Anaemia (Gastroenterology)

Introduction

The management of anaemia can become quite complicated, so the BNSSG Referral Service  has developed some guidelines with the support of local gastroenterologists and haematologists to help guide further investigation.

There are also guidelines from the British Society of Gastroenterologists that were published in 2021 (1).

The Haematology section of Remedy also has a link to Haematology Guidelines for Primary Care which includes advice on assessment and management of anaemia.

The following sections address some of the more common causes of anaemia and how to investigate and manage in primary care and when to refer.

Vitamin B12 and Folate Deficiency Anaemia

Please refer to the NICE Clinical Knowledge Summaries for the management of B12 and folate deficiency anaemia.

Please note that secondary care referral is not routinely required for pernicious anaemia which can usually be managed with hydroxocobalamin injections within the primary care setting.

Consider further investigation or referral in the following circumstances:

• Suspected Coeliac disease
• Gastrointestinal malabsorption - consider referral to gastroenterology or the Gastroenterology Advice and Guidance service.
• Neurological symptoms - refer to haematology or the Haematology Advice and Guidance service.
• Pregnancy - see Folic acid and vitamin B12 in pregnancy
• Haematological abnormalities or suspected malignancy - See Urgent Suspected Cancer guidelines

Anaemia of Chronic Disease

Where haematinics are normal, an anaemia of chronic disease should also be considered - see the  Anaemia guidance on Patient.co.uk for further information - chronic infection, inflammation (eg rheumatoid arthritis), neoplasia and chronic kidney disease are the main culprit causes. Mild anaemia of chronic disease may not require any treatment.

Suspected Iron Deficiency Anaemia with normal ferritin

The important thing not to miss is an underlying iron deficiency as iron deficiency anaemia may be normocytic in some elderly patients and sometimes the ferritin is spuriously raised and so appears to be “normal”. Any inflammatory condition (such as rheumatoid disease) can falsely raise the ferritin even in the presence of iron deficiency anaemia, as can chronic kidney disease, liver disease, malignancy, hyperthyroidism and heavy alcohol intake.

To help clarify the situation, it may be worth also checking the patient’s iron status:

• NBT - available on ICE as 'iron status' under haematology panel
• UHB - there is no iron studies box to tick, so please request Transferrin saturation and Ferritin.

The finding of a low serum iron and/or low transferrin saturation would point towards an iron deficiency. Dr Charlotte Bradbury (Consultant Haematologist at BRI) has previously advised us on this and recommends the following:

'If microcytic anaemia/possible iron deficiency, it may be worth checking another marker of iron status – if transferrin saturation <20%, and ferritin <200, a trial of iron is reasonable.'

Iron Deficiency Anaemia

Please refer to the NICE clinical knowledge summary guidance for the management of iron deficiency anaemia.

Investigation of IDA should initially prioritise exclusion of lower GI causes (unless symptoms suggest an upper GI cause).

Lower GI Investigation

Please see the Lower GI - USC (2WW) for advice on appropriate investigation of patients with iron deficiency anaemia and suspected colorectal cancer.

Please also see guidelines on when to do a FIT test in patients with iron deficiency anaemia or non-iron deficiency anaemia.

Upper GI Investigation

An upper GI endoscopy outside of 2WW is recommended in people over 55 with upper abdominal pain and low haemoglobin levels (see NICE).

Otherwise upper GI endoscopy outside of 2WW should be considered if lower GI investigations are negative.

The quickest way to organise this would be to request a direct access upper GI endoscopy available from InHealth (Prime Endoscopy) or PPG (Emersons Green Treatment Centre) - see the Endoscopy page for details. If patients do not meet criteria for direct access endoscopy then please refer to your local trusts upper GI team via eRS.

It is  recommended that all endoscopy referrals (other than 2WW referrals) be submitted on one of the BNSSG endoscopy forms (embedded in EMIS). If patients do not meet criteria for direct access endoscopy then please send a referral letter to your local trust's upper GI team via eRS.

Further investigation

Please see the section below for indications of further investigation if the lower and upper GI investigations are normal.

Non-Anaemic Iron Deficiency (under review)

The British Society of Gastroenterology Guidelines on Management of IDA (2011 - updated 2021) has advice on how to manage patients with low iron and normal Hb (page 5 or see below)

'Non-anaemic iron deficiency (NAID)

The development of anaemia from iron deficiency goes through an initial phase where body iron stores are depleted resulting in hypoferritinaemia, but the Hb concentration is still within the normal range (non-anaemic iron deficiency (NAID)). For example, in a study of young women with menorrhagia, over half had reduced iron stores but only 25% were actually anaemic.

The overall prevalence of significant underlying GI pathology, and in particular of GI malignancy, is low in NAID. In the absence of other pointers, GI investigation generally is not warranted in premenopausal women since the cause is likely to be menstrual blood loss and/or recent pregnancy (see the Special situations section). The threshold for investigation of NAID should however be low in men, postmenopausal women, and those with GI symptoms or a family history of GI pathology'. (1)

Investigation of NAID

It is less certain who needs investigating in iron depletion, but the following information may be relevant (2):

• Coeliac Disease is common and easily missed. Some authors state that coeliac disease may also manifest as iron depletion.

• The British Society of Gastroenterology guidelines (1) comment that, on current evidence, the prevalence of GI malignancy is low in patients with iron depletion. They suggest that, from the available evidence, the threshold for investigation should be low in the following groups: men, postmenopausal women, those with GI symptoms or a family history of GI pathology.

• Diets which are borderline low in iron are common.

• If the blood picture does not improve with treatment - eg, a trial of iron therapy - then evaluate further. 

If further investigation of NAID is considered appropriate then this should be along the lines of investigation for IDA. If there is uncertainty about the need for investigation then please consider Gastroenterology advice & guidance.

Normal Colonoscopy and Gastroscopy in Iron Deficiency Anaemia

If a GI cause for iron deficiency anaemia is not apparent from initial upper and lower GI investigations, then please consider the following:

1. Medication - culprit drugs (e.g. NSAIDs, aspirin, anticoagulants, bisphosphonates) should be reviewed. 
2. Ensure the picture is true iron deficiency (you would be surprised how often patients are investigated in whom it isn’t true iron deficiency….)
3. Dip the urine for blood - consider urological investigations if positive. See Haematuria page.
4. Check the patient has had upper and lower GI endoscopy within the recent past (certainly within 12 months) and ensure that the quality of the endoscopic investigations are good (e.g. sometimes there is very poor bowel prep, incomplete colonoscopy etc) and consider repeating if concerned.
5. Check coeliac serology – if positive then see Coeliac disease page.

In all patients, consider oral iron supplements which can be started prior to endoscopy (although if 2ww colonoscopy is requested it would be best to advise patient to not start taking the iron until the colonoscopy has been performed, but they can be given the prescription).

Monitor Hb and if it drops again or fails to increment adequately with oral iron then refer to secondary care for consideration of small bowel investigation.

Referral

If referral is indicated, then please refer to gastroenterology via eRS (UHBW or NBT) initially where a decision on further investigation can be made (including onward referral for capsule endoscopy if this is necessary).

If you are uncertain about appropriateness of referral, then consider requesting gastroenterology A and G.

Further investigation

For iron-deficient anaemia, small bowel investigation is only indicated for cases that fail to correct with iron replacement (or maybe need transfusion), or sometimes when there is recurrent IDA. This is because the pathology yield from small bowel investigation is relatively low.

Proceeding directly to small bowel investigations is only indicated when there is ongoing Melaena with normal investigations – these patients tend to be under secondary care already.

The above advice is based on BSG guidelines (1) with local guidance provided by Dr Ana Terlovich (Consultant gastroenterologist at NBT).

Iron Infusions

Before considering referral for iron infusion, please see the Treatment of iron deficiency in adults document which is on the Nutrition and Blood Guidelines section of the BNSSG formulary (scroll down to bottom of page under iron).

If iron infusion is still indicated then please see the Blood Transfusions & Iron infusions page on Remedy for advice on services available at UHBW and NBT and how to refer.

Resources

(1) Guidelines for the Management of Iron Deficiency Anaemia in Adults - The British Society of Gastroenterology (bsg.org.uk)

(2) Non-anaemic Iron Deficiency | Doctor

Efforts are made to ensure the accuracy and agreement of these guidelines, including any content uploaded, referred to or linked to from the system. However, BNSSG ICB cannot guarantee this. This guidance does not override the individual responsibility of healthcare professionals to make decisions appropriate to the circumstances of the individual patient, in consultation with the patient and/or guardian or carer, in accordance with the mental capacity act, and informed by the summary of product characteristics of any drugs they are considering. Practitioners are required to perform their duties in accordance with the law and their regulators and nothing in this guidance should be interpreted in a way that would be inconsistent with compliance with those duties.

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