Nelson Ch. 215 Flashcards
Specialized culture medium for M. tuberculosis
Lowenstein-Jensen
Lowenstein-Jensen: Carbon source
Glycerol
Lowenstein-Jensen: Nitrogen source
Ammonium salts
Hallmark of all mycobacteria
Acid fastness
Capacity to form stable mycolate complexes with aryl methane dyes and resist decoloration with ethanol and hydrochloric acids
Acid fastness
Hallmark of latent Tb
Reactive tuberculin test and absence of clinical and radiographic manifestations
Primary complex or Ghon complex is the combination of
1) Parenchymal pulmonary lesion 2) Lymph node site
PTb that occurs >1 year after the primary infection, usually caused by endogenous REGROWTH of bacilli persisting in partially encapsulated lesions
Reactivation Tb
MC form of reactivation Tb
Infiltrate or cavity in the apex of the upper lobes, where O2 tension and blood flow are great
MC result of female genital tract Tb
Infertility
Reason why congenital Tb is rare
Because MC result of female genital tract Tb is infertility
MC infectious route of neonatal Tb infection
POSTNATAL airborne transmission from adult with infectious PTb
Conditions that adversely affect ___ immunity predispose to progression from Tb infection to disease
Cell-mediated
TST is what type of hypersensitivity
Delayed type or Type IV
Approximately ___% of infants who receive a BCG vaccine never develop a reactive TST
50
Usually, reactivity to TST of infants who receive a BCG vaccine wanes in ___ years
2-3
Most crucial risk factor for development of tuberculosis in children
Possible exposure to an adult with or at high risk for infectious PTb
Preferred test in determining patient’s T cell response to specific M. tb antigens in cases where specificity is important as in patients who received a BCG vaccination
IFN-γ release assays
Hallmark of primary PTb
Relatively large size of regional lymphadenitis compared with relatively small size of the initial lung focus
Sequence of primary PTb lesion
Hilar lymphadenopathy > focal hyperinflation > atelectasis (collapse-consolidation) or segmental tuberculosis
The presence of calcification implies that a Tb lesion has been present for at least ___
6-12 months
MC symptoms of pulmonary tuberculosis
Nonproductive cough, mild dyspnea, and CLADs
Reactivation Tb or Chronic PTb is uncommon in this age group
Healed Tb infection acquired less than 2 years
Reactivation Tb or Chronic PTb is more common in those who acquire the initial infection > ___ years of age
7
MC pulmonary sites of reactivation Tb
1) Original parenchymal focus 2) Lymph nodes 3) Apical seedings
Apical seedings of Tb established during the hematogenous phase of the early infection
Simon foci
MC radiographic presentations of reactivation Tb
Extensive infiltrates or thick-walled cavities in the upper lobes
Pleural fluid findings in tuberculous pleurisy (6)
1) Yellow 2) SG 1.012-1.025 3) Protein 2-4 g/dL 4) Glucose low to normal (20-40 mg/dL) 5) Hundreds to thousands of WBCs per mm3 with early predominance of PMNs followed by a high percentage of lymphocytes 6) AFB RARELY POSITIVE
MC form of cardiac Tb
Tb pericarditis
Most clinically significant form of disseminated Tb
Miliary Tb
MC form of extra pulmonary Tb in children
Scrofula or Tb of the SUPERFICIAL LNs
Scrofula: Unilateral vs Bilateral
Unilateral
Most serious complication of Tb in children
Tb of the CNS
Tb of the CNS: Often the site of greatest involvement
Brainstem
3 stages of CNS Tb
St 1 (stage of irritability) - nonspecific, St 2 (pressure or convulsive stage) - generalized and focal neurologic signs, St 3 (paralytic or terminal stage) - Coma, hemiplegia or paraplegia, hen, decerebrate posturing, deterioration of vital signs and death
Most important lab test for diagnosis of Tb men
CSF studies
CSF findings in Tb men
1) WBC 10-500 cells/mm3 with PMNs predominant in the early phase and lymphocytes later in the disease process 2) CSF glucose less than 40 but rarely less than 20 mg/dL 3) Protein markedly high 400-5000 mg/dL
Brain CT or MRI findings in Tb meningitis
1) Basilar enhancement 2) Communicating hcp 3) Cerebral edema 4) Early focal ischemia
MC location of brain tuberculoma in children
Infratentorial or at the base of brain near the cerebellum
Classic manifestation of Tb spondylitis
Pott’s disease
Tb enteritis usually involves
Jejunum and ileum near Peyer patches and the appendix
Standard therapy for intrathoracic Tb in children
2 HRZE, 4 HR
Adverse reactions to commonly used Tb drugs: Ethambutol
1) Reversible optic neuritis 2) Decreased red-green color discrimination 3) GI disturbances 4) Hypersensitivity
Adverse reactions to commonly used Tb drugs: INH
1) Hepatitis 2) Peripheral neuritis 3) Hypersensitivity 4) Optic neuritis
Adverse reactions to commonly used Tb drugs: Pyrazinamide
1) Hepatotoxicity 2) Hyperuricemia 3) Arthralgias 4) GI tract upset
Adverse reactions to commonly used Tb drugs: Rifampin
1) Orange discoloration of secretions 2) Vomiting/GI intolerance 3) Hepatitis, increased if given with INH 4) Influenza-like reaction 5) Thrombocytopenia 6) Pruritus 7) Oral contraceptives may be ineffective
Duration of treatment for bone and joint, disseminated and CNS Tb
9-12 months
Interaction of some antiretrovirals and rifampin
1) Subtherapeutic blood levels of protease inhibitors and non-nucleoside reverse transcriptase inhibitors 2) Toxic levels of rifampin
Corticosteroids are beneficial in patients with what types of Tb
1) Meningitis 2) Endobronchial 3) Acute tb pericardial effusion 4) Miliary tb
Highest priority of any Tb control program
Case finding and treatment
Official recommendation of WHO for BCG in high risk Tb populations
Single dose BCG during infancy
Best use of BCG vaccination
Prevention of life-threatening forms of Tb in infants and young children
