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Principles and practice of Clinical parasitology - Gillespie S.

Gillespie S. Principles and practice of Clinical parasitology - Wiley publishing , 2001. - 675 p.
ISBN 0-471-97729-2
Download (direct link): principlesandpracticeofclin2001.pdf
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Mucosal Leishmaniasis (Espundia)
Healing of cutaneous lesions due to L. (V.) braziliensis and occasionally other Leishmania (V.) spp. is followed in a small percentage of cases by the development of destructive mucosal lesions months to years later. The nose is frequently involved (Figure 13.6). Presenting symptoms include nasal stuffiness, discharge or discomfort. Over time the septum may be destroyed, resulting in nasal collapse and the development of a ‘tapir’ nose. Destructive lesions of the lips, oral pharynx or larynx can also develop. If untreated, mucosal leishmaniasis can progress to substantial disfigurement
Fig. 13.6 Mucosal leishmaniasis due to L. (V.) braziliensis. (A) Mucosal leishmaniasis develops months to years after the primary cutaneous lesion(s) heal. This patient had involvement of the nasal mucosa and septum, which has collapsed, resulting in the development of a ‘tapir’ nose. (B) Further collapse of nasal structures occurred after successful chemotherapy with meglumine antimonate
(Figure 13.7). In rare instances, death has resulted from chronic aspiration pneumonia.
Mucosal involvement is occasionally seen with other Leishmania spp. as a result of contiguous spread of cutaneous leishmaniasis of the face and in some persons with HIV-associated visceral leishmaniasis. The pathophysiology and natural history in those instances are similar to those of cutaneous leishmaniasis and visceral leishmaniasis, respectively, rather than that of mucosal disease due to L. (V.) braziliensis.
Visceral Leishmaniasis (Kala-azar)
Leishmania (L.) donovani, L. (L.) chagasi and L. (L.) infantum are responsible for the majority of cases of visceral leishmaniasis, although occasionally other Leishmania spp., such as L. (L.) amazonensis or L. (L.) tropica, are isolated.
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PRINCIPLES AND PRACTICE OF CLINICAL PARASITOLOGY
Fig. 13.7 Mucosal leishmaniasis due to L. (V.) braziliensis involving the lips and face
The clinical spectrum is similar throughout the world.
In early epidemiological studies in East Africa and Italy, many persons living in endemic areas were found to have positive leishmanin skin tests, even though they had never been diagnosed or treated for visceral leishmaniasis. This suggested that the majority of L. (L.) donovani and L. (L.) infantum infections might be subclinical and selfresolving. The full spectrum of L. (L.) chagasi infection was subsequently defined in prospective studies in north-eastern Brazil (Badaro et al., 1986b, 1986c; Evans et al., 1992). The ratio of symptomatic visceral leishmaniasis to selfresolving infections ranged from 1:4.5 to 1:18, depending on the subject’s age and the geographic location. Young children living in highly endemic areas were the most likely to develop disease. In one study, a subset of those infected were observed to have a subclinical course before either progressing to typical visceral leishmaniasis or spontaneously clearing infection (Badaro et al., 1996b).
The time from inoculation of promastigotes by sand flies to the development of clinically apparent visceral leishmaniasis is variable. It is typically several months, but it has been reported to be as short as 10 days or as long as 34 months in immunocompetent persons. In a few instances, persons who have moved from endemic areas have developed visceral leishmaniasis years later after becoming immunosuppressed (Badaro et al., 1986a).
Persons with visceral leishmaniasis typically experience the subacute onset of fever, weakness, fatigue, weight loss, splenomegaly and hepatomegaly (Evans et al., 1985) (Figure 13.8). In some cases, the onset is more acute and suggestive of malaria. Fever may be intermittent, remittent with twice daily temperature spikes, or continuous. Patients tolerate the fever relatively well.
The liver and spleen progressively enlarge; they are firm in texture, not hard. In some cases the spleen becomes massively enlarged and may extend into the left lower quadrant. In a few cases it is not palpable. Hyperpigmentation is observed in Indian patients. It is the basis for the Hindi term ‘kala-azar’, which means black fever. It is not a feature of visceral leishmaniasis in other geographic areas. Peripheral lymphadenopathy is associated with visceral leishmaniasis in patients in the Sudan and China, but it is not common elsewhere. Wasting occurs as an apparent consequence of cytokines such as TNF-a and IL-1 (Pearson et al., 1992), and severe cachexia may be observed late in infection.
The laboratory findings of visceral leishmaniasis include anemia, leukopenia and hypergammaglobulinemia (Evans et al., 1985). Anemia may be pronounced, particularly in areas where malaria and hookworm infections are also endemic. The total white count may be as low as 1000/mm3. The platelet count is frequently decreased as well. Eosinophilia, which is prevalent in the tropics because of concurrent infection with helminths, is absent in patients with visceral leishmaniasis.
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