Confusion

Confusion
By Dr A McLeod

Distinguish between acute and chronic confusion

The distinction between the acute and chronic syndrome is obviously straightforward if a full history is available. Symptomatic differences are not consistent, but the following features favour an acute disturbance:

Impairment of consciousness
Fluctuating level of consciousness
Nocturnal worsening
Intact memory for recent events
Visual hallucinations and other perceptual disturbances
Vivid emotional states.

The common and serious causes for acute confusion / delirium

These can be split into intrinsic brain pathology, extrinsic brain pathology and iatrogenic causes. You can remember them as the 10 P's. In alphabetical order these are:

Paget's disease of the skull:

Pain:

Pancreas: Diabetes and its associated conditions

Parched: Dehydration is a major cause of confusion - any of the following can result in dehydration:

Low intake - the thirst response is often blunted in the elderly
Diarrhoea
Vomiting
Loss of urine concentration (kidney failure, age related)
Inappropriate iatrogenic diuresis
Increased antidiuretic hormone (e.g. paraneoplastic or less commonly hypothyroid disease, intermittant porphyria)

Party:

Alcohol
Withdrawal
Chronic alcohol diseases e.g. Wernicke's / Korsakoff's
Illicit drugs

Pee: The urinary system

UTI: One of the commonest causes of confusion in the elderly - must be checked early, remembering the poor accuracy of urine dipsticks.
Acute renal failure

Pre-renal: reduced perfusion (e.g. Hypotension, post MI), dehydration,
Renal: GN, renal artery thrombosis / embolism, nephrotoxic substances
Post renal: BPE and urinary retention are common. Check catheter tubes for blockages.

Acute urinary retention

Pharmacy: The iatrogenic causes. Of particular importance are:

Digoxin
Overly rapid correction of hypertension
Over-diuresis
Potassium sparing diuretics / K+ supplements
Simple POLYpharmacy - interaction between various drugs

Pneumonia: This gets its own section as it is so common and so often causes confusion in the elderly

pO2: The brain is heavily dependent on oxygen and anything that interfers with its supply may result in confusion. Conditions that may reduce pO2 include:

Arrythmias
Heart failure
MI
Subacute bacterial endocarditis
COPD exacerbation
Pulmonary embolism
Pleural effusion
Pneumothorax

Poor nutrition: Especially with regard to certain vitamins

B12:
Folate: Usually nutritional
Thiamine

Confusion in younger patients - the commonest casues are:

Party - by far the commonest and should be excluded in all younger patients.
Pancreas -

But don't forget the rest..

Confusion in the elderly - the commonest causes are

Pee - Urine dispstick has a sensitivity of 90% - should ALWAYS be checked. Repeat if negative.
Poo
Pneumonia -
Pharmacy / Polypharmacy - check the drug chart with the BNF and get a pharmacist's advice if needed.

But don't forget the rest...

Outline important initial investigations, including electrolytes, cultures, full blood count, ECG, blood gases, thyroid function tests.

Immediate

'Obs' - including BP, HR, RR, SaO2 and Temp. Pyrexia may not be present in infections in the elderly.
Capillary blood glucose
ABG
Urinary dipstick - ketones + signs of infection
ECG

First line 'routine'

Chest X-ray
U+Es

Hyponatraemia
Hypokalaemia
Hyperkalaemia

Hb: for anaemia - leading to low oxygen carrying capacity to the brain
MCV: If elevated may be a sign of B12 / folate deficiency
WCC: Increased (or sometimes decreased) in infection. Leucopenia may indicate B12 deficiency.

Troponin I (or T): Silent MI is common in the elderly and may not show on ECG. This test will help to exclude.
Liver function tests including gamma glutamyl transaminase and INR: Hepatic damage
Thyroid function tests

Later investigations

Calcium
B12 / Folate
Thiamine
Urine / vs serum osmolality for antiduretic hormone. Increased ratio when there is high antidiuretic hormone.
Bladder scan for residual urine
CT of brain / skull

Outline indications for further investigation including head CT, lumbar puncture

Recognise the factors that can exacerbate acute confusion / delirium e.g. change in environment, infection

List the pre-existing factors that pre-dispose to acute confusion / delirium

Outline pharmacological management of confused patient and associated risks

Skills

Take a history of confusion

Ask relatives, neigbours and others who know the pt well
Differentiate between acute confusion and chronic, progressive confusion

Acute confusion

Self neglect, urinary / faecal incontinence are less common and more recent in origin

Chronic, progressive condition

Hallucinations less common

Past medical history
Drug history

Examine to elicit cause of acute confusion / delirium
Remember that there may be more than one cause of confusion present - especially in the elderly.

General

General inspection: toxic, sweating, unilateral loss of facial tone, rash or cellulitis.
Eyes: jaundice, uneven pupils, reaction to light. Fundoscopy for papilloedema (raised ICP)
Lips / tongue: cyanosis
Lymph nodes: Infection
Pulses: rate and character
Oedema: sacral or ankle as appropriate
Leg swelling: ?DVT

Cardiorespiratory

Respiratory rate
Tracheal shift: pneumothorax / tension pneomothorax.
Full lung auscultation + percussion
Heart percussion

Gastrointestinal + urinary

Distension

Ascites - hepatic failure
Gas - ileus, intestinal obstruction

Palpate liver

Hard (and possibly craggy): cancer
Enlarged: heart failure, cirrosis, cancer
Myeloproliferative disorder - look for splenomegaly

Palpate bladder: retention
Palpate spleen

portal hypertension - also look for ascites + caput medusa
myeloproliferative disorder - likley also hepatomegaly

Digital rectal examination: prostate ca / obstruction, impacted faeces

Nervous system

Mini mental state examination: gives a baseline for management
Tone + power: CVA / TIA
Cranial nerves including fundoscopy: Raised ICP / possible position of cerebral lesion.

Other

Check catheter tubes for blockages
Ensure capillary blood glucose has been done

Perform mental state examinations (abbreviated mental test and mini-mental test) to assess severity and progress of cognitive impairment

Recognise pre-disposing factors: cognitive impairment, psychiatric disease

Post-operative state
Pre-existing dementia - even at a mild level
Use of physical restraints (e.g. tucking tightly in with sheets, cot sides)
Malnutrition
>3 medications added during hospital stay
Bladder catheter
Visual or hearing impairment
Psychiatric illness (especially depression)

Updated October 2009