PGMEE, MRCS, USMLE, MBBS, MD/MS visual cycle

Visual cycle – Simplified

Dr. Sulabh Kumar Shrestha, MS Orthopedics,

11-cis-retinal combines with opsin protein to form rhodopsin. Light stimulates conversion of rhodopsin bound 11-cis-retinal to all-trans-retinol (all-trans-retinol is transported from photoreceptor cells to retinal pigment epithelium), which subsequently dissociates from opsin (bleaching), leading to membrane depolarization and initiation of action potential in photoreceptors in the neural retina. Once in…

PGMEE, MRCS, USMLE, MBBS, MD/MS primary bone tumors and tumor-like lesions

Differential Diagnoses of Bone Tumors : Mnemonic Approach

Epomedicine,

Lytic and Sclerotic Bone Lesions Mnemonic for Solitary lytic lesions: FEGNOMASHIC Fibrous dysplasia Enchondroma Eosinophilic granuloma Giant cell tumor Nonossifying fibroma Osteoblastoma, Osteosarcoma (telangiectatic) Metastases Myeloma Aneursymal bone cyst Simple bone cyst Hyperparathyroidism (brown tumor) Infection Chondroblastoma Chondromyxoid fibroma Mnemonic for Multiple lytic lesions: FEMHI Fibrous dysplasia Eosinophilic granuloma/Enchondroma Metastasis/Mutiple…

Blog defensive medicine

Doctor-Patient mistrust may be expensive to patients

Dr. Sulabh Kumar Shrestha, MS Orthopedics,

The risks of malpractice litigation are proving to be harmful to the US health system; the number of practitioners practicing defensive medicine is increasing. “Defensive medicine” is a practice where a doctor suggests clinical investigations or remedies that do not have to be the best choice for the patient. The main role…

PGMEE, MRCS, USMLE, MBBS, MD/MS type 1 and 2 error

Errors and P-value

Epomedicine,

Statistical hypotheses Null hypothesis (H0): No difference or relation exists; e.g. Treatment A is not better than Treatment B Alternative or research hypothesis (H1): Some difference or relation exists, e.g. Treatment A is better than Treatment B Statistical errors Type I error (alpha): False positive (Falsely rejecting Null-hypothesis; i.e. null…

PGMEE, MRCS, USMLE, MBBS, MD/MS PPV NPV baye

Baye’s theorem derived PPV and NPV

Epomedicine,

Let’s unveil the mathematics behind the relation between: Prevalence (Pre-test probability) Predictive value (Post-test probability) Sensitivity Specificity SYMBOLS: Total screened population = nPrevalence = PSensitivity = SnSpecificity = SpTrue positive = TPTrue negative = TNFalse positive = FPFalse negative = FNWith disease = D+Without disease = D-Positive predictive value =…