Category: Fundamentals
Although the posterior circulation is smaller and usually supplies only 20% of the brain, it supplies the brainstem, cerebellum, thalamus, auditory and vestibular centers of the ear, medial temporal lobe, and visual occipital cortex.
Category: Fundamentals
Blood is supplied to the brain by the anterior and posterior circulations. The anterior circulation originates from the carotid system and perfuses 80% of the brain, including the optic nerve, retina and frontoparietal and anterior-temporal lobes.
Category: Fundamentals
When cerebral blood flow is below 10 mL/100 g of brain per minute, membrane failure occurs, with a subsequent increase in the extracellular potassium and intracellular calcium and eventual cell death.
Category: Fundamentals
Normal cerebral blood flow (CBF) is approximately 40 to 60 mL/100 g of brain per minute. When CBF drops below 15 mL/100 g of brain per minute, several physiologic changes occur. The brain loses electrical activity, becoming electrically silent.
Category: Fundamentals
The cerebral vasculature supplies the brain with blood that contains oxygen and glucose necessary for normal brain function. When a stroke occurs, there are alterations in cerebral blood flow and extensive changes in cellular homeostasis.
Category: Fundamentals
TIAs constitute an important warning sign for the future development of cerebral infarction. Nearly 10% of the patients who experience a TIA will experience a stroke within 3 months and one-half of these occur within the first 2 days.
Category: Fundamentals
A transient ischemic attack (TIA) was historically defined as a neurologic deficit with complete resolution within 24 hours. However, a portion of TIA cases have evidence of permanent brain ischemia on neuroimaging.
Category: Fundamentals
A stroke can be defined as any vascular injury that reduces cerebral blood flow (CBF) to a specific region of the brain, retina or spinal cord, causing neurologic impairment. Nearly 90% of all strokes are ischemic in origin.
Category: Fundamentals
Chlamydia is the most commonly reported STD in the United States, with more than 1.4 million cases reported to the CDC in 2013. Approximately 50% of men and 70% of women who are infected with chlamydia are asymptomatic.
Category: Fundamentals
Genital herpes is treated with the antiviral medications acyclovir, famciclovir, or valacyclovir. Antiviral therapy is not curative but has been shown to decrease the duration and severity of symptoms.
Category: Fundamentals
Genital herpes is a lifelong viral infection caused by one of two types of herpes simplex virus (HSV): HSV-1 or HSV-2. Herpes, like other ulcerating STDs, facilitates the transmission and acquisition of HIV.
Category: Fundamentals
The CDC supports expedited partner therapy (EPT) to ensure treatment in sexual partners of patients with gonorrhea or chlamydia. With EPT, the clinician provides patient-delivered treatment for sexual partners without personally evaluating them.
Category: Fundamentals
The BUN level also rises with renal dysfunction but is also influenced by many extrarenal factors. Increased protein intake, GI bleeding and the catabolic effects of fever, trauma, infection, and drugs are common factors.
Category: Fundamentals
Common precipitants of acute tubular necrosis are renal ischemia occurring during surgery or after trauma and sepsis. Other cases occur due to medical illness, usually as a result of antibiotics, radiocontrast or with rhabdomyolysis.
Category: Fundamentals
Acute tubular necrosis refers to a generally reversible deterioration of kidney function associated with a variety of renal insults. The diagnosis is made after prerenal and postrenal causes have been excluded.
Category: Fundamentals
The presence of hematuria, proteinuria or red cell casts is highly suggestive of glomerulonephritis. Conversely, the absence of red cell casts, proteinuria and hematuria usually excludes glomerulonephritis as the cause of AKI.
Category: Fundamentals
Patients who have congestive heart failure or cirrhosis form an important subset of those with prerenal azotemia. These patients often are salt-overloaded and water-overloaded, yet their effective intra-arterial volume is decreased.
