7 - Lung Infections Flashcards
What are the most likely organisms causing the following types of phneumonia:
- Community acquired
- Hospital acquired (>48h post admission)
- Aspiration
- Immunocompromised
Community: S.Pneumoniae, Haemophilus influenzae, Moraxella cattarhalis (atypical include Mycoplasma pneumoniae, S.Aureus, Legionella, Chlamydia)
Hospital: Gram -ve enterobacteria, Staph Aureus, Pseudomonas, Klebsiella
Aspiration: oropharyngeal anaeorobes
Immunocompromised: fungi, viruses (CMV, HSV), Pneumocystis jirovecii, S.Pneumoniae, S.Aureus
What are some sings and symptoms of pneumonia?
Symptoms: fever, rigors, malaise, dyspnea, cough, purulent sputum, pleuritic pain, haemoptysis
Signs: pyrexia, consolidation on CXR, crackles, dull to percussion, reduced expansion, confusion, increased vocal resonance, pleural rub
What investigations should you do if a patient comes in with suspected pneumonia and what will they show?
- O2 sats and ABGs if <92%
- Blood tests: FBC, U+Es, LFTs, CRP
- Blood cultures: if febrile
- CXR: consolidation, cavitation or pleural effusion
- Sputum culture and microscopy
- Check legionella/pneumonococcal urinary antigens
- ?Pleural effusion aspiration and culture
What are some causes of consolidation on a CXR?
- Pneumonia
- TB
- Lung cancer
- Lobar collapse
- Haemorraghe
How is pneumonia severity graded?
CURB-65
Higher mortality with higher score
If someone has a high CURB65 score, what do you need to screen for?
Atypicall pneumonia screen by doing serology and urine legionella test
How is pneumonia managed in hospital?
- Antibiotics
- Oxygen to keep sats>94% and PaO2>8
- IV fluids if dehydration, shock or anorexia
- Paracetamol for pleurisy
- VTE prophylaxis
- ITU referral if high CURB65
What antibiotics are generally used for community acquired pneumonia in UHL?
Mild/CURB 1: amoxicillin or doxycycline
Moderate/CURB2: amoxicillin + doxycycline (or clarithromycin) or higher dose doxycycline
Severe/CURB3 upwards: co-amoxiclav and clarithromycin
PROPHYLACTIC DALTEPARIN FOR VTE PREVENTION
What antibiotics are generally used for hospital acquired pneumonia in UHL?
Mild/Moderate: Co-amoxiclav for 5 days or Doxycyline
Severe: Co-amoxiclav higher strength fro 5 days or Meropenem
What antibiotics are generally used for apiration pneumonia in UHL?
Mild/Moderate: co-amoxiclav, if atypical pathogen suspected add doxycycline or clarithromycin
Severe: co-amoxiclav or penicillin
How is pneumonia followed up?
Need a repeat CXR and CRP in 6 weeks to check full resolution and no underlying malignancy/complications
What are some causes of non-resolving pneumonia?
CHAOS
What are some complications of pneumonia?
- Pleural effusion
- Empyema
- Lung abscess
- Respiratory failure
- Septic shock
- Pericarditis/myocarditis
- AFib
- Jaundice secondary to sepsis or antibiotic therapy
What are some features of a lung abscess and how is it treated?
Who should be offered a pneumoncoccal vaccine and which patients is it contraindicated in?
Who are more likely to suffer from the following pneumonias:
- Pneumococcal
- Staphylococcal
- Klebsiella
- Most common. More prevalent in elderly, alcoholics, post-splenectomy, immunosupressed, heart failure
- IVDU, CF, lymphoma, leukaemia. Causes bilateral cavitating bronchopneumonia
- Rare. In elcerly, diabetics, alcoholics. Usually drug resistant
How does legionella pneumophilia present and how is it treated?
Presentation: flu like symptoms (malaise, fever, myalgia) then dry cough and dyspnea. Can have D+V, hepatitis, renal failure
Treatment: diagnose with urine antigen/culture and give fluoroquinolone or clarithromycin for 2-3 weeks
Colonises water tanks kept at <60 degrees, e.g hotel air conditioning and hot water systems
What is chlamydophila psittaci and how is it treated?
Causes psittacosis and comes from infected birds (often parrots)
Symptoms: headache, dry cough, fever, lethargy, arthralgia, D+V
Diagnosis: chlamydophila serology
Treatment: Doxycycline or Clarithromycin
What are some causes of viral pneumonia?
- Influenza (most common)
- Swine flu
- Measles
- CMV
- Varicella zoster
Treat with oseltamivir, zanamivir, nebulisers and high flow oxygen
How do you diagnose and treat pneumoncystis pneumonia?
What are the clinical features of respiratory TB?
- Low grade fever
- Drenching night sweats
- Cough that starts dry then becomes purulent
- Haemoptysis
- Fever
- Weight loss
- Malaise
- Clubbing
- Pleural effusion
What are some non-respiratory manifestions of TB?
- Erythema nodosum
- Lymphadenopathy
- Bone/joint tenderness
- Abdominal (colicky pain)
- Meningitis
- Milliary (disseminated)
- Cardiac (pericardial effusion)
- Genitourinary
What are some differentials for haemoptysis?
What are some risk factors for TB?
- Past history of TB
- Known history of TB contact
- Born in a coutry with high TB incidence
- Foreign travel to area with high TB levels
- Immunosuppression e.g IVDU, HIV, Diabetes, low BMI, dialysis, alcoholism
How is latent TB diagnosed?
- Tuberculin skin testing Mantoux
- Interferon gamma release assays
How is active TB diagnosed?
- CXR
- Sputum smear (Ziehl-Neelsen Acid fast)
- Sputum culture
- NAAT (rapid diagnosis in 8 hrs and can detect drug resistance)
If TB is diagnosed, what further testing is offered?
HIV
If a patient with suspected TB is admitted to hospital, how should you manage them before the definitive management?
- Admit to side room and use infection control measures (PPE)
- Notify public health and TB nurses
- CXR
- 3 early morning sputum samples for AFB and TB culture
- Routine bloods (LFTs) and Vitamin D
- HIV test
- Consider CT chest if CXR not typical
- Start anti-TB therapy as culture can take 6-8 weeks
What are some features of TB on a CXR?
Usually in upper lobes:
- Cavitation
- Pleural effusion
- Mediastinal or hilar lymphadenopathy
- Parenchymal infiltrates
What is the antibiotic regime for active TB?
- Rifampicin 6 months
- Isoniazid 6 months
- Pyrazinamide 2 months
- Ethambutol 2 months
What monitoring is needed whilst on anti-TB therapy?
- Patient’s weight as dose is weight dependent
- Check baseline LFTs and monitor
- Check visual acuity before ethambutol
- Pyridoxine should be given with Isoniazid as prophylaxis for peripheral neuropathy
DIRECTLY OBSERVED THERAPY THE WHOLE TIME!!!!!!
What are the major side effects of TB treatment?
IMPORTANT TO COUNSEL ON
Check visual acuity, LFTs and give pyroxidine for Isoniazid
What people with latent TB should you treat as they are at increased risk of developing active disease?
- HIV
- Transplantation
- Chemotherapy
- Bioloical agents (TNF-a inhibitors)
- Diabetes
- CKD
Treat for 3-6 months with follow up CXR at 12 months
What is bronchiectasis?
Chronic dilatation of one or more bronchi. They have poor mucus clearance so there is a predisposition to recurrent chronic bacterial infections
What are the causes of bronchiectasis?
- Post infective: whooping cough, TB
- Congenital: CF, Young;s, Kartagener’s,
- Obstructive: foreign body, tumour, lymph node
- Immune deficiency: hypogammaglobulinaemia
- Secondary immune deficiency: HIV, malignancy
- RA
- IBD
What is Kartagener and Young’s syndrome?
Kartagener: bronchiectasis, sinusitis, situs invertus
Young’s: bronchiectasis, infertility, sinusitis
What are the common infectious organisms in bronchiectasis?
- Haemophilus influenzae
- Pseudomonas aeruginosa
- Moraxhella catarrhalis
- Strep pneumonia
- Staph Aureus
What are the signs and symptoms of bronchiectasis?
Symptoms: persistent cough, copious purulent sputum, intermitten haemoptysis
Signs: finger clubbing, coarse inspiratory crepitations, wheeze
What is the gold standard diagnostic test for bronchiectasis?
High resolution CT
Signet ring appearance and Tram track signs
What other tests can you do for a patient with suspected bronchiectasis?
- Sputum culture (P.Aeruginosa and Non TB mycobacterium)
- CXR (tramline and ring shadows and look for pneumonia)
- Spirometry (obstructive pattern)
- Bronchoscopy to locate site of haemoptysis and exclude obstruction
- CF sweat test
How is bronchiectasis managed?
- Treat underlying cause
- Chest physiotherapy for mucus clearance
- Antibiotics accord to cultures/sensitivity
- Bronchodilators if required
- Steroids for allergic bronchopulmonary aspergilliosis or asthma
- Flu vaccine
- Pulmonary rehab if MRC dyspnea score 3 or more
What is the pathophysiology of CF?
Autosomal reccesive disease that leads to a mutation in CFTR
Chromosome 7
Defective chloride secretion and excess Na absorption across epithelium. Leads to excessive mucus. Predisposes them to bronchiectasis and lung infections
What are some of the clinical features of CF?
Neonate: meconium ileus, failure to thrive, rectal prolapse
Children and Young adults: cough, wheeze, recurrent infections, pneumothorax, diabetes mellitus, steatorrhea, distal intestinal obstruction syndrome, male infertility, osteoporosis, gallstones
How is CF diagnosed?
- Sweat test
- Genetic testing
- Can look at faecal elastase for pancreas exocrine dysfunction
How is CF most commonly picked up?
- Meconium ileus
- Intestinal malabsorption
- Newborn heelprick screening
- Recurrent chest infections
What are some common complications of CF and how are they managed?
Respiratory Infections: Physiotherapy and prophylactic antibiotics
Low Body Weight: Due to pancreatic insufficiency, meed to give pancreatic enzyme replacement therapy with high calorie intake. May need NG or PEG
DIOS: Due to insufficienct pancreatic enzymes or hot weather or salt deficiency. Replace salts, drink fluids, give laxatives
CF related diabetes: give insulin
What is DIOS and how is it diagnosed?
Faecal obstruction in ileocaecum (not whole bowl like constipation) due to faeces being thick and dehydrated. From insufficient pancreatic enzymes, hot weather or salt deficiency
Often palpable faeces in right iliac fossa
Diagnosis: symptoms, palpable mass in right iliac fossa, AXR showing faecal loading at junction of small and large bowel
What is DIOS in cystic fibrosis?
Distal Intestinal Obstruction Syndrome (DIOS) is a complication of Cystic Fibrosis (CF). It occurs when the bowel becomes partially or completely blocked. Symptoms. Symptoms vary widely and can include: * Cramps, abdominal pain and bloating.
What lifestyle advice should you give to CF patients?
- Clean and dry nebs properly
- Avoid other CF patients
- Avoid jacuzzis
What are the common pathogens seen in the sputum of patients with bronchiestasis?
- H.Influenzae
- S.Pneumoniae
- Pseudomonas aeruginosa
What are the principles of treating bronchiectasis?
How is TB managed?
- Notify PHE
- Multi drug treatment
- Await culture results for sensitivities
What is the pathophysiology of TB?
Primary Ghon’s focus
Transmission:
TB is primarily transmitted through the air when an infected person with active TB disease coughs, sneezes, or talks, releasing respiratory droplets containing the bacteria. Individuals who inhale these droplets may become infected.
Infection and Primary TB:
Once inhaled, the bacteria reach the alveoli (air sacs) of the lungs and are engulfed by macrophages, a type of immune cell. The bacteria can resist destruction within the macrophages.
The infection can lead to primary TB, characterized by the formation of small, localized lesions called granulomas. These granulomas contain immune cells, including macrophages and T lymphocytes, which attempt to contain the infection.
Latent TB Infection (LTBI):
In many cases, the immune response is effective in controlling the infection, leading to a state known as latent TB infection. In LTBI, the bacteria are still present but are held in check by the immune system, and the individual does not exhibit symptoms.
A collection of these granulomas are known as a ghons focus
Reactivation or Progression to Active TB:
In some individuals, especially those with weakened immune systems, the bacteria can escape control and multiply, leading to reactivation of TB. This can occur years after the initial infection.
Factors contributing to reactivation include immunosuppression (HIV infection, certain medications), malnutrition, diabetes, and aging.
Spread of Active TB:
Active TB disease occurs when the bacteria overcome the immune system’s defenses, leading to the destruction of lung tissue and the formation of larger cavities. The bacteria can then spread through the bloodstream to other organs, causing extrapulmonary TB.
If the granulomas spread to the lymph nodes, its then a primary complex
Clinical Manifestations:
Active TB is characterized by symptoms such as persistent cough, chest pain, hemoptysis (coughing up blood), fatigue, weight loss, and night sweats. Extrapulmonary TB can affect various organs, such as the kidneys, bones, and central nervous system.
Immune Response:
The immune response involves both innate and adaptive immunity. Macrophages play a central role in recognizing and attempting to destroy the bacteria. T lymphocytes also contribute to the immune response by releasing cytokines and activating other immune cells.
Granuloma Formation:
Granulomas are a hallmark of TB infection. They are organized structures formed by immune cells attempting to contain the bacteria. While granulomas can prevent the spread of the bacteria, they may also serve as a reservoir for latent infection.
How do the antibiotics for community and hospital acquired pneumonia differ?
HAP:
PIPERACILLIN
CEFUROXIME
CAP:
Amoxicillin
