OPPORTUNISTIC INFECTIONS - PowerPoint Presentation

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OPPORTUNISTIC INFECTIONS

In patients with untreated HIV infection, decreasing CD4 cell counts predispose them to infections that do

not usually occur in persons with an intact immune system. These opportunistic infections usually develop

when the CD4 cell count is less than 200/

μL

and become even more likely when the count is lower. However,

mucocutaneous

Candida

infection can develop with CD4 cell counts greater than 200/

μL

. Oral candidiasis

(thrush) most often can be treated with topical agents such as clotrimazole troches. Dysphagia or other

swallowing symptoms indicate esophageal involvement, and treatment of esophageal candidiasis requires

a systemic agent such as fluconazole.

Cryptoccocal meningitis

Cryptococcus may be isolated to the lung but usually has disseminated before diagnosis and manifests as subacute or chronic meningitis,cryptoccocal meningitis is usually diagnosed by CSF culture or by cryptoccocal antigen test in serum or CSF fluid.

Treatment includes antifungal agents and control of increased ICP by serial LP and shunting.

Pneumocystis jirovicii pneumonia

Pneumocystis jirovecii

pneumonia is a common complication in patients with HIV infection who have not

received prophylaxis. Patients present with subacute onset of fever, dyspnea, and dry cough, and chest

radiographs most commonly show diffuse interstitial or alveolar infiltrates

.Although

the

microorganisms may be found in induced sputum, diagnosis usually requires stains of bronchoalveolar

lavage fluid. High-dose trimethoprim-

sulfamethoxazole

is the treatment of choice. During treatment, an

immune response to dying microorganisms may actually worsen disease in the first few days. Adjunctive

glucocorticoids are beneficial and should be used in patients with an arterial partial pressure of oxygen

(breathing ambient air) of less than 70 mm Hg (9.31

kPa

) or an alveolar-arterial gradient of greater than 35

mm Hg (4.66

kPa

).

Toxoplasma gondii

Toxoplasma gondii

can cause encep

halitis in patients with CD4 cell counts less than 100/

μL

. Diagnosis is

typically based on signs and symptoms and imaging findings. Patients present with headache, fever, focal

neurologic deficits, and possibly seizures. Multiple ring-enhancing lesions are seen on imaging

studies.

MRI is preferred to CT because of higher sensitivity. Toxoplasmosis in patients with

AIDS is almost always a reactivation disease; therefore, results of serologic testing for anti-

Toxoplasma

IgG

antibodies are usually positive. After presumptive treatment (with pyrimethamine plus either sulfadiazine or

clindamycin), patients should be assessed for response within 1 or 2 weeks of starting therapy.

Mycobacterial infections

Tuberculosis and MAC infection are the most common mycobacterial infections in patients with AIDS.

Tuberculosis may present at any CD4 cell count, is more likely to be

extra pulmonary

at presentation, and

may not have the classic chest radiographic findings. Treatment of tuberculosis and HIV

confection

must

take into account drug interactions between the rifamycins and many antiretroviral agents. MAC infection in

patients with AIDS is usually disseminated at presentation and

develops at CD4 cell counts less than 50/

μL

.

Clinical features include fever, sweats, weight loss, lymphadenopathy, hepatosplenomegaly, and

cytopenias. Treatment involves a multidrug regimen with clarithromycin or azithromycin as the cornerstone

of therapy.

CMV infections:

Cytomegalovirus (CMV) infection in patients with AIDS usually presents with specific end-organ dysfunction

rather than a nonspecific systemic illness. The most common manifestations are retinitis, esophagitis or

colitis, and polyradiculitis or encephalitis. The diagnosis may be made clinically or by demonstrating CMV

by

histopathology

studies or NAAT. Initial treatment of CMV infection is oral valganciclovir or intravenous

ganciclovir.

Skin opportunistic infections:

Molluscum contagiosum is a poxvirus infection that most commonly causes multiple small papules on the

face and trunk; it usually responds to immune reconstitution after treatment of the HIV

infection.

Bartonella

infection causes bacillary angiomatosis and is characterized by skin lesions that

resemble Kaposi sarcoma (KS). KS is caused by a herpes family virus (human

herpes virus

8) and presents

with lesions that may vary in color from red to purple to brown and may be macules, papules, plaques, or

nodules. KS is most often found on the skin but may also occur on mucous membranes of the respiratory

and gastrointestinal tracts.

Management guidelines:

1-the treatment by HAART(highly active antiretroviral therapy).

2-the treatment should be initiated in any adult with symptoms ascribed to HIV infection regardless of CD4 count.

3-the treatment should be initiated in any asymptomatic patients with CD4 cell count less than 350 cells per microliter.

4-treatment is recommended for 3 conditions regardless of CD4 count or whether the patient symptomatic or not. (pregnancy,HIV nephropathy, hepatitis B virus confection).

5-Antiretroviral treatment should be offered to all patients who are ready to take treatment.