W/S 1 Flashcards
What is the difference between lateral flow tests and polymerase chain reactions?
LFTs
- rapid antigen test that detect specific viral proteins
- take cultures from the nose or throat
- are simple and fast tests that give results within 15-30 minutes
- are less sensitive than PCR and have a higher rate of false negatives
PCR
- molecular test that detects the genetic material, ribonucleic acid (RNA), of a virus
- take cultures from the nose or throat
- take longer than LFTs as it requires specialised equipment and trained personnel
- highly accurate and reliable, detect virus even in individuals with a low viral load
What is the significance of faecal calprotectin, CRP and ESR in inflammatory bowel disease (IBD)?
faecal calprotectin
- is a calcium and zinc binding protein that is predominantly found in neutrophils
- its presence within faeces is a result of neutrophil migration into the GI tissue during inflammation
- concentration of faecal calprotectin correlates with intestinal inflammation
C-reactive protein and erythrocyte sedimentation rate
- are markers of inflammation
What are the treatment options for Crohn’s disease?
exclusive enteral nutrition
corticosteroids
- prednisone or budesonide
- are prescribed for a short duration to reduce inflammation and control symptoms quickly
aminosalicylates
- sulfasalazine, mesalazine
- are used in mild to moderate cases
immunosuppressants
- thiopurine = azathiopurine, 6-mercaptopurine
- methotrexate
- cyclosporin
biologicals
- anti-TNF agents = infliximab, adalimumab, golimumab
antibiotics
- metronidazole, ciprofloxacin
probiotics
prebiotics
How do corticosteroids treat Crohn’s disease?
effective at inducing remission in IBD
inhibit synthesis and transcription of pro-inflammatory proteins
- this down-regulates the production of nuclear factor kappa-B and inflammatory cytokines such as IL-1, IL-6 and TNF-alpha
up regulate anti-inflammatory mediators
How do aminosalicylates treat Crohn’s disease?
Inhibit eicosanoid synthesis - leukotrienes and prostaglandins
Inhibit production of proinflammatory cytokines - TNF-alpha
stimulates production of anti-inflammatory molecules.
How do thiopurines treat Crohn’s disease?
are immunosuppressants
it is converted to its active metabolites, mercaptopurine (6-MP) and thioguanine (6-TGN)
It then inhibits DNA and RNA synthesis by preventing purine (A/G) metabolism which as a result blocks lymphocyte proliferation (B and T cell) and IL-2 production (pro-inflammatory)
How does methotrexate treat Crohn’s disease?
is an antimetabolite and antifolate
it inhibits the synthesis of purine (A/G) and pyrimidines (C/T) by inhibiting dihydrofolate reductase as well as thymidylate synthase
- these catalyse the formation of thymine residues, thereby inhibiting the formation of DNA, RNA and protein
- suppressing the proliferation of inflammatory cells
How does cyclosporin treat Crohn’s disease?
is an immunosuppressant
inhibits T cell proliferation by suppressing IL-2 synthesis
What non-pharmacological treatments are available for Crohn’s disease?
gut rest
- strategy where food intake is restricted to ease Crohn’s disease symptoms
total parenteral nutrition
- allows bowel rest while supplying adequate calorific intake and essential nutrients, and removes antigenic mucosal stimuli
exclusive enteral nutrition (EEN)
- a special liquid formula which is administered as a sole nutrition without the addition of a regular diet.
What is the first line therapy for Crohn’s disease?
exclusive enteral nutrition
- to induce remission in active disease
involves replacing all food and drinks with specialised liquid nutrition formula and water.
provides a constant flow of formula, which prompts better absorption of nutrients and less distention, stomach pain, and vomiting
- all symptoms associated with Crohn’s disease.
What are the side effects of long term steroid treatment?
osteoporosis
adrenal insufficiency
skin thinning
increased appetite/weight gain
hyperglycaemia
insomnia
rapid mood swings
hypertension
cushing’s syndrome (elevated cortisol levels)
eye conditions (glaucoma, cataracts)
What are the different anti-TNF agents? What is their mechanism of action?
infliximab, adalimumab, golimumab
binds to the soluble and transmembrane forms of TNFα with high affinity and blocks the interaction of TNFα with its receptors.
- stops the cascade of the inflammatory reaction, leading to improved disease conditions
Why can you not take live vaccines while on immunosuppressants? What are the different live vaccines?
higher risk of getting infections due to the treatment with immunosuppressant
- immune system is compromised
BCG, chicken pox, MMR, yellow fever
What must be monitored when on azathiopurine?
full blood count due to bone marrow suppression that is caused by azathiopurine
- myelosupression
check leukocyte and thrombocyte levels
- neutrophils, lymphocytes
What must be screened for before taking azathiopurine and why?
enzyme thiopurine methyltransferase (TPMT)
- it metabolises thiopurine drugs
= azathioprine, mercaptopurine, tioguanine
the risk of myelosuppression is increased in patients with reduced activity of the enzyme
