The role of chest radiography

Clinical description

Radiography-based examinations are crucial in a variety of medical setting and at all major levels of health care. Chest radiography, or chest x-ray (CXR) is an essential tool for early detection of TB, and therefore fundamental to achieving the targets set out in WHO’s End TB Strategy5.

5 http://apps.who.int/iris/bitstream/10665/252424/1/9789241511506-eng.pdf. Accessed 4 April 2017.

National Tuberculosis Control Programme 37 CXR is a rapid imaging tool that allows for easy identification of lung abnormalities. It has high sensitivity, but limited specificity for the diagnosis of pulmonary TB. It is therefore especially suitable for screening and triaging. Recommendations for CXR are included in several WHO policies, summarized below.

Classic radiographic findings suggestive of TB, particularly in patients who are not immunocompromised, include:

• Upper lobe infiltrates
• Cavitary lesions
• Hilar and/or para-lymphadenopathy

In patients with primary PTB and HIV infection, the x-ray findings can be quite different:

• Lower lobe infiltrates
• A Miliary or “scattered seed”-like pattern

CXR is a sensitive tool for screening for active TB. It has a much higher sensitivity for pulmonary TB than screening for TB symptoms, and can be used as a supplementary diagnostic tool, although the specificity is low. While a bacteriologically confirmed diagnosis is always preferable, an abnormal CXR is an indication for full diagnostic evaluation.

CXR is an important tool for childhood TB. It is useful in the diagnosis of pulmonary and extrapulmonary TB in children, in combination with history, evidence of TB infection and microbiological testing.

CXR can improve the efficiency of using the Xpert MTB/Rif assay. CXR and further clinical assessment can be used to triage who should be tested with Xpert MTB/Rif to reduce the number of individuals to be tested with Xpert MTB/Rif, as well as to improve the pre-test probability of TB.

CXR can assist the diagnosis of TB among PLHIV initiating treatment of latent TB infection.

Individuals with TB symptoms or any radiological abnormality should be investigated further for active TB and other conditions.

CXR is also an essential technology for TB prevalence surveys.

4.2.12 FASH ultrasound (Focused Assessment with Sonography for HIV- associated TB)

FASH will be implemented in central and selected district hospitals to improve TB diagnosis among high risk groups. 6 Key application and interpretation

• Presumptive TB cases, particularly HIV infected patients with low CD4 counts and

weight loss, night sweats and chronic cough, should be investigated by FASH

• Pericardial effusion, (unilateral) pleural effusions and, to a lesser extent, ascites can be

signs of extra-pulmonary TB 6 FASH ultrasound (Focused Assessment with Sonography for HIV-associated TB)

38 National Tuberculosis Control Programme

• Enlarged abdominal lymph nodes and focal micro-abscesses in the spleen (and liver)

1.!Introduction!of!FASH,!FAST!and!PLUS! are frequently seen in disseminated !TB !"#$%&'()*+&,(%#(-#./012#./03#4%)#5670# # !# #! #! #! # ! # ! ( "

• In the resource-poor high-prevalence setting many FASH findings are specific enough

Focused(Assessment(with(Sonography(for(HIV/TB((FASH)(has(been(developed(in(recent( #$%&'()"*''(''+(,-"./-0"1$,$234506"7$3"89:;<=">#*18?"04'"@((,")(A(B$5()"/,"3(%(,-" 1 ! to initiate empiric TB treatment 6(43' years "-$"0(B5"/,"-0(")/42,$'/'"$7"(C-34D5&B+$,436"4,)")/''(+/,4-()"7$3+'"$7" (to(help(in(the(diagnosis(of(extraCpulmonary(and(disseminated(forms(of( -&@(3%&B$'/'"><=?".0/%0"43("73(E&(,-B6"'((,"/,"54-/(,-'"/,7(%-()"./-0"-0("0&+4," tuberculosis((TB)(which(are(frequently(seen(in(patients(infected(with(the(human( FASH ultrasound should be considered for all patients with a high clinical probability of /++&,$)(7/%/(,%6"A/3&'">89:?F"<0("+4/,"$@G(%-/A('"$7"-0/'"&B-34'$&,)"(C4+"43("-$" immunodeficiency(virus((HIV).(The(main(objectives(of(this(ultrasound(exam(are(to( disseminated and extra-pulmonary TB. Patients with HIV infection belong to this group;

)(-(%-"(77&'/$,'".0/%0"+/20-"'&22('-"5B&34BH"5(3/%43)/4B"$3"4@)$+/,4B"<=H"4'".(BB"4'" particular patients with low CD4 counts and therefore, severe immunosuppression is at highest detect(effusions(which(might(suggest(plural,(pericardial(or(abdominal(TB,(as(well(as( risk. The patient should be screened for clinical symptoms of TB. Frequently, clinical (and (,B432()"4@)$+/,4B"B6+50",$)('"4,)"7$%4B"B('/$,'"/,"-0("'5B((,"4,)"B/A(3H".0/%0"+/20-" enlarged(abdominal(lymph(nodes(and(focal(lesions(in(the(spleen(and(liver,(which(might( sonographic) findings of disseminated TB become apparent a few weeks after HIV infected '&22('-"-0(")/''(+/,4-()"$3"+/B/436"<="(,%$&,-(3()"/,"'(A(3(B6"/++&,$%$+53$+/'()" suggest(the(disseminated(or(miliary(TB(encountered(in(severely(immunocompromised( patients start antiretroviral therapy (ART) and the immune reaction improves, a phenomenon 54-/(,-'"><4@B("I?F" patients((Table(1).( known " as “demasking IRIS” (immune reconstitution inflammatory syndrome).

( 3489:#!;"#*18"(C4+/,4-/$,J"53$@("5$'/-/$,"4,)"7/,)/,2'" Figure 4.2-1 FASH exam: Probe position and possible FASH findings Table!1:(FASH(examination:(probe(position(and(findings( " Probe position No. Localization Possible FASH Findings 1 Epigastric - pericardial effusion angle - abdominal lymph nodes 2 Right axillary - pleural effusion line thorax 3 Right axillary - focal liver lesions line abdomen - ascites in the pouch of Morison 4 Left axillary - pleural effusion line thorax 5 Left axillary - focal spleen lesions line abdomen - ascites in spleno-renal pouch 6 Suprapubic - ascites in the pouch of pelvis Douglas " ( ( 4.3 " TB Diagnostic pathways ( " Early identification of TB cases and putting patients on effective treatment is important for TB PointCofCcare(limited(ultrasound((PLUS)(techniques(have(pioneered(the(use(of( K$/,-D$7D%43("B/+/-()"&B-34'$&,)">KLM1?"-(%0,/E&('"04A("5/$,((3()"-0("&'("$7" control and reducing TB-related mortality, particularly in TB/HIV co-infected patients.

ultrasound(outside(its(wellCestablished(use(in(the(imaging(department,(especially(since( &B-34'$&,)"$&-'/)("/-'".(BBD('-4@B/'0()"&'("/,"-0("/+42/,2")(543-+(,-H"('5(%/4BB6"'/,%(" the(midC1990s.(Diagnostic(ultrasound(has(been(used(for(decades(in(the(diagnosis(of(a( -0("+/)DINNO'F"P/42,$'-/%"&B-34'$&,)"04'"@((,"&'()"7$3")(%4)('"/,"-0(")/42,$'/'"$7"4"

• Diagnosis of tuberculosis depends on the identification of the tubercle bacilli in sputum

variety(of(diseases,(but(initially(the(technology(was(mainly(used(by(radiologists(and( by microscopy, culture or newer molecular tests OR a strong suspicion of TB based on A43/(-6"$7")/'(4'('H"@&-"/,/-/4BB6"-0("-(%0,$B$26".4'"+4/,B6"&'()"@6"34)/$B$2/'-'"4,)" sound clinical judgement.

imaging(specialists.(During(the(past(twenty(years(ultrasound(scanners(have(found(their( /+42/,2"'5(%/4B/'-'F"P&3/,2"-0("54'-"-.(,-6"6(43'"&B-34'$&,)"'%4,,(3'"04A("7$&,)"-0(/3" way(out(of(imaging(departments.(Clinicians(from(diverse(specialties(are(now(using( .46"$&-"$7"/+42/,2")(543-+(,-'F"QB/,/%/4,'"73$+")/A(3'("'5(%/4B-/('"43(",$."&'/,2"

• The overall diagnosis of TB starts with TB screening which was presented in the

ultrasonography(to(examine(particular(organs(and(disease(processes(and(to(assist( &B-34'$,$234506"-$"(C4+/,("543-/%&B43"$324,'"4,)")/'(4'("53$%(''('"4,)"-$"4''/'-" previous section.

53$%()&3('"3(B(A4,-"-$"-0(/3"'5(%/4B-6F"*"3(%(,-"3(A/(.<2"+(,-/$,'"4@$&-"RO"+()/%4B" procedures(relevant(to(their(specialty.(A(recent(review (mentions(about(20(medical(

• Once a presumptive TB client is identified, the decision for further diagnostics will be

'5(%/4B-/('"$-0(3"-04,"34)/$B$26H"&'/,2"KLM1"-(%0,$B$26"/,"-0(/3")4/B6"3$&-/,(F" specialties(other(than(radiology,(using(PLUS(technology(in(their(daily(routine.( made as per information on 15(%/4B-/('"B/S("30(&+4-$B$26H",(503$B$26"4,)"4,4('-0('/$B$26"@(,(7/-"73$+"-0(" Specialties(like(rheumatology,(nephrology(and(anaesthesiology(benefit(from(the( /++()/4-("4A4/B4@/B/-6"$7"4,4-$+/%4B"/,7$3+4-/$,">#/2FIFI?F" o Risk of MDR TB immediate(availability(of(anatomical(information((Fig.1.1).( " o HIV test result ( o Age National Tuberculosis Control Programme 39 ! o Association with another high-risk group. The revised national algorithm for TB diagnosis, drug susceptibility testing and management of the patients is based on the results of recommended tests.

• All individuals who present with symptoms of pulmonary TB should have a

bacteriological confirmation either with Xpert MTB/RIF or sputum microscopy.

• Use of rapid screening tests, such as Xpert or LPA, is recommended for screening of

drug resistant TB in nationally prioritized patients groups.

• Supportive evidence from X-ray abnormalities or histopathological examinations may

be used to investigate patients for whom the clinician has a high suspicion of TB despite the negative results from confirmatory tests.

• Interpretation of test results and decision to treat for TB should be made carefully to

avoid patient mismanagement.

• The choice of microscopy and Xpert MTB/RIF assay as a primary test for TB depends

on the age, HIV status, risk of harbouring drug-resistant TB and the anatomic site of presumptive TB disease.

The following algorithms are intended to guide management of presumptive TB cases based on assessment of risk conditions, availability of diagnostics and patient conditions.

• Overall approach to presumptive TB case ( Figure 4.31)
• HIV-positive presumptive TB with no danger signs (Figure 4.32)
• HIV-positive presumptive TB with danger signs (Figure 4.33).

Figure 4.3-1: General diagnostic approach to presumptive TB cases in Malawi *** for those with negative Rif resistant result on second test ,clinicians need to use additional patient level information to guide further action 40 National Tuberculosis Control Programme Figure 4.3-2: TB diagnosis for critically ill HIV-positive patients ***For PLHIV who have CD4 counts ≤100 cells/μl or are seriously ill with one or more danger signs, a urine LF-LAM assay may also be used where ever it is available **** If patient is diagnosed through LF LAM, Final patient classification will depend on clinical assessment of patients.

*****For patients who cannot produce sputum LF -LAM should be used.

****** The danger signs are: respiratory rate >30/min, temperature >39OC, heart rate >120/min and unable to walk unaided.

Presumptive treatment of TB for PLHIV The rationale for presumptive TB treatment for PLHIV is to prevent death in situations where expedited diagnosis of TB is not possible or feasible due to the clinical condition of the patient or where there is limited access to TB diagnostic services.

National Tuberculosis Control Programme 41 Figure 4.3-3: Presumptive TB HIV positive with no danger sign 42 National Tuberculosis Control Programme