NICE guidliner oppdater 06.03.2024

Vitamin B12-mangel hos over 16 år: diagnose og behandling

NICE-retningslinje [NG239] Publisert:6. mars 2024

Up to date 

Oppdatert nov 2019 eller 2019/fra hjemmesiden 

BRITISKE RETNINGSLINJER FOR B12-MANGEL

Britiske retningslinjer: Last opp fil: 2014

Sammendrag av viktige anbefalinger

1. Det kliniske bildet er den viktigste faktoren ved vurderingen av betydningen av testresultater som vurderer cobalaminstatus, fordi det ikke er noen "gullstandard" -test for å definere mangel.

2. Serumkobalamin forblir foreløpig førstelinjetest, i tillegg til plasma metylmalonsyre for å bidra til å klargjøre usikkerhetene til underliggende biokjemiske / funksjonsfeil.

 Serum holotranscobalamin har potensiell asa førstelinjetest, men et ubestemt "grått område" må hensyntaes. Plasma homocystein kan være nyttig som en sekundærest, men er mindre spesifikk enn metylmalonsyre. 

Tilgangsmulighetene til disse andre linjetester er for tiden begrenset.

3. Definitive avgrensningspunkter for å definere kliniske og subkliniske sviktstilstander er ikke mulig å fastsette, gitt ulike metodologier som brukes og tekniske problemer, og lokale referanseverdier  bør etableres.

4 I tilstedeværelse av uoverensstemmelse mellom testresultatet og sterke kliniske funksjonsfeil bør behandlingen ikke forsinkes for å unngå nevrologisk funksjonsnedsettelse.

5 Behandling av kobalaminmangel anbefales i tråd med British National Formulary. Oral therapymay er egnet og akseptabelt dersom avsatte doser er tatt og overholdelse ikke er et proble

Summary of key recommendations1 The clinical picture is the most important factor in assess-ing the significance of test results assessing cobalamin status because there is no 'gold standard' test to define deficiency.2 Serum cobalamin currently remains the first-line test, with additional second-line plasma methylmalonic acid to help clarify uncertainties of underlying biochemical/functional deficiencies. Serum holotranscobalamin has the potential as a first-line test, but an indeterminate 'grey area' may still exist. Plasma homocysteine may be helpful as a second-linetest, but is less specific than methylmalonic acid. The avail-ability of these second-line tests is currently limited.3 Definitive cut-off points to define clinical and subclinical deficiency states are not possible, given the variety of methodologies used and technical issues, and local refer-ence ranges should be established. 4 In the presence of discordance between the test result and strong clinical features of deficiency, treatment should not be delayed to avoid neurological impairment.5 Treatment of cobalamin deficiency is recommended inline with the British National Formulary. Oral therapy may be suitable and acceptable provided appropriate doses are taken and compliance is not an issue.6 Serum folate offers equivalent diagnostic capability to red cell folate and is the first-line test of choice to assess folate status. Merk punkt '3: Absolutte cut-off grenser for for klinisk og subkliniske verdier kan ikke defineres,......'

Absolutte nedre grenser for for klinisk og subkliniske verdier kan ikke defineres,...

 B12<150 er grensen for mangel in Norge og B12 <250 for subklinisk verdi.

Lav folat kan få inaktivt B12 -delen av total B12 til å stige.

Up to date, revidert utgave september 2019.

Britiske retningslinjer for B12 mangel av GUNHILD ISACHSEN

Dette dokumentet er opprinnelig 30 sider + 10 sider med referanser. I det siste er online-versjonen redusert til 13 sider inklusiv kildehenvisninger. Det er skrevet av en gruppe hematologer og inneholder mye forskning. Her er også et utsnitt fra BNF, British National Formula : (2013) How should I treat a person with vitamin B12 deficiency anaemia?

• For people with neurological involvement:
  • Seek specialist advice from a haematologist.
  • Initially administer hydroxocobalamin 1 mg intramuscularly on alternate days until there is no further improvement, then administer hydroxocobalamin 1 mg intramuscularly every 2 months.
• For people with NO neurological involvement:
  • Initially administer hydroxocobalamin 1 mg intramuscularly on alternate days for 2 weeks.
  • Maintenance dose (where the vitamin B12 deficiency is NOT thought to be diet related): administer hydroxocobalamin 1 mg intramuscularly every 3 months for life (standard dose). Note: the manufacturers' licence is for every 2-3 months.
  • Maintenance dose (where vitamin B12 deficiency is thought to be diet related): advise people either to take oral cyanocobalamin tablets 50-150 micrograms daily between meals, or have a twice-yearly hydroxocobalamin 1 mg injection (the injection regimen may be preferred in the elderly who are more likely to have malabsorption).
    • In vegans, this treatment may need to be life-long, whereas in other people with dietary deficiency replacement treatment can be stopped once the vitamin B12 levels have been corrected and the diet has improved.
    • Advise people to eat foods rich in vitamin B12. Foods which have been fortified with vitamin B12 (e.g. some soy products, and some breakfast cereals and breads) are good alternative sources to meat, eggs, and dairy products.
• Note: oral cyanocobalamin is suitable only for the small number of people with proven dietary deficiency of vitamin B12. It is available on an NHS prescription only for a person who is a vegan or who has a proven vitamin B12deficiency of dietary origin, and the prescription must be endorsed 'SLS' [BNF 54, 2007].

Nevrologiske symptomer, hva er det ? Er nevrografi pålitelig ?

Hvilke B12 symptomer er egentlig nevrologiske? Dette er en fil vi har fått av Pat Kornic, Canada, en fil som hennes Facebookgruppe bruker. Som dere ser er symptomene omfattende og vanskelog å avgrense, som f eks : "Pain" - Smerte. Det er jo alt mulig. Allikevel er denne lista nyttig for å vise at nevrologiske symptomer er mye mer enn det som kan vises på nevrografi. Neurological Symptoms: Members often ask what symptoms are classed as neurological. The following website, written by a Neurologist, gives an extensive list of what symptoms can be described as neurological in origin. This should help members decide if their own particular symptoms are neurological and give them confidence to ask to be treated in accordance with the British National Formulary (BNF) Guidance for those with neurological involvement. Below are the symptom headings and you should visit the website to get a fuller description of them . 

https://www.neurosymptoms.org/    

• Sensory Symptoms
• Pain
• Tiredness / Fatigue
• Sleep Problems
• Poor Memory / Concentration
• Dissociation
• Worry / Panic
• Dizziness
• Headache
• Low Mood
• Facial Spasm
• Visual Problems
• Functional Tremor
• Functional Dystonia/Spasm
• Functional Walking Problems
• Word Finding Difficult
• Slurred Speech
• Bladder Symptoms
• Bowel Symptoms
• Drop Attacks
• Swallowing Problems
• Complex Regional Pain
• Health Anxiety
• Post-Concussion Syndrome
• Functional Jerks and Twitches
• Functional weakness  
• Blackouts/attacs