Pneumocystis jirovecii pneumonia
(Redirected from Pneumocystis)
Note: this page is about the infection. For the drug PCP, see phencyclidine toxicity
Background
- Formerly known known as "pneumocystis carinii pneumonia" (i.e. "PCP")
- An atypical fungus [1]
- Most common opportunistic infection in AIDS patients
- Most common identifiable cause of death
Risk factors
- CD4 < 200
- Immunosuppressive medications
- Cancer
- Primary immunodeficiencies
- Severe malnutrition
Clinical Features
- Fever (62%)
- Dry cough
- Shortness of breath (progressive from exertion only to at rest)
Differential Diagnosis
Acute dyspnea
Emergent
- Pulmonary
- Airway obstruction
- Anaphylaxis
- Angioedema
- Aspiration
- Asthma
- Cor pulmonale
- Inhalation exposure
- Noncardiogenic pulmonary edema
- Pneumonia
- Pneumocystis Pneumonia (PCP)
- Pulmonary embolism
- Pulmonary hypertension
- Tension pneumothorax
- Idiopathic pulmonary fibrosis acute exacerbation
- Cystic fibrosis exacerbation
- Cardiac
- Other Associated with Normal/↑ Respiratory Effort
- Other Associated with ↓ Respiratory Effort
Non-Emergent
- ALS
- Ascites
- Uncorrected ASD
- Congenital heart disease
- COPD exacerbation
- Fever
- Hyperventilation
- Interstitial lung disease
- Neoplasm
- Obesity
- Panic attack
- Pleural effusion
- Polymyositis
- Porphyria
- Pregnancy
- Rib fracture
- Spontaneous pneumothorax
- Thyroid Disease
- URI
HIV associated conditions
- HIV neurologic complications
- HIV pulmonary complications
- Ophthalmologic complications
- Other
- HAART medication side effects[2]
- HAART-induced lactic acidosis
- Neuropyschiatric effects
- Hepatic toxicity
- Renal toxicity
- Steven-Johnson's
- Cytopenias
- GI symptoms
- Endocrine abnormalities
Evaluation
Workup
- CBC
- Chemistry
- LDH elevation - sensitive but not specific
- ABG
- CD4 count
- CXR - bat wing appearance (bilat interstitial infiltrates)
- A-a gradient
- P(A-a)O2 = 150 – (PaCO2/0.8) – PaO2 at sea level on RA (normal is <10 in young, healthy patients)
- Increased in PCP pneumonia secondary to decreased diffusion thru thick aveoli
Diagnosis
- Imaging
- CXR
- Normal in 25% of cases
- Diffuse, interstitial infiltrates
- CT Chest
- Sn 100%, Sp 89%
- May see ground glass infiltrative pattern
- CXR
Management
Antibiotics
- Require HCAP or CAP (ceftriaxone and azithromycin) coverage as well[3]
Mild Disease
- TMP/SMX 2 DS tablets PO q8hrs daily OR
- High incidence of allergy in HIV
- Dapsone 100mg PO once daily + TMP 5mg/kg PO q8hrs OR
- caution: dapsone can cause methemoglobinemia
- Atavaquone 750mg PO q12hrs OR
- Primaquine 30mg PO q24hrs + Clindamycin 450mg PO q8hrs
Severe Disease
- TMP/SMX 5mg/kg IV q8hrs daily x 21 days OR
- Pentamidine 4mg/kg IV daily infused over 60 minutes OR
- Watch for side effects of hypoglycemia and hypotension
- Primaquine 30mg PO once daily + Clindamycin 900mg IV q8hrs daily
Prophylaxis
- TMP/SMX 1 double strength tablet daily, but one single strength tablet daily or one double-strength three times weekly is acceptable.[4]
Corticosteroids
When used early, found to reduce the risk of progression of hypoxemia, respiratory failure, and death. [5]
- Only in patients with HIV with severe respiratory parameters:
- Room air PaO2 < 70 mmHg
- OR A-a gradient > 35 mmHg
- Treatment schedule for moderate to severe PCP[6]
- Day 1-5: 40mg prednisone BID
- Day 6-10: 40mg prednisone once daily
- Day 11-21: 20mg prednisone once daily
- Patients too ill to take PO may take equivalent IV methylprednisolone
Disposition
- Symptoms usually worsen 2-3d after start of treatment
- Patients with disease severe enough to warrant IV therapy or steroids should be admitted
References
- ↑ Chapman, M., Muse, V., Mojica, J., & Anahtar, M. (2021). Case 35-2021: A 50 Year Old woman with Pain in the Left Upper Quadrant and Hypoxemia. The New England Journal of Medicine, 385(21), 1995–2001.
- ↑ Gutteridge, David L MD, MPH, Egan, Daniel J. MD. The HIV-Infected Adult Patient in The Emergency Department: The Changing Landscape of the Disease. Emergency Medicine Practice: An Evidence-Based Approach to Emergency Medicine. Vol 18, Num 2. Feb 2016.
- ↑ Rothmans RE, Marco CA, Yang S. Human immunodeficiency virus infection and acquired immunodeficiency syndrome, in Tintinalli JE, Stapczynski JS, Ma OJ, et al (eds): Tintinalli’s Emergency Medicine, ed 7. New York, The McGraw-Hill Companies Inc., 2011.
- ↑ CDC Guidelines for Prophylaxis Against Pneumocystis carinii Pneumonia for Children Infected with Human Immunodeficiency Virus http://www.cdc.gov/mmwr/preview/mmwrhtml/00001957.htm
- ↑ Chapman, M., Muse, V., Mojica, J., & Anahtar, M. (2021). Case 35-2021: A 50 Year Old woman with Pain in the Left Upper Quadrant and Hypoxemia. The New England Journal of Medicine, 385(21), 1995–2001.
- ↑ Wilken A, Feinberg J. Pneumocystis carinii Pneumonia: A Clinical Review. Am Fam Physician. 1999 Oct 15;60(6):1699-1708. http://www.aafp.org/afp/1999/1015/p1699.html.