Acid-Fast Bacteria Flashcards
(42 cards)
What is scroffula?
Lymphadenitis due to mycobacterium, usually M scrofulaceum.
A refugee child is seen for a dermatitis that has not responded to topical therapies. A Fite stain is performed on a biopsy and confirms the diangosis. What is the infection?
Leprosy (M. leprae)
What are the treatment options for a 17 year old female volunteer of the local aquiarium who has developed non-healing ulcers on her skin which have not responded to topical therapy in for the last 4 months?
This is Mycobacterium marinum infection.
- Rifampin + ethambutol OR
- Rifampin + clarithromycin
Which mycobacterium is associated with drinking fresh cow’s milk?
Mycobacterium bovis
A parent returns to clinic with her 4-year old who is being treated for pulmonary tuburculosis which she contracted from her grandfather. She asks you about daycare and wonders what the risk is for her child spreading the illness to other children. What should you tell her?
It isn’t likely. Children < 10 don’t commonly spread the disease via airborn route.
Primary, non-latent TB infection occurred in a 18 year old male with HIV.
- Is it more likely he has infection in the upper or lower lobes?
- What about reactivation TB? Is it more likely in upper or lower lobes?
- More likely in lower lobes since they get more airflow.
- More likely in upper lobes.
A 3 year old immigrant infant with apparently normal immune system is seen for non-productive cough and reports of wheezing, especially at night. The chest x-ray shows hilar lynphadenophathy. What infection do you suspect?
Tuburculosis.
What signs/symptoms do most children with TB present?
NO SYMPTOMS! Infants and adolescents, however, are more likely to have symptoms.
How might tuburculous pericarditis present on exam?
Rub or distant heart sounds.
What age range is more likely to develop tuburculous meningitis as a complication of untreated TB?
- Children 6 months to 4 years
- Children > 5 years old
- Adolescents
- Infants < 6 months old
- Children 5 - 12 years old
Occurs in young children, 6 months to 4 years old.
In a child with TB meningitis, will sodium likely be low, normal, or high?
Low, because they often develop SIADH.
Which CSF profile fits best with TB meningitis?
- Protein low, glucose low, WBC high
- Protein high, glucose low, WBC low
- Protein high, glucose low, WBC normal or mildly elevated
- Protein low, glucose high, WBC high
Protein high, glucose low, WBC mildly elevated.
In TB meningitis, do you expect the CSF to have a lymphocyte or granulocyte predominance?
Lymphocyte predominance
True or False: Adolescents with pulmonary TB present like adults, with cough, fever, weakness, night sweats, and weight loss.
True
A 3 year old presents to clinic and she has risk factors for TB exosure. You are concerned about risk to follow-up regarding TB screening.
True or False? You should screen this child with Quantiferon Gold assay.
False. This can’t be used under age 5 because of no data regarding its use in that age group.
In terms of TB skin testing, you need to remember 3 different cutoff diameters. What are the three diameters upon which the guidelines are based?
5, 10, and 15 mm
In general, the three cutoffs for TB skin testing form three groups of possible positive testing. In general, how are these three cohorts described?
The test is positive for each cohort based on their risk factors:
- 5 mm: positive for HIGH RISK
- 10 mm: positive for INTERMEDIATE RISK
- 15 mm: positive for LOW RISK
List some risk factors that would classify a patient in the high risk group for TB infection. What measurement on skin testing would support a positive result?
5 mm is positive for people who:
- Have CXR consistent with TB
- Clinical symptoms consistent with TB
- HIV or other cell-mediated immune dysfunction
- Fibrotic changes on CXR consistent with TB
- Close contacts with documented TB
- Patients with organ transplant
- Patients getting > 15 mg/day prednisone for > 1 month
List some risk factors that would place someone n the moderate risk group for TB infection. What measurement in skin testing suggests a positive result?
10 mm is positive for:
- Homeless
- Recent travel or birth in a high prevalence region
- IV drug abusers who are HIV negative
- Prisoners
- Health care workers
- Nursing home patients/staff
- Diabetics
- People with CKD
- Persons getting immunosuppression but < equivalent 15 mg/day prednisone
- Children < 4
A child 3 years of age is screened with PPD for TB. His result was 12 mm. He has not had BCG. Is this a positive result?
YES! Although he seems like he’d be in the low risk group (and would need to be > 15 mm) he is < 4 which makes him intermediate risk.
Give a three-rule summary of the risk groups upon which PPD testing is based.
- 5 mm for HIV, abnormal CXR, close contact, severely immunocompromised.
- 15 mm for >= 4 and no risk factors
- 10 mm for all the rest
A 13 year old moved into the household 6 weeks ago of a grandparent who was just found out to have TB. TB skin test placed on the 13 year old was negative (no induration.)
- When should he be tested again?
- The result of the second test was 7 mm. Is this a positive result?
- 10-12 weeks after first exposure
- YES. It only need to be > 5 mm.
How long after initial exposure to TB should a patient who had close contact be tested?
10-12 weeks after first close contact exposure.
An IV drug user has HIV. His TB skin test will be considered positive at what diameter?
5 mm.
