Wednesday, April 7, 2010

April 6th - MHH - HIV and Shortness of Breath

Today at Morning Report a Case of Dyspnea in a Patient with HIV was discussed.  The differential for patients with HIV/AIDS presenting with dyspnea is varied, and one must add additional conditions not seen in immunocompetent patients.  Here is a general thought process to causes in these patients

Infectious Causes
Bacterial Pneumonia (i.e. "Community Acquired") is your number one thought in this category, as strept pneumoniae is the most common pathogen in HIV patients.  They are also at an increased risk of getting empyemas. If you see an effusion or consolidation, think this bug first.  Blood Cultures, Sputum Cultures and Urine Antigen can be sent, but you must think of this diagnosis clinically. 

PCP/PJP - We see this very commonly, especially in patients with CD4 Counts Less than 200. The "Classic" presentation is dyspnea on exertion, fever, scant productive cough and hypoxia that is progressive and worsened with exertion.  We all Send LDH Levels - the Sensitivity in studies ranges from about 86-97%, but the specificity hovers around 50%.  CXR can show the "batwing" appearace - but PCP can appear as any bilaterial or unilateral infiltrate.  Early in the disease, the CXR may be negative.  Sputum Cultures can be sent for diagnosis, but the sensitivity is about 40%.  In patients with suspected PCP and negative sputum cultures, bronch should be performed.  Treat with Bactrim and add Steroids is the Pa02<70 or the Aa Gradient >35.

Viral Causes - Especially CMV

Fungal Causes - Histoplasmosis and Crypto are high on the list, especially in Houston. Keep Blastomycosis in mind with Skin Lesions, and Coccidio with contact in the endemic SW region.

Tuberculosis -  Even if you are thinking PCP, sputum cultures for APB can be considered. A PPD can be placed, but doesn't tell you as much...

Atypical Mycobaterium - i.e. MAC. Have a high suspicion especially with CD4 Counts below 50, although not uncommon in counts <100.  Send Sputum Cultures.  If they stain Acid Fast Bacilli, you would usually treat for MTB untill the PCR/culture reveals an atypical organism.  Although, most would add a macrolide to the treatment regimen while awaiting final cutures, when they have a high index of suspicion of atypical mycobacterium.  


Lymphoma - Both NHL and Hodgkin's should be considered. In general, NHL (especially B Cell Types) are highest in these patients. Common forms include Burkitts, DLBC, and Large Immunoblastic Lymphoma.  Keep in mind, that the incidence of Hodgkin's Lymphoma is increasing in the HAART era, and is rising in patients on treatment for HIV.  The tumor burden in the lungs alone/mediastinal involvement can cause dypnea. Always consider that this may be happening with your patient as the CXR with lymphoma can easily mimic infectious causes. 

HHV-8 Associated Malignancies - Kaposi's Sarcoma involving the Lungs, Castleman's Disease (A lymphoproliferative disorder) and Primary Effusion Lymphoma

Consider other Malignancies - Think both Primary Lung Cancer and Metastatic Disease. HIV increases the risk of Primary Lung Cancer regardless of smoking, and there is evidence of increased risk of metastatic spread of other primary cancers.

Lung Disease

Interstitial Lung Disease - Nonspecific interstitial pneumonitis and lymphocytic interstitial pneumonitis are very prevalant in HIV patients. 
There is also reported evidence of increased incidence of pulmonary alveolar proteinosis and desquamative interstitial pneumonitis.

Pneumothorax - A result of PCP/PJP infection, or various other secondary causes

Pulmonary Hypertension - Remember that HIV is a cause of seconary Pulmonary HTN

Pulmomary Embolism

Cardiac Disease
Congestive Heart Failure - Especially Dilated Cardiomyopathy with HIV

Pericardial Effusion/Tamponade - HIV, Fungal, TB, Malignant Causes

Ischemic Heart Disease - There is evidence of increased risk of CAD with HIV and some interesting papers that Protease Inhibitors contribute to this

Other Causes to Consider:
Rheumatic Diseases  - i.e. Vasculitis
Drug Reaction
Anemia (Acute - bleed from carcinoma or other various causes of colitis in HIV Patients. Chronic - consider BM suppression from HIV itself or other malignant/infectious causes - although this is less likely to causes acute dyspnea)

Image courtesy of City University of New York

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