PAGE 01
/
Cerebrum Notes
|
Edition 2026

UPSC CMS • NEET PG • INICET • RUHS MO
Top ↑

High-Yield Subject Index

Interactive quick-jump reference for core clinical and preclinical concepts

RAPID REVISION

01

Anatomy & Physiology

Triangle of Koch (AV Node Localization)

High Yield

Boundary	Anatomic Structure
Superior / Posterior	Tendon of Todaro (subendocardial fibrous cord)
Inferior	Opening of Coronary Sinus (Thebesian valve)
Anterior / Base	Base of Septal Leaflet of Tricuspid Valve

•

Key Takeaway: AV node resides completely within this triangle. Limbus fossa ovalis does NOT form any boundary.

Cranial Nerve VII (Facial Nerve)

Brainstem Exit: Emerges at the Pontomedullary junction (cerebellopontine angle).
Skull Exit: Enters internal acoustic meatus → exits skull base at Stylomastoid foramen.

Postural Hemodynamics (Supine → Immediate Standing)

Supine Position → Immediate Standing

↓

Venous pooling in lower extremities (gravity) → Preload Decreases

↓

Transient MAP drop → Baroreceptor unloading → Sympathetic surge

↓

Compensatory Heart Rate Increase (Reflex Tachycardia)

PAGE 02
/
Cerebrum Notes

Top ↑

02

Biochemistry

Nitrogen Metabolism & Micronutrients

Urea Biosynthesis Nitrogens: 1st nitrogen from free ammonia (NH4+ via CPS-1); 2nd nitrogen directly from Aspartate. Glutamine serves as systemic nitrogen shuttle.
Vitamin B12 Status: Coenzyme for methylmalonyl-CoA mutase. Deficiency marked by elevated urinary Methylmalonic Acid (MMA). (Folate deficiency features normal MMA).
Enteric Iron Absorption: Vitamin C (Ascorbic acid) reduces ferric (Fe3+) to absorbable ferrous (Fe2+) state for DMT-1 uptake.
Pluripotent Gene Correction: Defective functional enzyme activity in human pluripotent stem cells restored via CRISPR/Cas9-based gene editing.

03

Pathology & Microbiology

Autoimmune Blistering Dermatoses

Feature	Bullous Pemphigoid	Pemphigus Vulgaris
Target Junction	Hemidesmosomes (BMZ)	Desmosomes (Stratum spinosum)
Antigens	BP180 & BP230	Desmoglein 3 & Desmoglein 1
Blister Type	Tense, subepidermal	Flaccid, intraepidermal
Nikolsky Sign	Negative	Positive

High-Yield Pearls

Asthma Airway Remodeling: Orchestrated primarily by Eosinophils driven by Th2 cytokines (IL-4, IL-5, IL-13); damage via Major Basic Protein.
Sickle Cell Anemia (HbSS): Autosomal Recessive. Point mutation (GAG → GTG) substituting valine for glutamic acid at codon 6 of beta-globin.
Prion Pathogenesis: Propagated strictly by conformational Proteinaceous particles (PrPSc) entirely devoid of nucleic acids.
TB Transmission: Spread exclusively via Airborne Droplet Nuclei (1–5 μm) reaching alveolar spaces.
Botulinum Toxin B: Inhibits ACh vesicle fusion via cleavage of Synaptobrevin (VAMP). (Types A & E cleave SNAP-25).

PAGE 03
/
Cerebrum Notes

Top ↑

04

Pharmacology & Therapeutics

Drug Interaction: Carbamazepine & Macrolides

Carbamazepine Maintenance + Co-administration of Erythromycin

↓

Erythromycin acts as a potent CYP3A4 Inhibitor

↓

Hepatic elimination blocked → Rapid accumulation of active parent drug

↓

Acute Toxicity: Ataxia, horizontal nystagmus, diplopia & extreme drowsiness

Gabapentin Pharmacokinetics

Saturable Absorption
Requires L-amino acid transport in gut. Absorption is non-linear and declines with higher single doses.

Zero Hepatic Metabolism
Excreted 100% unchanged in urine. Zero CYP involvement; dose must be titrated in renal impairment.

Insulin Formulations Overview

Class	Agents	Pharmacokinetic Profile
Rapid-Acting	Lispro, Aspart, Glulisine	Onset: 10–15 min \| Peak: 1 hr
Short-Acting	Regular Human Insulin	Onset: 30 min \| Peak: 2–3 hr
Intermediate	NPH (Neutral Protamine Hagedorn)	Duration: 12–18 hr (turbid suspension)
Long-Acting / Basal	Glargine, Detemir, Degludec	Peakless profiles; duration up to 24–42 hr

Clinical Pharmacology Essentials

Pulmonary Arterial Hypertension (PAH): Endothelin receptor antagonists, PDE-5 inhibitors & prostanoids indicated. Beta-blockers contraindicated (cause acute RV failure).
Diabetic Cellulitis (Uncomplicated): Staphylococci & Streptococci predominate. First-line oral regimen: Cephalexin or Amoxicillin-Clavulanate.
Severe Falciparum Malaria: Hyperparasitemia (≥4%), altered mentation, or renal dysfunction → immediate IV Artesunate regimen.
Organophosphate Ingestion: Muscarinic toxidrome (pinpoint pupils, bronchorrhea, shock) → Aggressive IV Atropine until clear lung fields, followed by Pralidoxime.

PAGE 04
/
Cerebrum Notes

Top ↑

05

Forensic Medicine & Toxicology

Post-Mortem Findings & Colors of Lividity

Tache Noire de la Sclérotique: Brownish-black triangular patch on sclera due to exposure, drying, and cellular oxidation when eyelids remain open.
Color Diagnostics in Post-Mortem Lividity:

Cherry Red
Carbon Monoxide (CO)

Brick Red
Cyanide Poisoning

Chocolate Brown
Nitrites & Methemoglobin
Grievous Hurt (IPC 320): Permanent damage or visual loss arising from traumatic corneal opacity meets criteria for grievous hurt.
Calotropis (Madar): Vesicating milky sap applied dermally creates intense pruritus, bullae, and brown artificial contusions (malingering).

06

ENT & Ophthalmology

ENT Points

• Onodi Cell: Clinically critical due to direct contact with the Optic Nerve.
• Haller Cell: Infraorbital ethmoidal cell positioned along the orbital floor.
• Epistaxis Protocol: Pinch anterior nose + tilt forward → gentle clot evacuation under direct vision.
• BPPV: Posterior semicircular canal is the predominant site involved.
• Caloric Test: Laboratory vestibular test, not an unassisted bedside maneuver.

Ophthalmology Points

• CRAO: Painless sudden visual loss; opaque white ischemic retina with a classic Cherry Red Spot.
• WHO Trachomatous Follicular (TF): Presence of ≥ 5 follicles (≥0.5 mm) on the upper tarsal conjunctiva.
• Enlarged Corneal Nerves: Seen in Keratoconus, Leprosy, NF-1, MEN 2B. Absent in Herpes Simplex Keratitis.

PAGE 05
/
Cerebrum Notes

Top ↑

07

Preventive & Social Medicine

Community Health & Systems

Health Education Pedagogy: Demonstration is proven most effective when teaching ORS formulation to community groups.
Communication Barriers: Vaccine refusal stemming from fear of secondary sterility/impotence is classified as a Cultural Barrier.
Committees: Kartar Singh (1973) introduced Multipurpose Workers (MPW); Bhore Committee (1946) laid the framework for Primary Healthcare in India.
PHC Classification: Type B PHC manages ≥ 20 institutional deliveries per month (Type A manages < 20 deliveries/month).
Cold Chain Storage: Walk-in Coolers (+2°C to +8°C) store DPT, Pentavalent, BCG, and Hep B. OPV is stored in deep freezers (-20°C).

08

General Medicine

Clinical Scenarios & Diagnostics

Extradural Hemorrhage: Impact at pterion → rupture of Middle Meningeal Artery → classic lucid interval followed by deterioration.
Persistent Vomiting Derangements: Hypochloremic, Hypokalemic Metabolic Alkalosis with paradoxical aciduria.
Primary Hyperaldosteronism (Conn): Screen hypertension + unprovoked hypokalemia using Plasma Aldosterone to Renin ratio (ARR).
Acute Septic Arthritis: Immediate blood cultures + joint arthrocentesis → prompt empiric IV Vancomycin.
Post-ACS Glycemic Add-on: Empagliflozin (SGLT2i) demonstrates proven reduction in CV mortality and HF hospitalizations.
Austin Flint Murmur: Mid-diastolic low-pitched apical rumble seen in severe Aortic Regurgitation mimicking Mitral Stenosis.
Neurogenic Shock: Interruption of descending sympathetic outflow → Hypotension accompanied by Bradycardia and Warm, dry skin.

PAGE 06
/
Cerebrum Notes

Top ↑

09

Surgery & Clinical Scores

Alvarado Score for Appendicitis (MANTRELS)

MAX SCORE: 10

Symptoms: Migration of pain (1), Anorexia (1), Nausea/Vomiting (1) •
Signs: Tenderness RIF (2), Rebound tenderness (1), Elevated temp (1) •
Labs: Leukocytosis >10,000 (2), Shift of neutrophils to left (1).

Score ≥ 7 strongly correlates with acute appendicitis requiring surgical evaluation.

Surgical Principles

• Feeding Gastrostomy: Wound category is classified as Clean-Contaminated.
• Follicular Thyroid Carcinoma: Hematogenous dissemination is typical; capsular or vascular invasion cannot be identified via FNAC alone.
• Enterocutaneous Fistula: Fistula track length < 2 cm significantly lowers probability of spontaneous closure.

10

OBGYN, Pediatrics, Ortho & Radiology

Obstetrics & Gynecology

• Shoulder Dystocia: McRoberts hyperflexion, Wood’s screw, Rubin, and Zavanelli maneuvers. Ritgen maneuver is NOT used.
• BRCA Mutation Carriers: Annual screening with Mammography + Contrast MRI commencing at age 25–30.

Pediatrics, Ortho & Imaging

• Cephalohematoma: Subperiosteal collection; never crosses cranial suture lines.
• Pediatric Diphtheria: Friable pharyngeal pseudomembrane → Immediate Diphtheria Antitoxin (DAT) + IV Penicillin/Erythromycin.
• Common Peroneal Nerve Palsy: Neck of fibula fractures → Foot drop due to deep peroneal denervation.
• Diagnostics: MRI is modality of choice for Acute Osteomyelitis; Diffusion-Weighted MRI (DWI) for hyperacute cerebral infarction.