CIS Resp Case 3

Question 1

Describe differential diagnoses for tuberculosis

Answer 1

Nontuberculosis mycobacterial infection (NTM) - M. Kansas

• fatigue, dyspnea, occasional hemoptysis
• NTM dx: sputum Cx and molecular diagnosis

Fungal infection

• varies by etiology but can present with PNA, nodules, cavitation
• fungal dx: Cx results, regional exposures

Lung cancer

• fevers, cough, chest pain, hemoptysis, dyspnea
• dx: histopathology

Lymphoma

• fevers, night sweats, weight loss
• dx: histopathology

Question 2

What are pt populations at risk for exposure and infection with tuberculosis?

Answer 2

Close contact with someone who has active tuberculosis
Immigrants from endemic areas (<5 years ago)
Residents and employees at high risk areas: jail, prison, nursing homes, homeless shelters, healthcare facilities, drug treatment facilities
Medically underserved, low-income populations
IV drug abuse
HIV/AIDS pts as well as other immunocompromised states

Question 3

Describe purified protein derivative (PPD) interpretation (type 4 hypersensitivity)

Answer 3

> 5 mm induration

• HIV
• Close contact with actively infected person
• Immunosuppression (TNF-a inhibitors, chronic glucocorticoids, chemotherapy, organ transplant)

> 10 mm induration

• persons with clinical conditions that increase reactivation risk: silicosis, DM, chronic renal failure with dialysis, malignancies (leukemia, lymphoma, lung, head/neck), malnourished, IV drug abuse
• children <4
• from country with high prevalance
• residents/employees in high risk setting: jail, healthcare facilities, mycobacterium las, homeless shelters

> 15 mm induration
-healthy individuals >4 with low likelihood of true TB infection

Anergy
-No rxn secondary to immune unresponsiveness

Question 4

List signs and symptoms that are associated with active pulmonary tuberculosis

Answer 4

Fever (can be diurnal)
Night sweats
Cough (generally > 2 weeks) (productive or hemoptysis)
weight loss
Lymphadenopathy

Question 5

Describe sputum culture (SCx) and sputum staining for tuberculosis

Answer 5

SCx
tuberculosis is a microbiological diagnosis
3 separate morning sputum samples taken for culture on liquid and solid media
Slow-growing: 6-8 weeks
*Gold standard for diagnosis

Sputum staining
Acid-fast bacillus (have to specifically ask for this)
Rhodamine-auramine stain: initial screening stain for TB
Ziehl-Neelsen and/or Kinyun stain: confirmatory AFB stain

Question 6

Describe PPD skin test (Mantoux) for diagnosis

Answer 6

Utilized to determine if person is currently infected or has been previously infected with M tuberculosis
NOT utilized to determine diagnosis but can support diagnosis and raise clinical suspicion
Positive in individuals who have received BCG vaccine

Question 7

Describe interferon gamma release assay (IGRA) for tuberculosis diagnosis

Answer 7

Used for diagnostics of LATENT tuberculosis
Indicates that there has been a cellular response to tuberculosis
Indications: individuals who have received a BCG vaccination and those with a positive PPD in whom latent tuberculosis is suspected

Question 8

Describe chest x-ray (CXR) for tuberculosis

Answer 8

Classic CXR of reactivation tuberculosis shows cavitation lesions that typically involve spices of lung

Question 9

Describe nuclei acid amplification test (NAAT) for tuberculosis

Answer 9

Utilized in conjunction with smear that is positive for AFB, while cultures are pending
NAAT-TB detects tuberculosis material
NAAT-R detects INH and rifampin resistance

Question 10

What is the standard 4 drug therapy for tuberculosis? For how long? Side effects?

Answer 10

6 months of continuous therapy

Isoniazid (INH)
-SE: hepatitis, N/V, *peripheral neuropathy (give pt vitamin B6), rash

Rifampin
-SE: *red/orange body fluids, N/V, rash, hepatitis, Steven-Johnson syndrome

Pyrazinamide
-SE: urticaria, hyperuricemia/gout, hepatitis, joint aches

Ethambutol
-SE: Optic neuritis, color-blindness

*Remember to follow pt with CMPs to monitor kidney and liver function. Also collect sputum to monitor efficacy

Question 11

Describe clinical diagnosis order of active TB

Answer 11

Clinical symptoms
Assess risk factors
Order radiography
Sputum culture
Don't delay treatment if clinical diagnosis and awaiting sputum culture
For active TB, start 4 drug therapy

Question 12

Describe latent TB considerations

Answer 12

Clinically silent but can become active
Get screening PPD

If PPD positive with NO h/o BCG vaccine, check CXR to make sure there is no active TB. If CXR negative, treat as latent TB with 9 months INH

If PPD positive with h/o BCG vaccine, check CXR and interferon gamma release assay.
If CXR negative for active TB and IGRA positive, treat as latent TB with 9 months of INH
If CXR negative and IGRA negative, NO active or latent TB. Positive PPD was from BCG vaccine, so no treatment needed.