the obsessions or compulsions is not restricted to it (e.g., preoccupation with food in the presence of an eating disorder; hair pulling in the presence of trichotillomania; concern with appearance in the presence of body dysmorphic disorder; preoccupation with drugs in the presence of a substance use disorder; preoccupation with having a serious illness in the presence of hypochondriasis; preoccupation with sexual urges or fantasies in the presence of a paraphilia; or guilty ruminations in the presence of major depressive disorder).
E. The disturbance is not caused by the direct physiological effects of a substance or a general medical condition.
Adapted from American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 4th rev. ed. Washington, DC: American Psychiatric Association, 1994.
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