Mycobacterial Infections and Tuberculosis Treatment Flashcards
What are mycobacteria?
Mycobacteria are aerobic, bacillary-type bacteria that grow like fungi and belong to the family Mycobacteriaceae (phylum: Actimomyceta)
Mention 4 characteristics of mycobacteria.
- They have thicker cell walls than many other bacteria
- Their cell walls contain peptidoglycans and mycolic acid
- They are acid fast
- Their cell walls are waxy and hydrophobic.
What mycobacterium is responsible for leprosy?
M. leprae
Classify mycobacterial infections.
- Tuberculosis
- Non-tuberculosis infection
a. Leprosy
b. Atypical
mycobacterial infections (e.g. pulmonary disease, lymphadentis)
i. Those that cause lung disease e.g. M. kansasii, M. avium-intracellulare
ii. Those that cause skin disease e.g. M. marinum, M. ulcerans, M. fortuitum
Where does non-tuberculosis MI originate from?
It originates in cervical lymph nodes, aural and ocular spaces.
How is non-tuberculosis MI managed?
Azithromycin + Ethambutol + Rifampin until monthly monthly culture is negative for a year.
Where does tuberculosis originate from?
It originates as a lung infection and spreads to the cervical lymph nodes, laryngeal, pharyngeal, aural, oral and ocular spaces
How is TB transmitted?
Through inhalation of aerosols (from coughing, sneezing, laughing, spitting or talking) generated from infected patients.
What are the types of TB?
- Latent TB
- Active TB
- Multidrug resistant TB
- Extensively multidrug resistant TB 5. Extra-pulmonary TB
What is multidrug resistant TB
It is a strain of TB that is resistant to the two most powerful first-line drugs: Isoniazid and Rifampin
What is extensively multidrug resistant TB
It is a strain of TB that is resistant to Isoniazid and Rifampin, any of the fluoroquinolones and any of the 3 injectable second-line injectables (Amikacin, Kanamycin and Capreomycin)
Mention 6 risk factors for TB.
- HIV
- Smoking
- Substance abuse diorder
- Organ transplant
- Head and neck cancer
- Scoliosis
- Diabetes
- Severe kidney disease
How do you prevent TB?
i. Early diagnosis and treatment
ii. Staying away from patients with active TB
iii. Using facemasks, covering the mouth.
iv Proper room ventilation
v. TB vaccination
What are the complications of TB?
i. Disseminated infection
ii. Sepsis
iii. Death
What are the first-line drugs used in TB treatment?
Rifampin
Isoniazid
Pyrazinamide
Ethambutol
Streptomycin (except in the US)
RIPES
Which of the first-line drugs are considered safe in pregnancy?
Rifampin
Ethambutol
What is the MOA of Rifampin?
Inhibition of RNA synthesis.
Mention 3 uses of Rifampin.
- Tuberculosis
- Leprosy
- Legionnaires’ disease
Mention 5 side effects of Rifampin?
- Nausea
- Vomiting
- Diarrhoea
- Loss of appetite
- Liver problems
- Red/orange colouration of tears, sweat and urine
- Allergic reactions
Which first-line drugs is recommended for latent TB?
Isoniazid
Which first-line drugs is a pro drug?
Isoniazid
What is the MOA of Isoniazid?
It blocks the synthesis of mycolic acid, an essential component of the mycobacteria cell wall.
_________ is a synthetic derivative of nicotinic acid.
Isoniazid
What are the uses of Isoniazid?
i. It is used alone for latent TB
ii. It is used with other first-line drugs (R, P, E/S) to treat active TB.
Isoniazid is recommended in pregnancy.
True or False
False
Mention 5 adverse effects of Isoniazid.
- Peripheral neuropathy due to Vit. B6 deficiency
- Hepatoxicity due to elevated ALT and AST
- Blood dyscrasia
- Nausea
- Vomiting
Mention 5 adverse effects of pyrazinamide.
- Nausea
- Loss of appetite
- Gout
- Muscle and joint pain
- Sunlight sensitivity
- Rash
What is the MOA of Ethambutol?
It interferes with mycobacteria metabolism
Mention 5 Adverse effects of Ethambutol.
- Nausea
- Headaches
- Fatigue
- Joint pain
- Vision problems
- Liver problem
What is the MOA of Streptomycin?
It blocks protein synthesis at the 30s ribosomal unit.
What are the uses of Streptomycin?
- Used with other first-line drugs for the treatment of active TB.
- Used for M. avium complex, endocarditis, brucellosis, Burkholderia fever, rat bite fever.
Mention 5 adverse effects of Streptomycin.
- Vomiting
- Vertigo
- Fever
- Deafness in neonates when used in pregnancy
- Facial numbness
Streptomycin is safe in pregnancy.
True or False?
False.
It is contraindicated in pregnancy. May lead to deafness of neonates.
What is the standard treatment for active TB?
Isoniazid (with Vit. B6) + Rifampin + Ethambutol for 2 months, followed by Isoniazid + Rifampin alone for 4 months.
Isoniazid should be taken with Vitamin B6
What is the standard treatment for latent TB?
6-9 months of daily Isoniazid alone
OR
3 months of weekly Isoniazid + Rifapentine
OR
2 months of Isoniazid + Rifampicin + Pyrazinamide (RIP), followed by 4 months of Isoniazid + Rifampicin
Mention 6 second-line TB drugs.
- Linezolid
- Fluoroquinolones
- Bedaquiline
- Cycloserine
- Amikacin
- Kanamycin
- Capreomycin
Mention 3 injectable-only second-line TB drugs
- Amikacin
- Kanamycin
- Capreomycin
What are the factors that affect the choice and length of TB treatment?
- Patient’s age
- Patients overall health
- Latent/active TB
- Location of infection
- multidrug resistant or not
How is TB diagnosed?
- Blood and sputum test
- Bronchoscopy
- CT scans to image lungs.
Vision problems are an adverse effect of _________.
Ethambutol
