Resident Version

Pulmonary Infections/Complications in HIV patients Module

Created by Peggy Beeley, MD

Objectives:

1. Name the most common pulmonary infections and complications in the setting of HIV.

2. Learn strategies for diagnosing common pulmonary conditions in HIV.

3. Learn generalities for empiric treatments for the most common pulmonary infections in this patient population.

References:

1. NHLBI Workshop summary, NIH Bethesda, Maryland

Pulmonary Complications of HIV Infection

Am J Respir Crit Care Med Vol 164. pp 2120-2126, 2001

2. Wolff, A, et al. HIV-related pulmonary infections: a review of the recent literature

Current Opinion in Pulmonary Medicine 2003, 9:210-214

3. Turner, D, et al. Induced sputum for diagnosing Pneumocystis carinii pneumonia in HIV patients: new data, new issues. Eur Respir J 2003;21: 204-206

4. Mandell, Douglas and Bennett’s Principles and Practice of Infectious Diseases, Sixth Edition

Pulmonary Complications of HIV Infection

I.  Incidence of opportunistic infections have drastically dropped since HAART therapy has improved survival and helped maintain good health in persons living with HIV.

II.  Pulmonary Disease in HIV continues to be the leading cause of morbidity and mortality in this group.

III.  Pathogenesis of Pulmonary Disease in HIV

a.  HIV infects, destroys and depletes T-cells, leading to impaired cellular immunity. This occurs throughout the body but seems to have a particular impact on the lung and protection against infections of the lung.

b.  HIV infection leads to defects in humoral immunity.

  1. Ability to generate antigen-specific responses is impaired.
  2. May be due to impaired ability of HIV-infected T cells to activate B Cells.
  3. Accounts for increased number of bacterial pneumonias.

c.  Immunological Reconstitution

  1. Occurs when Highly Active Anti-retroviral Therapy (HAART) leads to an increase in population of memory and naïve T cells.
  2. Some patients develop a granulomatous disorder that resembles sarcoidosis.
  3. Others with latent or active mycobacterial infections may develop fever, lymphadenopathy and opacities on chest x-ray.

IV.  Differential Diagnosis

a.  This is not an all inclusive list but rather lists the more common etiologies of infection and lung disease in HIV positive patients.

b.  Pneumocystis jirovecii

  1. Often still abbreviated as PCP, but will now use PJP.
  2. Will be discussed separately.

c.  Community Acquired Bacterial Pneumonia

  1. HIV positive patient have 100 fold higher risk of bacterial pneumonia than persons not infected with HIV.
  2. Most common:

1.  Streptococcus pneumoniae

2.  Staphylococcus aureus

3.  H influenzae

iii.  Less Common: Enterobacteriaceae, Pseudomonas aeruginosa, Moraxella catarrhalis, Group A streptococcus, Nocardia species, Legionella species, Rhodococcus equi, and Chlamydia pneumoniae.

d.  Mycobacterial Pathogens

  1. M. tuberculosis (major player in HIV in the developing world)
  2. M. kansasii (most common of the non-tuberculous mycobacterium)
  3. M. avium complex (more commonly causes disseminated; and other mycobacterium are less common causes of pneumonia.

e.  Viral Pneumonia

  1. Most Common: Influenza virus
  2. Less Common: Cytomegalovirus, Herpes simplex virus, Adenovirus, Respiratory syncytial virus, Parainfluenza virus

f.  Fungal Infections include (in relative order of frequency): Cryptococcus neoformans, Histoplasma capsulatum, Coccidioides immitis, Aspergillus species, Blastomyces dermatitidis, Penicillium marfeneffei

g.  Parasitic Diseases: Toxoplasma gondii, Strongyloides stercoralis

h.  Neoplasms: Kaposi’s sarcoma, Lymphoma, Lung Cancer

i.  Other pulmonary processes seen in normal persons, PE, CHF, COPD, etc.

V.  Relative Importance of the most common pathogens.

a.  Prospective Study designed to identify etiologic agents in HIV infected patients by Rimland, et al. in Atlanta studied 230 patients.

  1. Causative organism was identified in 67%.
  2. PJP in 36% of these.
  3. 35% due to Streptococcus pneumoniae.
  4. 28% due to Haemophilus influenzae.
  5. Only 3.7% were “atypical” organisms and were in the presence of a second pathogen.
  6. Mycobacterium tuberculosis accounted for 6.2%.
  7. 95% of those without a causative organism were deemed as probable bacterial processes.

VI.  Initial Clues to the Diagnosis.

a.  General Rules:

  1. Rule 1: Clinical or laboratory findings are not reliable features to make a diagnosis with the exception of microbiologic evidence.
  2. Rule 2: Finding one pathogen does not exclude a second pathogen.
  3. Rule 3: Early respiratory isolation of HIV patients with respiratory symptoms or pulmonary findings is important in reduction of hospital acquired tuberculosis.

b.  HIV staging

  1. PJP is much more likely if CD4 is < 200.
  2. If CD4 count is unknown, thrush, hairy leukoplakia (this finding is how HIV infection is recognized in some African countries that can not afford serology) and weight loss may act as clinical markers of a poor immune system.
  3. Some infections, i.e. bacterial pneumonia and tuberculosis may occur with relatively preserved CD4 counts.
  4. All infections and complications occur with more frequency in advanced HIV disease.

c.  Acute versus Sub-acute presentation

  1. Bacterial or viral pneumonias seem to display an abrupt onset and present within days of onset of symptoms. Bacterial pneumonia may have more prominent sputum production or pleuritic chest pain.
  2. PJP and TB tend to have a gradual progression of symptoms and often present after weeks of symptoms. But either can present with a more fulminate course, including ARDS-like picture.

d.  Local epidemiology or past residence

  1. Coming from or living in an area of high prevalence leads to higher suspicion of infection, i.e. Tuberculosis.
  2. Past residence or travel are important clues to determine risk for fungi, i.e. Coccidioides or Histoplasma.

e.  IVDU increases the risk for bacterial pneumonias including Staph aureus.

f.  Receipt of PJP prophylaxis, especially Bactrim dramatically reduces risk for PJP.

g.  Generalizations of radiographic findings.

  1. Diffuse interstitial infiltrates
  2. More likely to be PJP
  3. May also be seen in many other processes including TB and occasionally H influenzae.
  4. Consolidation
  5. More likely to be bacterial or TB.
  6. M also be an atypical presentation of PJP.
  7. Cavitary Lesions
  8. Tuberculosis, although often HIV patients have primary disease or atypical presentations of TB reactivation.
  9. Fungi, nocardia, PJP, MAC and even bacterial pneumonia may present with cavities.
  10. Normal Chest X-Ray
  11. Seen in 10% of PJP and TB infections in HIV positive patients.

VII.  Pneumocystis jirovecii, formerly P. carinii (a special pathogen)

a.  Microbiology and Epidemiology.

  1. In vitro culture is not reliable, thus scientific investigation is limited in the laboratory.
  2. Unicellular fungi.
  3. Unusual because it lacks ergosterol in its plasma membranes (antifungals do not work).
  4. Remains the most common AIDS-defining indicator condition.
  5. First described in malnourished and premature infants in central and Eastern Europe after World War II.
  6. Pneumocystis is host species specific.
  7. First recognized in rats by Dr. Carini, P. carinii was initially presumed to be the causative agent of human infection by an indistinguishable microscopic appearance.
  8. Correction of the taxonomy to reflect the human infecting species occurred in 2002, thus P. jirovecii
  9. Person-to-person transmission is assumed but unproven.
  10. Studies of recurrent PJP by genotyping have shown that 50% of cases were infected with strains of a different genotype, suggesting that patients are often infected with new strains rather that reactivating latent infections.

viii.  CD4 T cell are required to clear P.jirovecii and alveolar macrophages participate in defense against P. jirovecii.

  1. Surfactant proteins have been implicated in the pathogenesis, leading to microatelectasis, decreased lung compliance.

VIII.  Work-up of pulmonary findings in HIV patients.

a.  CBC with differential – toxic granulocytes and left shift suggestive of bacterial process.

b.  Blood cultures

c.  Chest x-ray – PA and lateral instead of portable if at all possible.

d.  Oxygen saturation at rest and with exercise. PJP patients may have normal resting saturation but a significant drop after exercise. Often used clinically but not specific.

e.  Arterial Blood Gas

  1. A-a gradient is may be very elevated and if > 30 mm Hg is a predictor of poor outcome.
  2. Use of A-a gradient provides perimeters for adjunctive corticosteroids.

f.  Sputum for gram stain, acid fast stains and cultures; requires an adequate specimen.

g.  LDH – tends to be elevated in most PJP infections.

h.  Induced Sputum for PJP and TB.

  1. Uses aerosolized isotonic saline to “induce” cough and sputum.
  2. This procedure is a common practice in most institutions for diagnosis of PJP.
  3. Sensitivity varies widely depending on the experience of the respiratory therapist and center. Overall sensitivity from all studies is 55%.
  4. Since this is a non-invasive test, it would seem that it would it would be cost effective. A cost-analysis study on PCR technique showed that induced sputum was actually more costly than BAL in a low prevalence population.

i.  CD4 counts and HIV viral loads are not very helpful in acute illness.

  1. CD4 counts may be only transiently low and viral loads transiently high in this setting.
  2. The values may not reflect the true status of the immune system.

j.  Tuberculin Skin Testing (TST, PPD)

  1. Only helpful if positive.
  2. A negative test is not uncommon in disseminated disease.

k.  Bronchoscopy and BAL

  1. Used less frequently than in the past.
  2. Many centers have high induced sputum yield for PJP.
  3. Observed improvement with empiric treatment leads to presumptive PJP diagnosis.
  4. Remains the highest yield procedure to isolate causative pathogens. Most sensitive test for PJP.
  5. Needed for visualization and confirmation of suspected Kaposi sarcoma.

l.  Biopsy: Trans-bronchial, Trans-thoracic and Open Lung.

  1. Reserved for cases in which initial diagnostic steps have failed to find cause or the patient is failing empiric therapy.
  2. Biopsy is required to establish invasive infection of cytomegalovirus and aspergillus (both of these may be respiratory tract colonizers)

m.  High Resolution CT of the Chest

  1. Shows subtle findings not evident on chest x-ray
  2. If normal, PJP is very unlikely

n.  Gallium Scan: Negative study helps rule out PJP, not often used.

o.  Serum Cryptococcal antigen and urine Histoplasmosis antigen may be helpful in disseminated disease.

IX.  Empiric Treatment

a.  This is an only an overview. Please see other sources, i.e. Sanford’s guide for details of dosing and alternative treatments.

b.  Community Acquired Pneumonia

  1. Coverage of Streptococcus pneumoniae and Haemophilus influenza is of the utmost importance.
  2. Cefotaxime or Ceftriaxone is generally the preferred empiric choice.
  3. Or a flouroquinolone with extended S. pneumococcus coverage, i.e. Levaquin. (caution: failures have been reported in patients with persistent bacteremias/endocarditis)
  4. If illness is severe, both a 3rd generation cephalosporin and a macrolide or flouroquinolone are warranted.
  5. If your community has a high rate of resistant S. pneumococcus, Vancomycin may need to be added.
  6. If the patient has a prior history of bronchiectasis or pseudomonas infections, use anti-pseudomonal B-lactam, i.e. Zosyn or Cefepime

Empiric Treatment, continued

c.  Pneumocystis jirovecii

  1. Trimethoprim-sulfamethoxazole (15-20mg TMP plus 75-100mg SMX) kg/day IV given q 6 or 8 hours
  2. Or for less severe disease TMP/SMX 2 double strength tablet po TID.
  3. Duration of treatment should be 21 days.
  4. Alternatives include Pentamidine 4mg/kg IV q day or other multi-drug regimens.
  5. Prednisone should be started if PaO2 < 70 mm Hg or A-a gradient > 35 mm Hg.

d.  Other suspected organisms - firm diagnosis is preferred.

Case Presentation

CHIEF COMPLAINT:

Shortness of breath.

HISTORY OF PRESENT ILLNESS:

Mr. X is a forty-three-year-old male with a history of advanced acquired immune deficiency syndrome and noncompliance with HAART and prophylactic treatments who presents with a complaint of cough and shortness of breath. He has recently had a progressive decline in his health. His last CD4 count of 7 was noted one month ago.

The patient comes to the Emergency Department complaining of worsening shortness of breath for the past few weeks, He has an associated cough productive of reddish yellow sputum. The patient denies chest pain, fever, weakness or numbness, headaches, vision changes, sick contacts. He has not found anything to relieve his symptoms other than partial relief with no activity.

The patient denies incarceration, past tuberculosis diagnosis, past PPD positivity or contacts of persons known to have tuberculosis.

PAST MEDICAL HISTORY:

1. Advanced acquired immune deficiency syndrome diagnosed 7 years ago, multiple resistant viral profile on genotype and phenotype testing.

2. Chronic noncompliance with HAART and prophylaxis.

3. Depression

4. Oral thrush with possible candidal esophagitis.

5. History of PJP.

6. Herpes zoster.

7. Hypotension with an admission workup of adrenal insufficiency last year. Cortsyn stim test was normal.

ALLERGIES: No known drug allergies

CURRENT MEDICATIONS – OUTPATIENT:

The patient has been noncompliant with his medications, specifically stopping some medications “weeks ago”. The barriers to his taking medications have been explored but remain unclear as the patient is not forthcoming with his reasoning.

Not taking Dapsone 100 mg by mouth every day, fluconazole 400 mg by mouth every day, or azithromycin 1200 mg by mouth every week.

Intermittent use of the following:

Fosamprenavir 700 mg by mouth twice a day, Tenofovir 300 mg by mouth every day, abacavir 300 mg by mouth twice a day and Ritonavir 100 mg by mouth twice a day. Oxycodone 500 mg by mouth as needed for pain and Boost for malnutrition are intermittently used.

FAMILY HISTORY:

The patient does not know family history.

SOCIAL HISTORY:

Ten-pack-year history for tobacco. In the past, he drank “a lot” of alcohol but currently denies drinking. Denies history intravenous drug use or other illicit drugs.

The patient is intermittently homeless but currently lives alone in a motel and works at the front desk for a few hours a week for his room and board.

REVIEW OF SYSTEMS:

GENERAL: Negative for any vision changes or headaches. He has night sweats but no fever.

Head and Neck: Reports difficulty with swallowing. The patient denies any nasal discharge or ear pain.

CHEST: See HPI

CV: Denies palpitations or exertional chest pain.

GASTROINTESTINAL: Denies abdominal pain, black tarry stools, bright red blood per rectum or diarrhea.

GENITOURINARY: Denies painful urination, increased urinary frequency or urgency.

EXTREMITIES: negative for edema.

PHYSICAL EXAMINATION:

VITAL SIGNS: T currently 36.3, T-max 36.3, blood pressure 85/56, heart rate 117, respiratory rate 32, oxygen saturation 95% on 5 liters NC.

GENERAL: The patient appears malnourished, alert and oriented x two. Does not know the date.

HEENT: Negative for nasal discharge. Positive for copius white-colored coalesced patches of tongue, palate and oral mucosa.

NECK: negative for lymphadenopathy, negative for thyromegaly.