Acute Confusional State Flashcards
(74 cards)
What is the definition of delirium?
An acute, transient and reversible cause of confusion - usually fluctuates in intensity.
What are the four DSM-IV criteria for delirium?
- Disturbance of consciousness (arousal/ awareness)
- Worsening confusion
- Acute onset with fluctuating course
- Due to a medical condition, substance intoxication, or withdrawal
Key questions to ask in a delirium history?
Collateral history:
- Onset and course of confusion
- Previous episodes
- Exclude head injuries
- Full systems review to establish cause
- Past medical history and medication history important
- Conversation with patient is also important
Two types of delirium…
Hypoactive: Lethargy, slowness, inattention, excessive sleeping
Hyperactive: Agitation, delusions, hallucinations, wandering, aggression
Causes of delirium…
PINCH ME: Pain Infection Nutrition Constipation Hydration Medication Environmental changes
Confusion Assessment Method
- Acute onset and fluctuating course
AND - Inattention (easily distracted, difficulty following conversation)
AND - Disorganised thinking
OR - Altered level of consciousness (GCS<15, vigilant, hyper-alert)
4-AT Method
- Alertness (normal=0, mild=0, clearly abnormal =4)
- AMT 4 - age,DoB, place, current year (0 mistakes =0, 1 mistake = 2, 2 or more mistakes =2)
- Attention - months backwards (7 or more= 0, less than 7 =1, cannot test =2)
4.Fluctuating course (No=0, Yes=4)
TOTAL SCORE: 4 or more =possible delirium, 1-3= possible mild cognitive impairment, 0 = delirium unlikely)
Investigations for delirium
Urinalysis and MC&S Drug levels (intoxication) Infection screen: CXR Head imaging EEG Specific cultures : blood, CSF, sputum
Management of delirium
Conservative:
- Quiet environment with clock to orientate
- Adequate spectacles and hearing aid
- Reassure patient frequently
- Encourage relatives to visit
Medical: (only when pt is danger to themselves/ others)
- Rapid tranquillisation - haloperidol 0.5mg PO (1st line), lorazepam 0.5-1mg PO (2nd line)
*UNDERLYING CAUSE MUST BE ADDRESSED: Remove offending meds, treat infections, correct hypoxia
What is the action of ADH?
- Stimulates thirst
- AQP2 channel insertion to increase renal water reabsorption
What is the normal range for Sodium?
133-146 mmol/L
Why is a faster rate of hyponatraemia developing more dangerous?
Water will move intracellularly in an attempt to increase the plasma Na+ conc, which will cause cerebral oedema
What are the symptoms of hyponatraemia?
<125mmol/L : headache, nausea, vomiting, muscle cramps, lethargy, restlessness, disorientation
<120mmol/L: seizure, coma, brain damage, brainstem herniation
Differential causes for hyponatraemia…
Dependent on urinary sodium and patient fluid status:
- Hypovolaemic + Urine [Na] >20 = high Na loss from kidneys (nephropathy, adrenal insufficiency, diuretics)
- Hypovolaemic + Urine [Na] <20 = extra-renal sodium loss i.e. diarrhoea, vomiting, GI fistula, burns
- Normovolaemic + Urine [Na] >20 = SIADH
- Normovolaemic + Urine [Na] <20 = severe polydipsia, hypothyroidism
- Hypervolaemic = likely to be fluid overload secondary to organ failure (renal, cardiac, liver)
Treatment of hyponatraemia…
Replace sodium and water at the rate they were lost
- Patient can be given dietary salt/ IV normal saline
- Oedematous patients should be fluid restricted
- In emergencies where patient is having seizures - hypertonic 1.8% saline can be used
Why is rapid correction of hyponatraemia dangerous?
Causes intracellular dehydration as water moves out, leading to pontine myelinosis (permanent spastic paraperesis, seizures, coma)
Causes of SIADH…
- Tumours - small cell lung carcinoma
- Chest disease - TB, pneumonia
- CNS disorders - pituitary adenomas, infections, head injury
- Iatrogenesis- chemotherapy agents, MAOIs, phenothiazines, carbamazepine
- Metabolic disorders - hypothyroidism, porphyria
Treatment of SIADH…
Treat the underlying cause with fluid restriction, and increased salt intake
Long term problem=>demeclocycline 600mg OD to induce nephrogenic DI
What are the symptoms of hypernatraemia?
[Na]> 145mmol/L = lethargy, thirst, weakness, irritability, confusion
[Na] > 160mmol/L = seizure , coma
Causes of hypernatraemia
- Water loss in excess of sodium loss / sodium excess
- Fluid loss without replacement e.g. dehydration, burns
- Diabetes insipidus
- Osmotic diuresis e.g. hyperglycaemia
- Primary hyperaldoseronism
- Iatrogenic- excessive saline use
Differential causes of hypernatraemia
High circulating vol= hyperaldosteronism (increased Na)
Low circulating vol= most other states
Hypertonic urine = extra-renal fluid losses, and reduced fluid intake
Hypotonic urine = diabetes insipidus
Isotonic urine = osmotic diuresis
Treatment of hypernatraemia
- Give water orally
- Give IV 5% dextrose solution
- Guided by urine output and plasma sodium level
Two types of Diabetes Insipidus
Central DI = reduced ADH production so less circulating ADH
Nephrogenic DI = caused by renal resistance to ADH (which is still being produced by the pituitary)
Investigations for DI
- 24 hour measurement of urine volume (>3L /day)
- Fluid deprivation testing: If patient continues to produce large volumes of urine despite high plasma osmolality, it is likely to be DI
- IM desmopressin given to distinguish between nephrogenic and central DI- increase in urine osmolality to >800mOsm/kg