misc medicine Flashcards
What are the different hypersensivity reactions according to the Gell-Coombs classifications?
Type 1-4, think ACID
A - Anaphlyaxis - IgE mediated
C - Cell bound - cytotoxic antibody-mediated responses involving IgG or IgM antibodies eg hemolytic transfusion reactions, ITP
I - Immune Complex - between antigens and IgG or IgM antibodies eg SLE
D - Delayed hypersensitivity - T lymphocytes eg contact dermatitis, MS, tuberculin skin reaction
IgG vs IgM positivity?
IgG positive & IgM negative - shows immunity
IgG negative & IgM positive - shows recent infection
What conditions tend to be AR vs AD inheritance?
Autosomal recessive conditions are often thought to be ‘metabolic’ as opposed to autosomal dominant conditions being ‘structural’, notable exceptions:
some ‘metabolic’ conditions such as Hunter’s and G6PD are X-linked recessive whilst others such ashyperlipidaemia type IIandhypokalaemic periodic paralysisare autosomal dominant
some ‘structural’ conditions such as ataxia telangiectasia and Friedreich’s ataxia are autosomal recessive
Mx of Ramsay Hunt syndrome
oral aciclovir + corticosteroids + eye protection
Dose of adrenaline in anaphylaxis for:
>12s
6-12 yrs
<6 yrs
> 12s - 500mcg
6-12 yrs -300mcg
<6 yrs - 150mcg
How often do you need one-off pneumococcal vaccination?
One off for most at risk groups
some need every 5 yrs - sickle cells, aspleenics
Skin patch vs prick test?
Patch - contact dermatitis, leave allergen on skin for 48 hrs
Prick - immediate hypersensivity (wheal) eg food or resp allergies
chadsvasc score?
CHF
HTN
Age (1 point for 65-74, 2 for >75)
Diabetes
Stroke/ TIA/ VTE - 2 points
vascular disease
sex
How do you calculate the anion gap? What should it be? Causes of raised vs normal anion gap?
The anion gap is calculated by:
(sodium + potassium) - (bicarbonate + chloride)
A normal anion gap is 8-14 mmol/L
It is useful to consider in patients with a metabolic acidosis:
Causes of a normal anion gap or hyperchloraemic metabolic acidosis
gastrointestinal bicarbonate loss: diarrhoea, ureterosigmoidostomy, fistula
renal tubular acidosis
drugs: e.g. acetazolamide
ammonium chloride injection
Addison’s disease
Causes of a raised anion gap metabolic acidosis
lactate: shock, hypoxia
ketones: diabetic ketoacidosis, alcohol
urate: renal failure
acid poisoning: salicylates, methanol
5-oxoproline: chronic paracetamol use
What is the parkland formula/ how do you calculate?
for burns
Volume of fluid = total body surface area of the burn % x weight (Kg) x 4ml
How do you treat tetanus status for wounds?
Patient has had a full course of tetanus vaccines (5 doses), with the last dose < 10 years ago
no vaccine nor tetanus immunoglobulin is required, regardless of the wound severity
Patient has had a full course of tetanus vaccines, with the last dose > 10 years ago
if tetanus prone wound: reinforcing dose of vaccine
high-risk wounds (e.g. compound fractures, delayed surgical intervention, significant degree of devitalised tissue): reinforcing dose of vaccine + tetanus immunoglobulin
X linked recessive inheritance mech?
In X-linked recessive inheritance only males are affected. An exception to this seen in examinations are patients with Turner’s syndrome, who are affected due to only having one X chromosome. X-linked recessive disorders are transmitted by heterozygote females (carriers) and male-to-male transmission is not seen. Affected males can only have unaffected sons and carrier daughters.
What are the main inhaled anaesthetic induction agents? Adverse effects?
volatile liquid eg isoflurane - can cause malignant hyperthermia
Nitrous oxide CI in pneumothorax
What IV agents are used for induction in anaesthetics? Adverse effects?
Propofol - causes hypotension, has anti-emetic properties
Thiopental- laryngospasm
Etomidate- myoclonus
Ketamine - hallucinations, not hypotensive
