BNP | Haemochromatosis | Vitamin D

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• BNP Haemochromatosis Vitamin D
• Testing in
• Primary Care

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• 1. BNP
• Haemochromatosis
• 3. Vitamin D

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BNP

• Key recommendations
• BNP is useful as a rule-out test of heart
  failure in acute dyspnoea
• The use of BNP in primary care is not yet
  established

BNP 1
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Introduction

• BNP assays have an important role in the
  exclusion of heart failure.
• Normal levels virtually exclude the diagnosis of
  heart failure
• High levels effectively confirm the diagnosis
• Intermediate levels require confirmation by
  echocardiography

BNP 2
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Underlying pathophysiology

• BNP
• secreted in response to ventricular distension
• helps regulate salt and water excretion
• helps maintain blood pressure
• NT-proBNP and BNP results are not comparable

BNP 3
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Underlying pathophysiology
BNP 4
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BNP is useful as a rule-out test of heart
failure when a patient presents with acute
dyspnoea and the diagnosis is not clear

• In patients with dyspnoea BNP levels have good
  sensitivity for heart failure
• BNP has low specificity it can be elevated by
  other conditions such as acute PE or cor pulmonale

BNP 5
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Interpretation of BNP results in acute dyspnoea

• It is important to interpret the result using
  the ranges provided by the testing laboratory.
  Laboratory ranges for low, indeterminate and high
  results vary between laboratories and the
  particular assay used.

BNP 6
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The use of BNP in primary care is not yet
established

• BNP and ECG are equally effective for initial
  workup
• BNPs role in identifying patients with
  asymptomatic ventricular dysfunction not yet
  determined
• No clear role for those already on therapy
• Inconclusive evidence for use in primary care

BNP 7
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Haemochromatosis gene testing

• Key recommendations
• Transferrin saturation and ferritin are used for
  diagnosis
• Population screening is not recommended
• First degree adult relatives of patients should
  be tested
• People with haemochromatosis should be monitored
  with transferrin saturation and ferritin

Haemochromatosis 1
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Defining haemochromatosis

• Approximately 1 in 7 people are carriers
• One in 200 are homozygous
• Occurs in people of Nordic or Celtic ancestry

Haemochromatosis 2
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Haemochromatosis

• Causes increased iron absorption
• ? transferrin saturation
• ? iron accumulation
• ? ferritin
• Iron deposition may cause organ damage

Haemochromatosis 3
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Haemochromatosis Gene

• C282Y mutation on the HFE gene
• 90 of people with clinical features are
  homozygous
• Other HFE gene mutations have now been recognised

Haemochromatosis 4
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Symptoms of haemochromatosis

• Fatigue, weakness, arthralgias, impotence, weight
  loss, abdominal pain and hyperpigmented skin
• Symptoms are often vague and nonspecific
• A poor indicator of disease

Haemochromatosis 5
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Serum transferrin saturation and ferritin are the
best initial tests

• ? transferrin saturation is usually the first
  change
• Ferritin levels rise as iron stores accumulate,
  but is non-specific
• 50 transferrin saturation warrants HFE gene
  testing

Haemochromatosis 6
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Population screening of asymptomatic individuals
for haemochromatosis is currently not recommended

• Haemochromatosis has been suggested for
  population screening
• Has not been widely supported
• Doubts about the cost-effectiveness of a
  screening programme

Haemochromatosis 7
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Test first degree adult family members

• Screen using transferrin saturation, ferritin and
  HFE gene testing
• Testing in children can be delayed until gt 20
  years old
• Partner can be tested to assess their carrier
  status, which can help determine the childs risk
• Counseling should be included in the process

Haemochromatosis 8
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Testing for haemochromatosis

• When haemochromatosis is suspected, tests should
  be requested in a cascade manner, with each
  result suggesting the path of further testing.

Haemochromatosis 9
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Monitoring haemochromatosis

• Test transferrin saturation and ferritin at least
  1-2 yearly
• Therapeutic phlebotomy is indicated when the
  ferritin is consistently elevated
• Target ferritin is lt 50 ug/L
• Gene should only performed one occasion

Haemochromatosis 10
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Vitamin D testing

• Key recommendations
• Increased sun exposure is advisable for people at
  high risk of vitamin D insufficiency due to
  inadequate exposure
• Vitamin D and calcium supplementation is
  appropriate for people at high risk who cannot
  increase their sun exposure

Vitamin D 1
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Vitamin D testing

• Key recommendations continued
• Routine testing of vitamin D levels is not
  usually necessary prior to or after starting
  vitamin D supplementation
• Vitamin D testing is appropriate for people in
  specific situations

Vitamin D 2
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Introduction

• Rickets and osteomalacia are rare
• Increasing concern of vitamin D levels in some
  people
• ? vitamin D levels more common in older people
• International interest in vitamin D
  supplementation for older people

Vitamin D 3
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Pathophysiology

• There are two main forms of vitamin D
• Vitamin D3 (cholecalciferol) produced in the
  skin by the action of UV light
• Vitamin D2 (ergocalciferol) produced by plants
• Most vitamin D is produced as a result of
  exposure to sunlight
• Food provides 10 of vitamin D

Vitamin D 4
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Recommended sun exposure

• Daily exposure 15 of body surface to 1/3 MED
  will provide sufficient vitamin D
• Older people and dark skinned people require more
  exposure
• Avoid deliberate exposure between 1000 and 1400
  
• Glass blocks vitamin D production

Vitamin D 5
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Recommended sun exposure
Dec - Jan July - Aug July - Aug
Region At 1000 or 1400 At 1000 or 1400 At 1200 Minutes
Auckland 6 8 Minutes 30 47 Minutes 24 Minutes
Christchurch 6 9 Minutes 49 97 Minutes 40 Minutes
Vitamin D 6
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People at risk of low vitamin D levels

• Older people in residential care
• Older people admitted to hospital
• Patients with hip fracture
• Dark-skinned men and women (particularly if
  veiled)
• Mothers of infants with rickets
• People unable to obtain regular sun exposure

Vitamin D 7
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Supplementing with cholecalciferol

• Supplementation may be given without testing for
  asymptomatic people at risk of low vitamin D
  because it is safe and relatively inexpensive,
  whereas testing is expensive

Vitamin D 8
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Supplementing with cholecalciferol

• Supplementation reduces the risks of fractures in
  the elderly, particularly those in institutions
• Supplementation must be combined with an adequate
  calcium intake
• the evidence is conflicting for other groups at
  risk of vitamin D deficiency

Vitamin D 9
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Cholecalciferol Dose

• An appropriate dose is a single tablet of
  cholecalciferol 1.25 mg (50,000 IU) monthly by
  mouth
• This dose is effective and not associated with
  risk of toxicity
• For effective supplementation adequate calcium
  intake is required (1.5 g daily). This may
  require calcium supplementation

Vitamin D 10
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Consider supplementation rather than testing

• Vitamin D testing is expensive
• Likely to be positive in people at high risk.
• Reasonable to supplement asymptomatic at risk
  people without testing

Vitamin D 11
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When should I test for vitamin D

• Unexplained raised serum alkaline phosphatase or
  low calcium or phosphate
• Atypical osteoporosis
• Unexplained proximal limb pain in older people
• Unexplained bone pain, unusual fractures or other
  evidence suggesting metabolic bone disease.
  (Consider specialist advice for people in this
  category)

Vitamin D 12