Psychiatry and the Lab

Question 1

how to make a psych diagnosis?

Answer 1

rule out organic (other medical causes caused by history and physical exam)

rule out effect of substances (drugs of abuse)

review symptoms as described in the DSM 5

Question 2

what is the utiluty if lab tests in psychiatry?

Answer 2

• used to rule out medical causes that can mimic psych conditions
• used to monitor side effects of meds
• used for therapeutic monitoring (only applies to few meds)

Question 3

typical investigations for psych

Answer 3

• imaging = CT head, chest x-ray
• bloodwork = TSH, electrolytes, glucose, creatinine, BUN, preg test
• tox (urine tox, blood ethanol level, ASA, acetaminophen level, lithium level)
• ECG = lots of meds can affect cardiac
• EEG = rule out seizure disorder
• pulmonary function tests

Question 4

diagnosis of major depressive disorder

Answer 4

• depressed mood
• loss of interest
• weight loss
• insomnia/hypersomnia
• psychomotor agitation/retardation
• lss of energy
• guilt/worthlessness
• decreased concentration
• recurrent thoughts of death

2 weeks
exclusions: med causes such as hyperthyroidism = screen w TSH, substances

Question 5

monoamine hypothesis

Answer 5

too low serotonin
biological hypothesis to cause of depression

Question 6

MDD treatment

Answer 6

SSRIs = first line optiions = increases serotonin between neurons)

• Fluoxetine or PRozac, Sertraline or Zoloft, etc.
• require no monitoring
• tricyclic (Nortriptyline) have therapeutic windows so blood levels guide dosing

Question 7

schizophrenia diagnosis

Answer 7

two or more of:
- delusions
- hallucinations
- disorganized speech
- disorganized or catatonic behaviour
- negative symptoms

impairment in multiple areas of life
acute symptoms = 1 mo and continuous symptoms for 6 mos
“exclusions = medical causes and substances such as marijuana and cocaine*

Question 8

dopamine hypothesis

Answer 8

schizo
- excess dopamine in subcortical areas = paranoia and hallucinations
- deficient dopamine in cortical areas = less drive and motivation

• lumbar puncture and imagine not commonly obtained for diagnosis

Question 9

schizophrenia treatment

Answer 9

1st gens = dopamine antagonists; Haloperidol
> can cause movement side effects
> can cause elevated prolactin = order serum prolactin levels

2nd gens = antipsychotic medications; Quetiapine, Clozapine
> side effects = weight gain, high BP, elevated glucose, elevated lipids, increased risk of diabetes

Question 10

how to monitor pts with schizo treated with newer antipsychotics

Answer 10

0 glucose, HbA1C, lytes, BUN, CR, lipids
- weight, wasit circumference, HR, BP, BMI
- prolactin levelks

Question 11

clozapine

Answer 11

“big guns”
used for treatment-resistant schizophrenia
- risk of agranulopcytosis
> CBC (weekly for first 6 mos, then every 2 weeks for 6 mos and then monthly thereafter (IMPORTANT!)

• troponin, CRP (first month only) bc of cardiac problems
• metabolic probs such as glucose, etc also monitored

Question 12

bipolar disorder type I diagnosis

Answer 12

• mania (any hospitalization for mania or one week or more of:
  > decreased sleep, increased activity, rapid speech, impulsivity, racing thoughts
• exclusions = medical causes or substances such as heroin, cocaine, etc.

Question 13

treatment for Bipolar disorder

Answer 13

• mood stabilizers
  > lithium
  > divalproex sodium

Question 14

lithium for bipolar disorder

Answer 14

• have therapeutic window
• use ECG to monitor cardiac side effects
• creatinine to monitor renal side effects

Question 15

divalproex sodium

Answer 15

• for bipolar disorder
• therapeutic window for anticonvulsant response only
• serum levels confirm adherence and ensure avoidance of toxic levels
• liver function tests to monitor side effects
• order CBCD = monitor low platelets side effects

Question 16

substance use disorders diagnosis

Answer 16

two or more of folloing in 12 mo period:

greater amt.time used
inability to fulfill roles
inability to cut down
activities give up
time to use/obtain/recover
craving
hazardous use
use despite psychosocial probs
use despite physical/psych probs
tolerance
withdrawal

Question 17

almost all drugs of abuse increase _______ in the reward pathway

Answer 17

dopamine

Question 18

naltrexone

Answer 18

opioid antagonist
- reduces pleasurable effects and/or craving of alcohol
- monitor lover function to ensure does not exceed 3x normal level
- oral; tablet

Question 19

substance use disorders monitoring

Answer 19

urine tox screening and monitoring
- cocaine
- cannabis
- opioids
- benzo’s
- amphetamine/methamphetamine

pulmonary function tests to measure effects of smoking
liver function tests