Genu Valgum
Overview Definition Classification Epidemiology Etiology Bilateral genu valgum: Unilateral genu valgum: Pathophysiology Clinical Presentation History Physical examination Diagnosis Diagnosis is primary based on clinical examination. It is critical to differentiate between normal physiologic genu valgum and a pathologic process. Diagnostic evaluation Imaging X-ray: Management The majority of cases of genu valgum are physiologic and should […]
Knee Dislocation
Overview Definition A dislocation of the knee (tibiofemoral joint) is a rare injury that is important to recognize due to the frequent association with vascular injury and associated risk of limb amputation. These are emergent cases that require immediate reduction and evaluation of the neurovascular system. Epidemiology Etiology Classification Knee dislocations (KDs) can be classified […]
Hydronephrosis
Overview Definition Hydronephrosis is defined as the dilation of the renal pelvis and calyces due to obstruction of urine outflow. Epidemiology Etiology Children: Adults: Pathophysiology Clinical Presentation Clinical manifestations vary depending on the acuity of symptom onset, the degree, and the site of the obstruction. Possible presentations include: Diagnosis The diagnosis of hydronephrosis is made […]
Multiple Sclerosis
Definition and Epidemiology Definition Multiple sclerosis (MS) is an immune-mediated disease resulting in demyelination of the nerves of the CNS. Epidemiology Etiology and Pathophysiology Etiology The exact etiology of MS is unknown. The disease is thought to be multifactorial with genetic predisposition and environmental factors playing contributive roles. Genetic factors: Environmental factors: Pathogenesis Clinical Presentation […]
Horner Syndrome
Overview Definition Horner syndrome, also known as oculosympathetic paresis, is a condition resulting from the interruption of the sympathetic innervation to the eyes. The syndrome is characterized by the classic triad of: Epidemiology Neuroanatomy Horner syndrome can result from a lesion anywhere on the 3-neuron sympathetic pathway supplying the eye. The nerve supply starts from […]
Hepatocellular Carcinoma (HCC) and Liver Metastases
Epidemiology and Etiology Epidemiology Risk factors Cirrhosis: One-third of patients with cirrhosis will develop HCC during their lifetime, including those caused by: Other: Pathogenesis and Pathology Pathogenesis Precursor (premalignant) lesions Hepatocytes show “large-cell change” and “small-cell change” with abnormal architecture (thick trabeculae) microscopically. Hepatocellular carcinoma (HCC) Gross appearance: Microscopic appearance: Clinical Presentation Four possible clinical […]
Platelets: Histology
Overview Definition Platelets are small cell fragments without nuclei, but with a variety of organelles. Platelets are involved in primary hemostasis by adhering to damaged blood vessels and aggregating with one another (platelet plug). Description: Diameter: 2–3 µm Lens-shaped biconvex discoid Normal count: 150,000–450,000 platelets/µL Lifespan: up to 10 days Structure Outer membrane: Receptors facilitate […]
Rare Malignant Liver Tumors
Cholangiocarcinoma Epidemiology and etiology Pathogenesis and risk factors Genetic disorders: Toxins: Cholangiocarcinoma is associated with work in the following industries: Precursor/pre-malignant lesions: Other causes: Pathology Clinical presentation Diagnosis Cholangiocarcinoma may be detected incidentally on imaging or may present with symptoms. Laboratory tests: Imaging: Management Prognosis Hepatoblastoma Epidemiology and etiology Pathogenesis and risk factors Pathology Clinical […]
Cowden Syndrome
Overview Definition Cowden syndrome is an autosomal dominant genodermatosis caused by a mutation in the PTEN gene and characterized by multiple benign hamartomas in any location of the body, mucocutaneous lesions, and macrocephaly. Epidemiology Etiology Pathophysiology Clinical Presentation History Findings Diagnosis Diagnostic criteria Laboratory tests and procedures Lab work-up is directed by the clinical presentation. […]
Familial Juvenile Polyposis
Overview Definition Familial juvenile polyposis, or juvenile polyposis syndrome (JPS), is an autosomal dominant condition characterized by the growth of hamartomatous polyps (juvenile type) in the colon. Epidemiology Etiology Pathophysiology Clinical Presentation History Findings Other manifestations can include: Diagnosis Criteria Diagnosis is made by visualizing > 5 polyps on colonoscopy, multiple juvenile polyps in other […]