VII. 5. When To See a Doctor

The book's safety layer: the red-flag symptoms that demand urgent care, symptom- and life-stage-specific referral thresholds, the Hungarian care pathways including FMT, and what not to waste money on.

This appendix is the book's safety layer. If any of the red-flag symptoms below appear, immediate medical consult is required — never replaceable by self-directed lifestyle or probiotic experimentation.

D.1 General red flags — immediate medical consult

Urgent — don't wait, don't experiment:

• Blood in stool — fresh red, dark, or black tarry (melena). Any form: urgent gastroenterology or ER.
• Unintentional weight loss — more than 5% body weight in 6 months without goal.
• Nocturnal abdominal pain or diarrhea — wakes you up.
• Persistent fever + abdominal symptom — more than 3 days.
• Acute severe abdominal pain — especially right lower quadrant (appendicitis suspicion), or with vomiting-diarrhea.
• Severe dehydration — dizziness, weak pulse, dry mucous membranes. Especially infants/elderly.

Family history red flags (proactive screening):

• Colorectal cancer in family member under 50 → CRC screening earlier (from 45, or 10 years before the earliest family diagnosis)
• IBD (Crohn's, ulcerative colitis) in direct relative → gastroenterology consult on symptoms
• Celiac disease in direct relative → screening on symptoms

D.2 Symptom-specific referral

A key part of microbiome literacy is recognizing when self-management is no longer the right frame. The subsections below map the most common gastrointestinal complaint patterns and the thresholds beyond which specialist (or emergency) consultation is not optional but required. The categorization is not meant to alarm but to prevent delay — most GI conditions have substantially better prognoses with early recognition.

Chronic diarrhea (>4 weeks)

• GP first step: calprotectin, FIT, H. pylori antigen, basic blood + liver function
• Further step per GP: gastroenterology, dietitian, infectious disease
• If blood, weight loss, or nocturnal symptom: urgent gastroenterology

Chronic constipation (>3 months)

• Lifestyle modification (fiber, hydration, movement) first trial — chapter 4
• Thyroid function check (TSH)
• GP: stimulant laxative or osmotic laxative recommendation
• Consider cancer screening at 50+, with family CRC, or symptom of short duration

IBS-like symptoms (bloating, cramps, alternating bowel)

• GP: workup (calprotectin, celiac screen [TTG-IgA], thyroid)
• Dietitian: FODMAP protocol
• Probiotic trial (subtype-matched, see chapter 11)
• Stress management (chapter 5)
• Consider SIBO breath test (chapter 10)

Chronic bloating

• Food diary — 1 week, identifying food dependencies
• Test for dairy and lactose intolerance (breath test or elimination-rechallenge)
• FODMAP reduction trial (dietitian supervised!)
• SIBO breath test
• Celiac screening (if not done)

Persistent diarrhea after antibiotics (>2 weeks)

• C. difficile test (stool GDH/toxin) — urgent
• Don't immediately start a probiotic; decide based on the test result
• If positive: vancomycin or fidaxomicin; on recurrence, consider FMT

New drug side effect (gastric pain, black stool, severe diarrhea)

• The prescriber immediately — don't discontinue the drug on your own
• In severe cases (bleeding, melena) → urgent

D.3 Life-stage-specific

The same symptom carries different meaning and different urgency across life stages. Diarrhea in a 3-month-old infant, abdominal pain in a pregnant woman, or fever in a 75-year-old immunocompromised patient activate age- and condition-specific thresholds that general adult protocols miss. The subsections below cover four special populations: infants, pregnant women, the elderly, and immunocompromised patients. For each we highlight the warning signs that warrant immediate medical consultation.

Infancy (0–24 months)

Urgent pediatrician:

• Persistent diarrhea (>1 day in infant), especially with fever or lethargy
• Signs of dehydration: dry mucous membranes, reduced urine, fatigue
• Poor weight gain
• Blood in stool
• Continuous vomiting
• High fever (>38.5°C in infant under 3 months = urgent)

Childhood

• Chronic IBS-like symptoms → pediatrician + gastroenterologist
• Growth deficiency → pediatrician + endocrinologist
• Allergic reactions → allergist
• Chronic abdominal pain + family IBD history → gastroenterologist

Pregnancy

• GBS (group B strep) screening — at 35–37 weeks
• Gestational diabetes (OGTT) — at 24–28 weeks
• Any unusual GI symptom → obstetrician (differentiation of GI symptoms in pregnant women is more nuanced)
• Considering probiotic use: only with specialist input, select strains

Old age (65+)

• Unintentional weight loss + fatigue → GP + geriatrician + cancer screening
• Frequent infections + dysbiosis suspicion → GP
• Polypharmacy (5+ drugs): annual pharmacist deprescribing review
• Frailty signs: weakness, fatigue, reduced activity → integrated care

D.4 When you need a dietitian

• Post-IBD-flare dietary rehabilitation — clinical dietitian
• IBS + FODMAP protocol — dietitian supervision mandatory during reintroduction phase
• After celiac diagnosis — gluten-free guidance
• During cancer treatment — chemo-associated mucositis diet
• Gestational diabetes — obstetric dietitian
• Kidney function decline — protein-sodium-potassium tracking
• Pediatric chronic symptomatic diet — pediatric dietitian

D.5 Care pathway

In most healthcare systems, microbiome-relevant care pathways are not always obvious: the hierarchy and referral logic between GP, gastroenterologist, dietitian, and clinical specialists is often confusing. The subsections below map which professional is responsible for which problem, in what order to consult them, and the situations in which private services (e.g., microbiome testing) meaningfully complement public care. The goal: reach a diagnosis faster, with fewer unnecessary loops.

GP (primary care)

• Indirectly responsible for initiating workup
• Can refer: gastroenterology, endocrinology, dietitian, oncology screening
• Public-finance covered in most EU jurisdictions

Gastroenterology consultation

• Public-finance (with referral) or private
• Wait times in public system vary by region
• Private: weeks shorter, costs $50–150/consultation typically
• IBD-specialized centers at major university hospitals

Dietitian

• Public coverage varies by jurisdiction
• Private: $30–80/hour; many quality practitioners
• Clinical dietitian for IBD, oncology, pregnancy often available in hospital primary care

Emergency

• Local emergency number — life threatening (severe bleeding, dehydration, collapse)
• ER — 24/7
• Acute GI bleeding: urgent, don't wait

Microbiota-specific consultation

• MicroBiome Bank consultation (Patay-Bezzegh-Munar team) — see book back cover and microbiomerun.com

FMT (Faecal Microbiota Transplantation) — care pathway

Recurrent C. difficile infection (≥2 episodes) is the clinical indication for FMT in most EU countries. Concrete pathway:

1. GP or infectious disease ward: diagnosis (stool GDH/toxin test), first-line treatment (vancomycin or fidaxomicin)
2. Upon recurrence: treating gastroenterologist refers to FMT service
3. FMT centers (typical EU access): major university hospitals — exact contact via treating physician
4. Procedure: screened donor stool suspension, via colonoscopy or nasogastric tube, with hospital admission
5. Cost: with clinical indication, insurance-covered in most EU countries. Other indication (UC, IBS) not financed outside clinical trial
6. Success rate: >85% after first FMT
7. Follow-up: clinical re-evaluation at 4–8 weeks

Don't do: DIY-FMT based on internet protocols. Since the 2019 ESBL E. coli FDA warning, donor screening is strict; serious infection and safety risks are real.

Psychological support pathway

Chronic GI disease, new diagnosis, or caregiver burnout often causes as much trouble as the disease itself. Options to consider:

When to involve a psychologist/psychiatrist:

• Sleep disturbance, appetite disturbance, loss of interest persisting beyond 4–6 weeks after new diagnosis
• Persistent anxiety or depression development (e.g. 25–30% of IBD patients)
• IBS symptoms together with psychosocial stress (dual lever)
• Suspected eating disorder (especially related to TRE or "cleansing" diet)
• Caregiver burnout (elderly parent caregiver, chronic pediatric patient caregiver)

Typical options:

• Psychological consultation (insurance-covered with referral, or private €40–80/hour in EU context)
• Psychiatric specialty clinic (covered by mandatory health insurance)
• Patient group: local IBD groups, online communities
• Cognitive behavioral therapy (CBT-I for insomnia, traditional CBT for anxiety/depression)

Microbiome aspect: chronic anxiety and depression themselves cause microbiome shifts via the HPA axis (chapter 5). Psychological support thus has indirect microbiome benefit — not "luxury" but clinical investment.

D.6 What not to do

• Don't discontinue prescribed medication on your own initiative, for microbiome reasons
• Don't start FMT for indications other than C. difficile outside a clinical trial
• Don't pay for "autism" or "Parkinson's" microbiome tests — clinical evidence doesn't support them
• Don't do "colon cleansing" — harmful microbiome-wise
• Don't fall into "detox" market traps — not justified microbiota-, liver-, or kidney-wise
• Don't request "microbiome testing" without symptoms if the price doesn't fit targeted clinical testing

D.7 When to try at home first (and only see a doctor if no improvement)

For some mild symptoms, a 2–4 week self-trial with lifestyle levers is reasonable before seeing a doctor:

• Mild-moderate bloating after meals — chapter 4 (FODMAP reduction trial)
• Occasional sleep deficit — chapter 5 sleep hygiene
• Moderate stress — chapter 5 stress management
• Mild constipation — chapter 4 fiber increase
• Mild heartburn — meal timing, reducing coffee/spicy

If after 2–4 weeks no improvement, or WORSENING: see a doctor.

Summary

Never ignore red flags. The microbiome strategy serves maintenance of good health and adjunct support, not disease treatment. Knowing when a doctor is needed is as important as knowing what you can eat or drink.