Chapter 9: Blood and Nutrition COPY COPY Flashcards
What are the MHRA warnings associated with epoetins?
- Risk of severe cutaneous adverse reactions including SJS.
- Overcorrection of [haemoglobin] may ^risk of death and serious CV events. CKD or chemo pts should not receive this unless symptoms of anaemia are present
- Unexplained excess mortality and ^risk of tumour progression in patients with anaemia associated with cancer who have been treated with erythropoietin
What are the main side effects of epoetins?
- Severe skin reactions and stop treatment and seek medical attention if they develop a rash (which often follow flu-like symptoms)
- Hypertensive crisis with encepathalopathy and tonic clonic seizures
- Pure red cell aplasia
What are epoetins used for?
Symptomatic anaemia in CKD or chemo patients
The daily oral dose of elemental iron for iron-deficiency anaemia should be what?
100-200mg
Are modified release iron preparations recommended in anaemias?
No - have no therapeutic advantage
In what situations would you opt for IV iron over oral iron?
When oral therapy is unsuccessful; intolerable oral iron, or not taken reliably, or if there is continuing blood loss, or in malabsorption
CKD patients on dialysis also require IV iron regularly
What are the IV forms of iron?
Iron dextran
Iron sucrose
Ferric carboxymaltose
Iron isomaltoside
Does IV iron work more quickly than oral iron?
Parenteral iron does not produce a faster haemoglobin response than oral iron provided that the oral iron is taken reliably and is absorbed adequately.
Exception: pts with severe renal failure receiving haemodialysis
IV iron does not work more quickly than oral iron except in what group of patients?
Patients with severe renal failure receiving haemodialysis
What is the MHRA advice surrounding injectable iron?
Serious hypersensitivity reactions including anaphylaxis
Pts should be monitored for such signs for 30 minutes after administration
Not recommended 1st trim. of preg. and only in 2nd and 3rd if vital
When should iron for iron deficiency anaemia be stopped?
3 months after haemoglobin is in the normal range
Are iron tablets best absorbed with or without food?
Without food
However because of the GI side effects, they can be taken with food
What are the main side effects of iron?
Constipation and diarrhoea
GI upset
Darkened stools
Most megaloblastic anaemias result from a deficiency of what?
Either vitamin B12 or folate
It is important to establish which deficiency before treatment but in an emergency can give both
What is pernicious anaemia?
An autoimmune gastritis causing malabsorption of vitamin B12
What is the choice of therapy for vitamin B12 replacement?
Hydroxocobalamin - initiated with frequent IM injections and then every 3 months
(used to be cyanocobalamin however hydroxocobalamin lasts longer in the body)
Why should undiagnosed megabloblastic anaemia not be treated with folic acid alone?
May precipitate neuropathy
If undiagnosed and needs to be given, always give vitamin B12 as well
What can be the causes of folate-deficient megaloblastic anaemia?
Poor nutrition
Pregnancy
Antiepileptic drugs
How do you treat folate-deficient megaloblastic anaemia and how long for?
Daily folic acid for 4 months
(Folic acid has few indications for long-term therapy since most causes of folate deficiency are self-limiting or will yield to a short course of treatment)
Why should folic acid never be given alone in pernicious anaemia?
Can cause compression of spinal cord
Haemochromatosis is associated with an overload of what?
Iron
Built up over several years
How do you manage haemochromatosis (result of iron overload)?
Venesection (removal of blood)
If contraindicated- long-term administration of the iron chelating compound Desferrioxamine mesilate - Vit C aids iron chelation started 1 month after desferrioxamine, taken daily, not with food.
What drug inhibits platelet formation and is used for thrombocythaemia (when too many platelets are produced in the bone marrow)?
Anagrelide
What is used in sickle cell anaemia to reduce the frequency of crises and need for blood transfusions?
Hydroxycarbamide
How do you manage severe acute hyperkalaemia?
1st = Calcium gluconate 10% slow IV injection titrated to ECG to temporarily protect against myocardial excitability
2nd = Soluble insulin IV injection 5-10u with 50 mL glucose 50% over 5-15 min, reduces serum-[K]; repeated if necessary or continuous infusion instituted
3rd = Salbutamol nebulised or slow IV injection [unlicensed] may also reduce plasma-potassium concentration
The correction of causal or compounding acidosis with Na bicarbonate infusion should be considered (important: prep of sodium bicarbonate and calcium salts should not be administered in the same line—risk of precipitation).
Drugs that exacerbate hyperkalaemia should be stopped as appropriate.
What is classed as acute severe hyperkalaemia?
> 6.5 mmol/L or presence of ECG changes
What is classed as hypokalaemia?
< 3.5 mmol/L
How do you manage hypokalaemia?
Potassium chloride
Or
Potassium bicarbonate with potassium acid tartrate.
Chronic hyponatraemia from inappropriate secretion of ADH should ideally be managed by what?
Fluid restriction
What is Hartmann’s solution?
Compound sodium lactate
How is severe hypercalcaemia managed?
Dehydration should be corrected with IV NaCl
Drugs that promote hypercalcaemia e.g. thiazides and Vitamin D should be stopped
Pharmacological management includes bisphosphonates, corticosteroids, calcitonin
When treating hypokalaemia, why shouldn’t you include glucose infusions?
That can cause a further decrease in plasma potassium concentrations
What can be given for severe metabolic acidosis?
IV sodium bicarbonate
What can be given for chronic acidotic states?
Oral sodium bicarbonate