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Answers

Question 1: What is A, B, C?

• A — Cervical (Pap) smear: A spatula/brush is used to collect cells from the ectocervix and endocervical canal onto a glass slide (or into liquid). The image shows the wooden spatula and glass slide alongside a cross-section of the cervix being sampled.
• B — Colposcopy: A binocular magnifying instrument (colposcope) that illuminates and magnifies the cervix. Biopsy forceps are used to take targeted biopsies of abnormal areas identified under colposcopic visualization.
• C — Cold cone biopsy (Cervical conization): A large cone-shaped area of tissue is excised around the cervix — both diagnostic and therapeutic. The image shows the cervix viewed through a speculum with the patient in lithotomy position and the cone-shaped excision being performed.

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Question 2: Give the alternative to A (Pap smear), and what is it used for?

• Reduces obscuring blood and mucus artifacts
• Allows co-testing for HPV from the same sample
• Lower unsatisfactory specimen rates
• Can be used for additional molecular testing (e.g., chlamydia, gonorrhoea)

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Question 3: A Pap smear was done for a patient showing HSIL — what is the next step?

1. Visualize the entire transformation zone (TZ) including the squamocolumnar junction (SCJ)
2. Apply acetic acid → identify acetowhite areas (abnormal areas turn white)
3. Take directed biopsies of all abnormal areas
4. Perform endocervical curettage (ECC) if the TZ cannot be fully visualized

Summary algorithm: HSIL on Pap → Colposcopy + biopsy → If unsatisfactory colposcopy or confirmed CIN 2–3 → Cone biopsy / LEEP

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Tuberculosis: Latest Guidelines (2025)

Key Guideline Sources

• WHO Consolidated Guidelines on TB, Module 4: Treatment and Care — April 2025 (most up-to-date, consolidates all prior modules)
• ATS/CDC/ERS/IDSA Clinical Practice Guideline — January 2025 (PMID: 40693952)

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1. Latent TB Infection (LTBI) Treatment

Pyridoxine (vitamin B6) 25–50 mg/day should be co-administered with any isoniazid-containing regimen.

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2. Drug-Susceptible (DS) Active TB — Adults & Adolescents ≥12 yrs

✅ NEW: Preferred 4-Month Regimen (Conditional Recommendation, Moderate Evidence)

Standard 6-Month Regimen (Still acceptable as alternative)

• Cavitary disease on CXR
• Sputum culture still positive at 2 months
• Pyrazinamide not completed in intensive phase

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3. Drug-Susceptible TB — Children (Non-Severe)

NEW: 4-Month Regimen for Children with Non-Severe TB

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4. Drug-Resistant TB (MDR/RR-TB)

🆕 LANDMARK: New WHO April 2025 Recommendation — BDLLfxC (6 months, all-oral)

• Recommended for MDR/RR-TB with or without fluoroquinolone resistance (pre-XDR-TB)
• All-oral, 6 months
• Major improvement over the previous 18–20-month injectable-containing regimens

Pre-XDR / XDR-TB: BPaL or BPaLM (ATS/CDC/ERS/IDSA 2025)

Modified 9-Month All-Oral Regimen (MDR/RR-TB, FQ-susceptible)

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5. Special Situations

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6. Diagnosis (for context)

• Preferred: Xpert MTB/RIF (WHO-recommended rapid diagnostic) — simultaneous TB detection + rifampin resistance
• Smear microscopy, culture (gold standard), IGRA/TST for LTBI
• Drug susceptibility testing (DST) mandatory to guide DR-TB regimens

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1. DS-TB: 4-month rifapentine-moxifloxacin regimen is now a valid alternative to the standard 6-month HRZE
2. MDR/RR-TB: New all-oral 6-month BDLLfxC regimen (WHO April 2025) — landmark change
3. XDR/pre-XDR-TB: BPaL/BPaLM remains the standard
4. LTBI: No changes — 3HP preferred

TACO vs TRALI — Comprehensive Comparison

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TACO — Transfusion-Associated Circulatory Overload

Definition

Pathophysiology

• Excessive transfusion volume → ↑ hydrostatic pressure in pulmonary capillaries → transudative pulmonary edema
• Aggravated by poor cardiac reserve, renal insufficiency

Risk Factors

Clinical Features

• Acute respiratory distress within 6 hours of transfusion
• Hypertension (key distinguisher from TRALI)
• Tachycardia, tachypnea
• S3 gallop, elevated JVP, peripheral oedema
• Bilateral crackles/rales
• Positive fluid balance

Investigations

• CXR: bilateral infiltrates + cardiomegaly, pleural effusions
• ↑ BNP / NT-proBNP (strongly supports TACO)
• PCWP >18 mmHg (elevated)
• Pulmonary edema fluid: transudate (low protein)
• Normal/↑ WBC

Diagnosis (NHSN Criteria) — ≥3 of the following within 6h of transfusion:

1. Acute respiratory distress (new or worsened)
2. Radiographic pulmonary edema
3. Elevated CVP
4. Evidence of left heart failure
5. Elevated BNP
6. Positive fluid balance

Management

1. Stop/slow the transfusion immediately
2. IV diuretics (furosemide) — hallmark treatment; rapid improvement expected
3. Supplemental O₂ / NIV (BiPAP/CPAP)
4. Upright positioning
5. Fluid restriction

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TRALI — Transfusion-Related Acute Lung Injury

Definition

Pathophysiology — "Two-Hit" Model

• Hit 1 (priming): Recipient's neutrophils are primed by underlying illness (sepsis, surgery, shock, smoking)
• Hit 2 (activation): Donor anti-leukocyte antibodies (anti-HLA class I/II, anti-HNA) in transfused product bind to primed neutrophils → neutrophil degranulation → capillary permeability → exudative pulmonary edema
• Multiparous female donors are the most common source (antibodies formed against paternal HLA antigens during pregnancy) — exclusion of multiparous female plasma donors has significantly reduced TRALI incidence

Risk Factors

Clinical Features

• Dramatic sudden onset of respiratory failure during or within 6 hours of transfusion
• Hypotension (key distinguisher from TACO)
• Fever (immune-mediated)
• Severe hypoxia (PaO₂/FiO₂ ≤300)
• No signs of volume overload

Investigations

• CXR: bilateral diffuse infiltrates, no cardiomegaly, no pleural effusions
• PCWP <18 mmHg (normal — no left heart failure)
• Normal/low BNP
• Transient leukopenia (neutrophil sequestration in lungs)
• Pulmonary edema fluid: exudate (high protein)
• Donor testing may reveal anti-HLA or anti-HNA antibodies

TRALI Definition (Delphi Consensus)

• Type I: No ARDS risk factors + acute hypoxia (PaO₂/FiO₂ ≤300 or SpO₂ <90% on RA) + bilateral infiltrates + no LAH + within 6h of transfusion
• Type II: Pre-existing mild ARDS (PaO₂/FiO₂ 200–300) or ARDS risk factor present, but clear respiratory deterioration attributable to transfusion

Management

1. Stop transfusion immediately
2. Supportive care — oxygen, mechanical ventilation if needed
3. Diuretics are NOT effective (not volume overload) and may worsen hypotension
4. Vasopressors if hypotensive
5. Report to blood bank → test donor for anti-HLA/HNA antibodies
6. Discard implicated unit; avoid same donor products

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Side-by-Side Comparison

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Prevention

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Memory hook: TACO = Too much fluid → HYPERtension, treat with diuretics. TRALI = Immune reaction → HYPOtension, no diuretics.

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The Heart — Complete Overview

1. Anatomy & Chambers

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2. Valves

Mnemonic: "Try Pulling My Aorta" (Tricuspid → Pulmonary → Mitral → Aortic, right-to-left flow)

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3. Blood Flow — Dual Circulation

Systemic veins → SVC/IVC → RA → [Tricuspid] → RV → [Pulmonary valve] 
→ Pulmonary artery → Lungs (gas exchange) 
→ Pulmonary veins → LA → [Mitral valve] → LV → [Aortic valve] 
→ Aorta → Systemic circulation

• Right side = low-pressure pulmonary circuit (~25/10 mmHg)
• Left side = high-pressure systemic circuit (~120/80 mmHg)

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4. Cardiac Conduction System

• P wave → atrial depolarization (SA node activity)
• PR interval → AV node delay (0.12–0.20 s)
• QRS → ventricular depolarization (<0.12 s)
• T wave → ventricular repolarization

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5. Coronary Circulation

Left Coronary Artery (LCA)

• Left Anterior Descending (LAD) — "widow maker"
  • Supplies: anterior LV, interventricular septum (2/3), apex
• Left Circumflex (LCx)
  • Supplies: lateral and posterior LV, left atrium

Right Coronary Artery (RCA)

• Supplies: RV, RA, inferior LV, SA node (60%), AV node (85–90%)
• Gives posterior descending artery (PDA) in right-dominant circulation (~85% of people)

Coronary blood flow is predominantly diastolic — the LV compresses its own vessels during systole, so perfusion occurs when the heart relaxes.

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6. Cardiac Physiology

The Cardiac Cycle

Key Parameters

Frank-Starling Law

Determinants of Cardiac Output

• Preload (filling pressure / EDV)
• Afterload (resistance against which heart pumps = SVR)
• Contractility (intrinsic myocardial force)
• Heart rate

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7. Pericardium

• Fibrous pericardium: tough outer layer, anchors heart
• Serous pericardium: visceral (epicardium) + parietal layers with ~20–50 mL pericardial fluid for lubrication
• Pathology: pericarditis (inflammation), cardiac tamponade (fluid compression)

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8. Cardiac Muscle (Myocardium) — Key Features

• Involuntary, striated muscle
• Connected by intercalated discs with gap junctions → functions as a syncytium
• Action potential plateau phase (Phase 2) due to slow Ca²⁺ influx — prolongs contraction, prevents tetany
• Energy: primarily fatty acids (60–70%), glucose, lactate; relies almost entirely on aerobic metabolism
• Capillary density: >3,000/mm² (much higher than skeletal muscle)

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