Laboratory and ECG assessment Flashcards
Medical conditions which are associated with depression
Coronary artery disease Diabetes End stage renal disease Malignancy HIV Degenerative neurological disorders Stroke
Conditions which can mimic depression
Addison’s disease
Hypothyroidism
Vitamin B12 deficiency
Reason to take FBC when depression is suspected
Rule out infectious or inflammatory pathology
Reason to take TSH when depression is suspected
Rule out hypothyroidism
Reason to take B12 level when depression is suspected
Rule out deficiency which can mimic depression
Reason to take electrolyte levels such as calcium, magnesium when depression is suspected
Abnormalities can cause fatigue which could mimic depression
Reason to take renal function when depression is suspected
To prepare for starting antidepressants
Reason to take LFTs when depression is suspected
To rule out alcohol related damage is concomitant alcohol misuse is suspected
To prepare for starting antidepressants
Reason to take 24 hour free urinary cortisol when depression is suspected
To rule out Cushing’s disease if suspected - more common in patients with depression than the general population
Reason to take ACTH stimulation test when depression is suspected
To rule out Addison’s disease which can mimic depression
Depression related conditions in which a dexamethasone suppression test is more likely to be positive
Major depressive disorder
Psychotic affective disorder
Depression with suicidality
Somatic syndrome
Non-depression related psychiatric conditions in which a positive dexamethasone suppression test can be seen
Anorexia nervosa Bulimia nervosa Alcoholism OCD Anxiety
Prognostic feature of a positive dexamethasone suppression test in depression
More likely to respond to medication
Common result of corticotropin releasing hormone test in major depression
Blunted ACTH due to HPA axis abnormality
Percentage of patients presenting with depression who have overt hypothyroidism
1-4%
Percentage of patients with depression who have subclinical hypothyroidism
4-40%
Differential diagnoses for anxiety attacks
Paroxysmal atrial tachycardia PE Seizures Meniere's disease TIA Carcinoid syndrome Cushing's Hyperthyroidism Hypoglycaemia Pheochromocytoma
Substance that causes a panic attack in 72% of patients with panic disorder when injected
IV sodium lactate
Infusion rarely used in clinical practice which worsens organic conditions, and improves non-organic conditions, causing anxiety
Amobarbitol
Differential diagnosis for psychosis
Head injury
Seizures
Recreational drug use
Dietary deficiencies e.g. B12, folate, niacin, thiamine
Reason to take FBC when investigating psychosis
Rule out infections or inflammatory causes
Baseline if starting antipsychotics
Reason to take TFTs when investigating psychosis
Rule out hypothyroidism or hyperthyroidism
Reason to take glucose and lipid profile when investigating psychosis
As a baseline prior to starting antipsychotics to rule out pre-existing metabolic syndrome
Reason to take an ECG when investigating psychosis
As a baseline prior to starting antipsychotics
Reason to take prolactin level when investigating psychosis
As a baseline prior to starting antipsychotics
Reason to take electrolytes when investigating psychosis
To rule out an underlying cause
Reason to take LFTs when investigating psychosis
To rule out chronic alcohol use if suspected
To investigate for Wilson’s disease if suspected
As a baseline prior to starting antipsychotics
Tests to consider if delirium suspected
FBC CRP Urine MC&S CXR Blood culture Blood alcohol Blood glucose
Tests to consider if STDs suspected
HIV test
Syphilis
STD testing
Tests to consider if encephalitis suspected
NMDA receptor antibodies Voltage-gated potassium channel antibodies - LGI 1, CASPR 2, contactin-2 AMPA receptor GABA-B Glycine receptor
Tests to consider if Cushing’s disease suspected
24 hour urinary free cortisol
Evening salivary cortisol
Dexamethasone suppression test
Symptoms of acute intermittent porphyria
Muscle weakness Seizures Coma Anxiety Confusion Hallucinations Rarely overt psychosis Abdominal pain NOT a rash - unlike other types
Tests to consider if porphyria suspected
Spot urine sample for porphobilinogen during attack
24 hour urine for porphyrins, porphobilinogen and delta-aminolevulinic acid
Tests to consider if hyperparathyroidism suspected
Serum calcium
Serum parathyroid hormone
Neuropsychiatric symptoms of Wilson’s disease
Cognitive deterioration Clumsiness Parkinsonism Depression Anxiety Psychosis Frontal lobe dysfunction Migraine Seizures
Non-neuropsychiatric manifestations of Wilson’s disease
Signs of chronic liver disease - oesophageal varices, splenomegaly, spider naevi
Kayser-Fleischer rings in the eyes on slit lamp examination
Renal tubular acidosis
Cardiomyopathy and heart failure
Tests to consider if Wilson’s disease suspected
Serum ceruloplasmin
24 hour copper excretion
Tests to consider if lysosomal storage diseases are suspected
Skin biopsy
Genetic testing
Serum alpha-galactosidase enzyme
Tests to consider if homocystinuria suspected
Homocysteine in urine and blood
Genetic testing
Tests to consider if CNS lesions suspected
MRI or CT
EEG if temporal lobe epilepsy suspected
Medications that can precipitate an episode of acute intermittent porphyria
Oestrogens
Benzodiazepines
Barbiturates
Diclofenac
Most common sex to suffer from anti-NMDA receptor encephalitis
Female
Malignancy found in 50% of women presenting with anti-NMDA receptor encephalitis
Ovarian teratoma
Most common first presentation of anti-NMDA receptor encphalitis
Psychosis
Mania
Prodrome associated with anti-NMDA receptor encephalitis
Fever
Headache
Malaise
Confirmatory test to diagnose anti-NMDA receptor encephalitis
CSF analysis
Treatment of anti-NMDA receptor encephalitis
Steroids
Plasma exchange
Complications caused by giving antipsychotics in cases of anti-NMDA receptor encephalitis
NMS-like syndrome
Tests to consider to investigate dementia
FBC CRP TFT Electrolytes Thiamine Syphilis and HIV if suspected Glucose, lipids - if vascular dementia suspected CT or MRI head
Endocrine abnormalities expected in anorexia nervosa
Low LH, FSH, oestradiol Low T3, normal T4, normal TSH Mildly raised cortisol Raised growth hormone Low glucose Low leptin
ECG abnormalities in anorexia nervosa
Bradycardia AV block ST depression TWI Prolonged QT Arrhythmias
Haematological abnormalities expected in anorexia nervosa
Normocytic normochromic anaemia
Mild leucopaenia
Thrombocytopaenia
Metabolic abnormalities expected in anorexia nervosa
Raised cholesterol Raised phosphate Raised serum carotene Low potassium Raised chloride alkalosis
Electrolyte abnormalities seen in repetitive vomiting
Metabolic alkalosis
Hypokalaemia
Electrolyte abnormalities seen in laxative misuse
Metabolic acidosis
Hyponatraemia
Hypokalaemia
BMI for underweight
<18.5
BMI for normal weight
18.5-24.9
BMI for overweight
25-29.9
BMI for obesity
30 or greater
Method to calculate BMI
weight in kg/(height in metresxheight in metres)
BMI if weight is 60kg and height is 170cm
20.8
BMI if weight is 35kg and height is 150cm
15.6
Most specific and sensitive test for detecting heavy alcohol use over the last 10 days
Carbohydrate deficient transferrin
Neurological complications of alcohol abuse
Seizures Wernicke's Korsakoff syndrome Peripheral neuropathy Coma Amnesia Cerebellar degeneration
GI complications of alcohol abuse
GI bleeds/oesophageal varices Peptic ulcer NAFLD Malnutrition Cirrhosis Portal hypertension Pancreatitis Hypoglycaemia
Cardiovascular complications of alcohol abuse
Cardiomyopathy
HTN
Raised lipids
Haematological complications of alcohol abuse
Raised MCV anaemia
Folic acid and B12 deficiency
Pancytopaenia
Clotting disorders
Respiratory complications of alcohol abuse
Klebsiella pneumonia
Lung cancer
Endocrine complications of alcohol abuse
Testicular atrophy
Sexual disorders
Menstrual irregularities
Complications of alcohol abuse in pregnancy
Low birth weight
Foetal alcohol syndrome
Developmental delays
Neural tube defects
Normal QTc in women
470ms
Normal QTc in men
440ms
QTc associated with an increased risk of torsades de pointes
> 500ms
Medical causes of prolonged QTc
Hypokalaemia Hypomagnesaemia Hypocalcaemia Hypothermia MI Congenital long QT syndrome
Common psychotropics that prolong the QTc
Haloperidol Venlafaxine Chlorpromazine Quetiapine Amisulpride Olanzapine Amitriptyline Doxepin Citalopram Moclobemide Escitalopram Bupropion
Common non-psychotropic drugs that prolong QTc
Erythromycin Clarithromycin Sotalol Amiodarone Flecainide Loratidine Hydroxychloroquine
Antipsychotics with high effect on QTc
Haloperidol
Pimozide
High Dose Antipsychotic Therapy
Antipsychotics with moderate effect on QTc
Chlorpromazine
Quetiapine
Amisulpride
Antipsychotics with low effect on QTc
Clozapine Flupentixol Olanzapine Prochlorperazine Risperidone Sulpride Paliperidone
Antipsychotics with no effect on QTc
Aripiprazole
Zuclopenthixol
Lurasidone
Urine test to check for adulteration with tap water
Specific gravity
Time alcohol can be present in urine
Up to 12 hours
Time amphetamines can be present in urine
Up to 48 hours
Time benzodiazepines can be present in urine
Up to 3 days (depending on half life)
Time cannabis can be present in urine if occasional use
Up to 3 days
Time cannabis can be present in urine if regular use
Up to 4 weeks
Time cocaine can be present in urine
6-8 hours
Time cocaine metabolites can be present in urine
Up to 4 days
Time codeine can be present in urine
48 hours
Time heroin can be present in urine
1-3 days
Time methadone can be present in urine
3 days or more
Time morphine can be present in urine
2-3 days
Time phencyclidine (PCP) can be present in urine
8 days
Renal diseases associated with IV drug use
Nephrotic syndrome Acute glomerulonephritis Amyloidosis Interstitial nephritis Rhabdomyolysis
Plasma osmolality in diabetes insipidus
High
Urine osmolality in diabetes insipidus
Low
Urine osmolality after fluid deprivation in cranial diabetes insipidus
Low
Urine osmolality after desmopressin in cranial diabetes insipidus
High
Urine osmolality after fluid deprivation in nephrogenic diabetes insipidus
Low
Urine osmolality after desmopressin in nephrogenic diabetes insipidus
Low
Plasma osmolality in psychogenic polydipsia
Low
Urine osmolality in psychogenic polydipsia
Low
Urine osmolality after fluid deprivation in psychogenic polydipsia
High
Urine osmolality after desmopressin in psychogenic polydipsia
High
Plasma osmolality in SIADH
Low
Urine osmolality in SIADH
High
Symptoms of mild/moderate hyponatraemia
Lethargy Muscle cramps Anorexia Nausea Vomiting
Symptoms of severe hyponatraemia
Coma
Convulsions
Death
Medications which can trigger an episode of acute intermittent porphyria in a susceptible individual
Oestrogens/progesterone/testosterone Barbiturates Benzodiazepines Diclofenac Fluconazole/ketoconazole HIV medication Nifedipine Chloramphenicol Anticonvulsants
Times when REM sleep patterns can be seen during the daytime
Narcolepsy
Sleep deprivation
Withdrawal from stimulants
ECG abnormality associated with TCAs
Heart blocks
Psychotropic medications associated with bradycardia on ECG
SSRIs
Lithium
Acetylcholinesterase inhibitors
Psychotropic medications associated with tachycardia on ECG
Clozapine TCAs MAOIs Antiparkinsonian drugs Antipsychotics
Psychotropic medications associated with ST and T wave abnormalities on ECG
Thioridazine
Chlorpromazine
Raised levels of metabolites found in a phaeochromocytoma
Vanillylmandelic acid
Homovanillic acid
Prolactin levels following seizures and non-epileptic seizures
Usually raised following seizures to >500
Usually normal following non-epileptic seizures
Laboratory findings in Wilson’s disease
Reduced serum caeruloplasmin
Reduced serum copper
Increased 24 hour urinary copper excretion
Normal rate on ECG
60-100
Normal PR interval on ECG
0.12-0.2s
Causes of U waves
Normal ECG
Hypokalaemia
T waves seen in hyperkalaemia
Tall, tented
T waves seen in hypokalaemia
Flat, prolonged
Most common thyroid function abnormality seen in sick euthyroid syndrome
Low T3
Waist circumference in men considered normal
94-102cm
Waist circumference in women considered normal
80-88cm
Waist circumference in men considered high
> 102cm
Waist circumference in women considered high
> 88cm
Drug causes of hypercalcaemia
Thiazide diuretics
Lithium
Vitamin D
Vitamin A
Use of the carbohydrate deficient transferrin blood test
To detect recent heavy alcohol consumption
Abnormal blood tests seen in alcohol depenence
Raised GGT
Raised ALT and AST
Raised MCV
Decreased WCC
BMI under which an ECG should be carried out in patients with anorexia
16
ECG changes seen in Huntington’s disease
Conduction abnormalities
Bradycardia
Normal ratio of CSF to serum glucose
0.6:1
Proteins in the CSF associated with CJD
14-3-3
Most sensitive test to investigate for clozapine induced myocarditis
Troponin
CSF finding associated with aggressive and impulsive behaviour, and increased suicidality
Low 5-HIAA
Psychiatric disorders which show a reduced CSF concentration of somatostatin
Depression
Bipolar disorder
Alzheimer’s dementia
Type of heart block where there is gradual prolongation of the PR interval until there is a p wave not followed by a QRS complex
Second degree AV block, Mobitz type 1
Type of heart block where there are intermittent p waves without a following QRS without gradual prolongation of the PR interval
Second degree AV block, Mobitz type 1