Menopause
Definition and Epidemiology Definition Menopause is the permanent physiologic cessation of menses due to loss of ovarian activity determined retrospectively after 12 consecutive months of no menstrual bleeding and low estrogen levels. Epidemiology Physiology Menopause is characterized by a physiologic ↓ in oocytes due to progressive atresia, ultimately leading to a chronic hypoestrogenic state in […]
Lung Cancer
Overview Epidemiology Risk factors Pathophysiology and Classification Pathophysiology Classification scheme 2015 classification Pathology Adenocarcinoma Subtypes: Squamous cell carcinoma Subtypes: Large cell carcinoma Small cell lung carcinoma Large cell neuroendocrine carcinoma Carcinoids Clinical Presentation General symptoms Regional spread Metastasis Paraneoplastic syndrome Diagnosis Chest radiography Computed tomography Follow-up imaging In addition to CT, the following modalities are […]
Cervical Cancer
Epidemiology and Risk Factors Epidemiology Risk factors High-risk human papillomaviruses (hrHPVs, “oncogenic viruses”) are strongly associated with high-grade lesions and progression to invasive cancer. HPV-related: Non–HPV-related: Pathophysiology Human papillomavirus Pathogenesis Pathology of precursor lesions SIL classification: Gross appearance of HSIL: Microscopic appearance: Pathology of invasive carcinomas Gross appearance: Microscopic appearance: Clinical Presentation General Advanced disease […]
Diarrhea
Overview Definition Diarrhea is the passage of ≥ 3 watery or loose stools in 24 hours. Classification Diarrhea can be classified by the duration of symptoms: Additionally, diarrhea may be classified based on the underlying etiology and pathophysiology: Etiology Infectious diarrhea Inflammatory/invasive: Noninflammatory/noninvasive: Risk factors: Noninfectious diarrhea Secretory: Osmotic: Malabsorption: Inflammatory/exudative: Altered motility: Pathophysiology Infectious […]
Hypopituitarism
Overview Definition Hypopituitarism is the condition resulting from inadequate production of pituitary hormones: Epidemiology Etiology Pathophysiology Pituitary gland Loss of pituitary gland function Hormones of anterior pituitary: target organs, function, and effects Hormone Pituitary cell type Target organ Function Decreased production ACTH Corticotroph Adrenal cortex Stimulates: Cortisol Androgen Aldosterone Secondary adrenal insufficiency GH Somatotroph Liver […]
Primary Ovarian Insufficiency
Definition and Epidemiology Definition Primary ovarian insufficiency is the depletion or dysfunction of ovarian follicles resulting in cessation of ovulation and menses. The disorder is accompanied by high levels of FSH prior to age 40. Epidemiology Pathophysiology Normal physiology of hypothalamic–pituitary–ovarian (HPO) axis Hypothalamus: Pituitary: Ovary: Clinical importance of functioning HPO axis in younger women: […]
Squamous Cell Carcinoma (SCC)
Overview Defintion Cutaneous squamous cell carcinoma (cSCC) is a malignant tumor of the skin arising from epidermal keratinocytes. Epidemiology The 2nd most common skin cancer after basal cell carcinoma Accounts for 20% of all nonmelanoma skin cancers Men > women Incidence increases with age. Incidence higher in people with fair skin Risk factors Exposure to […]
Volvulus
Overview Definition A volvulus is the twisting of a segment of bowel on its mesentery, which results in bowel obstruction. Epidemiology Etiology Sigmoid volvulus: Cecal volvulus: Pathophysiology Clinical Presentation Sigmoid volvulus Cecal volvulus Diagnosis History Physical exam Laboratory studies Imaging Management Initial supportive management Sigmoid volvulus Sigmoidoscopy with detorsion: Surgery: Cecal volvulus Prognosis Overall mortality: […]
Osteoporosis
Overview Definition Osteoporosis is a metabolic bone disorder characterized by low bone mass and increased bone fragility. Epidemiology Classification Etiology Primary osteoporosis: Secondary osteoporosis: Pathophysiology Normal bone physiology Pathogenesis of osteoporosis Clinical Presentation Diagnosis History Physical exam Clinical criteria Laboratory studies Dual-energy X-ray absorptiometry (DXA) Management Prevention/lifestyle modifications Indications for pharmacologic treatment in postmenopausal women […]
Osteomalacia and Rickets
Overview Definition Rickets and osteomalacia are disorders of decreased bone mineralization. Rickets affects the cartilage of the epiphyseal growth plates in children, while osteomalacia affects the sites of bone turnover in children and adults. Epidemiology Rickets: Osteomalacia: Etiology Rickets and osteomalacia can be caused by deficiencies in vitamin D, calcium, or phosphorus, or by abnormalities […]