Organ failure Flashcards
Pt has jaundice, coagulopathy and encephalopathy. Likely dx?
Acute liver failure
What is acute liver failure?
Complex multi system illness after insult to liver has: Jaundice Coagulopathy - INR >1.5 Hepatic encephalopathy Absence of chronic liver disease Onset within 12 weeks Rare but high mortality
How is ALF graded and what are their causes
O’Grady
Jaundice to encephalopathy:
Hyper acute - within 7 days (best prognosis) - cause is paracetamol, drugs, viral hepatitis
Acute - 8-28 days - cause is viral hepatitis, ischaemic hepatitis
Subacute - 29+ days (worst prog) - cause is seronegative/autoimmune hepatitis
Most common cause of ALF?
paracetamol OD
Others: viral hepatitis A and E, maybe B - common in developing countries
Also: Mushrooms (amanita phalloides)
Drugs which cause ALF:
Dose dependent & therefore predicatble - Paracetamol, alcohol, isoniazid/rifampicin, NSAIDs, sulphonamides, valproate, carbamazepine, ecstasy
Rarer: phenytoin, isoflurane, allopurinol, mono-amine oxidase inhibitors, tricyclic antidepressants, amiodarone
Not predictable: Legal highs
Anabolic steroids
Herbal meds
Viruses which cause ALF
Viral hepatitis - A, E< B
Rarely: HSV, cytomegalovirus, EBV, parvovirus
Rare causes of ALF?
Ischaemic hepatitis Autoimmune hepatitis Acute fatty liver of pregnancy Wilsons disease Budd chiari (clot of hepatic circulation) Mushrooms Post hepatectomy
If pt has unknown cause of ALF - what might you see/how would you treat?
Female 20-40 Recent jaundice + coagulopathy, previously normal LFT ?Liver biopsy ?trial of steroids Liver transplant
Suspect ALF from paracetamol OD. Assessment and treatment?
LFTs, FBC, U&E Paracetamol level Blood gas Lactate, blood gas, pH IV N-acetylcysteine early IV crystalloid fluids IV broad spectrum Antibiotics (coamoxiclav) & antifungals (fluconazole) in severe cases Discuss w/ transplant centre
Investigation for AFL?
Viral screen Paracetamol level & drug conc Autoantibodies (IgG) USS, platelet count (HELLP) Ceruloplasmin, Urinary copper 24h (for Wilsons) and slit lamp (see Keiser-Fleisher rings) USS/venography - budd Chairi Imaging & histology (malignancy) Transaminases - ischaemic hepatitis
RF for paracetamol OD?
Staggered OD Excessive alcoholic consumption malnutrition HIV cancer liver enzyme inducers:(rifampicin, anti-epileptic, spironolactone)
What is paracetamol metabolised by?
CYP450 in N-acetyl-p-benzoquinoeinine toxic metabolite, detoxified by glutathione
Treatment of hep B ALF?
Inform transplant centre
Tenofovir
Complication of ALF?
Encephalopthy - cerebral oedema CVD Renal failure Sepsis Malnutrition
Big reason for hypoxia in A&E?
V/Q mismatch (blood is flowing through lungs but can’t get oxygen as lung isn’t ventilating properly)
Causes of collapsed alveoli?
Pneumonia, anaesthetics, lying down
Fluid in alveoli?
pulmonary oedema
Constricted terminal alveoli?/bronchiole obstruction
Asthma/COPD
Types of resp failure?
1: pO2 <8kPa, normal PCO2 (or lowdue to hyperventilation) - failure of oxygenation.
Then pt tires and increased ventilation is not maintained. ->
2: pO2 < 8kPa, PCO2>6kPa
T1 resp failure treatment?
CPAP
T2 resp failure treatment?
BiPAP - EPAP (expiratory positive airway pressure for low O2)
IPAP - inspiratory PAP - when high CO2
When to use NIV?
Pneumonia
post op (collapsed alveoli)
COPD
Oedema
When not to use NIV?
Asthma
Pneumothorax
Agitation
Airway loss
When is it resp failure?
PaO2 <8kPa
Stage 1 AKI?
Creatinine 1.5X baseline
Urine output <0.5ml/kg/hr for > 6 hrs
Stage 2 AKI?
Creatinine 2X baseline
Urine output <0.5ml/kg/hr for > 12 hrs
Stage 3 AKI?
Creatinine 3X baseline
Urine output <0.3ml/kg/kr for >24hrs
Anurina for >12hrs
If needs renal replacement therapy
Causes of AKI
STOP Sepsis/shock (pre) Toxins (intra) Obstruction (post) Pressure optimaisation (pre)
Pre-renal causes of AKI? +treatment
Poor pressure optimatisation
Sepsis/shock - hypovolaemic shock (less fluid to filter toxins), septic shock (leaking from capillaries into interstitial space -> hypovolaemia), cardiogenic shock (fluid moves through the same, but it’s less fluid, pressure remains the same)
Reduction in blood flow -> hypoxia in kidney –> acute tubular necrosis
Treat = fluids
Intrarenal causes of AKI? +treatment
Toxins - acute interstitial nephritis -> from NSAIDs
Tubular toxicity - from radio-opaque contracts and gentamicin
Treat = Stop drugs
Post-renal cause of AKI? +treatment
Obstruction - stones and cancer
Need nephrostomy
Treat cancer
Complications of AKI?
Hyperkalaemia
Metabolic Acidosis
Due to inability to excrete K+ and H+, also sodium doesn’t get reabsorbed.
What does high anion gap show?
Normal anion gap = 4-12 High <12 eg 18 - excess H+ from somewhere "Left total knee replacement" Lactate Toxins (CSP MIGE G) - cyanide, salicylates, paraldehyde, methanol, iron, CO, ethylene, glycol Ketones (DKA) Renal failure - also in Addison's
Ix for ?uretic stone?
CT
Ultrasound is good at looking for hydronephrosis (where there is a stone but you see the dilatation of pelvis and ureters but doesn’t see stones)
What are the functions of the liver?
Synthesis: protein, clotting factors, bile, glucagon
Detoxification: alcohol, drugs, ammonia, bilirubin
Storage: energy, vitamins and minerals
Important in immune system
In renal failure who drugs should you watch out for?
Ace-inhibitors
Also any ending in -pril
