Chapter 9: Blood and Nutrition Flashcards
What are the MHRA warnings associated with epoetins?
- Risk of severe cutaneous adverse reactions including Stevens-Johnsons syndrome.
- Overcorrection of haemoglobin concentration may increase the risk of death and serious cardiovascular events. CKD or chemotherapy patients should not receive this unless symptoms of anaemia are present
- Unexplained excess mortality and increased risk of tumour progression in patients with anaemia associated with cancer who have been treated with erythropoietins
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 encepatholopathy and tonic clonic seizures
- Pure red cell aplasia
What are epoetins used for?
Symptomatic anaemia in CKD or chemotherapy 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?
Reserved for use when oral therapy is unsuccessful because the patient cannot tolerate oral iron, or does not take it 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 preparation is taken reliably and is absorbed adequately.
Exception - patients 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
Patients should be monitored for such signs for 30 minutes after administration
Not recommended 1st trimester of pregnancy 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
How do you manage haemochromatosis (result of iron overload)?
Venesection (removal of blood)
If this is contraindicated- long-term administration of the iron chelating compound desferrioxamine mesilate
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 2nd = Soluble insulin IV injection 3rd = Salbutamol nebulised or slow IV injection [unlicensed].
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 antiduretic hormone 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
Compared to crystalloid solution, would a larger or smaller amount of colloid solution be required for fluid resuscitation?
Smaller amount would be required of colloid
True or false:
In osteoporosis, a calcium intake which is double the recommended amount reduces the rate of bone loss.
True
What is given in severe acute hypocalcaemia/hypocalcaemic tetany?
Slow IV calcium gluconate 10%
Why should calcium gluconate IV be given slowly?
If given too rapidly, risk of arrhythmias
What is cinacalcet used for?
Hyperparathyroidism and hypercalcaemia in parathyroid carcinoma
Reduces parathyroid hormone which leads to a decrease in serum calcium concentration
Calcium carbonate is used for what two indications?
Calcium deficiency
Phosphate binding in renal failure
Aluminium hydroxide can be used for the treatment of what in renal failure?
Hyperphosphataemia
What is sevelamer used for?
Phosphate binder for CKD patients including those on dialysis
How do you manage hypercalciuria?
Find the underlying reason
Increase fluid intake and give bendroflumethiazide
What is Wilson’s disease?
Genetic disorder causing build up of copper in body tissues e.g. brain
How do you manage Wilson’s Disease?
Zinc acetate as it prevents the absorption of copper
Chelating agents are given for the first 2-3 weeks as well as zinc as zinc has a slower onset of action
Vitamin A deficiency is associated with what?
Occular defects
Thiamine is what vitamin?
B1
Riboflavin is what vitamin?
B2
Severe Vitamin B deficiency can lead to what?
Wernicke’s encephalopathy and Korsakoff’s psychosis
Pyridoxine is what vitamin?
B6
Pyridoxine may be needed in patients taking what drugs?
Isoniazid therapy
or penicillamine treatment in Wilson’s disease
Penicillamine is what kind of drug?
Chelating agent used for e.g. Wilson’s Disease, RA
Vitamin C deficiency can result in what condition?
Scurvy
What are the fat soluble vitamins?
ADEK
What are the water soluble vitamins?
B and C
Vitamin A is otherwise known as?
Retinol
Vitamin D deficiency can result in what condition?
Rickets
In renal patients, why is alfacalcidol and calcitrol more appropriate for Vitamin D deficiency treatment over other Vitamin D replacement?
Vitamin D requires hydroxylation by the kidney to its active form, therefore the hydroxylated derivatives alfacalcidol or calcitriol should be prescribed if patients with severe renal impairment require vitamin D
If Vitamin D replacement is needed in severe renal impairment, what are the most appropriate to prescribe?
Alfacalcidol
Calcitriol
What is the water soluble Vitamin K preparation called?
Menadiol
What is the MHRA advice surrounding IV thiamine?
Risk of serious allergic reaction
Should be given over 30 mins
Facilities to treat anaphylaxis should be close by
Calcichew D3 is used for what?
Prevention and treatment of Vitamin D and calcium deficiency
What is cholecalciferol used for?
Prevention and treatment of Vitamin D deficiency
When would the higher dose of 5mg folic acid be recommended in pregnancy?
High risk of neural tube defects: Epilepsy Diabetes Sickle cell Previous infant with neural tube defect e.g. spina bifida
Otherwise the dose would be 400mcg folic acid daily
What is a Coombs test?
Test for autoimmune hemolytic anaemia
Methyldopa can cause a positive test result
What is the treatment regimen for hydroxocobalamin in the treatment of pernicious anaemia (without neurological involvement)?
What route?
IM injection
Initially 1 mg 3 times a week for 2 weeks, then 1 mg every 2–3 months.
If neurological involvement- this would be 1mg on alternate days until improvement
Iron absorption is impaired if having what foods/drinks?
Tea
Milk
Eggs
