Tuberculosis - Cases in the form of questions and answers PDF

Preview

Summary

TUBERCULOSIS: CASE 1: Miss IG is a 23-year-old woman who presents with a four-week history of coughing, fever, exhaustion, and weight loss. Prior to this Miss IG was well and had recently returned from travelling across Asia. She was referred to a chest physician by her GP. On investigation the foll...

Description

TUBERCULOSIS: CASE 1: Miss IG is a 23-year-old woman who presents with a four-week history of coughing, fever, exhaustion, and weight loss. Prior to this Miss IG was well and had recently returned from travelling across Asia. She was referred to a chest physician by her GP. On investigation the following was noted: Chest X-ray: infiltrative destructive changes in the left upper lung lobe. Mycobacterium tuberculosis detected in bronchial aspirate and sputum. Bloods: Within reference range with exception of raised Erythrocyte sedimentation rate (78 mm) and CRP concentration (65 mg/L.) A diagnosis of Active Pulmonary Tuberculosis was made and multi drug treatment was commenced with the following regime: Rifater Five tablets daily Ethambutol 800mg daily Comment on the suitability of this regime and describe what counselling you would provide for Miss IG regarding her medication. Standard treatment consists of an initial treatment with the four drugs, rifampicin, isoniazid, pyrazinamide and ethambutol for two months (as prescribed for Miss IG) followed by a further 4- 7 months treatment with rifampicin and isoniazid alone. Ethambutol may be omitted if the risk of isoniazid resistance is low however Miss IG’s recent travel may have increased risk of isoniazid resistance. Fixed dose combination tablets are first choice to improve adherence Counselling points: Importance of adhering with the medication regime exactly as prescribed and completing the full course which is likely to be at least 6 months if not longer. This must be fully explained so that the patient understands the profound consequences of non-adherence. Interactions with other medications must be explored, for this patient it is important to inform her of the interaction with contraceptives if relevant Side effects of medicines should be explained e.g the patient may experience nausea, mild stomach pains which may diminish as treatment continues but should be reported at the next clinic visit. Rifampicin stains urine and tears red/ orange and patient need not be alarmed by this but care with contact lenses as may stain. Patients may also experience pain, tingling or numbness in hands and feet (side effect of isoniazid) and some joint pain.

The patient should immediately report to the clinic if any of these symptoms become severe, or if they develop rash, yellow skin or eyes, or dark-coloured urine (liver toxicity). Ethambutol can cause visual disturbances (loss of visual acuity and colour recognition) and the importance of regular vision tests should be stressed to the patient who should also be counselled to report any changes in vision or eyes. People prescribed TB treatment should be advised limit alcohol intake. Students must demonstrate knowledge of what clinical information would be provided. Full marks cannot be achieved if student states would discuss side effects, interactions without demonstrating knowledge of what this would involve With reference to the therapy initiated, explain the rationale for this combination of drugs and the properties that make them suitable for the treatment of TB. Answer: 4 concurrent drugs, with different MOAs, used in combination to reduce bacterial population and risk of resistance Properties: Rifampicin: slow, time-dependent bactericidal effect in growth phase, long PAE, can eliminate TB bacteria, require 4x rifampicin concentration for lag phase Isoniazid: rapid strongly bactericidal in growth phase (less effective in lag phase), cannot eliminate TB bacteria (due to development of resistance), required 64x concentration of isoniazid for effective action in lag phase Together, rifampicin and isoniazid (Rifinah) have v long PAE (>5½d): suitable for daily dosing and treatment of slow growing bacteria. Ethambutol: bacteriostatic, reduces growth to make other bactericidal agents more effective Pyrazinamide: increases susceptibility of TB bacteria to other drugs, so shortens treatment time A week after therapy initiation, Miss IG experienced severe nausea, anorexia and malaise. Blood tests were repeated, and Miss IG was closely monitored: Week Ref range Baseline 2 3

AST u/l 0-35

19 163 1020

ALT u/l 2-50 15 109 1547

ALP u/l 30-130 67 90 145

GGT u/l...