Presentation on theme: "Paper PBL 15 – Extreme Lethargy Group 4 MMC Kate, James, Lee, Quaderi, Jeeves, Satwik, Helen, Shravya, Jo, Nikhil."— Presentation transcript:
Paper PBL 15 – Extreme Lethargy Group 4 MMC Kate, James, Lee, Quaderi, Jeeves, Satwik, Helen, Shravya, Jo, Nikhil
Case History Mr Josh Felix 25 years old, roadie for a “grunge band” Grew up in Wagga Wagga, moved to Glen Waverly 5 years ago Presenting Complaint: 6 week history of increasing lethargy, productive cough, weight loss he assumed it was exacerbation of asthma
Assuming 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…
Josh’s History Productive cough – sputum thick, light brown, coughing one “table spoon” each morning No haemoptysis Mild dsypnoea on exertion No chest pain Fever; chills & muscle aches followed by profuse sweating Asthma since age 5; 3-4 attacks each year; uses inhalers intermittently No other medications Smokes 25 cigarettes per day, done so for 7 years Non-IVDU; Alcohol: 4 drinks per day binges per month
Further 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 relevance Immunisations – can’t be recalled Dietary Hx – erratic diet, mainly junk food, no fresh fruit or vegetables
Physical Examination Gaunt, white male; not acutely ill. Pulse 98/min BP 130/74 mmHg RR 16/min Oral temp 37.6°C Weight 58kg Hyperexpanded chest, soft rhonchi bilaterally, no other focal resp signs CVS normal, no hepatomegaly Additional notes of tattoos, multiple piercings, cigarette pack in t-shirt sleeve and no BCG scar
Initial Investigation Results FBE: Hb 109g/L, WBC 14.5x10^9/L, platelets 140x10^9/L HIV serology: negative LFT’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 normal Sputum Gram stain: WBC +++, mixed Pos and Neg organisms Sputum Culture: normal oral flora Special Cultures: – Burkholderia pseudomallei: pending – AFB stain: positive ++ (first specimen) – AFB culture: in progress
Differential Diagnosis Country of birth: Australia Productive cough – sputum thick, light brown, coughing one “table spoon” each morning Mild dsypnoea on exertion Fever; chills & muscle aches followed by profuse sweating Symptoms progressively worse over 6 weeks with weight loss FHx – 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 scar 7 pack years smoking, high alcohol intake, poor nutrition Gaunt, white male; not acutely ill, weight 58kg Hyperexpanded chest, soft rhonchi bilaterally, no other focal resp signs LFT’s: intrahepatic pattern with GGT CXR: hyperexpanded lung fields, right apex opacity with 2x2cm cavity, no cardiomegaly, hilar regions normal Sputum AFB stain: positive ++ Summary of Findings Tuberculosis Pneumonia/Atypical Pneumonia Asthma exacerbation COPD Bronchiectasis Lung carcinoma HIV Lung abscess
I(x) Active PTB Diagnostic Chest X-Ray Abnormal CXR often found with no symptoms but reverse extremely rare PTB is unlikely in absence of radiographic abnormalities Exception is miliary TB or non-respiratory TB Findings Patchy or nodular shadows in the upper zones Loss of volume and fibrosis (with or without cavitation) Calcification may be present Similar CXR findings Histoplasmosis, fungal infections (cryptococcosis, coccidiomycosis, blastomycosis, aspergillosis), bronchial carcinoma, cavitating pulmonary Infarcts EVERY EFFORT MUST BE MADE TO OBTAIN MICROBIOLOGICAL EVIDENCE
A cavity is a walled hollow structure within the lungs. Diagnosis is aided by noting: wall thickness wall outline changes in the surrounding lung
I(x) Active TB Culture Clinical Samples sputum, pleura & pleural fluid, urine, pus, ascites, bone marrow, CSF Induce if non-productive (bronchoscopy & lavage) Prolonged culture – 12wks AFB – acid fast bacilli Ziehl-Neelsen stain Acid fast bacilli are stained bright red and stand out against a blue background Resistant to de-colouring when washed with acid
I(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
I(x) Latent TB When 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.
Investigations – 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.
Investigations – 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 problems – Does not boost responses measured by subsequent tests, which can happen with tuberculin skin tests – Is not affected by prior BCG vaccination.
Pathophysiology of TB
The 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.
Infection & Dormancy M. 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.
Infection & 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.
Reactivation The 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
Clinical Manifestations of TB Pulmonary disease – Primary disease Occurs soon after the initial infection in areas of high TB transmission, often in children. Generally spreads to the upper zones of the lung The 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.
Clinical Manifestations of TB Pulmonary disease – Post-primary Also 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.
Clinical Manifestations of TB Extrapulmonary disease – Miliary or Disseminated Tuberculosis Due 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 appear – Tuberculous meningitis Seen 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.
Clinical Manifestations of TB Extrapulmonary disease – Cardiac Pericarditis and pericardial effusions This can lead to constrictive pericarditis due to fibrosis and calcification an can be fatal. – Eyes Choroiditis – Genitourinary Pyuria and haematuria, flank pain, frequency, dysuria, nocturia – GIT Peritoneal TB causing abdominal pain and GI upset (AFB in ascites). – Skeletal Vertebral collapse, septic arthritis and osteomyelitis – Skin Jelly-like nodular rash (lupus vulgaris) and possible erythema nodosum due to hypersensitivity reaction to infection
Bed rest doesn’t affect outcome Hospitalisation: – Ill, smear positive, highly infectious patients – Esp in multi-drug resistant TB Continuous self-admin of drugs for 6 months vital for successful Rx – Lack of compliance 5% pts unresponsive to Rx – Resistance to anti-TB drugs increasing Isoniazid resistance 4-6% Multidrug resistance 1% Before treatment: – Test FBC, liver, and renal function Need to alter dosages in pts with liver/renal failure – Test colour vision & acuity Ethambutanol can cause (reversible) ocular toxicity
Treatment 6 months – Rifampicin mg, daily – Isoniazid 300 mg daily – Pyrazinamide 2.5g, 3/week First 2 months – Ethambutanol 30 mg/kg 3/week First 2 months Longer regimen: – For bone TB (9 months), tuberculosis meningitis (1yr) NEVER use monotherapy – Except when using Isoniazid for latent TB Rx DOTS: Directly Observed Therapy (short-course) – WHO incentive, to improve detection and compliance – DOT plan: treating physician/TB nurse – Bi-weekly, thrice-weekly treatment instead of daily
Side Effects Rifampicin: – Hepatitis – Small rise in AST acceptable – Stop if bilirubin rises – Orange discolouration of urine & tears – Inactivation of the Pill Isoniazid – Hepatitis – Neuropathy – Pyridoxine deficit – Agranulocytosis Ethambutanol – Optic neuritis (colour vision fist to deteriorate) – Pyrazinamide: Hepatitis – Athralgia (CI: gout, prophyria)
Resistance Seen in non-compliant pts MDR (multi-drug resistance) – High mortality (esp in HIV pts) Use at least 3 drugs to which organism is sensitive Follow-up – Patients should be seen regularly for duration of chemotherapy – Once more after 3 months to check for relapse Chemoprophylaxis: – Pts with x-ray xhanges compatible with TB, but about to undergo immunosuppresive long-term Rx (ie dialysis) – Isoniazid mg/day
Drug 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.
Result 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 – 1.Previous treatment for TB especially if prolonged 2.Contact with a patient known to have drug resistant TB or live in an area with high drug-resistant TB prevalence 3.Immunocompromised (HIV in particular) 4.Poor compliance 5.Culture +ve after 2 months treatment Can take up to 2 years to treat with drugs less potent, more toxic and more expensive. Higher mortality rate.
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. ResistanceAlternative INH, RIFLEVO, PZA, EMB, AMK INH, RIF, EMBLEVO, PZA, AMK, CS +/- PAS/ETH INH, RIF, PZALEVO, EMB, AMK, CS +/- PAS/ETH INH, RIF, PZA, EMBLEVO, AMK, CS, PAS/ETH, +/- one more drug First Line DrugCross-resistance INHEthionamide RIFAll Rifamycins PZA and EMBNone
Worldwide 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.
Clinical 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 TB – Those with reactivated TB – Impaired immunity ( * CD4 count < 200 per microlitre) CharacteristicLate HIV infection * Early HIV infection Pulmonary : extra pulmonary disease 50:5080:20 Clinical presentationOften resembles primary TB Often resembles post-primary TB Chest radiograph Intrathoracic lymphadenopathy CommonRare Lower lobe involvement CommonRare CavitationRareCommon Tuberculin responseRareCommon Sputum smear positivity Less commonCommon Adverse drug reactions CommonRare Relapse after treatment CommonRare
Tuberculin 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 findings – Atypical radiographic findings – Higher prevalence of extra-pulmonary TB at inaccessible sites – Resemblance to other opportunistic pulmonary infections Mycobacterium culture is most useful in Dx in such cases
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 (2 nd 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.
What do all of these people have in common... John Keats – english poet movie Bright Star with Abbie Cornish. Singer Tom Jones, of“It’s not unsual” fame. Had TB at each 12 (obviously recovered). Singer Cat Stevens (Yusam Islaf) was close to death with TB in Nicole Kidman’s character Satine, died from TB in Moulin Rouge...they’ve all had tuberculosis