Alcohol Flashcards
Methanol is toxic and not for consumption but where can it be found?
It is present in anti-freeze, solvents and some fuels. It may also be present in contaminated home brews.
What is methanol metabolised to form?
Formaldehyde and formic acid both which are toxic to the body.
What properties do both ethanol and methanol have?
Depressant (you’ll act drunk with both)
What are the potential harmful things methanol can do to the body?
Acidosis, blindness (destruction of the optic nerve) and renal failure
What is used to treat methanol poisoning? How does it work?
Ethanol- it is a competitive inhibitor so stops methanol being metabolised as they both are metabolised by alcohol dehydrogenase
Why shouldn’t you drink on an empty stomach?
There is limited alcohol absorption in the stomach so the longer food stays in the stomach the slower the alcohol will be absorbed. A full stomach slows gastric emptying and therefore alcohol absorption.
Name two drugs that increase gastric emptying and therefore alcohol absorption?
Antihistamines and metoclopramide
Aerated drinks are absorbed faster or slower?
Faster
Why do women tend to have a lower alcohol tolerance?
Women usually have higher levels of subcutaneous fat and as alcohol is water soluble it can’t be absorbed here. Men have a bigger pool for solution. In general women also have lower levels of alcohol dehydrogenase.
Why can some ethnic groups not handle alcohol? What groups?
Certain groups have constitutionally lower levels of alcohol dehydrogenase or aldehyde dehydrogenase. Aborigines, inuits and japanese.
What happens to certain ethnic groups when they drink?
Flushing, itching and feeling warm.
Describe the drug antabuse
It inhibits aldehyde dehydrogenase which makes drinking unpleasant, this helps alcoholics stop drinking even if they crave the alcohol.
Does drinking regularly improve alcohol tolerance?
Yes- it is possible to up regulate alcohol dehydrogenase activity. In heavy drinking alternative pathways are also activated.
Why does alcohol make you need to pee more?
Usually you are consuming more fluid. Alcohol also inhibits ADH so there is reduced water reabsorption and therefore clearer urine.
Does drinking occasional volumes of alcohol have overall health benefits?
No
Where does 90% of alcohol metabolism occur? Where does the rest occur?
The liver
Small volume in pancreas and brain
Describe simple alcohol metabolism
Ethanol converted to acetaldehyde by alcohol dehydrogenase. Acetaldehyde converted to acetate by aldehyde dehydrogenase.
Alcohol is generally removed from the blood at rate of ________ which is equivalent to ______
15mg/100ml/hr
1 UNIT PER HOUR
When does alcohol concentration usually peak?
60 minutes after consumption and it then decreases linearly.
The MEOS pathway is triggered in heavy drinking and results in excess hydrogen ions which have to be disposed of, this inhibits/ impairs three things which are?
Hepatic gluconeogenesis (you become hypoglycaemic)
Citric acid cycle
Fatty acid oxidation
Why do you become hungry when you drink? Who is this particularly relevant in?
Every stores in the liver can’t be used so blood sugar falls. Especially relevant in diabetics.
Explain alcoholic ketoacidosis?
Happens when you run out of glucose to metabolise (usually only occurs in malnourished states). As the body can’t use glucose it starts to burn fat and the by product is ketone bodies. If there is no insulin ketone bodies will begin to build in the blood stream.
Why are you dehydrated when hungover?
Inhibition of ADH means you haven’t been able to reabsorb as much water so have lost lots in urine
Why do you have sensation of a heavy heart beat when hungover?
Alcohol has negative inotropic effects (decrease heart contractility)
What is holiday heart syndrome?
It is associated with binge drinking, basically you get a SVT in an otherwise healthy heart with spontaneous resolution (the mechanism is unclear)
What can cause headaches apart from dehydration when hungover?
Congeners in alcohol- serotonin is produced from sulphites, tannins and phenols all present in red wine
There is no evidence for hangover cures but what may work?
Anything that speeds up the metabolism.
After how many units of alcohol do you begin to see fatty liver changes?
6 units
Explain what you might look for in the hands if you suspected alcoholism/ liver disease during general examination?
Palmar erythema- redness of palms usually related to underlying liver cirrhosis
Dupuytrens contracture- fingers permanently bent, this is not just caused by alcoholism and not all alcoholics have it
What condition in the lungs may alcoholics get?
Aspiration pneumonia- drinking too much suppresses the immune system and relaxes smooth muscle and there can then be migration of microbes due to vomiting or the gag reflex induced by drinking.
What heart condition can be caused by alcoholism?
Dilated cardiomyopathy
This is rare compared to it being caused by a genetic defect
What is dilated cardiomyopathy?
Heart is much bigger than normal but still weighs the same so is floppy and unable to pump blood effectively. Clinical features are generally symptoms of heart failure.
Why do you get a fatty liver when you drink?
Mitochondrial oxidation of fatty acids is reduced by alcohol. This causes decreased transport of fat out of hepatocytes due to intracellular tubular impairment
Define cirrhosis of the liver
The end stage of many liver diseases defined as a diffuse process characterised by fibrosis and conversion of the normal liver architecture into abnormal liver nodules.
Why does alcohol cause gastritis?
Alcohol irritates the gastric mucosa
What is a mallory weiss tear?
Repeated vomiting or retching from drinking alcohol causes a mucosal tear which will present as small amount of blood in the vomit. Most are small tears but if large you can get haemorrhage or oesophageal rupture.
Why do you get reflux oesophagitis and Barrett’s if you drink a lot of alcohol?
Alcohol is a smooth muscle relaxant meaning that the LOS is relaxed allowing reflux of gastric contents into the oesophagus. Repeated assault can result in metaplasia and Barretts.
Define Barretts oesophagus
Metaplastic change in the epithelium in the oesophagus from squamous epithelium to intestinal columnar epithelium.
Describe subdural haemotoma
This is related to repetitive trauma and alcohol related coagulopathies, blood collects between skull and brain.
What is the common mechanism of cirrhosis?
Hepatic stellate cells found in the space of Disse are activated and transformed into myofibroblasts under the influence of cytokines. These activated cells synthesis collagen leading to fibrosis.
Explain what portal hypertension is and why it relates to alcoholism
Note: portal hypertension can happen in other conditions.
Normal portal vein pressure is only 5-8mmHg. Alcoholism will damage the liver (fatty liver-> cirrhosis) and distortion of the liver architecture will result in increased pressure. As pressure rises the blood takes other paths with less resistance (porto-systemic anastamoses) and these anastamoses become engorged and dilated.
Describe symptoms of decompensated cirrhosis?
Jaundice, ascites, encephalopathy.
Why are oesophageal varices a problem in alcoholics?
As alcohol damages the liver, you get portal hypertension so blood collects in porto systemic anastomoses, one of these is in the oesophagus. As these veins are superficial they are prone to rupture and this can cause massive haemorrhaging. Ruptured oesophageal varices is usually catastrophic and is a medical emergency.
What is the most common primary malignancy of the liver?
Hepatocellular carcinoma
What is the most important risk factor in development of hepatocellular carcinoma?
Cirrhosis of any cause (can be alcoholics could be hepatitis etc)
What is caput medusae? What is it a sign of?
Distended veins around the umbilicus. Sign of portal hypertension
Three sites of porto systemic anastomoses?
Rectum, oesophagus and umbilicus
What are spider naevi? Why do you get them in liver disease?
Swollen blood vessels on skin surface. Happen due to excess oestrogen as the liver can’t break it down.
What is and why do you get gynaecomastia?
Swelling of breast tissue in men caused by oestrogen imbalance
What is and why do you get ascites?
Ascites is fluid within the peritoneal cavity due to Na and H2O retention, portal hypertension and low serum albumin. Abdominal swelling occurs and the presence of fluid is demonstrated by shifting dullness.
What is and why do you get hepatic encephalopathy?
In cirrhosis the blood bypasses the liver via collaterals and toxic metabolites pass directly to the brain, ammonia is the main cause.
Signs and symptoms of hepatic encephalopathy?
Patient may have disorder of personality, mood and intellect. May also be disorientated with slurred speech or be vomitting/ nauseous.
Signs include fetor hepaticus (sweet smelling breath), liver flap, constructional apraxia (can’t copy a drawing) and decreased mental function.
What is chronic pancreatitis a risk factor for?
Pancreatic cancer
The main cause of acute pancreatitis is ______ it can also be caused by ______ but the mechanism is not fully understood
gallstone blocking the ampulla of vater causing reflux of bile up the pancreatic duct
can be caused by excess alcohol also
2 signs that support severe necrotising pancreatitis?
Periumbilical bruising (Cullens sign) Flank bruising (Grey Turners sign)