Pathophysiology
1) psychiatric disorder marked by unpredictable swings in mood from mania to depression 2) variants exist where there are repeated manic episodes without the intervening depressive episodes and vice versa 3) rapid cycling variant – four or more episodes of mania or depression per year
Signs and Symptoms
Manic phase – 1) increased psychomotor activity 2) decreased need for sleep 3) excessive social extroversion 4) impulsive actions 5) irritability 6) grandiose delusions 7) paranoia Depressive phase – 8) loss of interest in life or surroundings 9) decreased libido 10) significant weight gain or loss 11) feelings of fatigue and tiredness 12) sleep disturbances 13) feelings of hopelessness and intense sadness
Characteristic Test Findings
Radiology – abnormally high incidence of subcortical white matter abnormalities
Associated Conditions
1) strong genetic predisposition (30% concordance rate in monozygotic twins) 2) altered circadian rhythms
Biochemistry
exact underlying biology is unknown but may involve alterations in glutamate regulation
Inheritance/Epidemiology
1) affects 3 million people in USA 2) occurs roughly equally in men and women, but men have more manic episodes and women have more depressive episodes 3) age of onset is most common in late teens to age 30 4) prognosis is mixed, with 50% of patients unable to function normally in work and psychosocial roles even with treatment
Treatment
1) lithium and valproate are mainstays of treatment 2) common adjunctive drugs – carbamazepine and lamotrigine 3) antidepressants – used if depressive phase is severe but should not be started in maintenance phase, as they may precipitate a manic breakthrough
Tips for USMLE
if a 23 year old man returns home from graduate school and excitedly tells his family that he is quitting school because he has founded a company that he is sure will revolutionize the computer industry and he is so confident of his success that he has purchased (on credit) a Mercedes Benz and 500 bottles of expensive wine, think bipolar disease
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