Pathophysiology
1) compulsive behavior and/or obsessive thoughts that impair everyday functioning 2) usually occurs for at least one hour a day
Signs and Symptoms
1) repetitive handwashing 2) repetitive counting 3) checking repeatedly as to whether a task has been accomplished 4) fear of germs or contamination 5) repetitive hair pulling (trichotillomania) with bald spots or missing eyebrows or lashes 6) wish to conceal their compulsion 7) feeling of anxiety if compulsive behavior is denied 8) tends to have a prolonged and waxing and waning course
Characteristic Test Findings
Radiology – positive PET scan findings in caudate nucleus and frontal white matter (PET scans “light up positive) in areas that have high glucose metabolism)
Histology/Gross Pathology
1) decreased size of caudate nucleus 2) abnormal frontal lobe white matter
Biochemistry
increased glucose metabolism in head of caudate nucleus and orbital cortex of frontal lobes
Associated Conditions
Tourette’s disorder
Inheritance/Epidemiology
1) lifetime prevalence is 2% worldwide 2) onset is usually in early adulthood but adolescent onset does occur 3) more common in males and firstborn 4) familial predisposition does occur with increased concordance in monozygotic twins
Treatment
1) drugs – fluoxetine, fluvoxamine (sometimes in combination with buspirone and benzodiazepine) 2) behavior therapy – with gradual increase in stressors and substitions of less disruptive activity for compulsions
Tips for USMLE
if the patient is a 23 year old man who cannot start work in the morning without washing off the surface of his desk exactly 17 times, think obsessive compulsive disorder
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