Schizophrenia - Psychiatry - Medbullets Step 2/3

Snapshot

A 21-year-old male college student has become increasingly bizarre over the course of the last semester and is referred by his academic advisor to the student health clinic. He will not leave his room for weeks at a time because he believes that voices in his head are telling him to continue searching the internet for hidden alien messages. He believes he is the only one on earth with this special ability. He is paranoid that the FBI knows this secret and is trying to prevent him from receiving these messages. A consulting psychiatrist admits the patient to the psychiatry ward. The patient is started on low doses of risperidone.

Introduction

Epidemiology
- genetic factors outweigh environmental factors in etiology
- 1.4 times more diagnoses in men than women
- presents earlier in men
  - late teens to early 20s in men
  - late 20s to early 30s in women
- higher risk for suicide than general population
Potential causes
- overactive dopaminergic activity (association for board exams)
  - in reality, this hypothesis is weak based on fact that the weakest D2 antagonist used for treatment (clozapine) is most effective agent for schizophrenia
    - NMDA, GABA, acetylcholine are all implicated
NOTE: subtypes (paranoid, disorganized, catatonic, undifferentiated, residual) have been eliminated from DSM-V due to poor validity and low reliability
Associated conditions
- brief psychotic disorder
  - schizophrenic symptoms lasting < 1 month
  - usually stress related
- schizophreniform disorder
  - schizophrenic symptoms lasting between 1 and 6 months
- schizoaffective disorder
  - schizophrenic symptoms with manic or depressed episode
    - mood disturbance must be present for majority of total duration of disorder

Presentation

Positive symptoms
- delusions
  - fixed, false beliefs
- hallucinations
  - sensory perceptions without physical stimuli
  - auditory is most common
- disorganized speech
  - loose associations, word salad, tangential speech
- grossly disorganized behavior
Negative symptoms
- flat affect
- social withdrawal
- lack of motivations
- lack of speech or thought
- grossly catatonic behavior
  - symptoms improve with lorazepam

Evaluation

Diagnostic criteria
- at least 2 of symptoms listed above (so-called Criterion A symptoms)
  - at least 1 must be a delusion, hallucination, or disorganized speech
  - these have to manifest for a 1 month period
- persistent symptomatic dysfunction lasting > 6 months
- rule out schizoaffective disorder
  - mood disturbances only present during minority of symptomatic period
- rule out depressive/bipolar disorder with psychotic features
  - schizophrenic symptoms manifest only during mood disturbances
- rule out substance use and other medical conditions
Imaging (boards knowledge, not part of diagnostic criteria)
- may demonstrate increased ventricular size, decreased cerebral mass, decreased hippocampal mass, decreased temporal mass

Management

Hospitalization for acute psychotic episode
- baseline physical and neurological exam
  - important to establish existing musculoskeletal symptoms
  - do not confront or deny delusions
- investigations
  - best initial test: urine toxicology to rule out an easy and reversible cause
  - CBC, Chem-7, LFTs, TSH, fasting glucose, EKG
    - important to assess presence or absence of metabolic syndrome
    - important to know baseline QTc interval before starting antipsychotic
- atypical (2nd generation) antipsychotic medications
  - first-line drug due to less extrapyramidal side effects compared to 1st generation (typical) antipsychotics
  - typical first agents: olanzapine, ziprazidone, quetiapine
  - if not compliant, long-acting risperidone or depot haloperidol may be used
  - clozapine used as a last-line drug for refractory schizophrenia
    - refractoriness established if first-line drug fails to improve symptoms after 2-6 weeks
    - adding a second first-line drug is not effective

Blood, Plasma, Serum	Reference Range
ALT	8-20 U/L
Amylase, serum	25-125 U/L
AST	8-20 U/L
Bilirubin, serum (adult) Total // Direct	0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca²⁺)	8.4-10.2 mg/dL
Cholesterol, serum	Rec: < 200 mg/dL
Cortisol, serum	0800 h: 5-23 μg/dL //1600 h: 3-15 μg/dL 2000 h: ≤ 50% of 0800 h
Creatine kinase, serum	Male: 25-90 U/L Female: 10-70 U/L
Creatinine, serum	0.6-1.2 mg/dL
Electrolytes, serum
Sodium (Na⁺)	136-145 mEq/L
Chloride (Cl^-)	95-105 mEq/L
Potassium (K⁺)	3.5-5.0 mEq/L
Bicarbonate (HCO₃^-)	22-28 mEq/L
Magnesium (Mg²⁺)	1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)
24-28 wks // 32-36 wks	30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks	40-220 ng/mL // 80-350 ng/mL
Ferritin, serum	Male: 15-200 ng/mL Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma	Male: 4-25 mIU/mL Female: premenopause: 4-30 mIU/mL midcycle peak: 10-90 mIU/mL postmenopause: 40-250
pH	7.35-7.45
PCO₂	33-45 mmHg
PO₂	75-105 mmHg
Glucose, serum	Fasting: 70-110 mg/dL 2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation	Fasting: <5 ng/mL Provocative stimuli: > 7ng/mL
Immunoglobulins, serum
IgA	76-390 mg/dL
IgE	0-380 IU/mL
IgG	650-1500 mg/dL
IgM	40-345 mg/dL
Iron	50-170 μg/dL
Lactate dehydrogenase, serum	45-90 U/L
Luteinizing hormone, serum/plasma	Male: 6-23 mIU/mL Female: follicular phase: 5-30 mIU/mL midcycle: 75-150 mIU/mL postmenopause 30-200 mIU/mL
Osmolality, serum	275-295 mOsmol/kd H₂O
Parathyroid hormone, serume, N-terminal	230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C)	20-70 U/L
Phosphorus (inorganic), serum	3.0-4.5 mg/dL
Prolactin, serum (hPRL)	< 20 ng/mL
Proteins, serum

Hematologic	Reference Range
Bleeding time	2-7 minutes
Erythrocyte count	Male: 4.3-5.9 million/mm³ Female: 3.5-5.5 million mm³
Erythrocyte sedimentation rate (Westergren)	Male: 0-15 mm/h Female: 0-20 mm/h
Hematocrit	Male: 41%-53% Female: 36%-46%
Hemoglobin A1c	≤ 6 %
Hemoglobin, blood	Male: 13.5-17.5 g/dL Female: 12.0-16.0 g/dL
Hemoglobin, plasma	1-4 mg/dL
Leukocyte count and differential
Leukocyte count	4,500-11,000/mm³
Segmented neutrophils	54%-62%
Bands	3%-5%
Eosinophils	1%-3%
Basophils	0%-0.75%
Lymphocytes	25%-33%
Monocytes	3%-7%
Mean corpuscular hemoglobin	25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration	31%-36% Hb/cell
Mean corpuscular volume	80-100 μm³
Partial thromboplastin time (activated)	25-40 seconds
Platelet count	150,000-400,000/mm³
Prothrombin time	11-15 seconds
Reticulocyte count	0.5%-1.5% of red cells
Thrombin time	< 2 seconds deviation from control
Volume
Plasma	Male: 25-43 mL/kg Female: 28-45 mL/kg
Red cell	Male: 20-36 mL/kg Female: 19-31 mL/kg

Cerebrospinal Fluid	Reference Range
Cell count	0-5/mm³
Chloride	118-132 mEq/L
Gamma globulin	3%-12% total proteins
Glucose	40-70 mg/dL
Pressure	70-180 mm H₂O
Proteins, total	< 40 mg/dL

Sweat	Reference Range
Chloride	0-35 mmol/L
Urine
Calcium	100-300 mg/24 h
Chloride	Varies with intake
Creatinine clearance	Male: 97-137 mL/min Female: 88-128 mL/min
Estriol, total (in pregnancy)
30 wks	6-18 mg/24 h
35 wks	9-28 mg/24 h
40 wks	13-42 mg/24 h
17-Hydroxycorticosteroids	Male: 3.0-10.0 mg/24 h Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total	Male: 8-20 mg/24 h Female: 6-15 mg/24 h
Osmolality	50-1400 mOsmol/kg H₂O
Oxalate	8-40 μg/mL
Potassium	Varies with diet
Proteins, total	< 150 mg/24 h
Sodium	Varies with diet
Uric acid	Varies with diet
Body Mass Index (BMI)	Adult: 19-25 kg/m²