NEET MDS Lessons
General Medicine
| Virus | Key Info |
|---|---|
| Hepatitis E | Feco-oral spread; pregnancy = high mortality |
| Hepatitis B |
- Perinatal transmission (90%)
- Window phase: HBsAg ↓, anti-HBs ↑
- Infectivity: HBsAg + HBeAg
- First marker post-infection: HBsAg
- IgM anti-HBc = acute infection
- Reverse transcriptase → P gene
| Hepatitis C | Most chronic & linked to liver disease
| Hepatitis A | Prophylaxis: Human IgG
| Hepatitis E | Most epidemic-prone in India
| Councilman bodies | Seen in acute viral hepatitis
🧬 Blood Disorders
- Polycythemia vera: Common cause of Budd – Chiari
- PNH: Rare cause of Budd – Chiari
- Thalassemia & Hemolytic anemia: Lead to unconjugated hyperbilirubinemia
- Anemia: Can cause high-output heart failure
- Hemophilia A: Deficiency of Factor VIII
- ITP vs TTP: ITP = isolated thrombocytopenia; TTP = microangiopathy
🧬 Risk Factors
- Increased homocysteine levels
- Raised lipoprotein(a)
- Nephrotic syndrome increases CAD risk
- Unsaturated fatty acid intake: Protective
- Best probability predictor in elderly: LDL/HDL ratio
⚕️ Diagnosis & Presentation
| Condition | Diagnostic Best Practice |
|---|---|
| Angina pectoris | History |
| Stable angina | Cardiac markers unchanged |
| Acute MI | Tall T wave (earliest ECG sign) |
| MI ≥12 hrs post-onset | Test of choice: Cardiac troponin |
| Prinzmetal’s angina | First-line agent: Nitrates |
| Intraoperative MI | Transesophageal echocardiography |
| Best biomarker of MI | Troponin T |
| WHO MI criteria | Echo not part of official criteria |
🧪 Enzymes & Drugs
- Enzyme ↑ at 4 – 6 hrs, ↓ in 3 – 4 days: CPK
- Stress ECHO agent: Dobutamine
- Intervention of choice: Streptokinase + Heparin
- Thrombolytics window: Within 12 hrs of MI
🚨 Prognosis & Complications
- Day 1: Maximum MI mortality
- Post-MI valvular lesion: Mitral regurgitation
- Best predictor of morbidity: LVEF
- Fatal thrombolysis complication: Intracranial hemorrhage
- LAD artery nicknamed: Widow’s artery
Infection Timeline Post-BMT
Phase I: Pre-engraftment (0-30 days)
- Earliest infection: Herpes Simplex Virus (HSV)
- Other pathogens: Bacteria, Candida, Aspergillus
- Risk factors: Neutropenia, mucositis, central lines
Phase II: Early post-engraftment (30-100 days)
- ~7th week (50 days): Interstitial Pneumonitis peak incidence
- Causes: CMV, Pneumocystis jirovecii, idiopathic
- GVHD: Acute graft-versus-host disease peak
Phase III: Late post-engraftment (>100 days)
- Chronic GVHD: Major concern
- Encapsulated bacteria: Due to functional asplenia
- Varicella-zoster virus: Reactivation common
Specific Infectious Complications
CMV Disease
- Timeline: 30-100 days post-BMT
- High risk: CMV+ recipient or donor
- Manifestations: Pneumonitis, gastroenteritis, retinitis
Interstitial Pneumonitis (IP)
- Peak incidence: ~7th week (50 days) post-BMT
- Types:
- CMV pneumonitis (most common infectious cause)
- Idiopathic IP
- Pneumocystis pneumonia
- Mortality: High, especially CMV pneumonitis
Prophylactic Strategies
- Antibacterial: Fluoroquinolones
- Antifungal: Fluconazole or newer azoles
- Antiviral: Acyclovir for HSV/VZV
- PCP prophylaxis: Trimethoprim-sulfamethoxazole
- CMV monitoring: Pre-emptive therapy based on viral load
GVHD Prevention
- Immunosuppression: Methotrexate + calcineurin inhibitors
- T-cell depletion: In some protocols
- HLA matching: Reduces risk significantly
Full Mouth Debridement (Quirynen)
- Scaling in 2 appointments within 24 hours
- Tongue brushing with 1% chlorhexidine gel
- 0.2% chlorhexidine rinse
- 1% chlorhexidine pocket irrigation
Oral Hygiene Tools
Toothbrush Bristle Diameter:
- Soft: 0.007" (0.2 mm)
- Medium: 0.012" (0.3 mm)
- Hard: 0.014" (0.4 mm)
Brushing Techniques:
- Roll: Modified Stillman
- Circular: Fones
- Vertical: Leonard
- Horizontal: Scrub
Scaling Instruments
- Gracey curettes: Only outer cutting edge
- Universal curettes: Both edges cutting
- Langer curettes: Gracey shank + Universal blade
- Best grasp: Modified pen grasp (tripod effect)
- Scaling angle: 45 – 90°
Ultrasonic Scaling
- Vibration frequency: 18,000 – 50,000 cycles/sec
Stroke Types
- Exploratory: Light feeling (with probes)
- Scaling: Short powerful pull
- Root planing: Moderate to light pull
Junctional Epithelium
The junctional epithelium (JE) is a critical component of the periodontal tissue, playing a vital role in the attachment of the gingiva to the tooth surface. Understanding its structure, function, and development is essential for comprehending periodontal health and disease.
Structure of the Junctional Epithelium
-
Composition:
- The junctional epithelium consists of a collar-like band of stratified squamous non-keratinized epithelium.
- This type of epithelium is designed to provide a barrier while allowing for some flexibility and permeability.
-
Layer Thickness:
- In early life, the junctional epithelium is approximately 3-4 layers thick.
- As a person ages, the number of epithelial layers can increase significantly, reaching 10 to 20 layers in older individuals.
- This increase in thickness may be a response to various factors, including mechanical stress and inflammation.
-
Length:
- The length of the junctional epithelium typically ranges from 0.25 mm to 1.35 mm.
- This length can vary based on individual anatomy and periodontal health.
Development of the Junctional Epithelium
- The junctional epithelium is formed by the confluence of the oral epithelium and the reduced enamel epithelium during the process of tooth eruption.
- This fusion is crucial for establishing the attachment of the gingiva to the tooth surface, creating a seal that helps protect the underlying periodontal tissues from microbial invasion.
Function of the Junctional Epithelium
- Barrier Function: The junctional epithelium serves as a barrier between the oral cavity and the underlying periodontal tissues, helping to prevent the entry of pathogens.
- Attachment: It provides a strong attachment to the tooth surface, which is essential for maintaining periodontal health.
- Regenerative Capacity: The junctional epithelium has a high turnover rate, allowing it to regenerate quickly in response to injury or inflammation.
Clinical Relevance
- Periodontal Disease: Changes in the structure and function of the junctional epithelium can be indicative of periodontal disease. For example, inflammation can lead to increased permeability and loss of attachment.
- Healing and Repair: Understanding the properties of the junctional epithelium is important for developing effective treatments for periodontal disease and for managing healing after periodontal surgery.
| ECG Component | Notes |
|---|---|
| Heart rate | 1500 / RR interval |
| P wave | Atrial depolarization |
| PR interval | Reduced in WPW syndrome |
| QT interval | Shortened in hypercalcemia |
| Hypokalemia | ↑ PR interval + ST depression |
| Acute MI | Earliest sign is Tall T wave |