Fungal and parasitic infections of the eye.

The unique structure of the human eye as well as exposure of the eye directly to the environment renders it vulnerable to a number of uncommon infectious diseases caused by fungi and parasites. Host defenses directed against these microorganisms, once anatomical barriers are breached, are often insufficient to prevent loss of vision. Therefore, the timely identification and treatment of the involved microorganisms are paramount. The anatomy of the eye and its surrounding structures is presented with an emphasis upon the association of the anatomy with specific infection of fungi and parasites. For example, filamentous fungal infections of the eye are usually due to penetrating trauma by objects contaminated by vegetable matter of the cornea or globe or, by extension, of infection from adjacent paranasal sinuses. Fungal endophthalmitis and chorioretinitis, on the other hand, are usually the result of antecedent fungemia seeding the ocular tissue. Candida spp. are the most common cause of endogenous endophthalmitis, although initial infection with the dimorphic fungi may lead to infection and scarring of the chorioretina. Contact lens wear is associated with keratitis caused by yeasts, filamentous fungi, and Acanthamoebae spp. Most parasitic infections of the eye, however, arise following bloodborne carriage of the microorganism to the eye or adjacent structures.

Anthrax pneumonia.

Inhalation anthrax is a rare and almost uniformly fatal form of human anthrax caused by the inhalation of spores of Bacillus anthracis. A clue to the diagnosis is provided by taking a work history which will disclose patient exposure to contaminated animal products, most often animal hair and wool used in the textile industry. It is an illness with a biphasic course marked by the presence of a widened mediastinum on chest radiograph and often accompanied by hemorrhagic meningitis. The pathogenesis of this disease as well as the differential diagnosis of inhalation anthrax in the context of other zoonotic pneumonias is discussed. Therapy has been ineffectual probably because it has begun too late, but includes intravenous high dose penicillin G and perhaps vaccination to prevent relapse.

Bronchiolitis following infection in adults and children.

Since its recognition as a clinical entity in the 1940s, our knowledge of bronchiolitis has grown with respect to the breadth of disease, epidemiology, treatment, and long-term effects. Bronchiolitis occurs most commonly in infants and children in association with a predictably small number of respiratory pathogens. Our knowledge of the association of bronchiolitis to subsequent wheezing is in a state of evolution. Rarely, bronchiolitis may progress to a chronic obstructive process, bronchiolitis obliterans, seen most often following adenovirus infection. The diagnosis of bronchiolitis in adults is relatively rare and although specific information on etiologic agents is lacking, it is not unlikely that the implicated infectious agents in infant bronchiolitis may play a role in the adult form of the disease. Bronchiolitis obliterans in adults occurs as a result of many possible causes, including infection. Although infection probably contributes to the pathogenesis of bronchiolitis obliterans in the post-organ-transplant population, this process appears to be a complex interaction centering around graft rejection.