Substances acting antagonistically at the M-cholinoceptor are designated parasympatholytics (prototype: the alkaloid atropine; actions shown in red in the panels). Therapeutic use of these agents is complicated by their low organ selectivity.
Approximately 1% to 2% of patients with hypertension will present with a hypertensive emergency, defined as organ dysfunction due to an elevated blood pressure. Importantly, there is no specific blood pressure threshold that identifies a patient with a hypertensive emergency.
Hematemesis is the vomiting of fresh (bright red) or altered ("coffee ground") blood. Melena is the production of black, tarry stools and is due to bleeding from the upper gastrointestinal (GI) tract of more than 100 mL of blood.
Antiadrenergics are drugs capable of lowering transmitter output from sympathetic neurons, i.e., “sympathetic tone”. Their action is hypotensive (indication: hypertension) however, being poorly tolerated, they enjoy only limited therapeutic use.
When an acute inferior myocardial infarction is diagnosed, a right-sided ECG should be obtained to exclude the presence of a concomitant right ventricular myocardial infarction (RVMI). RVMIs can complicate 30% to 50% of acute IMIs.
Beta-Sympatholytics (Beta Blockers) are antagonists of norepiphephrine and epinephrine at β- adrenoceptors; they lack affinity for alpha-receptors. Beta-Blockers protect the heart from the oxygen wasting effect of sympathetic inotropism by blocking cardiac beta-receptors; thus, cardiac work can no longer be augmented above basal levels (the heart is “coasting”). This effect is utilized prophylactically in angina pectoris to prevent myocardial stress that could trigger an ischemic attack.
The goal of a cardiac stress test is to identify the patient with obstructive coronary artery disease (CAD), typically defined as stenosis of 50% or more of a coronary artery on angiography.
Correct classification of stones is important since it will impact treatment decisions and outcome. Urinary stones can be classified according to the following aspects: stone size, stone location, X-ray characteristics of stone, aetiology of stone formation, stone composition (mineralogy), and risk group for recurrent stone formation.
VAD (Ventricular assist device) patients are a special challenge for the EP. Through a careful assessment of the VAD, physical exam, MAP, ECG, and echo, the EP can resuscitate the good VAD that has gone bad.
Infections due to fungi are usually confined to the skin or mucous membranes: local or superficial mycosis. However, in immune deficiency states, internal organs may also be affected: systemic or deep mycosis. Mycoses are most commonly due to dermatophytes, which affect the skin, hair, and nails following external infection.