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Obstetric Questions - Topic-Wise Answers

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TOPIC 1: Obstetric History Taking

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Q1. What are the steps involved in comprehensive obstetric history taking?

• Name, age, parity, gestational age

• Routine antenatal visit, bleeding, pain, loss of fluid, reduced fetal movement, etc.

• Last Menstrual Period (LMP) - first day
• Expected Date of Delivery (EDD)
• Gestational age in weeks
• Symptoms: nausea, vomiting, bleeding, leaking, pain, fetal movements

• Total number of pregnancies (gravidity)
• Parity (live births, preterm, abortion, living children) - use GTPAL format
  • G = Gravida, T = Term, P = Preterm, A = Abortus, L = Living children
• Each pregnancy: year, outcome, gestational age at delivery, mode of delivery, birth weight, complications
• Any history of: Caesarean section, instrumental delivery, perineal tears, PPH, IUFD, congenital anomalies

• Age at menarche, cycle regularity
• LMP, contraceptive use
• STIs, fibroids, ovarian cysts, previous pelvic surgery
• Pap smear results

• Hypertension, diabetes, renal disease, cardiac disease, epilepsy, asthma, thyroid disease
• Blood transfusions, TB, malaria

• Previous abdominal or pelvic surgery, anaesthetic complications

• Twins, genetic disorders, hypertension, diabetes, congenital anomalies

• Marital status, occupation, education level, alcohol, smoking, drugs
• Partner's health, domestic support

• Current medications including traditional remedies
• Drug allergies

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Q2. Different areas of history taking and their specific relevance in antenatal patients

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TOPIC 2: Obstetric Physical Examination

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Q3. Which assessments make up the obstetric physical examination?

• General appearance, nutritional status, pallor, jaundice, oedema (facial, pedal), cyanosis
• Vital signs: BP, pulse, temperature, respiratory rate, weight, height (calculate BMI)
• Lymph nodes, thyroid
• Breast examination

• Inspection
• Fundal height measurement
• Leopold's manoeuvres (four abdominal palpations)
• Auscultation of fetal heart

• Speculum examination: cervix, vaginal discharge, bleeding
• Digital vaginal examination: cervical dilatation, effacement, station, membrane status

• Urine dipstick (protein, glucose, leukocytes)
• Blood pressure recording

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Q4. Observations in obstetric examination and steps of each examination

1. Shape and size of abdomen - consistent with gestational age?
2. Linea nigra, striae gravidarum
3. Scars from previous surgery
4. Fetal movements visible?
5. Uterine contractions visible?

1. Empty bladder
2. Patient in supine position, knees slightly flexed
3. Locate fundus by palpation
4. Measure from upper border of symphysis pubis to top of fundus with tape measure
5. In cm: roughly equals gestational age in weeks after 20 weeks (McDonald's rule)

• Use Pinard stethoscope or Doppler
• Best heard over fetal back
• Normal fetal heart rate: 110-160 bpm
• Count for 1 full minute

1. Position patient (dorsal/lithotomy)
2. Aseptic technique
3. Inspect vulva and perineum
4. Introduce 2 fingers gently
5. Assess: cervical position, consistency, effacement (%), dilatation (cm 0-10), membranes intact/ruptured, presenting part, station (in relation to ischial spines), moulding and caput

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TOPIC 3: Obstetric Investigations

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Q5. Common obstetric investigations and their indications

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TOPIC 4: Signs, Symptoms, and Diagnosis of Early Pregnancy

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Q6. Signs and symptoms of early pregnancy

• Amenorrhoea - absence of expected menstrual period (most common first symptom)
• Nausea and vomiting - especially morning sickness (peaks 6-12 weeks)
• Breast tenderness and enlargement - from week 4 onwards
• Urinary frequency - growing uterus pressing on bladder
• Fatigue and lethargy
• Food cravings or aversions (pica)
• Quickening - first fetal movements (16-20 weeks; earlier in multigravidae)
• Leukorrhoea - increased vaginal discharge

• Chadwick's sign - bluish/violet discolouration of vagina and cervix (from ~6 weeks)
• Goodell's sign - softening of cervix (from ~6 weeks)
• Hegar's sign - softening of uterine isthmus (6-8 weeks)
• Uterine enlargement - palpable above symphysis pubis from 12 weeks
• Positive urine pregnancy test
• Breast changes: Montgomery's tubercles enlarge, areola darkens

• Ballottement - fetal pole rebounds on palpation (~16-28 weeks)
• Fetal heart sounds heard on Doppler from 10-12 weeks; Pinard from 20 weeks
• Fundal height measurable and corresponding to weeks

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Q7. Investigations confirming pregnancy diagnosis and timing

• A single positive urine hCG only confirms pregnancy, not viability - USS is needed to confirm intrauterine location and cardiac activity
• A quantitative serum hCG combined with USS is used to diagnose ectopic pregnancy
• hCG should rise by at least 53-66% in 48 hours to suggest a viable intrauterine pregnancy

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TOPIC 5: Calculation of Gestation and EDD

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Q8. How to calculate gestation period and EDD; precautions in calculation

• Formula: EDD = LMP + 9 months + 7 days (or LMP - 3 months + 7 days + 1 year)
• Example: LMP = 1 January 2024 → EDD = 8 October 2024
• Based on: 280-day (40-week) gestation from LMP, assuming a regular 28-day cycle

• Count completed weeks from first day of LMP to current date
• E.g., LMP = 4 weeks ago → 4 weeks gestation

• Crown-Rump Length (CRL) - most accurate, done at 6-13 weeks (±3-5 days accuracy)
• Biparietal diameter (BPD), head circumference, femur length used at 14-20 weeks (±1 week accuracy)
• After 28 weeks, USS accuracy decreases (±3 weeks)

• Rough guide: fundus at symphysis pubis ≈ 12 weeks; umbilicus ≈ 20-22 weeks; xiphisternum ≈ 36-38 weeks

1. Irregular menstrual cycles - Naegele's rule assumes a 28-day cycle; adjust if cycle is longer or shorter
2. Uncertain LMP - patient may not remember exact date; use USS for dating
3. Oral contraceptive pill use - ovulation may be delayed after stopping OCP; LMP may be unreliable
4. First-trimester bleeding - may mimic a period and cause incorrect dating
5. IUFD or missed abortion - fetal size smaller than expected
6. Multiple pregnancy - individual fetal measurements may not reflect true gestational age
7. Racial and genetic variation - fetal biometric parameters vary
8. Prefer USS dating if discrepancy >7 days in first trimester or >10-14 days in second trimester between LMP-based and USS-based EDD

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TOPIC 6: Physiological Changes During Pregnancy

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Q9. Physiological changes in the mother during pregnancy

• Blood volume: +35%; Plasma volume: +55% (dilutional anaemia)
• Cardiac output: +40% (peaks at 28-32 weeks)
• Stroke volume: +30%; Heart rate: +20 bpm
• Systolic BP decreases slightly (-5%); Diastolic BP decreases more (-15%)
• Peripheral vascular resistance decreases (-15%)
• Compression of inferior vena cava by gravid uterus in supine position → supine hypotensive syndrome (always nurse in left lateral tilt)

• Oxygen consumption: +20-50%
• Minute ventilation: +50%; Tidal volume: +40%; Respiratory rate: +15%
• Functional residual capacity (FRC): -20% (diaphragm pushed up by uterus)
• PaO₂ increases (+10%); PaCO₂ decreases (-15%) → respiratory alkalosis compensated by metabolic acidosis
• HCO₃⁻ decreases (-15%) - compensatory
• Airway resistance decreases (-35%) - mucosal oedema, use smaller ETT if intubating
• Risk of hypoxia during apnoea (desaturates faster)

• Haemoglobin decreases (-20%) due to dilution - physiological anaemia
• Platelets slightly decrease (-10%)
• Coagulation factors increase (+30-250%) → hypercoagulable state → risk of DVT/PE
• Fibrinogen increases - ESR rises
• WBC increases (leucocytosis up to 15,000 in labour)

• GFR increases +50% → serum creatinine and urea appear lower than normal
• Glycosuria may occur at normal blood glucose levels
• Ureteric dilation (progesterone effect) → increased UTI risk
• Urinary frequency in first and third trimester

• Gastric emptying delayed; lower oesophageal sphincter tone reduced → heartburn, increased aspiration risk
• Nausea & vomiting in first trimester (due to hCG and progesterone)
• Constipation (progesterone slows peristalsis)
• Haemorrhoids (constipation + increased pelvic venous pressure)

• Ligament laxity (relaxin hormone) → low back pain, pelvic girdle pain, sciatica
• Centre of gravity shifts → lordosis

• Striae gravidarum (stretch marks)
• Linea nigra, chloasma (mask of pregnancy) - due to MSH hormone
• Palmar erythema, spider naevi (oestrogen effect)

• Insulin resistance increases in second half of pregnancy (HPL/hCS) → gestational diabetes
• Thyroid enlarges; total T3 and T4 increase but free levels remain near normal
• Prolactin increases for lactation preparation

• MAC (minimum alveolar concentration) for anaesthetic agents decreases by 40%
• Increased sensitivity to local anaesthetics

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TOPIC 7: Uterine and Placental Blood Supply

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Q10. Uterine/placental blood supply in pregnancy vs. normal; characteristics of uterine arterioles in pregnancy

• Uterus receives blood mainly from uterine arteries (branches of internal iliac/hypogastric artery) and ovarian arteries
• In non-pregnant state: uterine blood flow is approximately 50-100 mL/min
• The spiral arterioles are thick-walled, muscular, vasoconstriction-capable vessels

• Uterine blood flow increases dramatically to ~750-1000 mL/min at term (10-15x increase)
• This represents ~10-12% of cardiac output at term
• Blood flow increases as placenta grows and progesterone/oestrogen cause uterine vasodilation

• In normal pregnancy, trophoblast cells (extravillous trophoblasts) invade the spiral arterioles in two waves:
  • 1st wave (6-10 weeks): decidual portion of spiral arteries
  • 2nd wave (14-18 weeks): myometrial portion of spiral arteries
• This invasion destroys the muscular and elastic wall of the spiral arterioles
• The vessels are converted from narrow, high-resistance, vasoconstrictive vessels into wide, low-resistance, high-flow uteroplacental vessels that cannot vasoconstrict
• This makes them unresponsive to vasoconstrictor agents and ensures constant blood flow to the placenta

• Large diameter, thin walls (no smooth muscle)
• Low resistance, high flow
• Cannot autoregulate - passive conduits
• Maintain intervillous space perfusion

• The 2nd wave of trophoblast invasion FAILS
• Spiral arterioles retain their muscular walls and remain narrow/vasoconstrictive
• This leads to reduced placental perfusion → placental ischaemia → release of anti-angiogenic factors (sFlt-1, soluble endoglin) → maternal hypertension and proteinuria

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TOPIC 8: Preconception Counselling

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Q11. Health education and counselling for a patient who is not yet pregnant but wants to conceive

• Achieve healthy BMI (18.5-24.9)
• Stop smoking, alcohol, and recreational drugs
• Avoid teratogenic medications (e.g., ACE inhibitors, warfarin, valproate, isotretinoin) and switch to pregnancy-safe alternatives
• Optimise management of chronic diseases (diabetes - HbA1c <6.5% before conception; epilepsy - review anticonvulsants; hypertension - switch to methyldopa/labetalol/nifedipine)

• 0.4 mg/day starting at least 1 month before conception and continuing to 12 weeks gestation (reduces neural tube defects by 70%)
• 5 mg/day if previous NTD baby, anti-epileptic drugs, obesity, or diabetes

• Confirm rubella immunity (MMR vaccine if not immune - wait 1 month before conceiving)
• Hepatitis B vaccination
• Varicella if non-immune

• Iron-rich diet; iodine supplementation in iodine-deficient areas
• Avoid: undercooked meat, soft cheese, raw fish (Listeria, Toxoplasma risk)
• Avoid vitamin A excess (teratogenic)

• Explain fertile window: ovulation occurs approximately day 14 of a 28-day cycle
• Cervical mucus changes, BBT method
• Discontinue DMPA (Depo-Provera) well in advance (fertility may take 6-12+ months to return)

• Family history of hereditary conditions
• Advanced maternal age (>35): discuss risks of Down syndrome, aneuploidy
• Consanguinity: increased risk of autosomal recessive conditions

• Avoid workplace toxins (radiation, heavy metals, solvents)
• Domestic safety

• Screen and treat HIV, syphilis, gonorrhoea, chlamydia before pregnancy

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TOPIC 9: Focused Antenatal Care

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Q12. Describe focused antenatal care

• Goal-directed, problem-solving approach
• Each visit has a specific purpose
• Minimum of 4 visits (WHO 2002 model) or 8 contacts (updated 2016 WHO model) for low-risk women

1. Clinical assessment - history, physical exam, BP, weight, fundal height, FHR, urinalysis
2. Screening and treatment - anaemia, malaria (in endemic areas), syphilis, HIV, pre-eclampsia, GDM
3. Preventive interventions - TT vaccine, iron & folate, IPTp (intermittent preventive treatment for malaria), LLIN (insecticide-treated nets)
4. Health education - nutrition, danger signs, birth preparedness, breastfeeding
5. Birth preparedness and complication readiness (BPCR) - identify where to deliver, transport, blood donors

• More efficient use of healthcare resources
• Reduces overcrowding at clinics
• Ensures every visit is meaningful and evidence-based
• Equivalent maternal/perinatal outcomes to traditional frequent visit models for low-risk women

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TOPIC 10: Health Education and Counselling for Antenatal Patients

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Q13. Important aspects of health education and counselling for antenatal patients

• Increase caloric intake by ~300 kcal/day
• Iron-rich foods (red meat, legumes, leafy vegetables)
• Calcium-rich foods (dairy, fortified foods)
• Folic acid supplementation (continue until 12 weeks)
• Avoid: alcohol, raw meat, unpasteurised cheese, excess vitamin A, caffeine >200mg/day

• Daily oral ferrous sulphate (200mg elemental iron) + folic acid (5mg in LMIC settings)

• Vaginal bleeding at any gestation
• Severe headache, blurred vision, facial oedema (pre-eclampsia)
• Epigastric pain
• Fever
• Reduced or absent fetal movements
• Leaking liquor
• Convulsions
• Severe abdominal pain

• Mother should feel movements from ~18-20 weeks (later for primigravidae)
• Reduced movements require urgent assessment
• Kick count: expectation of >10 movements in 2 hours

• Malaria prevention: ITNs (insecticide-treated nets), IPTp
• HIV: PMTCT education, ARV adherence
• Hygiene: handwashing, safe food preparation

• Moderate exercise (walking) is safe and beneficial
• Avoid heavy lifting, prolonged standing, contact sports
• Rest in left lateral position after 28 weeks

• Tetanus Toxoid (TT): 2 doses (TT1 and TT2) at least 4 weeks apart
• Influenza vaccine safe in pregnancy

• Plan for place of delivery (skilled attendant)
• Identify transport
• Save money for costs
• Identify blood donor
• Pack maternity bag early

• Regular bathing, dental hygiene (periodontal disease associated with preterm birth)

• No alcohol (fetal alcohol syndrome)
• No smoking (IUGR, preterm birth, placental abruption)
• No recreational drugs

• Regular uterine contractions 5 min apart lasting 30-60 sec
• Show (mucus plug)
• Rupture of membranes

• Encourage exclusive breastfeeding from birth to 6 months
• Discuss latch technique, benefits

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TOPIC 11: Common Complaints of Pregnancy (Normal Changes)

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Q14. Common complaints of pregnancy related to normal anatomical and physiological changes

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Summary: Potential Examination Questions and Answers

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🪱 HELMINTH LIFE CYCLES - FLOWCHART FORMAT

KMTC Level | Simple English | Short Sentences

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HOW TO READ THESE CHARTS

[Stage] ──→ means "leads to" or "becomes"
HOST = the body it lives in
INFECTIVE STAGE = the form that enters humans

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GROUP 1: NEMATODES (Roundworms)

Round body, no segments

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1. ASCARIS LUMBRICOIDES

(Giant Intestinal Roundworm)

ADULT WORM lives in human small intestine
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Lays EGGS → pass out in FAECES
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Eggs fall on CONTAMINATED SOIL
        │
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Eggs become EMBRYONATED (infective) in soil
(takes 2-3 weeks, need warmth & moisture)
        │
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Human SWALLOWS embryonated egg
(through contaminated food, water, dirty hands)
        │
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Egg HATCHES in small intestine → LARVA
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Larva PENETRATES gut wall → enters BLOOD
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Blood carries larva to LIVER → then LUNGS
(this causes Löffler's syndrome - cough, eosinophilia)
        │
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Larva travels up TRACHEA → swallowed again
        │
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Larva reaches SMALL INTESTINE → matures to ADULT WORM
        │
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CYCLE REPEATS (cycle takes ~2-3 months)

• Only ONE host (human)
• No intermediate host
• Lives 1-2 years in intestine
• Treatment: Albendazole or Mebendazole

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2. HOOKWORM

(Necator americanus / Ancylostoma duodenale)

ADULT WORM attaches to human small intestine
(sucks blood → causes anaemia)
        │
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Lays EGGS → pass out in FAECES
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Eggs hatch in WARM MOIST SOIL
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→ RHABDITIFORM larva (Stage 1 - feeds in soil)
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→ FILARIFORM larva (Stage 3 - infective, does NOT feed)
        │
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Human walks BAREFOOT on soil
→ Larva PENETRATES SKIN of feet
(causes "ground itch" / creeping eruption)
        │
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Larva enters BLOOD → travels to LUNGS
        │
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Larva goes up TRACHEA → swallowed
        │
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Larva reaches SMALL INTESTINE
→ Matures to ADULT WORM
        │
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CYCLE REPEATS

• Ancylostoma can ALSO be swallowed (oral route)
• Main effect: IRON DEFICIENCY ANAEMIA (blood sucker)
• Prevention: wear shoes!
• Treatment: Albendazole / Mebendazole

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3. STRONGYLOIDES STERCORALIS

(Threadworm - UNIQUE: can autoinfect!)

ADULT FEMALE lives in human small intestine wall
(no male worm in gut - females reproduce by parthenogenesis)
        │
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Lays EGGS → hatch inside gut → RHABDITIFORM larvae
        │
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Larvae pass out in FAECES into SOIL

        ┌──────────────────┬──────────────────────┐
        ▼                  ▼                      ▼
  FREE-LIVING         DIRECT CYCLE          AUTOINFECTION
  CYCLE in soil       in soil               (UNIQUE to Strongyloides)
  (adults mate,       Rhabditiform          Larvae become filariform
  produce larvae)     → Filariform          INSIDE the gut/perianal skin
        │              larva                → penetrate intestinal wall
        ▼                  │                or skin around anus
  Filariform larva         │                → reinfect same person
  penetrates skin          │                (can persist for decades!)
        └──────────────────┘
                │
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        Larva → BLOOD → LUNGS
                │
                ▼
        Up TRACHEA → swallowed
                │
                ▼
        SMALL INTESTINE → Adult female
                │
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        CYCLE REPEATS

• AUTOINFECTION is the hallmark - unique among nematodes
• In immunocompromised patients → hyperinfection syndrome (life-threatening)
• Treatment: Ivermectin (drug of choice)

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4. ENTEROBIUS VERMICULARIS

(Pinworm / Threadworm / Seat worm)

ADULT WORMS live in human large intestine (caecum)
        │
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At NIGHT, female migrates to PERIANAL REGION
→ Lays THOUSANDS of eggs on perianal skin
        │
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Child SCRATCHES bottom
→ Eggs get under FINGERNAILS
        │
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Child touches MOUTH → swallows eggs
(autoinfection = reinfects themselves)
OR eggs spread to bedding, clothing
→ other family members swallow eggs
        │
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Eggs HATCH in small intestine
        │
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Larvae migrate to LARGE INTESTINE
→ Mature to ADULT WORMS
        │
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CYCLE REPEATS (2-4 weeks)

• Main symptom: PERIANAL ITCHING at night
• Diagnosis: Scotch tape test (cellophane tape pressed on perianal skin in morning)
• Treat entire family at once
• Treatment: Mebendazole or Albendazole (single dose, repeat after 2 weeks)

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5. TRICHURIS TRICHIURA

(Whipworm)

ADULT WORM lives in human LARGE INTESTINE (caecum/colon)
(anterior end buried in intestinal wall)
        │
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Lays EGGS → pass out in FAECES
        │
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Eggs mature in SOIL (2-4 weeks)
→ Become EMBRYONATED (infective eggs)
        │
        ▼
Human SWALLOWS embryonated eggs
(contaminated food, water, soil-to-mouth)
        │
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Eggs HATCH in SMALL INTESTINE
→ Larvae mature in large intestine
→ Adult worms (no lung migration!)
        │
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CYCLE REPEATS

• NO lung migration (unlike Ascaris and hookworm)
• Heavy infection → rectal prolapse (especially children)
• Treatment: Albendazole or Mebendazole

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6. WUCHERERIA BANCROFTI

(Filarial Worm - causes Lymphatic Filariasis / Elephantiasis)

ADULT WORMS live in human LYMPHATIC VESSELS
(cause lymphatic blockage → elephantiasis)
        │
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Adult female releases MICROFILARIAE into BLOOD
(microfilariae appear in blood at NIGHT = nocturnal periodicity)
        │
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MOSQUITO (Culex sp.) bites human at night
→ Sucks up MICROFILARIAE with blood
        │
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Inside mosquito, microfilariae develop:
→ L1 larva → L2 larva → L3 larva (infective stage)
(takes ~2 weeks in mosquito thoracic muscles)
        │
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Mosquito bites ANOTHER HUMAN
→ L3 larvae deposited on skin at bite site
→ Larvae enter skin through bite wound
        │
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L3 larvae travel to LYMPHATIC VESSELS
→ Develop to L4 → ADULT WORMS (takes ~1 year)
        │
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CYCLE REPEATS

• TWO hosts: Human (definitive) + Mosquito (intermediate/vector)
• Nocturnal periodicity - microfilariae peak in blood at night (when Culex mosquito bites)
• Diagnosis: blood film at night, or antigen test
• Treatment: Diethylcarbamazine (DEC) + Albendazole

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7. ONCHOCERCA VOLVULUS

(River Blindness)

ADULT WORMS live in SUBCUTANEOUS NODULES in human skin
        │
        ▼
Female releases MICROFILARIAE
→ Microfilariae migrate through SKIN and into EYES
(cause skin rash and BLINDNESS)
        │
        ▼
BLACKFLY (Simulium sp.) bites human near fast-flowing rivers
→ Sucks up MICROFILARIAE from skin
        │
        ▼
Inside blackfly, microfilariae develop:
→ L1 → L2 → L3 larva (infective)
(takes ~1-2 weeks)
        │
        ▼
Blackfly bites another HUMAN
→ L3 larvae enter skin
→ Develop to ADULT WORMS in subcutaneous tissue
→ Form NODULES (onchocercomata)
        │
        ▼
CYCLE REPEATS

• Vector: Blackfly (Simulium) - lives near fast rivers
• Blindness caused by dead microfilariae in eyes (immune reaction)
• Treatment: Ivermectin (kills microfilariae)
• "River blindness" - endemic in Africa, Yemen

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GROUP 2: CESTODES (Tapeworms)

Flat, segmented (proglottids), have scolex (head)

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8. TAENIA SOLIUM

(Pork Tapeworm)

━━━━━━━━━━━━ NORMAL CYCLE ━━━━━━━━━━━━

ADULT TAPEWORM lives in HUMAN small intestine
(humans = definitive host)
        │
        ▼
Proglottids (segments) shed in FAECES
→ Contain THOUSANDS of EGGS
        │
        ▼
PIG eats faeces/contaminated grass
→ Swallows EGGS
        │
        ▼
Eggs hatch in pig gut → ONCOSPHERE (hexacanth embryo)
→ Penetrates pig gut wall → enters BLOOD
→ Travels to pig's MUSCLES
→ Develops into CYSTICERCUS (bladder worm)
(pigs = intermediate host)
        │
        ▼
Human EATS undercooked/raw pork
→ Ingests CYSTICERCUS
        │
        ▼
Cysticercus attaches to human small intestine
→ Develops to ADULT TAPEWORM (up to 7 metres!)
        │
        ▼
CYCLE REPEATS

━━━━━━━━━━━━ DANGER: CYSTICERCOSIS ━━━━━━━━━━━━

Human accidentally SWALLOWS T. solium EGGS
(from contaminated food, or from own faeces - autoinfection)
        │
        ▼
Eggs hatch → Oncospheres → enter BLOOD
→ Travel to BRAIN, muscles, eyes, skin
→ Form CYSTICERCI in human tissues
= CYSTICERCOSIS (especially NEUROCYSTICERCOSIS)
→ Causes EPILEPSY/SEIZURES

• Pigs = intermediate host; Humans = definitive host (tapeworm)
• Humans can ALSO become intermediate host if they swallow eggs (cysticercosis)
• Neurocysticercosis = most common cause of adult-onset epilepsy in endemic areas
• Treatment: Praziquantel (tapeworm); Albendazole (cysticercosis)

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9. TAENIA SAGINATA

(Beef Tapeworm)

ADULT TAPEWORM lives in HUMAN small intestine
        │
        ▼
Proglottids shed in FAECES → Eggs in environment
        │
        ▼
COW eats contaminated grass/water
→ Swallows EGGS
        │
        ▼
Eggs hatch → Oncospheres → enter COW blood
→ Travel to cow MUSCLES
→ Develop into CYSTICERCUS BOVIS
(cattle = intermediate host)
        │
        ▼
Human EATS undercooked/raw beef
→ Ingests cysticercus bovis
        │
        ▼
Develops to ADULT TAPEWORM in human intestine
        │
        ▼
CYCLE REPEATS

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10. ECHINOCOCCUS GRANULOSUS

(Hydatid Disease / Dog Tapeworm)

ADULT TAPEWORM (tiny, 3-6mm) lives in DOG intestine
(dogs = definitive host)
        │
        ▼
Eggs pass out in DOG FAECES
→ Contaminate soil, grass, water, dog fur
        │
        ▼
SHEEP/CATTLE eat contaminated grass
→ OR HUMAN accidentally swallows eggs
(from contact with infected dogs, contaminated food)
        │
        ▼
Eggs hatch in INTESTINE → Oncospheres
→ Penetrate gut wall → enter BLOOD
        │
        ▼
Travel to LIVER (most common) or LUNGS, brain, bone
→ Develop into HYDATID CYST
(slowly growing fluid-filled cyst over years)
        │
        ▼
If a DOG eats infected sheep/cattle organs
→ Scolices from cyst develop to ADULT TAPEWORM in dog
        │
        ▼
CYCLE REPEATS

• Dog = definitive host; Sheep/human = intermediate host
• Humans are a DEAD-END host (no further transmission)
• Hydatid cyst in LIVER = most common (right lobe)
• NEVER aspirate blindly - cyst fluid is anaphylactic!
• Treatment: Surgical removal + Albendazole (PAIR procedure)

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GROUP 3: TREMATODES (Flukes)

Flat, leaf-shaped, NOT segmented

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11. SCHISTOSOMA SPP.

(Blood Flukes - causes Bilharzia/Schistosomiasis)

• S. haematobium → urinary tract (haematuria)
• S. mansoni → intestine/liver (portal hypertension)
• S. japonicum → intestine/liver

ADULT WORMS live in human BLOOD VESSELS
(S. haematobium = bladder veins; S. mansoni = mesenteric veins)
        │
        ▼
Female lays EGGS → eggs pass out in URINE (S. haematobium)
or FAECES (S. mansoni, S. japonicum)
        │
        ▼
Eggs reach FRESH WATER
→ Hatch into MIRACIDIUM (free-swimming larva)
        │
        ▼
Miracidium PENETRATES SNAIL
(specific snail for each species)
        │
        ▼
Inside snail, miracidium develops:
→ SPOROCYST → REDIAE → CERCARIAE
(asexual multiplication - thousands of cercariae produced)
        │
        ▼
Cercariae RELEASED into water
→ FREE-SWIMMING for up to 48 hours
        │
        ▼
Human ENTERS WATER
(swimming, bathing, washing, farming)
→ Cercariae PENETRATE INTACT SKIN
(causes "swimmer's itch" / cercarial dermatitis)
        │
        ▼
Cercariae shed tail → become SCHISTOSOMULA
→ Enter BLOOD → travel to LUNGS → LIVER
→ Mature to ADULT WORMS in liver → migrate to veins
        │
        ▼
CYCLE REPEATS

• TWO hosts: Human (definitive) + Freshwater snail (intermediate)
• ONLY helminth that penetrates skin directly from water (no soil larval stage)
• Diagnosis: eggs in urine/stool; serology; rectal snip
• Treatment: Praziquantel (drug of choice)

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12. FASCIOLA HEPATICA

(Liver Fluke - causes Fascioliasis)

ADULT FLUKE lives in human/sheep BILE DUCTS
        │
        ▼
Eggs pass out in FAECES
        │
        ▼
Eggs reach FRESH WATER
→ Hatch into MIRACIDIUM
        │
        ▼
Miracidium PENETRATES SNAIL (Lymnaea snail)
        │
        ▼
Inside snail:
Miracidium → SPOROCYST → REDIAE → CERCARIAE
        │
        ▼
Cercariae RELEASED from snail into water
→ Attach to WATER PLANTS (watercress, water lettuce)
→ Become METACERCARIAE (encysted, infective)
        │
        ▼
Human/sheep EATS contaminated water plants
→ Metacercariae swallowed
        │
        ▼
Metacercariae EXCYST in small intestine
→ Larvae PENETRATE gut wall → enter PERITONEUM
→ PENETRATE LIVER CAPSULE → migrate through liver tissue
(causes acute phase: fever, hepatomegaly, eosinophilia)
        │
        ▼
Larvae enter BILE DUCTS
→ Mature to ADULT FLUKE (chronic phase: biliary disease)
        │
        ▼
CYCLE REPEATS

• Main reservoir: Sheep and cattle
• Human infection from eating raw watercress/water plants
• Treatment: Triclabendazole (drug of choice)

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13. CLONORCHIS SINENSIS

(Chinese Liver Fluke)

ADULT FLUKE lives in human BILE DUCTS
        │
        ▼
Eggs pass out in FAECES
        │
        ▼
Eggs reach FRESH WATER
→ Eaten by SNAIL (Bulinus sp.)
        │
        ▼
Inside snail:
Egg → MIRACIDIUM → SPOROCYST → REDIAE → CERCARIAE
        │
        ▼
Cercariae leave snail → penetrate FRESHWATER FISH
(second intermediate host)
→ Become METACERCARIAE in fish muscles/skin
        │
        ▼
Human EATS raw or undercooked FRESHWATER FISH
→ Metacercariae ingested
        │
        ▼
Metacercariae EXCYST in small intestine
→ Enter BILE DUCTS → mature to ADULT FLUKE
        │
        ▼
CYCLE REPEATS

• THREE hosts: Human + Snail + Fish
• Associated with CHOLANGIOCARCINOMA (bile duct cancer) in chronic infection
• Endemic: East/Southeast Asia
• Treatment: Praziquantel

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QUICK COMPARISON TABLE - ALL HELMINTHS

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KEY DRUGS TO REMEMBER (KMTC)

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MEMORY TRICKS

• "SWALLOWED worms need SOIL" - Ascaris, Hookworm, Trichuris, Whipworm all need soil phase
• "SKIN entry" = Hookworm, Strongyloides, Schistosoma, Onchocerca
• "MOSQUITO bite" = Wuchereria (Culex), Plasmodium (not a helminth but same route)
• "BLACKFLY bite" = Onchocerca (Simulium)
• "RAW MEAT" = Tapeworms (pork = T. solium; beef = T. saginata; fish = Clonorchis)
• "DOG contact" = Echinococcus
• "WATER contact" = Schistosoma
• "WATER PLANTS" = Fasciola
• Autoinfection only in: Strongyloides + Enterobius