Tuberculosis Flashcards
(41 cards)
What is Tuberculosis?
An aerobic, non spore forming AFB. It is non motile and slow growing.
What is the reservoir of TB?
Humans although rarely, elephants can contract the infection
What are the barriers to acquiring an infection with TB?
Public Health Structure
Air Exchange
Alveolar Macrophages
CD4 and CD 8 Lymphocytes
How is a TB infection acquired?
Aerosolized droplets from coughing and sneezing.
What is the pathophysiology of TB infection?
AFB inhaled. Upon arrival in alveolus, they enter the alveolar macrophage and is encased in phagosome. The phagosomes fuse with lysosomes which digest them. CD4 and CD8 lymphocytes attack the AFB. The AFB is surrounded by a granuloma- the Ghon Complex.
What organ systems are affected by TB?
Pulmonary
Lymph Nodes
Pleura
CNS
What findings are associated with TB?
Non Specific X Ray findings at 10 days
Granuloma at 4 weeks
Positive skin test at 5 weeks
Visible chest x ray changes at 6 weeks
What are the two types of TB?
Latent (LTBI) Isocitrate Lyase\
Active
What are the first line drugs to treat TB?
INH, Rifampin, Pyrazinamide, Ethambutol, Rifabutin, Rifapentine
What are the second line drugs?
Streptomycin, Cycloserine, PAS, Amikacin/Kanamycin, Capreomycin, Levofloxicin, Moxifloxicin,Gatifloxicin
What are mechanisms of action of the first line drugs?
INH- disrupts cell membrane by interfering with Mycotic Acid Synthesis
Rifampin acts on Bacterial RNA Polymerasealtering Protein
Pyrazinamide- requires intra-bacterial activation in an acidic environment. It alter membrane efflux.. Works on M TB only
Ethambutol- Disrupts cell wall. does not require activation.
What is MDR TB?
TB resistant to INH and Rifampin. Seen especially in India, China and Russia.
What is XDR TB?
TB resistant to INH, Rifampin, Flouroquinolones and Aminoglycosides.
What is DOTS therapy?
Directly
Observed
Treatment
Short Course
What are some facts about Scrofula?
Painless
Usually in HIV pts.
Skin test + 77-100% 0f the time
6 month treatment
What are some facts about Pleural TB?
Sputum helps less than 40% of the time
Aspirate is usually serosanguineous with elevated Lactate levels and low Glucose levels
What are new some new tests for TB?
Adenosine Deaminase (ADA) and ADA Iso2- hig PPV where incidence is high QuantIferon- 89% sensitive and 92% specific, not influenced by BCG
What are some facts about Bone and Joint TB?
Painful Takes about 2 years to diagnose Usually involves two vertebrae and disc space in between Cord Compression 25-75%of the time Abscess formation and sinus tracts Dx with MRI esp in early disease Treat for 6 to 9 months
Facts about GU TB?
Silly putty kidney
acts like Pyelonephritis
Causes infertility in women
6 month treatment
Facts about Pericardial TB?
Most common cause of Pericarditis in Africa and Asia
Effusion is Exudative
6 month treatment
Facts about GI TB?
Involves Ileocecal area
Facts about Miliary TB?
Dx by CXR Presents like the Flu More often in immunocompromised 6 month treatment Look alike is Lymphoid Interstitial Pneumonitis, seen in EB virus, associated with enlarged Parotids and Lymphadenopathy and clubbing
Facts about CNS TB?
Kids
presents like meningoencephalitis or non specific sx.
Blocks CSF flow in subarachnoid space
Tuberculomas in Brain
reduced serum Sodium
non specific CSF with high lymphocytes and protein but low glucose
Treated with INH/Cycloserine/Ethionamide/PAS and
FQ
Treat for 9 to 12 months, just like MDR TB
3 stages:
1. Fever, Listless, Irritable
2.Confusion, Focal CNS defects, papilledema
3. Coma, paralysis
Otitis Media with 7th nerve palsy, think TB
When to use steroids?
TB Meningitis, elevated ICP, Pericardial Effusion, Pleural Effusion with respiratory distress and mediastinal shift, enlarged mediastinum , Miliary TB with Capillary block