Most Common HK Primary Care Symptoms

Diarrhoea

Diarrhoea is the passage of three or more loose or watery stools per day, or more frequently than is normal for the individual, resulting from increased intestinal secretion, decreased absorption, or altered motility.

Murtagh Diagnostic Strategy

CategoryDiagnosisKey DiscriminatorCantonese Question / FindingProbability
Probability DiagnosisAcute viral gastroenteritis (norovirus, rotavirus)Acute onset, vomiting prominent, watery, self-limiting, contact Hx「屋企或者公司有冇其他人一齊肚痾嘔?」(Anyone else sick at home/work?)~35%
Food poisoning (bacterial)Acute, epidemiological link to food, incubation period「喺邊度食嘢之後開始痾?食完幾耐先開始?」(Where did you eat? How soon after?)~20%
IBS (if chronic)Chronic, relapsing, pain relieved by defecation, no red flags, no nocturnal symptoms [2]「去完廁所之後肚痛會唔會好啲?半夜有冇痾醒?」(Pain better after stool? Wake at night?)~15%
Serious Not To MissC. difficile colitisRecent antibiotics, hospital exposure, profuse watery/bloody diarrhoea「最近兩個月有冇食過抗生素或者入過醫院?」(Antibiotics or hospitalisation recently?)~2%
Severe dehydration / sepsisHypotension, tachycardia, oliguria, altered consciousnessCheck vitals, skin turgor, mucous membranes~2%
IBD (Crohn's / UC)Chronic bloody diarrhoea, mucus, extraintestinal features, young adult, fecal calprotectin elevated [6]「有冇口腔潰瘍、關節痛、或者眼紅?」(Oral ulcers, joint pain, red eye?)~1%
Colorectal carcinomaAge > 50, weight loss, rectal bleeding, change in bowel habit, iron-deficiency anaemia「大便有冇血?體重有冇輕咗?」(Blood in stool? Weight loss?)~1%
PitfallsLactose intoleranceDiarrhoea after dairy, bloating, very common in Asians [3]「飲完牛奶會唔會肚脹痾肚?」(Bloating/diarrhoea after milk?)~10%
Overflow diarrhoea (faecal impaction)Elderly, paradoxical diarrhoea, constipation Hx「之前有冇便秘呀?」(Any prior constipation?) DRE for faecal loading~3%
Coeliac diseaseSteatorrhoea, weight loss, iron/folate deficiency (less common in HK but testable)「大便有冇好油好臭、浮喺水面?」(Greasy stools that float?)< 1%
MasqueradesDrug-induced diarrhoeaTemporal link to medication (metformin, Mg-antacid, PPI, antibiotics, colchicine) [1]「食咗新藥之後幾時開始痾?」(When did diarrhoea start relative to new medication?)~10%
DepressionLow mood, altered appetite, functional GI symptoms「心情點呀?有冇失去興趣做嘢?」(How's your mood?)~5%
HyperthyroidismWeight loss despite good appetite, tremor, heat intolerance, tachycardia「有冇心跳快、手震、怕熱、食得多但瘦咗?」(Fast heart, tremor, heat intolerance?)~2%
Diabetic autonomic neuropathyKnown DM, nocturnal diarrhoea, alternating with constipation [5]「你有冇糖尿病?半夜會唔會痾?」(Do you have DM? Diarrhoea at night?)~1%
Trying to Tell Me Something?Stress / anxiety / work pressure / fear of cancerHidden agenda beneath somatic complaint「你最擔心係咩呀?有冇嘢令你好大壓力?」(What worries you most? Any big stressors?)~10%

TimeTaskCantonese Key PhrasesWhy It Scores Marks
0:00–0:30Greeting, rapport, set agenda「你好呀,我係今日嘅醫生。請問點稱呼你呀?今日咩事嚟睇醫生呀?」Friendly opening = interpersonal marks. Open question lets patient tell their story.
0:30–1:30HPI – symptom analysis「肚痾咗幾耐呀?一日去幾多次?啲大便係水樣定有血有膿呀?有冇肚痛、嘔吐、發燒呀?」Duration, frequency, character, blood/mucus, associated Sx → builds chief complaint.
1:30–2:30Red flags + focused Hx「體重有冇輕咗?有冇食過唔乾淨嘢、去過旅行、或者有冇人同你一齊肚痾呀?最近有冇食過抗生素或者其他藥?」Red flags (weight loss, blood), epidemiological clues, drug-induced diarrhoea → DDx.
2:30–3:30PMH, DHx, FHx, Social Hx「你以前有冇腸胃病、糖尿病、或者甲狀腺問題呀?食緊咩藥?有冇藥物敏感?屋企人有冇類似嘅病?你做咩工作呀?食飯方面規唔規律?」Masquerades (DM neuropathy, hyperthyroidism, drugs). Social context for biopsychosocial.
3:30–4:30ICE + Hidden agenda「你自己覺得係咩原因呀?(Ideas)你最擔心啲咩?(Concerns)你嚟到最希望醫生可以幫你做啲咩?(Expectations)」ICE = direct exam marks. Hidden agenda: maybe worried about cancer, IBD, or work impact.
4:30–5:15Functional impact + psychosocial「肚痾對你返工/返學有冇影響呀?瞓得好唔好?有冇壓力或者心情唔好?」Biopsychosocial problems. Screen depression/anxiety (masquerade + IBS link).
5:15–6:00Summarise, signpost, safety-net, close「等我總結吓:你肚痾咗X日⋯⋯我有冇漏咗啲咩?我想幫你檢查吓同做啲化驗。如果大便有血、發高燒、或者飲唔到水,就要即刻返嚟。」Summarising scores marks. Safety-net demonstrates safe practice. Checking understanding = empathy.

Uncovering the hidden agenda: Ask 「其實你今日嚟最主要想解決咩問題呀?」 — the RFC is often NOT "diarrhoea" itself but fear of cancer, need for sick leave, travel concern, or worry about a chronic condition like IBD.


DomainEnglish QuestionCantonese QuestionWhy It MattersIf Positive, Think Of
DurationHow long have you had diarrhoea?「肚痾咗幾耐呀?」Acute ( < 4 wk) vs chronic ( ≥ 4 wk) changes entire DDx [1]Chronic → IBS, IBD, malabsorption, Ca colon
Frequency/VolumeHow many times a day? Large or small amounts?「一日去幾多次?每次多唔多?」Large watery = secretory/osmotic; small frequent = inflammatory [1]Large volume → infectious, secretory; small bloody → dysentery, IBD
CharacterWatery, bloody, mucoid, or greasy/oily?「啲大便係水樣、有血、有膿、定係好油好臭?」Differentiates inflammatory vs watery vs fatty diarrhoea [1][2]Blood/mucus → IBD, dysentery; fatty → malabsorption, chronic pancreatitis
Blood in stoolAny blood or dark stools?「有冇血或者黑色大便呀?」RED FLAG: Ca colon, IBD, dysenteryRefer urgently if > 50 y/o + rectal bleeding + weight loss
Abdominal painAny tummy pain? Where?「有冇肚痛?邊度痛呀?」LLQ cramp → inflammatory; periumbilical → IBS; RLQ → Crohn's/appendicitisCramping relieved by defecation → IBS
FeverAny fever?「有冇發燒呀?」Fever → infectious/inflammatory cause≥ 38.5°C = indication for stool C/ST & empirical Abx [1]
VomitingAny vomiting?「有冇嘔呀?」Associated vomiting → viral GE, food poisoning, dehydration riskV+D in < 6 h → preformed toxin (S. aureus, B. cereus) [3]
Weight lossAny weight loss?「體重有冇輕咗?」RED FLAG: Ca colon, IBD, malabsorption, hyperthyroidismSignificant weight loss → urgent referral
Food historyAny raw/undercooked food, eating out, or spoiled food?「最近有冇食過生嘢、街邊嘢食、或者唔新鮮嘅嘢?」Incubation period helps identify pathogen [3]: < 6 h toxin, 8–16 h C. perfringens, > 16 h viral/bacterialRaw oysters → Hep A, Vibrio; undercooked poultry → Campylobacter, Salmonella
TravelAny recent travel?「最近有冇去過旅行呀?」Traveller's diarrhoea (ETEC, Giardia, amoeba) [4]Tropical → parasites, typhoid
Contacts/clusterAnyone else with the same symptoms?「屋企人或者同事有冇一齊肚痾?」Cluster → viral GE outbreak, food poisoningNorovirus outbreaks common in HK
Drug historyAny medications? Antibiotics recently?「食緊咩藥呀?最近有冇食過抗生素?」Drug-induced diarrhoea is a key masquerade [1]: antibiotics → C. difficile; metformin, Mg-antacid, colchicine, PPIRecent Abx → C. difficile (CDAD)
PMHDiabetes? Thyroid problems? Previous bowel disease or surgery?「有冇糖尿病、甲狀腺問題、或者以前有冇腸道病?」DM autonomic neuropathy → nocturnal diarrhoea [5]; hyperthyroidism → chronic watery diarrhoeaDiabetic nocturnal diarrhoea; thyrotoxicosis
AllergyAny drug allergies?「有冇藥物敏感呀?」Safety + exam requirement—
Family historyAny bowel disease or cancer in the family?「屋企人有冇腸癌或者腸炎病史呀?」FHx IBD, colorectal CaFHx + rectal bleeding → urgent colonoscopy
Social/occupationWhat's your job? Any stress?「做咩工作呀?最近壓力大唔大?」IBS strongly linked to stress; food handler → public health implicationsStress + abdominal pain relieved by defecation → IBS
Functional impactHow does this affect your daily life/work?「影響咗你返工/日常生活嗎?」Biopsychosocial assessment—
MoodAny low mood or anxiety?「心情點呀?有冇唔開心或者好緊張?」Depression as masquerade; anxiety worsens IBSDepression can cause altered bowel habit
LactoseDoes milk or dairy make it worse?「飲牛奶或者食奶製品之後會唔會特別痾?」Lactase deficiency: up to 90% of adult Asians [3]Osmotic diarrhoea after dairy → lactose intolerance

Case Report Form Answer Builder

  • Template: "Diarrhoea for [duration]"
  • Must capture: Onset, duration (acute vs chronic), frequency, stool character (watery/bloody/fatty), volume, associated symptoms (pain location, fever, vomiting, weight loss), food/travel/contact Hx, drug Hx, dehydration status, red flags assessed and negative/positive.

  • Likely examples: "Worried about persistent diarrhoea affecting work"; "Concerned about cancer"; "Wants medication to stop diarrhoea"; "Needs sick leave certificate"
  • Best phrasing: Write ONE sentence combining symptom + motivation, e.g. "Patient presents with 5-day diarrhoea causing inability to work, seeking treatment and reassurance that it is not something serious."

Example Wording
Ideas"I think I ate something bad" / "I'm worried it could be cancer" / "Maybe it's stress-related"
Concerns"I'm worried because I saw blood" / "I'm scared of losing weight" / "Worried it won't stop"
Expectations"I want medicine to stop the diarrhoea" / "I want a blood test/colonoscopy" / "I need a sick note"

  • Acute presentation (most common exam scenario): Acute gastroenteritis (viral or bacterial) — supported by acute onset, watery diarrhoea ± vomiting, contact/food Hx, self-limiting course, no red flags.
  • Chronic presentation: IBS — supported by Rome IV criteria (recurrent abdominal pain ≥ 1 day/week in last 3 months, related to defecation, change in frequency/form, no red flags, no nocturnal symptoms).
  • Minimum evidence to write: Duration + stool character + epidemiological context + absence of red flags.

DDxOne Key Discriminator
IBD (UC or Crohn's)Chronic bloody/mucoid diarrhoea + extraintestinal features (oral ulcers, arthritis, eye inflammation)
Drug-induced diarrhoeaTemporal relationship to medication initiation (metformin, antibiotics, PPI, Mg-antacid)
Colorectal carcinomaAge > 50, rectal bleeding, iron-deficiency anaemia, weight loss, change in bowel habit

Alternative DDx if scenario fits: Hyperthyroidism, C. difficile colitis, lactose intolerance, coeliac disease

DomainExample
BiologicalDehydration and electrolyte imbalance from ongoing fluid loss
PsychologicalAnxiety about serious underlying cause (e.g., cancer worry)
Social/FunctionalInability to attend work/school; impact on daily activities and social life

Diagnosis/DDxBest Supporting Physical SignHow to ElicitWhy It Supports This Diagnosis
Acute gastroenteritisDry mucous membranes / reduced skin turgor (signs of dehydration)Inspect oral mucosa, pinch skin on dorsum of handConfirms significant fluid loss from acute diarrhoea; determines need for rehydration
IBSNo reliable physical sign in brief FM stationMild diffuse/LLQ tenderness on palpation (non-specific)Diagnosis is clinical (Rome IV); exam is mainly to exclude red-flag signs. State: "Examination expected to be unremarkable, supporting functional diagnosis"
IBD (UC/Crohn's)Perianal disease (fistula, skin tag, abscess) – especially Crohn's; or oral aphthous ulcersInspect perianal area; inspect oral cavityExtraintestinal/perianal features are characteristic of Crohn's
Colorectal carcinomaPalpable abdominal mass or blood on digital rectal examinationAbdominal palpation (RLQ/LLQ); DREMass or blood on DRE with altered bowel habit strongly suggests malignancy
HyperthyroidismGoitre with lid retraction, tremor, tachycardiaInspect and palpate neck; check pulse; observe for hand tremorThyrotoxic signs explain chronic watery diarrhoea as a systemic cause
C. difficile colitisFever + diffuse abdominal tenderness (may have distension)Vital signs; abdominal palpationRecent antibiotics + fever + tenderness = high suspicion for CDAD

Top Traps That Lose Marks

  1. Forgetting to ask about medications — drug-induced diarrhoea (metformin, antibiotics, PPI, Mg-antacids) is a top masquerade and commonly tested [1].
  2. Not differentiating acute vs chronic — changes the entire differential; always clarify duration first.
  3. Missing red flags then writing IBS as diagnosis — IBS is a diagnosis of EXCLUSION. You must document that you screened for blood, weight loss, nocturnal symptoms, fever, anaemia, family Hx of Ca/IBD.
  4. Writing too many diagnoses instead of ONE main RFC — Q2 asks for ONE reason. Pick the most specific.
  5. Forgetting ICE — marks are given for specific patient-centred phrases, not generic statements.
  6. Not asking about lactose intolerance in an Asian patient — 90% prevalence of lactase deficiency in adult Asians [3].
  7. Ignoring psychosocial domain — Q5b needs at least one psychological AND one social problem.

Must-Not-Miss Red Flags — Urgent Referral

  • Rectal bleeding + weight loss + age > 50 → urgent colonoscopy to r/o colorectal Ca
  • Severe dehydration (altered consciousness, hypotension, oliguria) → A&E for IV rehydration
  • High fever ( ≥ 38.5°C) + bloody diarrhoea → stool C/ST, empirical antibiotics, consider admission [1]
  • Recent antibiotics + profuse diarrhoea → suspect C. difficile, request toxin assay
  • Chronic diarrhoea with nocturnal symptoms, anaemia, raised inflammatory markers → suspect IBD/malignancy, refer for colonoscopy

Safety-net closing line: 「如果你發高燒、大便有血、飲唔到水、或者頭暈企唔穩,就要即刻去急症室。」 (If you develop high fever, blood in stool, can't keep fluids down, or feel dizzy/faint, go to A&E immediately.)


High Yield Summary

What to ASK: Duration (acute vs chronic), stool character (watery/bloody/fatty), food-travel-contact Hx, medications (especially antibiotics, metformin), red flags (blood, weight loss, nocturnal Sx, fever), dairy intolerance, thyroid Sx, DM Hx, stress/mood, ICE, functional impact.

What to WRITE: Chief complaint with duration + frequency + character. ONE clear RFC. Specific ICE. Most likely Dx with minimum 2–3 supporting points. Three DDx each with a discriminator. Biopsychosocial triad. Physical sign = dehydration signs (acute GE) or "unremarkable exam supporting functional diagnosis" (IBS).

What NOT to MISS: Drug-induced diarrhoea, colorectal Ca red flags, C. difficile in post-antibiotic patients, hyperthyroidism as masquerade, lactose intolerance in Asians, and always screen for the hidden agenda.


Active Recall - Family Medicine Clinical Test

[1] Senior notes: Ryan Ho GI.pdf (Section 3.1.3–3.1.4, Acute and Chronic Diarrhoea) [2] Lecture slides: Block A - Chronic diarrhoea_ irritable bowel syndrome and inflammatory bowel disease.pdf [3] Senior notes: Ryan Ho GI.pdf (Section on Lactose intolerance, p.130) [4] Lecture slides: GC 103. Fever after travelling.pdf [5] Senior notes: Block A - Deterioration of eyesight in a diabetic patient_ diabetic complications.pdf (Diabetic autonomic neuropathy — nocturnal diarrhoea) [6] Senior notes: Block A - Gastrointestinal Data Interpretation.pdf (Fecal calprotectin for IBD vs IBS)

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