1Paper PBL 15 – Extreme Lethargy Group 4 MMCKate, James, Lee, Quaderi, Jeeves, Satwik, Helen, Shravya, Jo, Nikhil
2Case History Mr Josh Felix 25 years old, roadie for a “grunge band” Grew up in Wagga Wagga, moved to Glen Waverly 5 years agoPresenting Complaint:6 week history of increasing lethargy, productive cough, weight loss he assumed it was exacerbation of asthma
3Assuming it was asthma, he attended 24 hour medical clinic for repeat prescription of asthma medications given salmeterol, fluticasone inhalers, prednisolone 5mg and amoxycillin 500mg for his cough.Returned 5 days later due to worsening symptoms. New doctor on duty takes thorough history and examination to find…Salmeterol – long acting B-agonist – symptom controllerFluticasone – coticosteroin preventor – inhaled steroid so wash mouth out to prevent thrushPrednisolone – oral steroid for acute attacksAmoxycillin – gram positves, not staph Aureus or B lactamase producing bacteria
4Josh’s HistoryProductive cough – sputum thick, light brown, coughing one “table spoon” each morningNo haemoptysisMild dsypnoea on exertionNo chest painFever; chills & muscle aches followed by profuse sweatingAsthma since age 5; 3-4 attacks each year; uses inhalers intermittentlyNo other medicationsSmokes 25 cigarettes per day, done so for 7 yearsNon-IVDU; Alcohol: 4 drinks per day binges per monthHow many pack years? – 7 pack years
5Further Relevant History FHx – Josh’s mother was treated for “spitting blood” 18 years ago. Brother has severe asthma.Contact Hx – members of band have a “cold”Sexual Hx – many different female partners, often unprotected. Sex with a man on once.Travel Hx – Never travelled overseas. Recently spent 2 months in Darwin.Animal contact – none of relevanceImmunisations – can’t be recalledDietary Hx – erratic diet, mainly junk food, no fresh fruit or vegetables
6Physical Examination Gaunt, white male; not acutely ill. Pulse 98/min BP 130/74 mmHgRR 16/minOral temp 37.6°CWeight 58kgHyperexpanded chest, soft rhonchi bilaterally, no other focal resp signsCVS normal, no hepatomegalyAdditional notes of tattoos, multiple piercings, cigarette pack in t-shirt sleeve and no BCG scarRhonchi – coarse low pitched “rattle” heard on auscultation usually due to mucous/secretion/partial obstruction in bronchi
7Initial Investigation Results FBE: Hb 109g/L, WBC 14.5x10^9/L, platelets 140x10^9/LHIV serology: negativeLFT’s:bilirubin 19 (N<17)ALP 110 (N<120)ALT 240 (N<56)GGT 150 (N<75)Albumin 26 g/L (N35-45)CXR: hyperexpanded lung fields, right apex opacity with 2x2cm cavity, no cardiomegaly, hilar regions normalSputum Gram stain: WBC +++, mixed Pos and Neg organismsSputum Culture: normal oral floraSpecial Cultures:Burkholderia pseudomallei: pendingAFB stain: positive ++ (first specimen)AFB culture: in progress
8Differential Diagnosis Summary of FindingsCountry of birth: AustraliaProductive cough – sputum thick, light brown, coughing one “table spoon” each morningMild dsypnoea on exertionFever; chills & muscle aches followed by profuse sweatingSymptoms progressively worse over 6 weeks with weight lossFHx – Josh’s mother was treated for “spitting blood” 18 years ago.Sexual Hx – many different female partners, often unprotected. Sex with a man on once.Travel Hx – nil overseas, 2 months in Darwin.Immunisations – can’t be recalled, no HBG scar7 pack years smoking, high alcohol intake, poor nutritionGaunt, white male; not acutely ill, weight 58kgHyperexpanded chest, soft rhonchi bilaterally, no other focal resp signsLFT’s: intrahepatic pattern with GGTCXR: hyperexpanded lung fields, right apex opacity with 2x2cm cavity, no cardiomegaly, hilar regions normalSputum AFB stain: positive ++TuberculosisPneumonia/Atypical PneumoniaAsthma exacerbationCOPDBronchiectasisLung carcinomaHIVLung abscessWhy not DDx?Pneumonia – 6 weeks is really too long a duration. Atypical – not caused by Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalisAsthma – no response to meds, weight loss, duration, aches, fever etcCOPD – only mild dyspnoea, fever, WBC raised ie. “infective pattern”Lung carcinoma – fevers, chillsHIV – serology negative
10I(x) Active TB Routine; FBE ↑ WCC (Infection) ↓ Hb (Anaemic of chronic disease)U&E’s(baseline)LFT’sESR/CRP(inflammation/infection)
11I(x) Active PTB Diagnostic Chest X-Ray Abnormal CXR often found with no symptoms but reverse extremely rarePTB is unlikely in absence of radiographic abnormalitiesException is miliary TB or non-respiratory TBFindingsPatchy or nodular shadows in the upper zonesLoss of volume and fibrosis (with or without cavitation)Calcification may be presentSimilar CXR findingsHistoplasmosis, fungal infections (cryptococcosis, coccidiomycosis, blastomycosis, aspergillosis), bronchial carcinoma, cavitating pulmonary InfarctsEVERY EFFORT MUST BE MADE TO OBTAIN MICROBIOLOGICAL EVIDENCE
12changes in the surrounding lung A cavity is a walled hollow structure within the lungs. Diagnosis is aided by noting:wall thicknesswall outlinechanges in the surrounding lung
13I(x) Active TB Culture Clinical Samples sputum, pleura & pleural fluid, urine, pus, ascites, bone marrow, CSFInduce if non-productive (bronchoscopy & lavage)Prolonged culture – 12wksAFB – acid fast bacilliZiehl-Neelsen stainAcid fast bacilli are stained bright red and stand out against a blue backgroundResistant to de-colouring whenwashed with acid
14I(x) Active TB Other Imaging for non-respiratory TB (CT, XR etc) PCR – rapid identification of sensitivity/resistance (rifampicin)Biopsies – pleura, lymph nodes, solid lesions etc
15I(x) Latent TBWhen infected with M Tuberculosis, but do not have active tuberculosis disease.Patients are not infectious.TB infections in Australia are predominantly due to reactivation of latent infection in people who were previously infected in their countries of birth or during their childhood when TB was more common in Australia.Simply put, the immune system ‘walls off’ the TB bacilli (in a granulomatous lesion), which can lie dormant for years. It is kept in this state by the cell-mediated immune system.Main Risk: around 10% of these people will develop active TB during some point in their lives – the greatest risk being within the first 2 years of being infected.Usually when their immune system is weakened.
17Investigations – Mantoux Test Readily available test for identifying latent M. tuberculosis infection.Works via a hypersensitivity reaction by the cell-mediated immune system to purified proteins from M. Tuberculosis (called Tuberculin).Tuberculin is injected intradermally in the forearm and the resulting area of induration (not erythema) is measured hours later.Positive result is based on the size of the induration, considering the risk-status and prevalence of TB in certain patients.Previous vaccination with BCC affects the way results are interpreted – may give false positives.Mantoux test should be done to identify people with an increased risk of TB, who would benefit from treating the latent infection.People with HIV, recent contacts of a person known to have clinically active TB, health care workers at increased risk, etc.
19Investigations – QuantiFERON-TB Assay A recently produced blood test that is able to measure quantitatively the production of cytokine Interferon-γ by lymphocytes sensitised to mycobacterial proteins using an ELISA technique.Advantages:Involves only 1 visit for a blood sample.No injection technique/subjective interpretation problemsDoes not boost responses measured by subsequent tests, which can happen with tuberculin skin testsIs not affected by prior BCG vaccination.
21The Pathogens TB is mainly caused by Mycobacterium tuberculosis. It can occasionally be caused by M. bovis or M. africanum.M. tuberculosis divides every hours.It is has a thick cell wall rich in lipids which prevents it taking up most stains and helps it resist digestion in macrophages.It is an aerobe & an acid fast bacillus.
22Infection & DormancyM. tuberculosis is spread in aerosols released by coughing/sneezing. It needs to be inhaled for infection to occur.Once inhaled, the bacteria reach the alveoli and are phagocytosed by the alveolar macrophages. Their lipid coating and ability to inhibit phagosome-lysosome fusion enables them to avoid digestion.This primary infection site is called a Ghon focus and is usually in the lower part of the upper lobe or the upper part of the lower lobe.The bacteria soon reach the lymph nodes at the hilum of the lung. The ghon focus and the infected node constitute a Ghon complex. These are visible on X ray.
24Infection & Dormancy ctd. The cell mediated immune reaction causes the formation of granulomas.These are composed of numerous leukocytes surrounding a core of infected macrophages.Most of the bacteria are destroyed but some enter a dormant state and survive by slowing down their metabolism.Cells in the centre of the granulomas undergo necrosis. The resulting dead matter looks pale and cheesy and is called caseous necrosis.Some granulomas undergo calcification and can be seen on X-rays after the disease ceases to be active.
26ReactivationThe primary infection may not be self limiting if the host is very young/old or immunocompromised.When the immune system is compromised in someone with latent TB (eg- HIV, diabetes, steroids) the M. tuberculosis can reactivate and cause secondary TB.Unlike the primary infection this is not self limiting.The bacteria can spread to many parts of the body and cause serious illness- eg: GIT, brain, liver
28Clinical Manifestations of TB Pulmonary diseasePrimary diseaseOccurs soon after the initial infection in areas of high TB transmission, often in children.Generally spreads to the upper zones of the lungThe lesion which is formed after infection is usually peripheral and is often accompanied by hilar or paratracheal lymphadenopathy.The initial lesion heals spontaneously in the majority of cases and may later be seen as a small calcified nodule (Ghon lesion)However in children and immunocompromised people, the lesion can increase in size and result in either a pleural effusion due to infiltration of bacteria into the pleural space, or the primary site may rapidly enlarge causing central necrosis and cavitation.Enlarged lymph nodes may compress bronchi, creating obstruction and hence segmental or lobar collapse.This presents generally with fever, malaise, cough, weight loss and haemoptysis.There may also be a small pleural effusion or erythema nodosum due to hypersensitivity reaction to the infective proves.
29Clinical Manifestations of TB Pulmonary diseasePost-primaryAlso known as reactivation TB, this results from endogenous reactivation of latent TB.This also favours the upper zones.Typically there is a gradual onset of symptoms over weeks to months.Presents with lethargy, malaise, anorexia and loss of weight with a fever and couch.Sputum may be mucoid, purulent or blood-stained. A pleural effusion or pneumonia may be the presenting feature.On examination, finger clubbing may be present in advanced disease. Often there are no physical signs in the chest though occasionally persistent crackles can be heard.Signs of pleural effusion, pneumonia and fibrosis may be seen.
30Clinical Manifestations of TB Extrapulmonary diseaseMiliary or Disseminated TuberculosisDue to haematogenous spread of bacteria and can be due to either primary infection or reactivation.Nonspecific signs such as fever, night sweats, anorexia, weakness and weight loss are the presenting symptoms.Eventually liver and spleen enlarge and tubercle lesions will appearTuberculous meningitisSeen most often in children or immunocompromised adults.Results from haematogenous spread of pulmonary disease.May present with headache and slight mental changes, weeks of low-grade fever, anorexia, malaise, anorexia and irritability.May evolve acutely with severe headache, confusion, lethargy, altered sensation and neck rigidity.Diagnosed via LP and if unrecognised it can be fatal.
31Clinical Manifestations of TB Extrapulmonary diseaseCardiacPericarditis and pericardial effusionsThis can lead to constrictive pericarditis due to fibrosis and calcification an can be fatal.EyesChoroiditisGenitourinaryPyuria and haematuria, flank pain, frequency, dysuria, nocturiaGITPeritoneal TB causing abdominal pain and GI upset (AFB in ascites).SkeletalVertebral collapse, septic arthritis and osteomyelitisSkinJelly-like nodular rash (lupus vulgaris) and possible erythema nodosum due to hypersensitivity reaction to infection
33Treatment Bed rest doesn’t affect outcome Hospitalisation: Ill, smear positive, highly infectious patientsEsp in multi-drug resistant TBContinuous self-admin of drugs for 6 months vital for successful RxLack of compliance 5% pts unresponsive to RxResistance to anti-TB drugs increasingIsoniazid resistance 4-6%Multidrug resistance 1%Before treatment:Test FBC, liver, and renal functionNeed to alter dosages in pts with liver/renal failureTest colour vision & acuityEthambutanol can cause (reversible) ocular toxicity
34Treatment 6 months Longer regimen: NEVER use monotherapy Rifampicin mg, dailyIsoniazid 300 mg dailyPyrazinamide 2.5g, 3/weekFirst 2 monthsEthambutanol 30 mg/kg 3/weekLonger regimen:For bone TB (9 months), tuberculosis meningitis (1yr)NEVER use monotherapyExcept when using Isoniazid for latent TB RxDOTS: Directly Observed Therapy (short-course)WHO incentive, to improve detection and complianceDOT plan: treating physician/TB nurseBi-weekly, thrice-weekly treatment instead of daily
35Side Effects Rifampicin: Isoniazid Ethambutanol Hepatitis Small rise in AST acceptableStop if bilirubin risesOrange discolouration of urine & tearsInactivation of the PillIsoniazidNeuropathyPyridoxine deficitAgranulocytosisEthambutanolOptic neuritis (colour vision fist to deteriorate)Pyrazinamide: HepatitisAthralgia (CI: gout, prophyria)
36Resistance Seen in non-compliant pts MDR (multi-drug resistance) High mortality (esp in HIV pts)Use at least 3 drugs to which organism is sensitiveFollow-upPatients should be seen regularly for duration of chemotherapyOnce more after 3 months to check for relapseChemoprophylaxis:Pts with x-ray xhanges compatible with TB, but about to undergo immunosuppresive long-term Rx (ie dialysis)Isoniazid mg/day
37Drug Resistance Mono-resistant TB – resistant to only one drug Poly-resistant TB – resistant to more than one drug but not the combination of isoniazid and rifampicin.Multidrug-resistant TB (MDR-TB)TB caused by bacteria resistant to at least isoniazid and rifampicin.Extensively drug-resistant TB (XDR-TB)TB caused by bacteria resistant to isoniazid and rifampicin (i.e. MDR-TB) plus any fluoroquinolone and any second-line anti-TB injectable drugs (amikacin, kanamycin or capreomycin)There is an estimated deaths per year from MDR-TB alone.
38Result from either primary infection with resistant bacteria or may develop secondarily in the course of treatment due to inadequate treatment regimens or poor compliance.Risk factors include –Previous treatment for TB especially if prolongedContact with a patient known to have drug resistant TB or live in an area with high drug-resistant TB prevalenceImmunocompromised (HIV in particular)Poor complianceCulture +ve after 2 months treatmentCan take up to 2 years to treat with drugs less potent, more toxic and more expensive. Higher mortality rate.
39Fluoroquinolone should be used where possible. Treatment is based on sensitivity testing with at least 3 drugs and an initial bactericidal injectable agent.Fluoroquinolone should be used where possible.XDR-TB Linezolid becomes mainstay treatment. Surgery is a limited option if disease localised.ResistanceAlternativeINH, RIFLEVO, PZA, EMB, AMKINH, RIF, EMBLEVO, PZA, AMK, CS +/- PAS/ETHINH, RIF, PZALEVO, EMB, AMK, CS +/- PAS/ETHINH, RIF, PZA, EMBLEVO, AMK, CS, PAS/ETH, +/- one more drugFirst Line DrugCross-resistanceINHEthionamideRIFAll RifamycinsPZA and EMBNone
41Worldwide TB is the most important opportunistic infection in HIV patients – its the commonest killer.Around 20 million people worldwide are co infected with HIV and TB.Dual infection of HIV and TB is very low in Australia (sub Saharan Africa > 70%). < 5% of AIDS patients in Australia develop active TB.1-7% of the HIV infected people with latent TB, will go on to develop active TB each year – a risk that is 4-25x higher than in non-HIV patients.TB affects the course of HIV infection: in vitro cytokines released because of Mycoplasma TB enhances HIV replication.HIV patients newly infected with Mycoplasma TB are more likely to develop symptomatic primary infection.
42Clinical manifestation depends on: CharacteristicLate HIV infection *Early HIV infectionPulmonary : extra pulmonary disease50:5080:20Clinical presentationOften resembles primary TBOften resembles post-primary TBChest radiographIntrathoracic lymphadenopathyCommonRareLower lobe involvementCavitationTuberculin responseSputum smear positivityLess commonAdverse drug reactionsRelapse after treatmentClinical manifestation depends on:CD4 status (level of immunosuppresion)Whether the TB is from recently acquired TB or from a reactivation of latent TB.HIV patients with preserved CD4 counts usually present with pulmonary TB.Atypical manifestations, extra pulmonary or disseminated TB are more common in:HIV patients with primary TBThose with reactivated TBImpaired immunity ( * CD4 count < 200 per microlitre)
43Tuberculin skin test should be part of the routine tests of every newly diagnosed HIV infection – test for latent TB.Also all newly diagnosed patients with TB should be asked for HIV risk factors, and tested for HIV.A Mantoux rxn of > 5mm is considered to indicated TB infection in people with HIV.Occasionally patients with pulmonary TB can have normal CXR - unusual.Diagnosis can be tricky particularly in advanced HIV:Frequently negative sputum smear findingsAtypical radiographic findingsHigher prevalence of extra-pulmonary TB at inaccessible sitesResemblance to other opportunistic pulmonary infectionsMycobacterium culture is most useful in Dx in such cases
44In HIV patients not on HAART, standard TB therapy is good. Rx of TB in HIV patients is complicated – only managed by expert doctors.Rifampicin has pharmacokinetic interactions with protease inhibitors (PI) – via hepatic cytochrome p450.There are also overlapping toxicities between HAART and anti-TB drugs: in particular hepatotoxicity, peripheral neuropathy and GI side effects.In HIV patients not on HAART, standard TB therapy is good.With those on HAART:Rifabutin is used instead of rifampicin.Or rifampicin could be used with efavirenz, or with ritonavir plus saquinavir.Isonazid, ethambutol and pyrazinamide are used in standard doses.MDR occurs in about 6% of cases of TB in HIV patients (2nd line Rx – aminoglycosides or quinolones).Paradoxical treatment rxn – patients who begin HAART and anti-TB drugs at same times can develop fever, lymph gland enlargement or pulmonary infiltration week later – due to heightened immune response to mycoplasma TB secondary to HAART therapy.
46What do all of these people have in common... ...they’ve all had tuberculosisJohn Keats – english poet movie Bright Star with Abbie Cornish.Singer Cat Stevens (Yusam Islaf) was close to death with TB in 1969.Nicole Kidman’s character Satine, died from TB in Moulin RougeSinger Tom Jones, of“It’s not unsual” fame. Had TB at each 12 (obviously recovered).