NBME PSYCH Form 3 - Answers & Explanations

Updated: Feb 25, 2020


1) Nucleus basalis of Meynert • Nucleus basalis of Meynert produces acetycholine; destruction → ↓ ACh → Alzheimer disease • Amygdaloid nucleus: Kluver-bucy syndrome • Caudate nucleus: Huntington disease • Medial geniculate nucleus: Auditory pathway • Red nucleus: mostly vestigial in mammals; crawling in human babies

• Substantia nigra: Parkinson disease • Subthalamic nucleus: Hemiballismus


2) Caudate nucleus

• Caudate & Putamen destruction → ↓ ACh and GABA → Huntington disease

• Amygdaloid nucleus: Kluver-bucy syndrome • Medial geniculate nucleus: Auditory pathway • Nucleus basalis of Meynert: Alzheimer disease • Red nucleus: mostly vestigial in mammals; crawling in human babies

• Substantia nigra: Parkinson disease • Subthalamic nucleus: Hemiballismus


3) Delirium due to anticholinergic medication • Certain antiparkinson drugs (eg, benztropine, trihexyphenidyl) curb excess cholinergic activity → side effects of dry mouth, flushed skin, tachycardia, etc.


4) PCP intoxication • PCP intoxication presents with violent behavior, dissociation, hallucinations, amnesia, ataxia, and nystagmus • Benzodiazepines treat severe psychomotor agitation


5) Reassure the father that this is normal development • Weight unchanged from the previous year, normal growth and development


6) Schizoaffective disorder • Delusions or hallucinations for ≥ 2 weeks in the absence of prominent mood symptoms


7) Borderline personality disorder

• Often have a history of childhood trauma (eg, physical/sexual abuse or neglect) → insecure attachment, unstable relationships, and fear of abandonment

• Cluster B personality disorders have a high rate of self-mutilation and suicide


8) Fragile site on the X chromosome • High forehead, large everted ears, prominent jaw, low IQ = Fragile X syndrome

• Fragile sites are discontinuity of staining in the region of the trinucleotide repeat on the long arm of the X chromosome (a diagnostic lab artifact)


9) Quetiapine

• This patient has Parkinson psychosis • Tx: Quetiapine or clozapine (lowest propensity to cause EPS)


10) Corticosteroid-induced psychotic disorder • Glucocorticoids, particularly at high doses, are often implicated in new-onset psychotic symptoms


11) Contact child protective services • Children who are victims of physical abuse often avoid eye contact on physical exam


12) Enlarged lateral and third ventricles on CT scan of the head • CT scans of patients with schizophrenia often show ventriculomegaly (particularly the lateral cerebral ventricles) and diffuse cortical atrophy


13) Obtain a rectal temperature under supervision • Temp of 107.6 F raises suspicion for factitious disorder


14) Conduct disorder • Repetitive and pervasive behavior that violates the basic rights of others or societal norms (eg, destruction of property)


15) Creutzfeldt-Jakob disease • Rapidly progressive dementia (weeks to months) • Periodic sharp waves on EEG • ↑ 14-3-3 protein in CSF


16) Discontinue clozapine therapy • Clozapine may lead to agranulocytosis (non-dose related) and seizures (dose related) • This patients leukocyte count is < 3000 and he has flu-like symptoms


17) Major depressive disorder • MDD has an atypical presentation with physical symptoms (eg, headache) in the elderly

• Sadness

• Guilt

• Weight loss

• Fatigue

• Psychomotor retardation (slowing of physical and/or emotional reactions, including speech and affect)

• Somatization and illness anxiety disorders require 6 months to diagnose (she has only been experiencing her headaches for 4 weeks)


18) Valproic acid • Valproic acid block box warning: hepatotoxicity, pancreatitis, fetal abnormalities


19) Drug-drug interaction • Switching from most antidepressants to a MAOI requires a 2-week washout; Fluoxetine, an SSRI, has a relatively long half-life and requires a 5 week washout

• Excess serotonin → serotonin syndrome


20) Discontinue desipramine therapy • TCA may cause prolonged QT • Tx: Stop medication and give NaHCO3 (prevents arrhythmia)



21) Alcohol use

• This patient drinks ‘several’ alcoholic beverages before sex and has ↑ GGT

• Alcohol is a depressant that can make it difficult to achieve erections or reach an orgasm


22) Propranolol

• The tremors in this patients hand are of 1 month duration which doesn’t indicate any anxiety disorder

• This patient likely has essential tremor (patients often self medicate with alcohol which decreases tremor amplitude, hence this patients alcohol abuse)

• Nonselective beta-blockers (eg, propranolol) are the treatment of choice