FRCA Notes

Alcohol Abuse

There haven't been any CRQs explicitly on alcohol abuse, though elements of the topic could presumably feature in questions on liver disease or trauma.

Alcohol appears only once in the curriculum, under the auspices of "demonstrates knowledge of the management of acute poisoning; alcohol"...

Resources

  • Alcohol is the most commonly consumed recreational drug in the UK (and probably the world)
  • It is also the second commonest drug of abuse amongst clinicians, after opioids

System Effect
Cardiovascular Alcoholic cardiomyopathy
CNS Coma (acute)
Peripheral neuropathy
Wernicke's encephalopathy
Korsakoff's dementia
Psychiatric Dependence
Addiction
Hepatobiliary Alcoholic hepatitis
Alcoholic liver disease
Pancreatitis
Metabolic Altered stress response to surgery
Thiamine deficiency
Malnutrition
Haematological Coagulopathy
Bone marrow toxicity
Immunological Immunosuppression
Pharmacokinetic CYP450 enzyme induction


Risk factors

  • Volume, type and pattern of alcohol consumption
  • Genetic factors e.g. CYP2E1, ADH, ALDH enzyme isoforms
  • Asian ethnicity
  • Female gender
  • Obesity ± poor diet
  • Coalescing liver disease, especially hepatitis C

Pathophysiology

  • There are three pathophysiological processes, which are not necessarily linear in apperance and may co-exist

    1. Alcohol hepatitis (35% of heavy drinkers)
      • Ethanol metabolism generates ROS and neoantigens, promoting an inflammatory response in the liver

    2. Steatosis/steatohepatitis (90 - 100% of heavy drinkers)
      • Alcohol metabolism causes lipid accumulation within hepatocytes

    3. Cirrhosis (20% of heavy drinkers)
      • Prolonged hepatocellular damage instigates collagen production from myofibroblasts - fibrosis ensues
      • The changing liver architecture causes increased resistance to portal blood flow and thus portal hypertension

  • This section is included mostly out of interest
  • Ethanol can cause analgesia, reducing pain intensity and elevating pain threshold (Journal of Pain, 2016)
    • Ethanol is metabolised by alcohol dehydrogenase to acetaldehyde, then to acetate by aldehyde dehydrogenase
    • Acetate appears to instigate GABAergic transmission in the spinal cord, mimicking inhibitory neuronal pathways and reducing pain (BJA, 2021)
  • There's also some suggestion alcohol consumption is non-linearly and inversely associated with the occurrence of chronic pain (BJA, 2022)

Perioperative management of the patient with a penchant for alcohol


History and examination

  • Screen for alcohol abuse e.g. with CAGE, AUDIT
  • Elicit degree of alcohol intake
  • If chronic abuse known/suspected, focus on elucidating the presence of:
    • Cardiovascular sequelae
    • Neurological sequelae
    • Hepatic sequelae

Investigations

  • FBC: may show pancytopaenia (bone marrow toxicity) or macrocytic anaemia (folate deficiency)
  • Renal function, electrolytes and glucose
  • Liver function
  • Clotting screen: a prolonged PT may be indicative of early liver disease
  • ECG
  • ± TTE if suspicion of alcoholic cardiomyopathy

Optimisation

  • Referral to the appropriate alcohol/substance misuse team
  • Abstention for 6 - 8 weeks reduces perioperative morbidity and mortality
  • Those at risk of withdrawal may need:
    • Elective surgery: a managed reduction in intake in a controlled fashion
    • Emergency surgery: IV thiamine and benzodiazepines

  • The acutely intoxicated patient presenting for elective surgery should be cancelled

Acute intoxication

  • Acutely intoxicated patients presenting for emergency surgery pose a challenge:
    • Consent may be difficult (impossible) to obtain
    • There may be confusion, agitation, psychomotor impairment or aggression which will impair ability to pre-oxygenate
    • An RSI approach is required owing to delayed gastric emptying and risk of vomiting, with cautious extubation too
    • Reduced doses of induction and maintenance agents are required
      • Ethanol itself can causes anaesthesia via an unknown mechanism separate from its analgesic mechanism

Chronic alcohol abuse

  • Regional techniques may be contraindicated if there are clotting diathesis
  • RSI approach still required owing to delayed gastric emptying
  • Increased doses of induction and maintenance agents are required owing to:
    • CYP2E1 enzyme induction
    • Development of cross-tolerance

  • Post-operative monitoring inc. for symptoms of alcohol withdrawal e.g. use CIWA scoring
  • Multimodal analgesia and anti-emesis as standard

  • There is a 2 - 5x increase risk of post-operative complications including:
    • Bleeding
    • Infection, be it at the surgical site, pneumonia or urinary tract
    • Post-operative arrhythmias and acute coronary syndromes
    • Delirium (± tremens)
    • Unplanned HDU/ICU admission
    • Length of hospital stay