Which of the following is TRUE regarding Pneumocystis jirovecil?
A. Occurs only in immune-compromised individuals.
B. Sputum examination is very helpful in diagnosis
C. Usually associated with CMV infection
D. Always associated with pneumatocele
Ans. B. (Sputum examination is very helpful in diagnosis)
Explanation
• P. jirovecii is the species found
in humans, while P cariniiis
the most common species found in rats. How frequently, we read P. carinii as affecting
immunocompromised humans in routine microbiology books! Actually, it is P.
jirovecii.
• P. jirovecii causes
opportunistic pneumonia infection in young immunocompromised adults.
• Pneumocystis may be associated with CMV, but not usually
• A definitive diagnosis requires the demonstration of P cariniiin the lung in addition to clinical signs and symptoms
of the infection. Methods for obtaining organisms include bronchoalveolar
lavage, tracheal aspirates, transbronchial biopsy, bronchial brushings,
percutaneous transthoracic needle aspiration, and open lung biopsy. Induced
sputum samples are useful if P. carinii is found, but the absence of the
organism does not exclude the infection.
• The epidemic infantile form of P
carinii interstitial plasma cell. Pneumonitis is seen predominantly in
infants between 3 and 6 mo of age. The onset is subtle with tachypnea and 101°
fever, progressing to intercostal suprasternal, and infrasternal real flaring,
and cyanosis. In the sporadic form of P
carinii,pneumonitis occurring in children and adults with underlying
immunodeficiency, the onset is usually abrupt with fever, tachypnea, dyspnea,
and cough progressing to nasal flaring and cyanosis.
Note:
• Pneumatocele are seen in staphylococcal infection, pneumocystic
disease, past traumatic (laceration), after treatment of metastasis).
• Risk factors of pneumocystic disease are
— Immunocompromized patients (HIV), primary immunodeficient diseases, patients
on immuno-suppressive therapy. Premature malnourished infants
(immunodeficient).
