Infections are often asymptomatic. In the immuno-compromised host, Strongyloides can progress to a fatal hyperinfection syndrome. Helminths include the roundworms (nematodes), flukes (trematodes), and tapeworms (cestodes). These parasites are large, ranging in size from 1 cm to 10 m, and they often live in the human gastrointestinal tract without causing symptoms.
Tissue And Blood Helminths
Trichinella is a roundworm whose larvae are released from cyst walls in contaminated meat by acid-pepsin digestion in the stomach. Upon entering the small intestine, larvae invade the intestinal microvilli and develop into adult worms.
Filariasis (Wuchereria Bancrofti And Brugia Malayi)
Microfilaria is less common than many parasites, being estimated to infect approximately 120 million people. Several strains of worm can cause this disease. Wuchereria bancrofii is found throughout the tropics, and Brugia malayi is restricted to the southern regions of Asia. A third strain, Brugia timori is found only in Indonesia.
Cardiovascular Infections
Acute endocarditis is life-threatening and often requires surgical intervention. Subacute endocarditis is an indolent disease that can continue for months. Infective endocarditis remains a serious but relatively uncommon problem.
Intravascular Catheter-Related Infections
Can be life-threatening. Often prolong hospital stay, and can be complicated by metastatic lesions and bacterial endocarditis. A 53-year-old white woman was admitted to the hospital with complaints of severe shaking during infusion of her hyperalimentation solution. She had been receiving intravenous hyperalimentation for 16years for a severe dumping syndrome that prevented eating by mouth.
Myocarditis
Fulminant myocarditis can be fatal or lead to chronic congestive heart failure. Most cases are self-limiting and are followed by full recovery The true incidence of myocarditis (inflammation of the heart) is unknown, because most cases are asymptomatic.
Central Nervous System Infections: Spinal Epidural Abscess
Central nervous system infections are fortunately rare, but they are extremely serious. The cerebral cortex and spinal cord are confined within the restricted boundaries of the skull and boney spinal canal. Inflammation and edema therefore have devastating consequences, often leading to tissue infarction that in turn results in permanent neurologic sequelae or death.
Meningitis
Bacterial meningitis remains one of the most feared and dangerous infectious diseases that a physician can encounter. This form of meningitis constitutes a true infectious disease emergency. It is important that the physician quickly make the appropriate diagnosis and initiate antibiotic therapy.
Encephalitis
A 74-year-old white man with a history of chronic steroid use (10 mg prednisone daily) and stage I chronic lymphocytic leukemia presented at the emergency room with confusion and fever. Four days before admission, he complained of being increasingly tired. Two days before admission, he became increasingly lethargic, sleeping on floor.
Central Nervous System Abscess
Brain abscess is an uncommon disease, found in about 1 in 10,000 general hospital admissions. Infection of the cerebral cortex can result from the direct spread of bacteria from another focus of infection (accounts for 20% to 60% of cases) or from hematogenous seeding.