Coeliac Disease & Malabsorption

Pathophysiology & Diagnosis

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Core definition: Coeliac disease is a chronic, immune-mediated enteropathy triggered by dietary gluten in genetically susceptible individuals, characterised by small intestinal villous atrophy and malabsorption.

Immune Pathogenesis

Trigger: Ingestion of gluten (storage proteins in wheat, barley, rye). The toxic fraction is gliadin (from wheat).

Gliadin peptides cross the gut epithelium and are deamidated by tissue transglutaminase (tTG) in the lamina propria.

Deamidated gliadin is presented to CD4+ T-cells via HLA-DQ2 (90–95% of patients) or HLA-DQ8 (5–10%).

Th1 immune response releases pro-inflammatory cytokines (IFN-γ, TNF-α) → villous atrophy, crypt hyperplasia, intraepithelial lymphocytosis.

Resultant mucosal damage → malabsorption of fat, fat-soluble vitamins, iron, folate, B12, calcium.

Genetic predisposition: HLA-DQ2/DQ8 is necessary but not sufficient. ~30% of the general population carry these alleles; only ~1–3% develop coeliac disease.

Marsh Classification

Marsh Grade	Histology	Significance
0 Normal	Normal villi, normal IEL count	Coeliac excluded (if serology positive, monitor)
1 Infiltrative	↑ Intraepithelial lymphocytes (>25/100 enterocytes); normal villi	Early/latent coeliac; also NCGS, H. pylori
2 Hyperplastic	↑ IEL + crypt hyperplasia; normal villi	Uncommon; supports diagnosis in context
3a Partial villous atrophy	↑ IEL + crypts + partial villous blunting	Diagnostic for coeliac in clinical context
3b Subtotal villous atrophy	Marked villous blunting (>50% loss)	Significant malabsorption
3c Total villous atrophy	Complete loss of villi; flat mucosa	Severe; highest risk of complications

Gastrointestinal Symptoms

Chronic diarrhoea — pale, fatty, offensive stools (steatorrhoea)
Abdominal bloating & pain
Malabsorption — weight loss, failure to thrive (children)
Nausea, vomiting
Aphthous mouth ulcers (recurrent)
Constipation (some patients — atypical)

Extraintestinal Symptoms

Iron-deficiency anaemia — fatigue, pallor (most common extraintestinal)
Dermatitis herpetiformis — intensely itchy blistering rash
Osteoporosis / osteomalacia — fracture risk
Infertility — unexplained, recurrent miscarriage
Neurological — gluten ataxia, peripheral neuropathy
Elevated transaminases (cryptogenic)
Short stature, delayed puberty (children)

Diagnostic Serology

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Key rule: Patient must be on a gluten-containing diet for at least 6 weeks before serology or biopsy (4 slices of bread/day equivalent). GFD invalidates testing.

Test	Notes	First-line?
Anti-tTG IgA	Highest sensitivity (95%) & specificity (97%). First-line test. Must check total IgA level simultaneously.	Yes
Total IgA level	Check to exclude selective IgA deficiency (~2–3% coeliac patients)	Yes (alongside)
Anti-tTG IgG + DGP IgG	Use if IgA deficient. Deamidated gliadin peptide IgG highly specific.	If IgA deficient
Anti-endomysial IgA (EMA)	High specificity (~99%); observer-dependent; confirmatory role	Confirmatory
Anti-gliadin antibodies	Older, less specific — no longer recommended for diagnosis	Not recommended

Duodenal Biopsy

Gold standard for diagnosis. Performed via upper GI endoscopy (OGD).

Minimum 4 biopsies from 2nd/3rd part of duodenum + 1–2 from duodenal bulb
Shows Marsh grading (IEL count, crypt hyperplasia, villous atrophy)
In children: ESPGHAN 2020 — biopsy may be avoided if tTG IgA >10× ULN + positive EMA + symptomatic

Genetic Testing (HLA-DQ2/DQ8)

Negative result virtually excludes coeliac disease (<1% risk)
Used in diagnostic uncertainty (patient already on GFD, equivocal biopsy)
Useful for first-degree relatives screening
Positive result does NOT confirm diagnosis — only shows susceptibility

Non-Coeliac Gluten Sensitivity (NCGS)

Symptoms similar to coeliac (bloating, diarrhoea, brain fog) triggered by gluten, but:

Negative coeliac serology (tTG IgA normal)
Normal duodenal biopsy (Marsh 0–1)
Negative HLA-DQ2/DQ8 (in some — though overlap exists)
No autoimmune mechanism; no nutritional deficiencies or villous atrophy
Management: GFD symptom-driven; less strict; may not be lifelong
Key distinction: NCGS carries no malignancy or bone disease risk

Gluten-Free Diet Management

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Strict lifelong GFD is the only proven treatment for coeliac disease. Even trace amounts (<20 ppm) may cause ongoing mucosal damage without symptoms in some patients.

BROW Mnemonic — Gluten-Containing Grains

Barley

Rye

Oats (contaminated)

Wheat (all types: spelt, kamut, durum, semolina, farro)

Gluten-Containing Foods — AVOID

Bread, pasta, noodles (wheat-based)
Pastries, cakes, biscuits, crackers
Semolina, couscous, bulgur wheat
Beer, ales, lagers (barley malt)
Soy sauce (often wheat-based)
Seitan (pure wheat gluten)
Most gravies and thickened sauces
Breaded/battered foods
Communion wafers (wheat-based)
Some medications (check excipients)

Naturally Gluten-Free Grains — SAFE

Rice (all types)
Maize / corn
Buckwheat (not wheat — a seed)
Quinoa
Millet
Teff
Sorghum
Potato starch, tapioca, arrowroot
Amaranth

Oats — Special Consideration

Oats contain avenin, a protein with structural similarity to gliadin. The majority of coeliac patients tolerate pure, uncontaminated oats (Codex-standard, labelled gluten-free oats). However:

Standard oats are frequently cross-contaminated with wheat/barley during growing or milling
A minority (~5–10%) of coeliac patients react to avenin itself and cannot tolerate any oats
Clinical guidance: Introduce pure GF oats slowly after diagnosis when symptoms are stable; monitor tTG levels; discontinue if symptoms return
Children: generally introduced after histological recovery

Hidden Gluten Sources

Food / Drink

Sauces: soy sauce, Worcestershire sauce, HP sauce
Soups (thickened with flour)
Processed meats (sausages, burgers — fillers)
Salad dressings, marinades
Flavoured crisps / chips
Ice cream cones, some sweets
Malt vinegar (barley-derived)
Barley water, malt drinks

Non-Food Sources

Medications (check BNF / PIL for starch excipients)
Lip balms / lipstick (ingestion risk)
Communion wafers (special GF wafers available)
Play-dough (children — hand-to-mouth)
Envelope / stamp adhesive (minimal risk)
Toothpaste (some contain wheat derivatives)
Herbal remedies / supplements

Food Labelling — UK / EU / International

Gluten-free = <20 ppm gluten (Codex standard)
Very low gluten = 21–100 ppm (not suitable for coeliac)
Crossed Grain Symbol (CGS) — licensed by Coeliac UK; rigorous testing (<20 ppm)
Always check "may contain" / "made in a facility with wheat" warnings — risk of cross-contamination
Naturally GF products (plain rice, meat) need no GF label

Cross-Contamination Prevention

Separate toaster (or toaster bags) for GF bread
Dedicated chopping boards, butter/spread containers
Separate pasta cooking water and colanders
Careful when frying — shared oil with breaded products
Restaurant: request separate preparation area; clean surfaces/utensils
Shared kitchens: label and store GF foods separately

Dietary Counselling & GFD Compliance Monitoring

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Referral to a registered dietitian with GI/coeliac expertise is essential at diagnosis and at annual review.

Compliance Monitoring Tools

Repeat tTG IgA — falls to normal within 6–12 months on strict GFD; persistently elevated = non-adherence or inadvertent gluten
Symptom diary — tracks trigger foods and symptoms
Dietitian review — dietary recall, label reading skills
Repeat biopsy — if no clinical/serological response after 12–24 months on strict GFD (Marsh grade reassessment)

Common Reasons for Non-Response

Inadvertent gluten ingestion (most common)
Incorrect initial diagnosis
Microscopic colitis / IBD (co-existing)
Small intestinal bacterial overgrowth (SIBO)
Lactose intolerance (secondary — villi recovery needed)
Refractory coeliac disease (rare)

Nutritional Deficiencies & Monitoring

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Villous atrophy impairs absorption in the proximal small bowel. Most deficiencies resolve with strict GFD, but active supplementation is required at diagnosis and in recovery.

Nutrient	Consequence of Deficiency	Clinical Features	Management
Iron	Iron-deficiency anaemia (IDA)	Fatigue, pallor, koilonychia, dyspnoea	Oral iron supplementation; IV if severe/malabsorption; GFD for recovery
Folate (B9)	Megaloblastic anaemia; neural tube defects in pregnancy	Fatigue, macrocytosis, glossitis	Folic acid 5mg OD; essential pre-conception
Vitamin B12	Megaloblastic anaemia; subacute combined degeneration of cord	Fatigue, peripheral neuropathy, cognitive impairment	IM B12 (hydroxocobalamin) if severe; oral if mild
Vitamin D	Osteomalacia, secondary hyperparathyroidism, osteoporosis	Bone pain, muscle weakness, fractures	Cholecalciferol 800–2000 IU/day; check 25-OH vitamin D levels
Calcium	Osteoporosis, tetany	Bone fragility, cramps, Chvostek's sign	Calcium 1000–1500 mg/day (diet + supplements)
Zinc	Impaired immunity, poor wound healing	Dermatitis, alopecia, taste changes	Zinc supplementation; reassess after GFD adherence
Magnesium	Neuromuscular excitability, arrhythmias	Cramps, tremors, hypomagnesaemia	Dietary and supplement replacement

Bone Health Management

DEXA scan at diagnosis in all adults (baseline bone mineral density)
Repeat DEXA at 2–5 years depending on baseline and GFD adherence
Calcium + Vitamin D supplementation — universal at diagnosis
Bisphosphonate (e.g., alendronate) if osteoporosis confirmed (T-score ≤ −2.5)
Note: Treat underlying coeliac first — bone density partially recovers with GFD
Weight-bearing exercise counselling
Fall prevention in elderly patients

Annual Monitoring — Blood Tests

FBC — anaemia surveillance
Ferritin — iron stores
Folate (serum or RBC)
Vitamin B12
25-OH Vitamin D
Calcium & albumin (corrected calcium)
LFTs — transaminase elevation in active coeliac
Anti-tTG IgA — compliance marker
Thyroid function (TFTs) — if autoimmune thyroid disease suspected
Weight / BMI at each visit

Refeeding Risk

Severely malnourished coeliac patients (e.g., prolonged untreated disease, hospitalised) are at risk of refeeding syndrome when nutrition is reintroduced:

Rapid shift of phosphate, potassium, magnesium into cells when insulin released
Monitor: phosphate, potassium, magnesium, glucose closely in first 72h of refeeding
Introduce calories slowly (start 5–10 kcal/kg/day if high risk)
Thiamine supplementation before refeeding (prevent Wernicke's encephalopathy)

Non-Responsive Coeliac Disease & Refractory Coeliac Disease (RCD)

Non-responsive coeliac: Persistent symptoms/villous atrophy after 12 months of strict GFD. Investigate cause before labelling RCD.

RCD Type I

Abnormal IEL phenotype but polyclonal T-cells (normal surface markers)
Better prognosis
Treatment: nutritional support, steroids (budesonide), immunosuppressants (azathioprine)

RCD Type II

Clonal intraepithelial lymphocytes — considered pre-lymphoma state
High risk of EATL (enteropathy-associated T-cell lymphoma)
Treatment: steroids, cladribine, stem cell transplant in specialist centres
5-year survival <50%

Complications & Associated Conditions

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Key principle: Strict lifelong GFD significantly reduces the risk of all major complications. Most complications arise in the context of poorly controlled or undiagnosed coeliac disease.

Malignancy Complications

Enteropathy-Associated T-Cell Lymphoma (EATL)

Rare but serious — most feared complication
Originates from intraepithelial T-lymphocytes
Suspect if: recurrent GI symptoms despite strict GFD, new weight loss, abdominal pain, fever, or night sweats
Diagnosis: CT abdomen/pelvis, PET-CT, capsule endoscopy, biopsy
Poor prognosis despite chemotherapy
RCD Type II is a direct precursor

Other Malignancies

Small bowel adenocarcinoma — 6× increased risk; presents with obstruction, anaemia, weight loss
Oesophageal squamous cell carcinoma
Pharyngeal carcinoma
Overall malignancy risk normalises with >5 years strict GFD adherence

Hyposplenism (Functional Asplenia)

Coeliac disease can cause functional hyposplenia (splenic atrophy/dysfunction) → impaired immunity against encapsulated organisms.

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Vaccinations required (as per British Society of Gastroenterology / Coeliac UK guidance):

Pneumococcal (PCV13 + PPV23) — primary + booster every 5 years
Meningococcal ACWY + B
Haemophilus influenzae type b (Hib)
Influenza — annually

Educate patients on signs of overwhelming post-splenectomy infection (OPSI)
Advise antibiotic prophylaxis if splenectomised
Carry antibiotic card
Consider lifelong penicillin V prophylaxis in some

Dermatitis Herpetiformis (DH)

The skin manifestation of coeliac disease — considered a separate but related condition.

Clinical Features

Intensely pruritic vesicular rash
Symmetrical distribution on extensor surfaces: elbows, knees, buttocks, scalp, shoulders
Blistering lesions that heal with pigmentation
Often no GI symptoms (silent coeliac)

Diagnosis & Treatment

Skin biopsy: granular IgA deposits in dermal papillae (immunofluorescence)
Positive tTG IgA serology in most
Dapsone — rapid itch relief (does NOT treat underlying coeliac)
Strict GFD — definitive treatment; may allow dapsone discontinuation after 1–2 years
Monitor dapsone for haemolytic anaemia, methaemoglobinaemia

Associated Autoimmune & Other Conditions

Condition	Association	Clinical Note
Type 1 Diabetes Mellitus (T1DM)	5–10% of T1DM have coeliac	Screen all T1DM patients for coeliac; shared HLA-DQ2/DQ8
Autoimmune thyroid disease	3–5× increased prevalence	Screen TFTs at diagnosis and annually; Hashimoto's and Graves'
IgA nephropathy	Elevated IgA deposition	Consider coeliac in unexplained IgA nephropathy
Down syndrome (Trisomy 21)	~5% prevalence	Routine coeliac screening recommended in Down syndrome
Turner syndrome	Increased prevalence	Screen if GI symptoms
Primary biliary cholangitis	Increased association	LFTs as part of monitoring
Selective IgA deficiency	10–15× more common in coeliac	Use IgG-based serology for diagnosis

Co-Existing IBS & Persistent Symptoms

Bloating and altered bowel habit may persist despite strict GFD and confirmed mucosal healing
Consider co-existing IBS (functional overlap) — very common in coeliac patients
Also consider: secondary lactose intolerance (resolves with villi recovery), SIBO, microscopic colitis, anxiety
Low-FODMAP diet trial (under dietitian guidance) may help IBS-type symptoms in adherent coeliacs

Patient Education & Practical Skills

Support Organisations

Coeliac UK — coeliac.org.uk; food database app, restaurant guide, helpline
Celiac Disease Foundation (US) — celiac.org
AOECS — Association of European Coeliac Societies
Local patient support groups
Online communities (Reddit r/Celiac, Facebook groups)

Eating Out Safely

Research restaurants in advance — look for GF menu or allergy menus
Apps: Find Me Gluten Free, Yelp (GF filter), Coeliac UK restaurant guide
Inform staff about coeliac (not preference — medical necessity)
Ask about dedicated GF fryers, separate prep areas
Beware shared buffets, salad bars (cross-contamination)
Safe cuisines: Mexican (corn-based), Thai (rice-based), Indian (rice/lentil dishes — check sauces)
High-risk cuisines: Italian, Chinese (soy sauce), Japanese (soy/tempura)

Travel Advice

General Travel Tips

Pack GF snacks and staples for journey
Research destination — GF awareness varies widely
Learn key phrases: "I cannot eat wheat, barley, or rye" in local language
Carry translation cards (available via Coeliac UK for many languages)
Self-catering accommodation gives more control
Flying: request GF meal in advance (code: GFML)

Middle Eastern / GCC Travel — Gluten Pitfalls

Bulgur wheat — in tabbouleh, kibbeh, some pilafs (unsafe)
Semolina (sameed) — in some Arabic breads, basbousa (unsafe)
Freekeh — wheat grain (unsafe)
Manakish (Arabic flatbread), khobz — wheat-based (unsafe)
Pita, kaak, samoon — all wheat-based (unsafe)
Safe GCC options: rice-based dishes (kabsa, machboos, plain rice), grilled meats (plain), meze: hummus, baba ganoush, plain salads (check for croutons)

Food Shopping & UK Prescriptions

Shopping Tips

Read every label every time (recipes change)
Look for Crossed Grain Symbol
Free-from aisles in supermarkets
Cost of GFD is significantly higher — budget planning important
Naturally GF foods (rice, potatoes, fresh meat, vegetables) are cheapest strategy

UK NHS GFD Prescriptions

GF bread and flour mix available on NHS prescription (England)
Must be confirmed coeliac (not NCGS)
Units per month based on age/sex (via ACBS)
Scotland: broader range available
Prescription charge exemption: coeliac not automatically exempt — consider prepayment certificate

Psychosocial Impact

Significant social isolation — meals are social events; GFD restricts participation
Increased risk of depression and anxiety in coeliac patients — screen regularly
Stigma — being "difficult" at restaurants or social gatherings
Disordered eating — orthorexia risk, especially in young women
Practical support: psychological referral if needed; peer support groups; family/carer education

Children with Coeliac Disease

School & Social

Communicate diagnosis to school nurse and canteen staff
Individual healthcare plan (IHP) for school meals
Peer pressure — navigating parties, school trips
Age-appropriate education for the child about their own condition
GF alternatives for school tuck shops

Clinical Considerations

Growth monitoring — height/weight on centile charts
Iron and folate supplementation if deficient
DEXA scan generally not done at diagnosis in children — calcium/vitamin D supplementation routinely
Transition to adult services — structured handover at 16–18; adolescent-specific support
Concordance issues during adolescence — peer pressure, denial of diagnosis

Pregnancy and Coeliac Disease

Uncontrolled coeliac increases risk of: miscarriage, low birth weight, preterm birth, IUGR
Strict GFD before and during pregnancy is essential
Folic acid 5mg (high dose) pre-conception and first 12 weeks — folate deficiency risk higher
Iron supplementation likely needed throughout pregnancy
Monitor nutritional status closely — increased demands in pregnancy
Breastfeeding is safe and recommended; does not trigger coeliac in infant
Infant screening: first-degree relatives — screen at age 3 or earlier if symptomatic

GCC Context & Exam Preparation

Coeliac Disease in the GCC Region

Epidemiology

Prevalence in Arab populations estimated ~1% (similar to global rates)
Likely significantly underdiagnosed — overlap with IBS and lactose intolerance
Symptoms often attributed to "food sensitivity" without formal investigation
HLA-DQ2/DQ8 present in Middle Eastern populations
Increasing awareness among GCC gastroenterologists

Cultural Dietary Challenges

Wheat is central to Arabic diet — khobz (flatbread), pita, couscous, bulgur
Tabbouleh (bulgur wheat), kibbeh (bulgur), fatayer (wheat pastry) — all unsafe
Rice-based dishes (kabsa, machboos, jollof) are inherently safe
Lentil and legume dishes — generally safe but check for added flour
Social pressure to eat bread at gatherings

Ramadan — Adherence Challenges

Iftar (breaking fast) traditionally includes bread-heavy dishes: khobz, samoon, kaak
Suhoor (pre-dawn meal) often includes flatbreads and pastries
Social and religious pressure to eat shared traditional foods
Nursing counselling: help patients plan GF iftar alternatives — rice, GF wraps, dates, fruit, legume-based dishes
Encourage planning ahead — prepare GF versions of traditional Ramadan dishes
Fast may worsen nutritional deficiencies in poorly controlled coeliac — monitor more closely in Ramadan

Halal Considerations for GFD Products

Some GF products contain gelatine — check source (pork vs. bovine halal)
Alcohol-based flavourings — present in some GF processed foods
Advise patients to check halal certification alongside GF labelling
Halal-certified GF options are available but may require specialty stores or online ordering in GCC
Naturally GF foods (unprocessed rice, fresh meat, vegetables) are automatically halal and GF

Healthcare System Context

Dietitian availability for GFD counselling varies across GCC — not universally accessible
GF products less widely available in smaller cities and rural areas
No NHS-equivalent prescription system for GF foods in GCC — patients pay out of pocket
DHA (Dubai Health Authority) and DOH (Abu Dhabi Department of Health) gastroenterology nursing competency frameworks include coeliac management
SCFHS (Saudi Commission for Health Specialties) nursing exams test GI conditions including coeliac

High-Yield Exam Topics

First-line serology: anti-tTG IgA + total IgA
IgA deficiency: use IgG-based tests
Marsh classification: 3c = total villous atrophy
Gold standard diagnosis: duodenal biopsy (OGD)
Hyposplenism vaccines: Pneumococcal, Meningococcal, Hib, Influenza
DH treatment: dapsone + GFD
EATL: suspect if symptoms despite strict GFD
Biopsy site: 2nd/3rd part of duodenum

Exam Practice Questions

Q1. A 32-year-old female presents with fatigue and iron-deficiency anaemia. Anti-tTG IgA is elevated. Total IgA is normal. What is the next investigation?

Answer: Upper GI endoscopy (OGD) with duodenal biopsies ×4 (minimum) from 2nd/3rd part of duodenum + bulb. This is the gold standard to confirm diagnosis via Marsh grading.

Q2. A coeliac patient's serology (anti-tTG IgA) remains elevated after 12 months on a "gluten-free diet". What is the most likely explanation?

Answer: Inadvertent gluten ingestion (most common cause of non-response). Dietary review by a dietitian is the first step — assess label reading, hidden sources, cross-contamination.

Q3. A patient with known coeliac disease develops recurrent abdominal pain, weight loss, and fever despite strict GFD. What serious complication must be excluded?

Answer: Enteropathy-associated T-cell lymphoma (EATL). Investigate with CT abdomen/pelvis, PET-CT, and consider capsule endoscopy. Also consider refractory coeliac disease (RCD).

Q4. Which vaccinations are required for a coeliac patient with hyposplenism?

Answer: Pneumococcal (PCV13 + PPV23), Meningococcal ACWY and B, Haemophilus influenzae type b (Hib), and annual Influenza vaccine.

Q5. A patient presents with a pruritic vesicular rash on elbows and knees. Skin biopsy shows granular IgA in dermal papillae. What is the diagnosis and treatment?

Answer: Dermatitis herpetiformis (DH). Treatment: Dapsone for rapid symptom relief + strict lifelong GFD as definitive treatment. Monitor dapsone for haemolytic anaemia.

Q6. What serology should be used to diagnose coeliac disease in a patient with selective IgA deficiency?

Answer: Anti-tTG IgG and/or deamidated gliadin peptide (DGP) IgG. IgA-based tests will be falsely negative in IgA deficiency.

Q7. A Marsh Grade 1 biopsy shows only intraepithelial lymphocytosis. What are the possible diagnoses?

Answer: Possible causes include early/latent coeliac disease, non-coeliac gluten sensitivity, H. pylori infection, NSAID use, Crohn's disease, and immune dysregulation. Correlation with serology and HLA typing is essential.

Interactive Gluten Safety Checker

Enter a food item to check if it is safe for coeliac patients. This tool checks against a comprehensive gluten safety database.

Coeliac Disease & Malabsorption GCC Nursing