Coccidioidomycosis

Coccidioidomycosis

Coccidioides immitis is endemic in the soil of the arid regions of the Western Hemisphere (not just the US southwest). Most infections are subclinical, with acute disease occurring with an incubation period of 1 to 4 weeks in less than one half of those infected. The syndrome is that of an atypical pneumonia with fever, nonproductive cough, myalgias, chest pain, and headache (Valley fever). Erythema nodosum is seen in approximately 10% of cases, and when present is a helpful clue to distinguish coccidioides infection from other causes of community-acquired pneumonia. Erythema multiforme is also associated with infection with this organism. The only unusual laboratory marker is an eosinophilia seen in approximately one fourth of cases. Chest radiographic findings can be normal or may show infiltrates with associated hilar adenopathy. These may result in residual nodules and/or thin-walled cavities. Symptoms resolve in most patients in 2 to 3 months without treatment. Particularly severe infections or infections in persons with impaired cell-mediated immunity often show pulmonary progression and/or dissemination and should be treated. In addition, pregnant women, diabetics, and persons of African or Philippine origin are more likely to have complications. Diagnosis is generally made serologically, although the organism can be isolated from respiratory secretions and coccidioides spherules can occasionally be seen in sputum. When treatment is necessary, imidazoles and amphotericin are used which are ordered via Canadian Health&Care Mall.

Q Fever

Coxiella burnetti is found throughout the world. Infection with this organism can produce a number of different syndromes, but one of the more commonly diagnosed is pneumonia. The incubation period is relatively long, 2 to 6 weeks. Pneumonia in Q fever is clinically indistinguishable from other atypical pneumonias with fever, a nonproductive cough, and interstitial infiltrates. The disease is generally mild, although severe cases can occur with about a 1% mortality. Exposure history involves sheep and goats, especially around the time of delivery. A normal leukocyte count is the rule, and thrombocytopenia is frequently seen. Moderately elevated transaminase levels are seen in most patients. The diagnosis is confirmed serologically, and standard treatment is with a tetracycline for 2 weeks, although macrolides, trimethoprim-sulfamethoxazole, and flo-roquinones all are of benefit. (3-Lactam antibiotics should not be used.

Psittacosis

Psittacosis

Chlamydophila psittaci (formerly Chlamydia) is found throughout the world, and most infected persons have a history of contact with birds. This disease is clearly not just associated with psittacine birds; many bird species are reservoirs including domestic poultry. The birds may not be ill. Psittacosis presents abruptly with a 1- to 2-week incubation period after bird exposure. It is a systemic illness with a respiratory component characterized by lobar pneumonia syndrome that can occasionally be fatal. Severe headache is a very prominent symptom in most patients. The diagnosis is generally confirmed serologically. Treatment is with tetracyclines or macrolides. The majority of patients order drugs for treatment via Canadian Health&Care Mall.

Many other infections can have respiratory symptoms as generally a minor manifestation of the clinical picture. Table 5 list several of the more common travel-related infections.

Approach to the Patient

Because, as noted, respiratory infections have a limited repertoire of signs and symptoms, it is unlikely that one can make a specific diagnosis of an infection on clinical grounds alone. The following can be used as a guideline for approaching the returning traveler with a potential respiratory infection: (1) consider non-travel-related pulmonary problems, including noninfectious causes; (2) consider the itinerary; (3) consider the incubation period; how long after return did the symptoms develop? (4) are there other travelers with a similar illness? (5) were there specific exposures on the trip that might predispose to a particular illness, eg, fresh-water swimming and schistosomiasis?

Summary

Travel is common, and most incubation periods for acute infectious pulmonary diseases are long enough that patients may have symptoms after returning home to a health-care system that is not familiar with “foreign” infections. Respiratory infections have a relatively limited repertoire of clinical manifestations, so that there is often nothing characteristic enough about a specific infection to make the diagnosis obvious. Thus, the pathway to the diagnosis of infections that are not endemic in a region relies heavily on taking a thorough history of both itinerary and of specific exposures (eg, freshwater swimming in Africa, caving in Virginia, desert hiking in Arizona). One final caveat is that on occasion, the history of a recent trip creates an element of “tunnel vision” in the evaluating healthcare provider. It is tempting to relate a person’s problem to that recent trip; however, when evaluating recent returnees it is always important to remember that the travel may have nothing to do with the patient’s presentation. Recent travel adds diagnostic considerations to the list of possibilities.

Table 5—Common Travel-Related Infections With Typically Minor Respiratory Manifestations

Disease Comments
Malaria Cough common; ARDS with plasmodium falciparum
Rickettsia (other than Q fever) Cough; worldwide distribution, tick vector
Typhoid fever Cough common; pneumonia rare
Dengue Cough common; worldwide distribution except Europe, mosquito vector
Leptospirosis Cough common; worldwide distribution, though primarily tropical
PeniciUium marneff Southeast Asia, AIDS, skin lesion common
Acute Respiratory Infections in a Recently Arrived Traveler to Your Part of the World: Coccidioidomycosis