General Flashcards
What are the signs and symptoms of anaphylaxis?
- acute onset
- Airway/breathing: dyspnoea, respitory distress, wheeze, stridor, cyanosis
- Circulation: tachycardia, hypotension
- Skin: urticaria, angiooedema
What is the pathophysiology of anaphylactic reaction?
sensitisation phase: immune system encounters allergen, makes IgE against it (no clinical features occur).
Effector phase: allergen cross-links IgE on the surface of mast cells. THis leads to widespread degranulation and histamine release which mediates inflammation, bronchospasm, vasodilation, increased capillary permeability, and tissue oedema.
What dose and route of adrenaline would you give to an adult patient with anaphylaxis?
500 micrograms (0.5ml of 1:1000) IM
What dose and route of adrenaline would you give a child aged 15 with anaphylaxis?
500 micrograms (0.5 ml of 1:1,000) IM Same as the adult dose until age 12!
What dose and route of adrenaline would you give a child aged 10 with anaphylaxis?
300micrograms (0.3ml of 1:1000) IM. This is the dose for a child aged 6-12 years.
What dose and route of adrenaline would you give a child aged 4 with anaphylaxis?
150micrograms (0.15ml of 1:1000). This is the dose for a child aged 5 and under.
What blood test can help with retrospective diagnosis of anaphylaxis?
Mast cell tryptase: take 3 samples ASAP (after 1-2 hours and after 24 hours). Absence of a rise doesn’t exclude anaphylaxis though!
Define: AKI, oliguria, anuria
AKI: sudden deterioration in renal function leading to inability to maintain fluid, electrolyte and acid:base balance
Outline the criteria for staging AKI.
1) Cr ≥1.5-2 times baseline or urine output (UO) <0.5 ml/kg/hours for >6 consecutive hours
2) Cr ≥2-3 times baseline or UO <0.5 ml/kg/hours for >12 hours
3) Cr ≥3 times baseline or UO <0.3 ml/kg/h for ≥24 hours or anuria for >12 hours
Prerenal, Renal and Postrenal causes of AKI.
Prerenal • hypovolaemia secondary to diarrhoea/vomiting • renal artery stenosis Renal • glomerulonephritis • acute tubular necrosis (ATN) • acute interstitial nephritis (AIN), respectively • rhabdomyolysis • tumour lysis syndrome Postrenal • kidney stone in ureter or bladder • benign prostatic hyperplasia • external compression of the ureter
4 types of nephrotoxic drugs to stop/avoid in AKI
ACEi’s (-prils)
ARB’s (valsartan, losartan, candesartan)
NSAID’s (ibuprofen, naproxen, diclofenac, high dose aspirin)
Aminoglycosides (e.g. gentamicin, other -mycin’s)
What are the signs if a patient is hypovolaemic?
Cold, pale peripheries Prolonged capillary refill times (CRT >2 s) Decreased skin turgor Reduced jugular venous pressure (JVP) Sunken eyes Dry lips, mouth and tongue Tachycardia Postural hypotension Absolute hypotension Dark urine
How can urinary and plasma osmolality and sodium help in determining cause of AKI?
Prerenal: kidney is functioning to RETAIN salt and water, so urinary osmolality is high (600-900 mosm/L) and urinary sodium is low(<10 mM).
ATN: kidney is functioning inadequately and is unable to retain salt and water, urinary osmolality approaches that of plasma (280mosm/L) and urinary sodium rises (>30mM)
Complications of AKI
Hyperkalaemia Hypo/hypernatraemia Hypercalcaemia Metabolic acidosis Pulmonary oedema Hypertension Uraemic encephalopathy Uraemic pericarditis
Indications for commencing dialysis (smaller molecules)/ filtration(larger molecules) in AKI?
Urine output <0.3 ml/kg for 24 hours Absolute anuria for >12 hours Multi-organ failure Refractory volume overload Complications of uraemia: Uraemic encephalopathy or Uraemic pericarditis Severe poisoning or drug overdose Severe hypo/hyperthermia Refractory hyperkalaemia >6.5 mM Serum urea >27 mM Refractory metabolic acidosis pH <7.15 Refractory electrolyte abnormalities: Hyponatraemia <115 mM, Hypernatraemia >165 mM, Hypercalcaemia
