Confusion

Question 1

Which syndromes may cause a patient to appear confused?

Answer 1

1. Delirium - acute impairment in cognitive ability alongside impaired consciousness
2. Dementia - chronic progressive impairment in cognitive ability - with intact consciousness.
3. Mental impairment
4. Psychosis - not confused but disorder of perception
5. Receptive dysphasia - difficulty comprehending questions (e.g. due to damage to Wernicke’s area)
6. Expressive dysphasia - patient cognitively intact but difficulty verbalising answers (e.g. due to damage to Broca’s area)

Question 2

With any confused patient, always do ABCDE first. Then how do you conduct a quick screen of confusion?

Answer 2

1. AMTS (Abbreviated Mental Test Score) = 10 questions to check if they’re orientated in time, place and person. <6/10 indicates cognitive impairment. (NB on MMSE, <26/30 indicates cognitive impairment).
2. If conversational ability impaired, can they follow a 3 step command? Can they name 3 common objects? - these test for receptive and expressive dysphasia
3. Other symptoms - e.g. pain, UTI etc

Question 3

How does time course of confusion affect the diagnosis?

Answer 3

Acute onset indicates delirium.

Fluctuating course of confusion indicates delirium also.

Question 4

What are the causes of delirium ? (INVITED MD)

Answer 4

Infectious - chest, urinary, sepsis
Neoplastic - brain tumour
Vascular - stroke, MI causing hypo perfusion
Immune - rare conditions,e.g. Hashimoto’s encephalopathy
Trauma - subdural haematoma
Endocrine - thyroid disorders, DKA
Drugs - alcohol, opiates, diuretics/digoxin/thyroid medication
Metabolic - electrolyte imbalances, hypoxia, hypercapnia
Degenerative conditions - they won’t cause delirium but predispose patients to becoming delirious

Question 5

Which vital signs are important in confused patients?

Answer 5

1. Pulse/resp rate = tachycardia/tachypnoea secondary to infection?
2. BP = hypotension may indicate hypo perfusion to brain - decreased consciousness. Bradycardia + hypertension (called Cushing’s response) indicates raised ICP
3. Oxygen saturation - hypoxia affects consciousness
4. Temperature - fever may suggest underlying infection. Hypothermia common in elderly and may cause confusion
5. Blood glucose - hypoglycaemia/hyperglycaemia? In T1DM, hyperglycaemia –> DKA? In T2DM, extreme hyperglycaemia —> HHS

Question 6

What does a “confusion screen” consist of?

Answer 6

1. Septic screen - FBC (WCC - infection. Anaemia - hypoxia). CRP. Blood cultures. Urine analysis - positive leukocytes and nitrites = UTI, positive glucose + ketones = DKA. Urine MC&S. Chest radiograph.
2. Metabolic screen - ABG (informs re hypercapnia and acid base balance. Uraemia/DKA can cause metabolic acidosis). U&Es - including calcium. TFTs. Liver enzymes (disproportionately raised GGT = alcohol abuse). Thiamine/folate/Vit B12 - indicates malnourishment.
3. Toxicology screen (if necessary)
4. ECG - arryhthmias/ischaemia can lead to low output state.

Question 7

How do you manage someone who is acutely confused? (e.g. with UTI)

Answer 7

1. ABCDE + resuscitation
2. Antibiotics - to treat UTI. Avoid unnecessary catheters/cannulas
3. Confusion - conservative measures + must treat any deficiencies (e.g. thiamine).
4. Sedation if patient is a risk to themselves/others. Sedation done by giving haloperidol (CAREFUL if they have Parkinsons/Lewy body dementia) or Lorazepam (quick acting)

Question 8

Irreversible damage to what system can thiamine deficiency cause?

Answer 8

Cerebral system - Wernicke’s encephalopathy

Question 9

If someone ha a history of alcoholism and perhaps an extended hospital stay (e.g. 4 days), what is the most likely diagnosis for confusion?

Answer 9

Alcohol withdrawal

Question 10

Alcohol withdrawal requires the immediate prescription of which drug?

Answer 10

Chlordiazepoxide (using CIWA scale as a guide).

Also prescribe thiamine to prevent irreversible brain damage

Question 11

What are the most common reasons why postoperative patients may be confused?

Answer 11

1. Hypoxia - e.g. anaemia from blood loss, opiate induced depressed respiratory rate, PE, etc
2. Opiates may directly affect their mental state
3. Electrolyte derangement - e.g. due to intra/postop fluid replacement, renal failure due to hypoperfusion
4. Infection
5. Sleep loss
6. Alcohol withdrawal

Question 12

In patients with bipolar disorder, what may cause confusion?

Answer 12

Lithium toxicity

Question 13

What may indicate an acute renal impairment (e.g. dehydration)?

Answer 13

Raised urea with normal creatinine

as urea normally reabsorbed in PCT, whereas creatinine isn’t

Question 14

What would be results indicative of meningococcal meningitis?

Answer 14

High WCC (mainly neutrophils), gram positive intracellular diplococci, high protein, CSF:blood glucose ration <0.5)

May/may not also present with neck stiffness etc

Question 15

In patients suspected to be hyponatraemic, what must you rule out and how do you do this?

Answer 15

Pseudohyponatraemia

Do this by checking serum osmolality - high or normal indicates pseudohyponatraemia (because Na is dominant ion determining osmolarity).

i.e. low sodium would give low osmolality, so if the serum osmolality is normal/high we know that it is not low sodium

Question 16

What signs may indicate hypervolaemia?

What conditions may hypervolaemic hyponatraemia suggest?

Answer 16

Raised JVP, peripheral/pulmonary oedema

Hypervolaemic hyponatraemia may indicate CCF, hepatic failure, nephrotic syndrome

Question 17

What is nephrotic syndrome?

Answer 17

Condition whereby you pass too much protein in your urine

Question 18

What signs would a hypovolaemic (dehydrated) patient have?

How does hypovolaemia result in hyponatraemia

Answer 18

Low urine output, tachycardia, low BP, dry mucous membranes, decreased skin turgor

Hypovolaemia stimulates secretion of ADH - which retains fluid in body - hence sodium levels are diluted

Question 19

To distinguish the site of sodium loss in hyponatraemic hypovolaemia, urine sodium is measured. How can we tell if the problem is renal or extra renal from the results?

Answer 19

Urine sodium <220mM = kidneys are normal. They are responding normally to drop in circulating volume by concentrating the urine. Thus the sodium loss is extra renal e.g. gut (vomiting/diarrhoea), skin (sweating/burns) or pancreatitis/small bowel obstruction

Urine sodium >220mM = kidneys abnormally concentrating the urine and salt is being lost in this manner. Causes include diuretics, renal failure, mineralocorticoid insufficiency (Addisons disease)

Question 20

If patients are euvolaemic, measure urine osmolality. What diagnoses may the results of the urine osmolality point towards?

Answer 20

High urine osmolarity (>500mmol/kg) = SIADH (NB other criteria must be met before diagnosing SIADH)

Fluid overload (psychogenic polydipsia / iatrogenic) - acute 
Severe hypothyroidism (rare) may also cause hyponatraemia

Question 21

What other sign may indicate Addisons disease except high urine sodium?

Answer 21

High potassium and low sodium in biochemistry.

Because in adrenal insufficiency, failure of Na/K exchange in DCT, due to lack of aldosterone synthesis.

Question 22

How does one confirm Addisons disease?

Answer 22

SynACTHen test = Addisons will show no increase in cortisol after stimulation with ACTH

Question 23

How is hypovolaemic hyponatraemia managed?

Answer 23

Slow infusion of normal saline - correcting Na too quickly may cause central pontine myelinolysis and death.

So infuse Na every 2-4 hours and try to increase his Na by <2mM/hour and no more than 10mM/day.

Question 24

To treat hypoglycaemia, what do you do?

Answer 24

Give a sweet drink/glucose tablet.

If unconscious, could give dextrose gel rubbed into mouth or glucose IV or glucagon IM

Seizures/coma may occur in hypoglycaemia.