Flashcards in Acute Care & Trauma Deck (76)
What is acute respiratory distress syndrome?
Condition occurring in critically ill patients, characterised by widespread inflammation of the lungs
- Clinical phenotype which may be triggered by various pathologies such as trauma, pneumonia and sepsis
What is the aetiology of acute respiratory distress syndrome?
- Diffuse compromise of pulmonary system resulting in ARDS often occurs in setting of critical illness
- May be seen in pulmonary (pneumonia) or systemic infection (sepsis), following trauma, multiple blood transfusions, severe burns, severe pancreatitis, near-drowning, drug reactions or inhalation injuries
What is the epidemiology of acute respiratory distress syndrome?
- Incidence is higher in mechanically ventilated population
- Worldwide, severe sepsis is common trigger
What are the signs and symptoms of acute respiratory distress syndrome?
- Often begin within 2 hours of inciting event but can occur after 1-3 days
- Shortness of breath
- Fast breathing
- Low oxygen level in the blood due to abnormal ventilation
What are the investigations for acute respiratory distress syndrome?
- CXR, CT thorax: bilateral opacities not explained by other lung pathology
- ABG: Pa02/Fi02 ratio: decreased
What is alcohol withdrawal?
Condition that occurs in alcohol abusers as a result of decrease or cessation of alcohol drinking, resulting in blood alcohol levels below the level to which the drinker has become habituated
- Commonly referred to as 'the shakes' and begins about 4-12 hours after last drink and may progress to delirium, seizures, hallucinations, coma and death
What are the risk factors for alcohol withdrawal?
- Cultural, parental, peer influences
- Availability of alcohol
- Occupation: lawyers, publican, doctors
What is the aetiology of alcohol withdrawal?
- Alcohol enhances inhibitory GABA activity and inhibits glutamate transmission
- Glutamate receptors upregulated and downregulated GABA receptors
- Abrupt cessation= overactive glutamate activity
What is the epidemiology of alcohol withdrawal?
1.8 million deaths per year
What are the presenting symptoms of alcohol withdrawal?
- Mild: Can't sleep, nausea, anxiety, irritable
- Sweating and tremor
- Sleep disturbance
- Visual hallucination: liliputian hallucinations, seeing little people
What are the signs of alcohol withdrawal on examination?
- Mild: Hypertension, tachycardia, hyperreflexia
- Derlium tremens (usually after 3rd day: 48-47h after cessation, agitation, fever, tachycardia, confusion, delusions, hallucinations (visual or tactile), dilated pupils
What are the investigations for alcohol withdrawal?
- FBC: hypoglycaemia
- Serum urea & creatinine: dehydration may occur if pt delirious -> impaired renal function. Uraemic encephalopathy may mimic alcohol withdrawal
- LFTs: Addition to Dx
- Toxicology screen: To determine other causes, serum and urine testing
- Electrolytes; lactic acidosis may be related to alcoholic seizures, ketoacidosis, ingestion of other alcohols
- CT head: exclude other causes of presentation in bran
- CXR: Exclude infection
How is alcohol withdrawal managed?
1) IV vitamin p complex (Pabrinex), folic acid, Mg (Mg sulphate infusion)
2) Thiamine in Wernicke's encephalopathy suspected
3) Reducing doses of chlodiazepoxide
4) Nutritional support as often malnourished
5) Lactulose and phosphate enemas if encephalopathy
What is the criteria for admission for alcohol withdrawal?
- Alcohol withdrawal and at high risk of developing seizures
- Under 16s
- Vulnerable people; frail, cognitive impairment, many comorbidities, lack social supports
- If not admitted, advise against sudden reduction in alcohol
What are the chronic complications of alcohol withdrawal?
- Cerebral atrophy and dementia
- Cerebellar degeneration
- Optic atrophy
- Peripheral neuropathy
- Hepatic encephalopathy
- Thiamine deficiency
- Wernicke's encephalopathy
- Korsakoff's psychosis
- Alcohol withdrawal seizures
- Sedation form benzodiazepine treatment
- Delirium tremens
What is the prognosis for alcohol withdrawal?
- Insomnia and autonomic symptoms last for a few months- at least 6
- 50% relapse after starting treatment
- To present relapse: Counselling, encourage alcohol support group attendance, Acamprosate for anxiety, insomnia, craving for 1y, Disulfiram causes acetaldehyde built up with unpleasant side effects for alcohol ingestion- flushing, throbbing, headache, palpitations
What is anaphylaxis
Acute life-threatening multisystem syndrome caused by sudden release of mast cell and basophil derived mediators into the circulation
What is the aetiology of anaphylaxis?
Can be classified as
- Immunological: IgE-mediated or immune complex/complement-mediated
- Non-immunological: Mast cell or basophil degranulation without the involvement of antibodies (e.g. reactions caused by vancomycin, codeine, ACE inhibitors
- Can be induced by exercise
- Common allergens (e.g. drugs, radiological contrast agents, latex, insect stings, egg, peanuts, shellfish, fish
- Repeated administration of blood products in pts with selective IgA deficiency (due to formation of anti-IgA antibodies)
What causes tissue oedema in anaphylaxis?
Inflammatory mediators such as histamine, tryptase, chimase, histamine-releasing factor, PAF, prostaglandins and leucotrienes cause bronchospasm, increased apillary ermeability and reduced vascular tone
What is the epdidemiology of anaphylaxis?
- Relatively common
- Occurs in 1/5000 exposures to parenteral penicillin or cephalosporins
What are the presenting symptoms of anaphylaxis?
Acute onset of symptoms on exposure to allergen
- Wheeze, shortness of breath or sensation of choking
- Swelling of lips and face
- Pruritis, rash
Severity of previous reactions does not predict the severity of future reactions. Pts may have history of other allergic hypersensitivity reactions e.g. asthma, allergic rhinitis. Biphasic reactions occur 1-72h after the first reaction in 20% of pts
What are the signs of anaphylaxis on examination?
- Tachypnoea. wheeze, cyanosis
- Swollen upper airways and eyes, rhinitis, conjunctival injection
- Urticarial rash (erythematous wheals)
- Hypotension, tachycardia
What are the investigations for anaphylaxis?
- Dx made clinically
- Serum tryptase, or histamine levels and urinary metabolites of histamine can support clinical Dx. normal levels of these do not exclude dx
What are the investigations for anaphylaxis after the attack?
- Allergen skin testing: Identifies allergen. Should be performed by allergy specialist because risk of anaphylaxis
- IgE immunoassays: E.g. radioallergosorbent tests (RASTs) to identify food-specific IgE in the serum
How is anaphylaxis managed?
Stop any suspected drugs
- Resuscitation: according to principles of airway, breathing and circulation
- Secure airway: and give 100% 02. Intubation and transfer to ITU may be necessary so anaesthetist must be informed early
- Adrenaline IM: Can be repeated ever 10m according to response of pulse and BP
- Antihistamine IV
- Steroids IV
- IV crystalloid or colloid: to maintain blood pressure. If hypotensive, lie pt flat with head tilted down
- Treat bromchospasm: with salbutamol +/- ipratropium inhaler. Aminophyllin IV infusion may be required
- Advice: Educate on use of adrenaline pen for IV administration. Provide Medicalert bracelet. make not in pts notes and drug charts. Referral to an allergy specialist for identification of culprit allergen and education in allergen avoidance
What are the possible complications of anaphylaxis?
- Respiratory failure
What is the prognosis of anaphylaxis?
Good if prompt treatment given
What is an arterial blood gas?
- Blood gas test of blood from an artery
- Measures amounts of certain gases e.g. oxygen and carbon dioxide - dissolved in arterial blood
What are the indications for an arterial blood gas?
- Determine pH of blood
- Partial pressure of C02 and 02
- Determine bicarbonate level
- Mainly used in pulmonology and critical care medicine to determine gas exchange which reflects gas exchange across the alveolar- capillary membrane