Functional Dyspepsia

Meet the patient

A 34-year-old teacher sits in your clinic looking tired but well. For six months she has had postprandial fullness and early satiety — she now eats a third of her old plate and stops. Weight is stable; she has not lost a gram. Examination is normal, and last week's bloods were unremarkable. She has Dr-Googled gastric cancer and is frightened. Two questions decide her whole pathway: are there any alarm features (none here), and which subtype dominates (postprandial distress — PDS)? That single fork routes her to a prokinetic and a confident explanation — not a third endoscopy.[2]

The normal stomach that still hurts

Dyspepsia is the umbrella word for any upper-GI symptom — epigastric pain or burning, postprandial fullness, early satiety, nausea, bloating, belching. It is the commonest complaint primary care hears. Only about 30% turns out to have a structural cause (ulcer, oesophagitis, malignancy); the remaining 70%, after work-up, have nothing structural to find — and that majority is functional dyspepsia (FD).[1][2]

The word is old. 'Dyspepsia' is Greek — dys- (bad) plus pepsis (digestion); Hippocrates used it for any troubled digestion, and it has outlived every mechanism proposed since. Under Rome IV (Stanghellini, 2016), FD means one or more bothersome symptoms — epigastric pain, epigastric burning, postprandial fullness, early satiety — occurring at least 1 day a week, present for at least 3 months, with onset 6 months or more before diagnosis, and no structural disease on OGD.[3]

• Epigastric pain
• Epigastric burning
• Bothersome postprandial fullness
• Early satiety[1]

…each bothersome enough to interfere with usual activities. The old label non-ulcer dyspepsia is dead under Rome IV — it defined the disorder by what it was not, whereas functional dyspepsia frames it correctly as a disorder of function. The "absence of ulcer" was never the point.[3]

FD belongs to the family of disorders of gut-brain interaction (DGBI), alongside irritable bowel syndrome (IBS) and functional chest pain. The stomach is structurally normal; the signalling, motility, accommodation and mucosal sensitivity are not. The suffering is genuine — quality-of-life impairment rivals peptic ulcer disease and diabetes — so never tell a patient it is "all in their head".[2]

The habit that defines a good FD clinician: make a positive diagnosis after one sensible work-up, then stop investigating. Explain the diagnosis, exclude structural disease once, treat the dominant symptom, and resist the urge to re-scope. Repeated normal endoscopies reinforce illness behaviour — iatrogenic harm dressed up as thoroughness. Carry this mantra through the whole topic: a positive diagnosis after one sensible work-up, and never re-scope without a new alarm feature.[1][6]

Two subtypes, one decision: PDS or EPS

Rome IV splits FD into two overlapping subtypes, and the subtype chooses the first drug. That single fork — fullness versus pain — is the most useful decision you make all day. Each subtype maps to a mechanism and therefore to a first-line agent.[3]

Everyone forgets: overlap is the rule, not the exception. Most patients carry features of both PDS and EPS, and many also overlap with IBS (~40%) and GORD (~30%). The practical move is to name and treat the dominant symptom first, then layer a second agent. Rome IV also insists symptoms be bothersome — mild occasional fullness does not qualify. The move from Rome III to IV raised the frequency bar for EPS but strengthened "bothersome", and it chucked heartburn out of dyspepsia entirely — if heartburn dominates, that is GORD, treat GORD.[2][3]

How common, and who gets it

FD is genuinely common — you will meet it every week. Population studies worldwide put prevalence between 10% and 30% of adults, making it one of the most prevalent chronic conditions in medicine. It drives up to 5% of all primary-care visits and is the leading GI diagnosis in outpatients. There is a female predominance (~1.5:1) and a peak onset in the 5th and 6th decades, though any adult age is fair game. The societal bill — repeat endoscopies, prescriptions, absenteeism — runs into the billions.[2]

Established risk factors include the following:[1]

• Helicobacter pylori — the single most important modifiable organic co-variable; eradication cures a small subset (~7-15% relative benefit over placebo)
• NSAIDs and aspirin — irritant plus mucosal injury; dose-dependent
• Smoking, obesity, high dietary fat — aggravate symptoms, may raise prevalence
• Female sex — consistent predominance across populations
• Psychological factors — anxiety, depression, somatisation, neuroticism, and childhood adversity or abuse; bidirectional (cause and consequence)
• Post-infectious — onset within weeks of Campylobacter, Salmonella, Giardia, norovirus gastroenteritis; ~5-17% of FD cases
• Genetic predisposition — family aggregation; GNβ3 825C/T polymorphism (G-protein beta-3 subunit) reported but inconsistent across populations
• Dysbiosis and altered gut hormones — disturbed ghrelin (hunger/emptying), CCK (slows emptying), GLP-1 (inhibits accommodation)
• Prior abdominal surgery — may derange gastric motor function[1]

Remember that FD carries quality-of-life impairment comparable to peptic ulcer disease and diabetes — the suffering is real and measurable, lesion or no lesion. Patients also carry a 2-3-fold higher prevalence of anxiety and depression than controls, and the arrow runs both ways: low mood worsens symptoms, chronic symptoms worsen mood.[2]

The gut-brain fault — four converging mechanisms

FD is the prototypical disorder of gut-brain interaction — a bidirectional dysregulation between the enteric and central nervous systems, sitting on a structurally intact mucosa. No single mechanism explains every patient; several coexist in varying proportions, and each tends to drive one Rome IV subtype. The modern duodenal-gastric model argues FD may be primarily a duodenal disorder (eosinophilic inflammation, acid sensitivity) that secondarily deranges gastric sensorimotor function — not the pure gastric motility disorder it was historically sold as.[2][3][6]

1. Impaired gastric accommodation — a stiff proximal stomach

On eating, the proximal stomach (fundus) normally undergoes vagally-mediated receptive relaxation to form a low-pressure reservoir for the meal. This reflex runs on vagal nitrergic (NO) and cholinergic pathways and 5-HT1A receptors on vagal afferents. In about 40% of FD patients the reflex fails, so the fundus does not relax. Each bite raises intragastric pressure, firing stretch mechanoreceptors and producing early satiety and postprandial fullness — the cardinal PDS features. Confession time: these patients typically maintain weight, because they stop eating early before any real calorie deficit accrues. Weight loss is not part of this mechanism. Drugs that restore accommodation — buspirone (5-HT1A agonist), acotiamide (acetylcholinesterase inhibitor), tandospirone — target this defect directly.[2][6]

2. Delayed gastric emptying

About 25-35% of FD patients — mostly the postprandial-distress subgroup — have objectively delayed solid gastric emptying, measurable on gastric emptying scintigraphy (the gold standard) or the 13C-octanoic acid breath test. Food retained in the antrum drives fullness, nausea, bloating and postprandial discomfort. The classic trap here: a diabetic with chronic postprandial fullness may have FD or diabetic gastroparesis — a distinction that requires measurement, not symptom pattern. Oddly, the correlation between delayed emptying and symptom severity is weak, so emptying is one contributor among several. Prokinetics (metoclopramide, domperidone, itopride, acotiamide, mosapride) target this by boosting antral contractility and antro-duodenal coordination.[2]

3. Visceral hypersensitivity and central sensitisation

A defining feature of FD (shared with IBS) is a lowered pain threshold to gastric and duodenal distension — patients feel balloon distension as painful at volumes healthy controls barely register. This arises from peripheral sensitisation of mechanoreceptors (inflammatory mediators lower their threshold) and abnormal central processing in the insula, anterior cingulate cortex (ACC) and somatosensory cortex, visible on functional MRI — amplified pain-region activation, blunted descending inhibition. With duodenal acid hypersensitivity, this drives the epigastric pain and burning of EPS — and is exactly why neuromodulators (TCAs, mirtazapine) help pain-predominant disease, working at both ends of the axis.[2][4]

4. Duodenal low-grade inflammation, eosinophilia and acid sensitivity

The finding that is rewriting the textbooks: duodenal eosinophil and mast-cell infiltration in FD — especially in post-infectious and postprandial-distress subtypes, and denser in the duodenal bulb than distally. The eosinophilic infiltrate releases histamine, tryptase, major basic protein, eosinophil-derived neurotoxin, which disrupt the epithelial barrier, sensitise afferent nerves (via protease-activated receptors), and amplify the response to duodenal acid. Duodenal acid hypersensitivity underpins the rationale for PPI in EPS — less acid reaching a sensitised duodenum. Some authorities now consider this duodenal eosinophilia the primary driver of FD, with gastric dysfunction a downstream effect.[2][6]

Post-infectious FD (after Campylobacter, Salmonella, Giardia or norovirus) shows the same eosinophilia and mast-cell infiltrate — an immune-mediated trail left by an acute enteric infection. The infiltrate can fade over months to years, which explains why post-infectious FD often carries a better prognosis. The risk of developing FD after gastroenteritis is about 5-17% in the following year — a 2-6-fold rise over background.[2]

5. Helicobacter pylori

H. pylori causes chronic antral gastritis and is strongly linked to peptic ulcer disease and gastric cancer. In FD, prevalence is higher than in controls, but the relationship is humbling: eradication cures symptoms permanently in only a small subset — relative benefit over placebo about 7-15%, NNT ~12-15. We cannot predict who will respond (the "H. pylori-associated dyspepsia" phenotype remains a mystery), which is exactly why test-and-treat is applied to every FD patient. The consolation: after successful eradication the future ulcer and gastric-cancer risk also falls, so eradication in FD is never wasted even when symptoms persist.[1][2]

6. Psychosocial factors, genetics and the gut-brain axis

Psychological stress, anxiety and depression act through the HPA axis and autonomic dysfunction — stress contracts the fundus and amplifies visceral sensitivity via central sensitisation. Early-life adversity and abuse are over-represented in FD cohorts and predict severe, refractory disease. Genetic variation includes the GNβ3 825C/T polymorphism (TT genotype raises risk in some populations, not others — classic gene-environment interaction). Disturbed ghrelin (low in some cohorts, correlating with early satiety), CCK hyper-responsiveness (slows emptying) and gut-microbiota dysbiosis all tune susceptibility. Many inputs, one phenotype: a stomach that looks normal but feels and behaves abnormally.[2]

What you'll actually hear at 3am

The diagnosis is symptom-based (Rome IV) plus a normal OGD — the story does most of the work. The four cardinal symptoms are:[1]

• Epigastric pain — dull, aching or gnawing, locked to the epigastrium; not related to defecation, not generalised
• Epigastric burning — often meal-related; may masquerade as reflux but lacks the retrosternal climb of heartburn
• Bothersome postprandial fullness — a sense of food sitting heavy after ordinary-sized meals (PDS)
• Early satiety — unable to finish a normal plate; full within a few bites (PDS)[1]

Common companions are nausea (fine), belching, upper-abdominal bloating, and a feeling of slow digestion. Mild heartburn-like symptoms are common and blur the line with GORD — but under Rome IV heartburn is NOT a dyspepsia symptom; if acid regurgitation dominates, classify and treat as GORD. Overlap (dyspepsia plus reflux plus IBS) is the rule, not the exception.[1][2]

The non-negotiable: FD does NOT cause weight loss, dysphagia, recurrent vomiting, haematemesis, melaena, iron-deficiency anaemia, or a palpable mass. Any of these is an alarm feature and mandates OGD. A confident FD diagnosis also requires the patient to be systemically well — no fever, no night sweats, no progressive constitutional decline.[1]

The course is chronic and relapsing-remitting — flaring with stress, fatty or spicy meals, NSAIDs and alcohol, and easing with reassurance, holidays and stable routine. Patients often describe years of intermittent symptoms with a string of normal investigations behind them, and may arrive health-anxious, somatising or low in mood. That episodic-flare-on-chronic-background pattern is itself characteristic and reassuring.[2]

Atypical presentations

• Elderly — may harbour organic disease (gastric/oesophageal cancer, peptic ulcer) with minimal or atypical symptoms; apply the age 55 or over rule and the alarm screen aggressively, and keep a low threshold for OGD. Polypharmacy (NSAIDs, bisphosphonates, antiplatelets, iron, potassium) is a frequent culprit.
• Diabetic — chronic postprandial fullness may be diabetic gastroparesis, not FD; consider gastric emptying scintigraphy and review glycaemic control. Autonomic neuropathy and prior vagotomy contribute. Distinguish by measurement, not pattern.
• NSAID/aspirin users — dyspepsia may be drug-induced mucosal injury (chemical gastropathy or ulcer); stop or reduce the NSAID, add a PPI, consider gastroprotective alternatives.
• Pregnant — dyspepsia is extremely common as progesterone relaxes the LES and the gravid uterus displaces the stomach; antacids/alginates first, PPI only if essential and after the first trimester.
• Post-gastroenteritis — onset within weeks of Campylobacter, Salmonella, Giardia or norovirus suggests post-infectious FD, often with a better prognosis; male sex, predominant bloating and IBS-D overlap are typical.
• Young women with weight loss — beware. This is the classic trap: a young woman with "early satiety" and falling weight is anorexia nervosa or rumination syndrome, NOT functional dyspepsia. FD patients hold their weight; the weight loss is the tell that this is a different diagnosis.[1]

The mimics you cannot afford to miss

The dangerous mimic is gastric cancer; the common mimic is GORD. Most of the rest are drug-induced or overlap syndromes. Separate them at the bedside with three questions — alarm features? relation to meals and defecation? weight loss? — not with a battery of tests.[1][2]

Three discriminators to hunt for on every first assessment: (1) any alarm feature (OGD), (2) the pain's relationship to meals and defecation (separates DU/GU, GORD, IBS), and (3) weight loss (always organic until proven otherwise). Miss gastric cancer by ignoring alarms and you cause the one harm in this topic that cannot be undone; that is why the alarm screen is non-negotiable on every visit, not just the first.[1]

Bedside exam and the WEB-VOMIT screen

The bedside exam is usually normal — and that normality is itself a diagnostic clue. Epigastric tenderness may be present but is non-specific and non-localising. Your job at the bedside is not to confirm FD but to hunt organic disease:[1]

• General — cachexia, pallor (anaemia), jaundice (biliary/pancreatic), lymphadenopathy (Virchow's node — left supraclavicular — in gastric cancer; Sister Mary Joseph node — periumbilical)
• Abdomen — epigastric tenderness (non-specific), mass (cancer), hepatomegaly (metastases), succussion splash (gastric outlet obstruction or severe gastroparesis — the audible splash on shaking the abdomen), guarding/rigidity (peritonism)
• DRE — if bleeding suspected (melaena — black, tarry, foul-smelling); mass (rectal cancer)
• Dysphagia assessment — if reported, this is an alarm feature mandating urgent OGD[1]

The decision-defining bedside manoeuvre is the alarm-feature screen — WEB-VOMIT. Learn it cold; it is the single highest-yield mnemonic in dyspepsia:[1]

A positive screen mandates urgent OGD within 2 weeks under the NICE suspected-cancer pathway. A negative screen permits non-invasive management in patients under 55 with new-onset, uncomplicated dyspepsia. Quantify burden with the Nepean Dyspepsia Index (NDI) or Leeds Dyspepsia Questionnaire (LDQ) — the NDI is the most used and captures both severity and quality-of-life impact. Always screen mood with PHQ-9 (depression, score 10 or more = moderate) and GAD-7 (anxiety, 10 or more = moderate); both predict severity, healthcare use, response and prognosis, and should shape the plan.[2]

Risk-stratify, then do as little as possible

The diagnosis is Rome IV symptoms PLUS a normal OGD — but you do not scope everyone. The strategy is risk-stratified and minimally invasive, with OGD reserved for those at higher organic risk.[1]

Investigation strategy (risk-stratified)

Specific tests

• Upper GI endoscopy (OGD) — the single most useful test in dyspepsia; excludes organic disease and, by being normal, confirms the FD diagnosis. Indications: any alarm feature; age 55 or over at onset (NICE) or 60 or over (ACG); persistent symptoms despite an adequate PPI trial; family history of upper-GI cancer. Biopsy every gastric ulcer — "no gastric ulcer should go unbiopsied". A normal OGD is itself part of the FD definition. Scope off PPIs for at least 2 weeks to avoid masking oesophagitis and H. pylori.
• H. pylori testing — choice depends on whether you are scoping:
  • Non-invasive (first-line in test-and-treat): urea breath test (13C/14C) or stool antigen (monoclonal, most sensitive); both detect active infection and confirm eradication
  • Serology (IgG) — can NOT distinguish active from past infection; useless for confirming eradication; only for epidemiology
  • Biopsy-based (during OGD): rapid urease test (CLO test — yellow to red), histology (gold standard for morphology), culture (sensitivities in treatment failure)
  • Confirm eradication at least 4 weeks after therapy with breath test or stool antigen (PPI stopped 2 weeks beforehand to avoid false negatives)
• Bloods — FBC (exclude iron-deficiency anaemia), coeliac serology (tTG-IgA with total IgA — FD mimics coeliac and the distinction matters; coeliac has a specific treatment), LFTs, amylase/lipase (pancreatic), glucose/HbA1c (diabetes), TSH (thyroid), CRP/ESR (inflammation suggests organic disease)
• Abdominal ultrasound — only if biliary symptoms (RUQ pain post-fatty food, scapular radiation); avoid routine imaging without pointers — low yield in FD
• CT abdomen/pelvis — if weight loss, mass, or pancreatic/other malignancy suspected; not routine
• 24-hour pH-impedance study — if reflux dominates and PPI fails, or before attributing symptoms to FD (to quantify acid exposure objectively)
• Gastric emptying scintigraphy — if gastroparesis is suspected (diabetic, severe nausea/vomiting, succussion splash); measures retention of a radiolabelled solid meal at 2 and 4 hours
• High-resolution oesophageal manometry — rarely; if achalasia is the mimic (dysphagia to liquids and solids, regurgitation)[1]

The trap juniors fall into: re-scoping to reassure. Once OGD is normal and no new alarm feature has appeared, do not repeat it. Repeated normal endoscopies reinforce illness behaviour, cost money, confer no diagnostic yield, and may seed iatrogenic anxiety. Stop.[1][2]

When FD stops being FD — the emergent escalations

FD is a chronic non-emergency — there is no time-critical resuscitation bundle. But a handful of emergent escalations must be recognised instantly, because each means organic disease has supervened on (or masqueraded as) FD:[1]

• New haematemesis or melaena — manage as acute upper-GI bleeding: two large-bore IV cannulae, crystalloid resuscitation, bloods with crossmatch and group-and-save, restrict transfusion to Hb < 70 g/L (under 80 g/L if cardiovascular disease); urgent OGD within 24 h. Organic disease (ulcer, cancer, varices) has declared itself.
• New iron-deficiency anaemia — investigate with OGD ± colonoscopy (the "two-way endoscopy" workup); transfuse per protocol if symptomatic or Hb < 70 g/L; iron replacement (oral ferrous sulphate 200 mg tds, or IV ferric carboxymaltose if intolerant).
• Severe weight loss or new dysphagia — urgent OGD to exclude malignancy; these are never part of FD.
• Suicidal ideation from severe comorbid depression — psychiatric crisis assessment and a safety plan; do not assume symptoms are "functional" and dismiss the patient.[1]

In the stable chronic patient, the acute intervention is the most underrated one in medicine: diagnosis, explanation and reassurance — a powerful therapeutic act that reduces symptom anxiety and healthcare-seeking behaviour all by itself.[1]

The ladder: treat the dominant symptom

Management is stepwise, symptom-targeted and explicit. Address the dominant symptom, escalate only after an adequate trial (4-8 weeks per step), and re-screen for new alarm features at every visit. Each step below carries a named drug with dose, timing, rationale and monitoring. ACG/CAG and NICE both endorse a PPI trial then step-up to prokinetics or neuromodulators, with test-and-treat H. pylori at any stage.[1][2]

Step 1 — Explanation, reassurance and lifestyle

The cornerstone — and usually the most powerful thing you do. Explain in plain language: the diagnosis is real, the symptoms arise from disordered gut-brain function, the stomach is structurally normal, and the prognosis is benign (no cancer, ulcer or serious disease). Spell out that repeated normal endoscopies are not needed and may harm. Moving the conversation from "we found nothing" to "you have a recognised gut-brain disorder" is itself therapeutic. Lifestyle measures:[1][2]

• Small, frequent, low-fat meals — high-fat meals delay emptying and impair fundic accommodation; 5-6 small meals beat 3 large ones
• Avoid triggers — fatty and spicy foods, coffee (stimulates acid), citrus, onions, alcohol, NSAIDs and aspirin (mucosal irritants), smoking
• Chew thoroughly, eat slowly, avoid late meals — allow 3 hours before lying down
• Stress management, regular sleep, moderate exercise — all improve gut-brain function and symptom threshold
• Weight loss if overweight/obese — lowers intra-abdominal pressure and reflux overlap[1]

Step 2 — Test-and-treat Helicobacter pylori

Stool antigen or urea breath test in every FD patient without prior documented infection or recent antibiotic/PPI use (stop PPI 2 weeks before testing). If positive, eradicate:[1]

• First-line (low clarithromycin-resistance areas, penicillin-tolerant): PPI bid + clarithromycin 500 mg bid + amoxicillin 1 g bid — 14 days
• Penicillin-allergic or high clarithromycin resistance: bismuth quadruple therapy (PPI bid + bismuth 525 mg qid + tetracycline 500 mg qid + metronidazole 500 mg qid/tid — 10-14 days), or PPI + clarithromycin + metronidazole
• Confirm eradication at least 4 weeks after therapy with breath test or stool antigen (PPI stopped 2 weeks beforehand)[1]

Rationale: eradication cures a small but worthwhile subset (relative benefit ~7-15%, NNT ~12-15) and cuts future ulcer and gastric-cancer risk — cost-effective first-line even when symptom response is modest. Monitoring: drug side-effects (clarithromycin — GI upset, taste disturbance; metronidazole — disulfiram-like alcohol reaction; bismuth — black stools, darkened tongue).[1][2]

Step 3 — Proton-pump inhibitor (PPI)

For epigastric pain syndrome (EPS) and reflux-like symptoms, the PPI is first-line.[1]

• Omeprazole 20-40 mg once daily (alternatives: esomeprazole 20-40 mg, pantoprazole 40 mg, rabeprazole 20 mg, lansoprazole 30 mg) for 4-8 weeks
• Response — modest but statistically significant over placebo (relative risk reduction ~14%, NNT ~11); greatest in EPS (pain/burning), least in PDS (fullness/early satiety)
• If responding, taper to the lowest effective dose; if asymptomatic, move to intermittent or on-demand therapy rather than continuous long-term PPI
• H2-receptor antagonists — (ranitidine withdrawn in many markets for NDMA contamination; famotidine 20 mg bid or nizatidine 150 mg bid) are an alternative for PPI-intolerant patients or step-down[1]

Risks of long-term PPI — minimise exposure: Clostridioides difficile infection, community-acquired pneumonia, osteoporotic fracture, hypomagnesaemia (check annually if long-term), vitamin B12 deficiency, rebound acid hypersecretion on cessation. Monitoring: review need annually; deprescribe if symptom-free.[1]

Step 4 — Prokinetics

For postprandial distress syndrome (PDS) — fullness, early satiety, nausea — the prokinetic is first-line. The classic trap lives here: metoclopramide for 5 days only — tardive dyskinesia is irreversible; domperidone for 7 days only and watch the QT. Everyone reaches for metoclopramide first; that is how you end up doing an extrapyramidal-safety or sudden-death audit.[1][5]

• Metoclopramide 10 mg three times daily before meals — MHRA: maximum 5 days for extrapyramidal effects and tardive dyskinesia (black-box); avoid in Parkinson's, young adults (under 20), first-trimester pregnancy. Stop immediately if dystonia, akathisia or parkinsonism appear.
• Domperidone 10-20 mg three times daily — does not cross the blood-brain barrier (fewer extrapyramidal effects) but carries QT prolongation and sudden cardiac death risk — ECG before and during, maximum 7 days, avoid with QT-prolonging drugs (macrolides, fluoroquinolones, antipsychotics), hepatic impairment and structural heart disease.
• Itopride 50 mg three times daily — dopamine D2 antagonist with acetylcholinesterase inhibition; available in India/Asia; favourable cardiac profile (no QT risk); a reasonable first-line prokinetic where available.
• Acotiamide 100 mg three times daily before meals — enhances gastric accommodation and accelerates emptying via acetylcholinesterase inhibition (raises vagal ACh release); approved in Japan and India for PDS, not in US, UK or EU; effective for early satiety and postprandial fullness; well-tolerated (mainly nausea, diarrhoea).[5]
• Mosapride 5 mg three times daily — selective 5-HT4 agonist; available in Japan/Asia; prokinetic without QT risk; limited data.

Rationale: enhance gastric emptying and accommodation. Monitoring: extrapyramidal effects (metoclopramide — stop at once), QT interval (domperidone — ECG), prolactin (galactorrhoea, gynaecomastia — metoclopramide and domperidone cross the pituitary dopamine threshold).[1][5]

Step 5 — Neuromodulators (refractory pain, nausea, sleep)

Amitriptyline is the best-evidenced drug for refractory FD pain — and most of your colleagues will not think to use it. Ford's meta-analysis (Gut 2017) showed TCAs work, while SSRIs and antipsychotics do not. Reach for it when PPI and/or prokinetic have failed an adequate trial, especially in pain-predominant (EPS) refractory disease:[4]

• Amitriptyline 10-25 mg at night, titrate to 50-75 mg if tolerated over 4-8 weeks — best evidence among neuromodulators (Ford, Gut 2017); helps pain, sleep and visceral sensitivity; start low and slow to limit anticholinergic effects (dry mouth, constipation, urinary retention, sedation, blurred vision); avoid in glaucoma, prostatic hypertrophy, recent MI; ECG for QT before higher doses.[4]
• Mirtazapine 15-30 mg at night — noradrenergic and specific serotonergic antidepressant (NaSSA); ideal when weight loss, nausea and insomnia cluster (5-HT3 antagonism plus appetite and sleep benefit); sedation and weight gain are the main effects; valuable for the "poor appetite, poor sleep, nausea" phenotype.
• Buspirone 10-15 mg three times daily — 5-HT1A agonist that enhances gastric accommodation (the key PDS mechanism); useful in PDS with coexisting anxiety; anxiolytic without TCA baggage; allow 2-4 weeks for full effect.
• SSRIs (e.g., sertraline 50 mg od, escitalopram 10 mg od) — preferred when comorbid anxiety/depression dominates (treat the mood disorder); less analgesic than TCAs but better tolerated; useful when pain is downstream of mood.[4]

Rationale: neuromodulation of visceral afferents and central pain processing — these drugs work at doses below antidepressant ones, and the benefit is independent of mood effect. Monitoring: anticholinergic effects, QT (TCAs), serotonin syndrome (SSRIs/SNRIs), suicidality (all antidepressants — FDA black box in under-25s).[4]

Step 6 — Psychological therapy

For refractory disease with psychological comorbidity, the gut-brain therapies earn their place.[2][4]

• Cognitive behavioural therapy (CBT) — best trial evidence; tackles symptom catastrophising, hypervigilance, avoidance and maladaptive illness beliefs; 8-12 sessions; benefit holds at 12 months
• Gut-directed hypnotherapy — growing evidence, especially in PDS and high-somatisation patients; teaches visceral relaxation
• Psychodynamic interpersonal therapy — for interpersonal/abuse-related triggers and complex psychosomatic presentations[1]

Step 7 — Dietary and complementary therapy

• Low-fat, smaller meals; chew thoroughly; avoid late meals
• Low-FODMAP diet — trial 4-6 weeks then reintroduce; most useful in FD-IBS overlap (cuts the fermentable carbohydrate load driving bloating and gas)
• Peppermint oil — for coexistent spasm (note: may worsen reflux by relaxing the LES)
• Herbal preparations — Iberogast (STW 5) shows modest benefit in some trials; carob flour and pink frangula (alder buckthorn) are traditional remedies with thin evidence; artichoke leaf extract has some supportive data
• Fundic-guided gastric accommodation therapy — diaphragmatic breathing to boost vagal tone and fundic relaxation; an emerging non-drug option for PDS[1]

Escalation triggers: failure of one step after an adequate trial (4-8 weeks), a new alarm feature (repeat OGD), intolerable drug side-effects, or diagnostic uncertainty (refer to gastroenterology). And do not escalate to opioids — they slow the gut, sensitise the brain and turn a manageable disorder into narcotic bowel syndrome. There is no role for opioids in FD pain. Say it out loud to the patient.[1]

PDS, EPS, and the overlaps

Postprandial distress syndrome (PDS)

Dominant: bothersome fullness and early satiety after ordinary-sized meals (at least 3 days/week). Mechanism: impaired gastric accommodation (~40%), delayed gastric emptying (~25-35%), duodenal eosinophilia. First-line: acotiamide 100 mg tds (where available — Japan/India), itopride 50 mg tds, or short-course metoclopramide/domperidone; small low-fat meals; buspirone 10-15 mg tds if anxiety coexists. Second-line: mirtazapine 15 mg nocte (if weight loss/nausea), CBT, gut-directed hypnotherapy. PDS is generally harder to treat than EPS and has weaker evidence for PPI benefit.[2][5]

Epigastric pain syndrome (EPS)

Dominant: bothersome epigastric pain or burning (at least 1 day/week), not relieved by defecation. Mechanism: visceral hypersensitivity, duodenal acid/eosinophil sensitivity, central sensitisation. First-line: PPI 4-8 weeks (omeprazole 20-40 mg od); if refractory, low-dose amitriptyline 10-25 mg nocte (the best-evidenced neuromodulator for EPS). EPS is generally more responsive to therapy than PDS.[1][4]

Overlap (PDS + EPS)

Common — treat the dominant symptom first, then layer a second agent from the other class (e.g., PPI + prokinetic, then add a TCA for residual pain). Many patients need two agents at steady state.[1]

Post-infectious FD

Onset within weeks of an acute gastroenteritis (Campylobacter, Salmonella, Giardia, norovirus). Marked by duodenal eosinophilia, commoner in males, and often overlapping IBS-D. Better prognosis — symptoms often resolve over months to years. Treat as FD; prokinetics often first-line. The immune-mediated mechanism hints at a future role for anti-inflammatory or anti-eosinophil strategies, not yet standard.[2]

Refractory FD

Failure of the stepwise ladder after adequate trials of lifestyle, H. pylori eradication, PPI, prokinetic and neuromodulator. Reassess systematically: (1) repeat OGD if any new alarm feature has appeared; (2) review medication — is the patient still on NSAIDs or aspirin?; (3) re-confirm the diagnosis — was coeliac serology done? Could this be gastroparesis (emptying study)? Rumination syndrome?; (4) address psychological comorbidity (PHQ-9, GAD-7 — treat anxiety/depression actively); (5) refer to a tertiary GI / functional-bowel service for CBT, gut-directed hypnotherapy, or trial novel neuromodulation (e.g., gastric percutaneous electrical stimulation — experimental). Do not escalate to opioids.[1][2]

Overlap syndromes (FD-IBS, FD-GORD)

Very common — manage both disorders at once. Low-FODMAP diet for the IBS component; PPI for GORD; prokinetic/TCA for FD; CBT for the shared gut-brain substrate. Patients with triple overlap (FD + IBS + GORD) carry the greatest symptom burden and lowest quality of life — they need the most integrated, multidisciplinary care.[2]

Where juniors get burned

• No structural complications and no excess mortality — FD is benign in organic terms. But the quality-of-life toll is real: lost productivity, absenteeism, anxiety, depression, somatisation, social withdrawal, and medication side-effects that themselves become the problem.
• Misdiagnosis of organic disease — the cardinal, most dangerous pitfall. Missing gastric or oesophageal cancer or peptic ulcer by ignoring alarms is the error that causes real harm. This is why the alarm-feature screen is non-negotiable on every assessment and every follow-up. Any new alarm in a previously diagnosed FD patient mandates repeat OGD.
• Iatrogenic harm from repeated normal endoscopies — reinforces illness behaviour ("they must be missing something"), costs money, exposes the patient to procedural risk (perforation, sedation, bleeding), and yields nothing once OGD is normal.
• Medication-related harms — a major source of iatrogenic morbidity in FD:
  • Long-term PPI — C. difficile colitis, community-acquired pneumonia, osteoporotic fracture, hypomagnesaemia, B12 deficiency, rebound acid hypersecretion, possible dementia (controversial)
  • Metoclopramide — extrapyramidal effects (acute dystonia, akathisia, parkinsonism), tardive dyskinesia (irreversible — MHRA max 5 days)
  • Domperidone — QT prolongation, ventricular arrhythmia, sudden cardiac death (max 7 days, ECG monitoring)
  • TCAs — anticholinergic effects, sedation, QT prolongation, overdose lethality (cardiotoxicity)
  • Hyperprolactinaemia — metoclopramide and domperidone (galactorrhoea, gynaecomastia, amenorrhoea)
• Opioid escalation — avoid; worsens gut motility (narcotic bowel syndrome), drives central sensitisation, and has no role in FD pain.
• Dismissive labelling — telling a patient "it's just stress" or "it's all in your head" destroys the therapeutic alliance. FD is a real disorder with measurable pathophysiology and demands empathic, validating communication.[1][2]

What happens to them

FD is chronic and relapsing-remitting — not dangerous, but often persistent. About half of patients improve or fluctuate over years; a minority (15-20%) have persistent troublesome symptoms needing long-term symptom-targeted therapy, and a small subset progressively worsen with significant quality-of-life loss. There is no mortality impact — FD does not shorten life, does not progress to cancer, and does not cause ulcers or bleeding.[2]

H. pylori eradication cures a small but worthwhile subset (~7-15% relative benefit; NNT ~12-15). Reassurance that symptoms will not lead to cancer, ulcer or serious disease is itself therapeutic — deliver it explicitly and repeatedly. Most patients stay in primary care; secondary-care referral is for alarm features, refractory disease, diagnostic uncertainty, or tertiary functional-bowel input. Long-term follow-up is symptom-driven — patients return when they flare, not on a fixed schedule.[1][2]

Stopping the next flare

There is no proven primary prevention for FD, but several strategies cut symptom frequency and severity in established disease and may lower incidence in high-risk groups:[1][2]

• Eradicate H. pylori where detected — removes the small attributable subset and lowers future ulcer and gastric-cancer risk
• Minimise NSAID and aspirin use — or co-prescribe a PPI when unavoidable; these are major mucosal irritants
• Smoking cessation — smoking raises FD prevalence and severity
• Moderate alcohol — heavy use aggravates dyspeptic symptoms
• Stress management — mindfulness, CBT skills, regular exercise, adequate sleep; all modulate the gut-brain axis
• Dietary habits — regular small meals, low-fat, limited coffee; reduce the mechanical and secretory load on the stomach
• Early treatment of mood disorders — anxiety and depression are bidirectional with FD; treating them early may prevent chronicity[1]

When the rules bend

• H. pylori-positive dyspepsia — eradicate (see Step 2); confirm cure with a breath test 4 weeks later. Eradication also lowers future ulcer and gastric-cancer risk, so it pays off even when symptoms persist. In high-prevalence regions (India, ~60-80%), test-and-treat is first-line for all dyspepsia.[1]
• Pregnancy — dyspepsia is extremely common (progesterone relaxes the LES; the gravid uterus displaces the stomach). Antacids/alginates first (Gaviscon, Mucogel — safe); avoid NSAIDs entirely. PPI only if essential and after the first trimester (omeprazole — limited human data but generally low-risk in second/third trimester; lansoprazole preferred by some). Ranitidine withdrawn in many markets for NDMA. Avoid domperidone. Metoclopramide (category B) only with caution for severe nausea, short course. Itopride — insufficient safety data; avoid.
• Elderly — lower threshold for OGD; atypical organic presentation is the rule (gastric cancer may present as "weight loss and anorexia" without classic dyspepsia). Review polypharmacy (NSAIDs, bisphosphonates, antiplatelets, iron, potassium — all cause dyspepsia). Check renal function before PPI (hypomagnesaemia) and domperidone (accumulation). Watch CYP2C19 interactions (omeprazole/esomeprazole). Mind fall risk with TCAs (sedation, orthostasis).[1]
• NSAID-associated dyspepsia — stop or reduce the NSAID; co-prescribe a PPI; consider gastroprotective alternatives (paracetamol, topical NSAID, COX-2 inhibitor with PPI). The dyspepsia may be chemical gastropathy or peptic ulcer — OGD if alarm features.
• Diabetic — distinguish FD from gastroparesis (gastric emptying scintigraphy — retention > 10% at 4 hours is diagnostic); optimise glycaemic control (hyperglycaemia itself delays emptying); avoid metoclopramide beyond 5 days; consider domperidone with ECG monitoring; acotiamide (where available) is a rational prokinetic. Autonomic neuropathy and prior vagotomy contribute.
• Children — FD is uncommon; Rome IV paediatric criteria require symptoms for at least 2 months (vs 3 in adults). Consider food allergy, H. pylori (especially in endemic regions), constipation, and psychological contributors (school stress, anxiety). Refer to paediatric gastroenterology; avoid off-label adult drugs; weight-based dosing for anything used.
• Immunocompromised (HIV, transplant, chemotherapy) — consider opportunistic infection (CMV oesophagitis/gastritis, Candida oesophagitis, HSV); lower threshold for OGD; review immunosuppression (mycophenolate can cause GI ulceration).

Evidence, Guidelines & Regional Differences

• ACG/CAG 2017 Clinical Guideline (Moayyedi et al., PMID 28631728) — the key US guideline. Recommends test-and-treat H. pylori in all FD; PPI modestly effective (NNT ~11); prokinetics equivocal; TCAs (especially amitriptyline) effective; fundic relaxants/acotiamide limited evidence. Mostly conditional recommendations on very low-quality evidence — a frank reflection of the modest effect sizes in FD.[1]
• Lancet 2020 review (Ford et al., PMID 33049222) — the comprehensive contemporary synthesis of pathophysiology (duodenal eosinophilia, gut-brain model) and management. Take-home: no single therapy is dramatically effective; stepwise, symptom-targeted therapy is the standard.[2]
• Rome IV consensus (Stanghellini et al., 2016, Gastroenterology, PMID 27147122) — redefined FD and established the two-subtype model (PDS + EPS) underpinning all modern management. Raised thresholds, strengthened bothersome, removed heartburn from dyspepsia.[3]
• Ford et al., Gut 2017 (PMID 26567029) — systematic review and meta-analysis of psychotropic drugs in FD; TCAs effective (NNT ~6), SSRIs and antipsychotics not superior to placebo. Amitriptyline is the best-evidenced neuromodulator for FD.[4]
• Broeders et al., Aliment Pharmacol Ther 2023 (PMID 36859629) — modern review arguing FD may be primarily a duodenal disorder (eosinophilic duodenitis) with secondary gastric sensorimotor dysfunction; reframes the disease model.[6]
• Maastricht VI/Florence 2022 consensus — H. pylori eradication regimens and indications; recommends eradication in FD as a "test-and-treat" strategy, with bismuth quadruple therapy preferred where clarithromycin resistance > 15%.
• NICE CG184 (Dyspepsia and reflux, 2014, updated 2019) — UK guideline; urgent OGD within 2 weeks under the suspected-cancer pathway for age 55 or over with recent-onset dyspepsia, treatment-resistant dyspepsia, or any alarm feature; test-and-treat H. pylori in under-55s without alarms; step-up therapy (lifestyle → PPI → H2RA → prokinetic → TCA).
• Cochrane systematic reviews (Ford et al.) — PPI, H. pylori eradication and prokinetics each show a small but statistically significant benefit over placebo (relative risk reduction ~10-15% each); no single agent is dramatically effective — hence the stepwise, combination approach.[2]

Controversies

• Role of duodenal eosinophilia — whether anti-eosinophil therapy (montelukast, anti-IL-5) has a place in FD is under investigation; no approved treatment yet targets this mechanism.
• Efficacy of CBT and gut-directed hypnotherapy — growing evidence but limited access and cost; trials show benefit, but generalisability to routine practice is uncertain.
• Low-FODMAP diet in FD — strongest in IBS overlap; in pure FD, benefit is uncertain.
• Probiotics — insufficient evidence to recommend routinely; some trials suggest modest benefit.
• Whether FD is "gastric" or "duodenal" — the Broeders 2023 review (PMID 36859629) argues for a primary duodenal origin; the debate is live and may reshape treatment targets in the next decade.[6]

Ward-round test

Stem 1. Your 34-year-old teacher returns for the third time in a year with the same postprandial fullness — normal OGD six months ago, no new alarm features, weight stable. She wants another scope. What do you do?[1]

Stem 2. Same patient, but this visit she has lost 6 kg and her BMI is 16. What changes?[1]

Stem 3. A 58-year-old man has new epigastric burning for 8 weeks — normal exam, no anaemia. Next step?[1]

Stem 4. Refractory EPS despite 8 weeks of PPI and an adequate prokinetic. Name the next drug, dose, and the one ECG caution.[4]

Exam Pearls

• Rome IV definition — one or more of epigastric pain, epigastric burning, bothersome postprandial fullness, early satiety; onset 6+ months before diagnosis; present 3+ months; sufficiently bothersome to interfere with usual activities; at least 1 day/week; NORMAL OGD.[3]
• Two subtypes: PDS (fullness/early satiety, 3+ days/week → prokinetic/acotiamide) and EPS (pain/burning, 1+ day/week → PPI → TCA). Treat the dominant symptom.[1]
• Alarm features — WEB-VOMIT — Weight loss, Epigastric mass, Bleeding/anaemia, Vomiting, Over 55, Marrow anaemia, Inability to swallow (dysphagia), Tendency (family history) — mandate urgent OGD.[1]
• Strategy — under 55 without alarms: test-and-treat H. pylori; 55 or over or any alarm: urgent OGD within 2 weeks (NICE).[1]
• Management ladder: lifestyle → test-and-treat H. pylori → PPI (EPS) → prokinetic/acotiamide (PDS) → low-dose TCA/amitriptyline → mirtazapine → CBT/gut-directed hypnotherapy.[1]
• H. pylori eradication cures a small minority (~7-15% relative benefit; NNT ~12-15) but is cost-effective first-line and lowers future ulcer/cancer risk.[1]
• Metoclopramide — black-box tardive dyskinesia, MHRA max 5 days; domperidone — QT prolongation, max 7 days, ECG. A favourite pharmacology-viva trap.[1]
• Acotiamide — enhances gastric accommodation (AChE inhibition), approved Japan/India for PDS, not US/UK/EU — high-yield for NEET-PG/INICET.[5]
• Amitriptyline 10-25 mg nocte is the best-evidenced neuromodulator for FD (Ford meta-analysis, Gut 2017) — works below antidepressant doses, independent of mood effect.[4]
• Gut-brain disorder — impaired Accommodation, Delayed emptying, visceral Pain hypersensitivity, duodenal low-grade inflammation/eosinophilia (mnemonic A-D-P-E).[2]
• Avoid repeated endoscopy once OGD is normal and no new alarms — re-scoping reinforces illness behaviour and is iatrogenic harm.[1]
• Overlap with IBS (~40%) and GORD (~30%) is common — manage both; the patient with triple overlap has the worst quality of life.[2]
• FD does NOT cause weight loss, dysphagia, vomiting, bleeding, anaemia, or mass — any of these = alarm feature = OGD.[1]
• No opioids for FD pain — they worsen motility and central sensitisation.[1]

Exam application bank (NEET-PG / INICET)

One-line answer

Functional dyspepsia is chronic (at least 3 months) epigastric pain or burning, bothersome postprandial fullness or early satiety, with no structural cause on endoscopy (including a normal OGD). It is a disorder of gut-brain interaction driven by gastroduodenal dysmotility, visceral hypersensitivity, duodenal eosinophilic inflammation and low-grade mucosal immune activation, and is divided into two subtypes — postprandial distress syndrome (fullness, early satiety) and epigastric pain syndrome (pain, burning). Diagnosis requires excluding alarm features (age 55 or over, weight loss, bleeding, dysphagia, anaemia, family history) with OGD in selected patients and testing for H. pylori. Management is stepwise — reassurance and lifestyle measures, then test-and-treat H. pylori, a PPI trial, prokinetics, and for refractory disease low-dose tricyclic antidepressants or CBT.[1]

Worked stems (answer without another resource)

Stem 1 — Classic presentation. Map symptoms to mechanism; name the first investigation and first treatment step with dose/route if drug therapy is standard.[1]

Stem 2 — Unstable / complicated. List red flags that force immediate resuscitation, theatre, ICU, antidote or reperfusion — and what you do in the first 15 minutes.[1]

Stem 3 — Atypical group. Elderly, pregnancy, child or immunocompromised: how presentation and thresholds change.[1]

Stem 4 — Differential trap. Name the three closest mimics and one discriminator for each.[1]

Stem 5 — Disposition. Who goes home with safety-netting, who is admitted, who needs HDU/ICU/theatre, and what follow-up is mandatory.[1]

Rapid viva checklist

1. Definition + classification
2. Pathophysiology chain
3. Bedside signs / criteria
4. Score with exact components (if any)
5. Emergency bundle
6. Definitive therapy with doses
7. Complications of disease and of treatment
8. Special populations
9. Guideline/trial name if classic
10. Three exam traps[1]

Coverage self-check

If you cannot answer any stem above from this page alone, re-read the matching section — the page is intended to be self-sufficient for final-prof and NEET-PG/INICET questions on Functional Dyspepsia.[1]