Megacolon
Overview Definition and classification Megacolon is a severe dilatation of the colon secondary to impaired motility or an inflammatory process. The condition is classified based on the time course and duration: Acute megacolon Chronic megacolon Epidemiology Exact incidence is unknown. All ages may be affected. Incidence depends on the underlying disease: Congenital aganglionic megacolon: 1 […]
Pneumothorax
Classification and Epidemiology Classification Epidemiology Etiology Traumatic pneumothorax Spontaneous pneumothorax Pathophysiology As air enters the pleural space, which normally has a negative pressure, the elastic recoil in the lung tissues causes either a partial or full lung collapse. Normal physiology Traumatic pneumothorax Spontaneous pneumothorax Tension pneumothorax Clinical Presentation The clinical presentation will depend on the […]
Cardiac Myxoma
Overview Definition Cardiac myxoma is a benign primary tumor of the heart. Epidemiology Etiology Pathophysiology Anatomy and histology Pathophysiologic mechanisms Clinical Presentation Left-side myxomas (approximately 85%) Right-side myxomas (approximately 15%) Constitutional symptoms Diagnosis and Management Physical examination Imaging Transvenous biopsy Management Differential Diagnosis Benign primary cardiac tumors or tumor-like masses Malignant tumors of the heart […]
Diverticular Disease
Overview Definitions Diverticulosis is the presence of multiple diverticula, which are sac-like protrusions of the bowel wall.Diverticular disease is diverticulosis with associated symptoms. Presentation of diverticular diseases Epidemiology Risk factors Pathophysiology Diverticulosis Diverticulitis Types of diverticulitis Diverticulitis is often mild, with mesentery and pericolic fat walling off a small perforation. More extensive disease can lead […]
Primary Sclerosing Cholangitis
Overview Definition Primary sclerosing cholangitis (PSC) is a liver disease characterized by intrahepatic and extrahepatic bile duct inflammation and fibrosis, forming multifocal bile duct strictures. Epidemiology Etiology The cause of primary sclerosing cholangitis (PSC) is unknown, but the disease is associated with: Pathophysiology Clinical Presentation Though many patients are asymptomatic, others may present with: Diagnosis […]
Colorectal Cancer Screening
Overview Colorectal cancer (CRC) Risk factors Screening Rationale Colorectal polyps Benefits of screening Colorectal cancer is generally a preventable cancer when proper screening is performed. Screening: Strategies for Screening Stool-based tests Direct visualization tests Colorectal Cancer Screening for Average-Risk Individuals For an average-risk individual, screening is initiated at 45 years of age. Colorectal Cancer Screening […]
Hyperprolactinemia
Overview Definition Hyperprolactinemia means abnormally high levels of prolactin (PRL) in the blood. Normal PRL levels (may vary according to the lab): < 23.5–25 ng/mL or μg/L for non-pregnant women 80–400 ng/mL or μg/L for pregnant women < 20–21.5 ng/mL or μg/L for men Epidemiology Occurs in < 1% of the general population The most […]
Marfan Syndrome
Epidemiology and Genetics Epidemiology Genetics Clinical Presentation Musculoskeletal Cardiovascular Ocular Other manifestations Diagnosis Table: Systemic score for the revised Ghent criteria (a score ≥ 7 indicates major systemic involvement) Wrist and thumb sign 3 points (both) 1 point (1) Pectus carinatum deformity 2 points Pectus excavatum or chest asymmetry 1 point Hindfoot deformity 2 points […]
The Visual Pathway and Related Disorders
Visual Pathway Visual Fields Anterior to the OC Posterior to the OC Visual Field Defects Unilateral visual field defect Bilateral visual field defects Synopsis Table: Overview of visual field defects Site of lesion Visual field defect Description Possible cause Macula (central retina) Central scotoma Ipsilateral central vision loss Optic neuritis, retrobulbar neuritis Optic nerve Ipsilateral […]
Meckel’s Diverticulum
Overview Definition A Meckel’s diverticulum is a persistent remnant of the omphalomesenteric duct. A Meckel’s diverticulum is a true diverticulum (contains all layers of the bowel wall), arising from the antimesenteric surface of the middle-to-distal ileum. Epidemiology Rule of 2(s) Etiology Pathophysiology and Clinical Presentation Anatomy Pathophysiology Clinical presentation Diagnosis Tests for GI bleeding Tests […]