About Pulmonary Nocardiosis.

1. Pulmonary Nocardiosis
D R . M D . S H A F I Q U L I S L A M D E WA N
R E S I D E N T ( P U L M O N O L O G Y )
D E PA RT M E N T O F R E S P I R ATO RY M E D I C I N E
D H A K A M E D I C A L C O L L E G E H O S P I TA L

2. Nocardia asteroides
Nocardia asteroides are thin, beaded and branching filaments that are gram-
positive on Gram stain.
Many isolates of N. asteroides are weakly acid-fast.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 2

3. Pulmonary Nocardiosis
Pulmonary Nocardiosis is subacute or chronic respiratory infection.
Nocardia asteroides cause approximately 90% of pulmonary nocardiosis, while
a range of other Nocardia species occasionally cause pulmonary disease.
Nocardia asteroides typically causes pneumonia, lung abscess with cavity
formation, lung nodules, or empyema.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 3

4. Transmission
Inhalation is the main route of infection.
skin inoculation and oral ingestion are alternative routes.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 4

5. Risk factor
Impaired cell-mediated immunity is the major risk factor.
Among transplant patients, lung transplant recipients are at particular risk.
Association with bronchiectasis and COPD, the latter linked to oral or inhaled
corticosteroid use.
Pulmonary alveolar proteinosis (lung disease involving surfactant accumulation
within the alveoli resulting from decreased clearance, rather than increased
production).
 Chronic granulomatous Disease.
**Approximately one-third of individuals may not have known
immunocompromise or a recognized risk factor such as alcoholism or diabetes.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 5

6. Clinical presentation
Usually present with subacute or chronic respiratory symptoms.
Some immunocompromised hosts present with a shorter duration of symptoms
mimicking CAP.
Symptoms_
 Cough, with or without sputum
 Dyspnoea
 Chest pain
 Haemoptysis
 Fever
 Fatigue
 Weight loss.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 6

7. Clinical presentation
Although nocardiosis and actinomycosis are clinically similar infections of the
LRT.
Nocardiosis can be distinguished by less proclivity for sinus tract formation and
a greater tendency for hematogenous dissemination.
Dissemination may involve almost every organ system, but the CNS and Skin are
most common.
Physical examination is non-specific unless sites of dissemination are present.
Neurologic signs of a mass lesion may be prominent.
Cutaneous dissemination appears as multiple subcutaneous abscesses with or
without sinus tracts.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 7

8. Investigation
Imaging: Chest x-ray, CT scan (chest, Brain)
Microscopy: Gram stain, modified Kinyoun acid-fast stain
Culture: Blood agar or Sabouraud medium
PCR
Tissue biopsy: may reveal granulomata
16S ribosomal RNA aids speciation
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 8

9. Imaging
Imaging commonly demonstrates localized bronchopneumonia or lobar
consolidation but there may also be solitary, multiple or miliary nodules and
abscesses.
Cavities are frequently observed.
Pleural effusion develops in up to one-third of cases.
CNS imaging should be considered in all patients with pulmonary nocardia
Because brain abscesses can develop in up to 40% of patients,
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 9

10. DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 10

11. DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 11

12. Microscopy
Sputum or invasively obtained material.
Branching rods or filaments that are gram-positive on Gram stain or weakly
acid-fast in an acid-fast stain.
The beaded appearance helps distinguish the microorganism from
mycobacteria.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 12

13. DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 13

14. Culture
Sputum or invasively obtained material.
Nocardia can be cultivated on conventional blood agar or Sabouraud medium
under aerobic conditions.
The organisms are typically identified after 3 to 5 days but growth may be
delayed, so cultures should be held for up to 21 days.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 14

15. Treatment
Susceptibility testing should be performed on all isolates.
Agents that often show activity against nocardia species include_
 TMP-SMX (Trimethoprim/sulfamethoxazole)
 Minocycline
 Amikacin
 Ceftriaxone
 Cefotaxime
 Imipenem
 Tigecycline
 Fluoroquinolones
 Linezolid
 But choices should always be guided by the results of susceptibility testing.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 15

16. Treatment
Initial regimens include Two agents or Three agents if there is severe disease.
Combinations usually include a β-lactam with amikacin and/or TMP-SMX.
Combination parenteral therapy is continued for several weeks until there is
clinical improvement and a continuation phase of oral therapy is used for a
prolonged period to prevent relapse.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 16

17. Treatment
Pulmonary disease in an immunocompetent patient is often treated with
approximately 6 months of therapy.
Severe disease, infections in immunocompromised hosts, or CNS disease
often receive 12 months of therapy or longer.
Adequate drainage or excision of abscesses and empyema is a crucial adjunct
to antimicrobial therapy.
Pulmonary nocardiosis can be prevented in at-risk immunocompromised
hosts by TMP-SMX prophylaxis.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 17

18. Prognosis
Mortality approaches 50% in those with CNS lesions.
But is less than 20% in those with isolated pulmonary disease.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 18

19. DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 19
Thank You