Mechanism of Ethambutol induced optic neuropathy Ethambutol is metabolized to a chelating agent. The chelating agent formed then may impair the function of metal-containing mitochondiral enzymes, such as the copper containing cytochrome-c oxidase of complex IV and the iron containing NADH:Q oxidoreductase of complex I. These mitochondrial respiratory chain play…
Category: PGMEE, MRCS, USMLE, MBBS, MD/MS
Medical knowledge in bullet points with understandable language, simplified images and graspable mnemonics.
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Thoracocentesis : Practical Essentials
Absolute contraindications of thoracocentesis There are no absolute contraindications to diagnostic thoracocentesis. If clinical judgement dictates that the information gained from the pleural fluid analysis may help in diagnosis and therapy, thoracocentesis should be performed. Necessity of an immediate alternative procedure such as open thoracostomy or thoracotomy is the only…
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Gastrinoma (Passaro’s) triangle
Boundaries of Gastrinoma Triangle It is an imaginary triangle formed by 3 points in upper abdomen: Apex: Cystic duct-CBD junction Inferior point: 2nd part duodenum-3rd part duodenum junction Left lateral point: Pancreatic neck-body junction This area is located to the right of Superior Mesenteric Artery (SMA) i.e. Proximal duodenum and…
PGMEE, MRCS, USMLE, MBBS, MD/MS 
MEN syndrome : Mnemonics
MEN syndrome is an autosomal dominant (AD) predisposition to developing multiple endocrine tumors. Mnemonic: MEN are Dominant. Points to remember: MEN I or MEN 1 (Wermer’s syndrome) Mnemonic: 3 X P’s MEN IIA or MEN 2A (Sipple’s syndrome) Mnemonic: 3 X C’s MEN IIB or 2B (MEN III) Mnemonic: 2C 2M…
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Why mild hypomagnesemia causes hyperparathyroidism and severe hypomagnesemia causes hypoparathyroidism?
You must have seen the statement in First Aid that says – low serum magnesium causes increase in Parathyroid hormone secretion and very low serum magnesium causes decrease in Parathyroid hormone secretion. Doesn’t this make you curious? Let’s explore the underlying mechanism in depth. How Calcium and Magnesium Mediated PTH…
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Rib Notching
Normal Rib Notching A small notch near the costo-vertebral joint is normal, so pathologic rib notching is more likely if the notching is more lateral. Types of Pathological Rib Notching 1. Superior rib notching 2. Inferior rib notching (more common) Inferior Rib Notching (Roesler’s sign) Mechanism: Enlargement of one or…
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Internal Carotid Artery – Segments and Branches
7 segments of Internal Carotid Artery We have already discussed a mnemonic to remember the course of Internal Carotid Artery with the help of 2 horizontal “S” under the topic of Circle of Willis. C1 – Cervical segment C2 – Petrous (horizontal) segment C3 – Lacerum segment C4 – Cavernous…
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Gestational Trophoblastic Neoplasia (GTN) : Quick review
Follow-up protocol Post-Evacuation of Molar Pregnancy Weekly hCG measurements until hCG becomes undetectable Once hCG is undetectable, 2 further specimens should be obtained at weekly intervals Then monthly for 6 months and then Every 2 months for a further 6 months Diagnosis of GTN The diagnosis of GTN is made…