Pneumonia in a 59-year-old kidney transplant patient

Written By Dr Ahmed Kazie

A 59-year-old male with CKD was admitted to hospital and underwent a bilateral kidney transplant. During the course of his admission he developed severe hypogastric pain and frank haematuria with blood clots. Rectal swabs were taken which came back positive for Klebsiella. His inflammatory markers were also raised and a few days later the patient developed flu-like symptoms, dyspnoea as well as a new oxygen requirement. Physical examination revealed reduced breath sounds bilaterally and Chest X-ray showed bilateral pulmonary infiltrates. The patient was then started on IV antibiotics for a suspected pneumonia. Further investigations were also which revealed that the patient had a Legionella pneumophila infection, and although treatment was escalated, the patient did eventually pass away from his illness.

From left to right: 1) Environmental sampling sites of water distribution systems, and Legionella concentration, identification, and typing. 2) The hospitalisation timeline and the clinical treatments. 3) Legionella pneumophila serogroup 1 (Lp1) and Klebsiella pneumoniae (Kp) antibiotic susceptibility from (a) lung tissue fragments and (b) rectal swab sample.

  • Pneumonia is primarily classified into CAP (community-acquired pneumonia), HAP (hospital-acquired pneumonia) and VAP (ventilator-acquired pneumonia) depending on its setting of infection (most common classification used):

    • CAP = any pneumonia occurring in the community (i.e. not associated with hospital/medical centre visit or attendance)

    • HAP = pneumonia not incubating at the time of hospital admission and occurring 48 hours or more after admission

    • VAP = pneumonia occurring >48 hours after endotracheal intubation

    In addition, it can also be further subclassified according to which part of the lower respiratory tract is affected:

    • Lobar pneumonia - causes typically include:

      • Streptococcus pneumoniae

      • Klebsiella pneumoniae

    • Bronchopneumonia - causes typically include:

      • Staphylococcus aureus

      • Haemophilus influenzae

      • Pseudomonas aeruginosa

      • Moraxella catarrhalis

      • Legionella pneumophila (sometimes classified as an atypical pathogen)

    • Interstitial pneumonia (AKA atypical pneumonia) - causes typically include:

      • Mycoplasma pneumoniae

      • Chlamydia pneumoniae

      • Respiratory syncitial virus (RSV)

      • Cytomegalovirus (CMV)

      • Influenza virus

      • Coxiella brunette

    In addition, pneumonia can be classified according to aetiology of infection:

    • Bacterial pneumonia (most common)

    • Viral pneumonia

    • Fungal pneumonia

    References:

    1) https://www.uptodate.com/contents/overview-of-community-acquired-pneumonia-in-adults#:~:text=Community%2Dacquired%20pneumonia%20(CAP)%20refers%20to%20an%20acute%20infection,acquired%20outside%20of%20the%20hospital.

    2) https://academic.oup.com/cid/article/63/5/e61/2237650#210142259

    3) https://radiopaedia.org/articles/pneumonia?lang=gb

    4) https://www.nice.org.uk/guidance/cg191/chapter/1-Recommendations

  • After taking a detailed history and conducting a thorough physical examination, and you’ve determined the patient to have a bacterial pneumonia, you can then grade its severity using the CURB-65 score:

    • Confusion (1 point)

    • Urea = >7mmol/L (1 point)

    • RR = >30 (1 point)

    • BP = systolic <90 or diastolic <60 (1 point)

    • Age >65yrs (1 point)

    The CURB-65 score is used to estimate 30-day mortality of community-acquired pneumonia and splits patients into three groups and determine whether inpatient or outpatient treatment is warranted:

    • CURB-1 —> Low-risk (2.7% 30-day mortality) = treat as outpatient

    • CURB-2 —> Moderate risk (6.8% 30-day mortality) = consider inpatient treatment

    • CURB-3 —> Severe risk (14.0% 30-day mortality) = treat as inpatient

    • CURB-4 —> Highest risk group (27.8% 30-day mortality) = treat as inpatient

    The BTS guidelines advise that high-risk patients (i.e. CURB-3 or above) should be reviewed at least every 12 hrs.

    If a patient presents to their GP with a suspected CAP, then the CRB-65 score can be used. NICE guidelines also recommend Primary Care testing of a person’s CRP level to evaluate if antibiotics are needed:

    • CRP <20 = unlikely bacterial pneumonia —> no antibiotics required

    • CRP 20-100 = possible bacterial pneumonia —> consider antibiotics

    • CRP >100 = likely bacterial pneumonia —> give antibiotics

    References:

    1) https://www.nice.org.uk/guidance/cg191/chapter/1-Recommendations

    2) https://www.brit-thoracic.org.uk/quality-improvement/guidelines/pneumonia-adults/

  • All patients attending hospital with a suspected CAP should have their NEWS score taken as well as a full set of bloods performed including CRP, FBC, U&Es & LFTs. Perform a POCT blood gas (ABG preferred) to assess the patient’s O2 and CO2 levels. Nose & throat swabs can be considered as per clinical judgement (e.g. for Mycoplasma pneumoniae, Influenza, RSV or Covid-19). A chest x-ray should also be taken.

    The aim is to make a diagnosis and initiate treatment of pneumonia within 4hrs of the patient presenting to the hospital.

    Further tests are determined according to the severity of disease:

    • CURB-2 or above = obtain cultures (sputum & blood) & perform urinary antigen testing (Pneumococcus & Legionella)

    • Sputum culture for TB should be considered in patients with a persistent productive cough, especially if malaise, weight loss, night sweats, or risk factors for TB (e.g. ethnic origin, social deprivation, elderly) are present.

    References:

    1) https://www.brit-thoracic.org.uk/quality-improvement/guidelines/pneumonia-adults/

  • Antibiotic therapy is determined according to pneumonia severity and local guidelines - typical regimens according guidelines are:

    1) CURB-1 = Amoxicillin 500mg tds for 5d total:

    • Alternatives to amoxicillin if penicillin allergic:

      • Doxycycline: 200mg on first day, then 100mg od for 4 days (5‑day course in total)

      • Clarithromycin: 500mg bd for 5 days

      • Erythromycin (in pregnancy): 500mg qds for 5 days

    2) CURB-2 = Amoxicillin 500mg tds for 5d total WITH EITHER:

    • Clarithromycin (if atypical organisms suspected) 500mg bd

    Or

    • Erythromycin (in pregnancy) 500mg qds for 5 days

    • Alternatives to amoxicillin if penicillin allergic:

      • Doxycycline: 200mg on first day, then 100mg od for 4 days (5‑day course in total)

      • Clarithromycin: 500mg bd for 5 days

    3) CURB-3 = Co‑amoxiclav 500/125mg tds orally OR 1.2 g tds IV for 5 days total WITH:

    • Clarithromycin 500mg twice a day orally or intravenously for 5 days

    Or

    • Erythromycin (in pregnancy) 500mg qds orally for 5 days

    • Alternatives to amoxicillin if penicillin allergic:

      • Levofloxacin 500mg bd orally or IV for 5 days

    The question stem mentions that the patient was started on IV antibiotics, indicating that this is a severe (CURB-3) pneumonia.

    General guidance:

    • ALWAYS prescribe medications (including antibiotics) according to your local Trust guidelines as these may differ from national guidelines

    • Give oral antibiotics first line if the person can take oral medicines, and the severity of their condition does not require intravenous antibiotics.

    • If intravenous antibiotics are given, review by 48 hours and consider switching to oral antibiotics if possible.

    • If the patient isn’t seen to be improving after 48hrs of antibiotic therapy, consider stepping up treatment (i.e. to a stronger antibiotic combination) or possibly reconsider diagnosis (e.g. Influenza can also cause pneumonia). Decisions regarding treatment options should be guided according to microbiology results and advice from the Microbiology Team.

    References:

    1) https://www.nice.org.uk/guidance/ng138/chapter/Recommendations

  • 1) Prescribe oxygen to the patient to be given as needed to maintain their target oxygen saturations. Patients may have different target oxygen saturations depending on whether they are at risk of suffering hypercapnic respiratory failure:

    • Scale 1 (no risk of CO2 retention & hypercapnic respiratory failure) = aim sats 94-98%

    • Scale 2 (risk of CO2 retention & hypercapnic respiratory failure) = aim sats 88-92%

    2) If the patient suddenly deteriorates then consider repeating the POCT blood gas as their condition may have changed and they may be retaining CO2 (respiratory acidosis)

    3) Prescribe IV fluids if volume deplete or hypotensive:

    • NICE guidelines advise 25–30 ml/kg/day sodium chloride 0.18% in 4% glucose with 27 mmol/l potassium ON DAY 1

    • Further prescriptions should be guided by monitoring

    • Generally, do not prescribe >2.0-2.5L of fluids per day —> Prescribing >2.5L/day increases the risk of dilutional hyponatraemia

    • Prescribe less fluids for patients who are:

      • frail/elderly

      • CKD

      • CCF

      • malnourished or at risk of re-feeding syndrome

    4) Prescribe VTE prophylaxis in patients with reduced mobility (or if illness likely to result in patient being bed-bound/moving less) - LMWH is generally used as first-line (e.g. Dalterparin). Example dosing regimen could be:

    • Dalteparin SCT 2500mcg/day nocte (if <50kg)

    • Dalteparin SCT 5000mcg/day nocte(if 50-100kg)

    • Dalteparin SCT 5000mcg bd (if 50-150kg)

    Always check your local Trust guidelines before prescribing any forms of medication.

    5) Consider appropriate nutritional support if illness is long-term (refer to Dieticians for advice)

    6) Encourage patient to sit out of bed for at least 20mins/day to help with mobility

    7) Perform routine bloods regularly according to clinical need and measure CRP at least every 3 days to determine response to antibiotic therapy

    8) Repeat chest X-Ray if no improvement in the patient’s condition despite 3 days of appropriate antibiotic therapy

    References:

    1) https://www.nice.org.uk/guidance/ng138/chapter/Recommendations

    2) https://www.brit-thoracic.org.uk/quality-improvement/guidelines/pneumonia-adults/

    3) https://www.nice.org.uk/guidance/cg174/chapter/1-Recommendations#assessment-and-monitoring-2

    4) https://www.nice.org.uk/guidance/ng89/chapter/Recommendations#all-patients-2

    5) https://bnf.nice.org.uk/drugs/dalteparin-sodium/

  • This patient has undergone a bilateral kidney transplant and would have been on immunosuppressive medication to prevent organ rejection. His chronic illness (only patients with CKD5 are considered for transplant) coupled with his recent transplant surgery as well as the fact that he was on immunosuppresive medication, all mean that he was at an increased risk of suffering infection, in particular from atypical pathogens such as Legionella pneumophila (which he was eventually diagnosed with).

    The most commonly associated clinical features of Legionella pneumophila infection include:

    • Diarrhoea

    • Encephalopathy and other neurological symptoms

    • Severe infection

    • Evidence of multisystem involvement (e.g., abnormal liver function tests, elevated serum creatine kinase)

    Other features of Legionella infection include:

    • More likely in young patients without comorbidities

    • Smokers

    • Immunocompromised people

    • People exposed to contaminated artificial water systems (e.g., air conditioning units, spas, fountains, repair of domestic plumbing systems)

    • Higher frequency in severe illness (patients in the intensive care unit)

    Enquire about foreign travel if Legionella is suspected

    Remember, all patients presenting with CURB-2 pneumonia or above should undergo urinary antigen testing for Legionella & Pneumococcus.

    Antibiotics for atypical pathogens work against Legionella and include both Fluoroquinolones & Clarithromycin (as per BTS Guidelines).

    References:

    1) https://www.brit-thoracic.org.uk/quality-improvement/guidelines/pneumonia-adults/

  • This case describes a rare coinfection of Legionella pneumophila and Klebsiella pneumoniae in a bilateral kidney transplanted patient with CKD. The patient likely picked up the Legionella infection from contaminated water sources in his home (following his death his home water supply was tested for Legionella and came back positive).

    Co-infections with both Legionella and Klebsiella are infrequently reported, and previous cases have been primarily associated with viral co-infections. The patient's diagnosis of Legionnaires' disease was based on the presence of Legionella-specific antibodies, whilst Klebsiella infection was confirmed by culture results. Klebsiella is an opportunistic pathogen and is part of normal of the mouth and GIT; the patient's severely immunocompromised condition likely contributed to the transition from colonisation to infection; where the initial infection was likely gastrointestinal in origin but later on, due to probable haematogenous spread, developed into a urinary infection (presenting as haematuria) and LRTI (pneumonia).

    It is difficult to determine which pathogen caused the patient's death.

    References:

    1) https://www.ahajournals.org/doi/10.1161/CIRCINTERVENTIONS.119.008087

    2) https://academic.oup.com/eurheartjsupp/article/24/Supplement_K/suac121.286/6911435


Source: https://doi.org/10.3389/fmed.2022.912649

Case Summary & Questions written by Dr Ahmed Kazie


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Dr Ahmed Kazie