Cough, dyspnoea and fever in a 55-year-old man

Published on 10/04/2015 by admin

Filed under Surgery

Last modified 22/04/2025

Print this page

rate 1 star rate 2 star rate 3 star rate 4 star rate 5 star
Your rating: none, Average: 0 (0 votes)

This article have been viewed 1122 times

Problem 33 Cough, dyspnoea and fever in a 55-year-old man

Narin Bak

A 55-year-old man presents with 3 days of anorexia, headache, general weakness, aches and pains all over his body. He thought he had the flu and has been treating himself with paracetamol.
However, in the last 24 hours he has become very unwell, with a high fever, irritating dry cough, breathlessness and diarrhoea and he has vomited a number of times. He has no pleuritic pain but has a dull generalized ache in his abdomen. There is no significant past medical history. He has no pets, animal contacts or recent holiday travel but likes gardening. He smokes about 20 cigarettes a day and consumes 30–50 g of alcohol daily. He is not on any regular medications and has no known allergies.
On examination he looks unwell and flushed. He is orientated but agitated and easily distracted. He has a temperature of 39.5°C. The patient is not cyanosed, clubbed, jaundiced or anaemic. He has dry mucous membranes and a coated tongue. His pulse rate is 105 bpm and regular, his blood pressure is 120/75 mmHg and his oxygen–haemoglobin saturation is 90%. His cardiovascular system is otherwise normal. His respiratory rate is 30 breaths per minute and he has a hacking cough productive of small amounts of mucoid sputum. His chest is resonant and the breath sounds vesicular. There are scattered inspiratory crepitations throughout the right lung only. His abdomen is soft and non-tender. There is no neck stiffness and there are no focal neurological signs.

Q.1

What is the most likely diagnosis?

Q.2

What initial diagnostic investigations would you perform and why?

You review the chest X-ray Figure 33.1 and the results of your other tests can be seen in Investigation 33.1.

image

Figure 33.1

Investigation 33.1 Summary of results

image

Q.3

What do the results show ? How would you interpret them?

Q.4

What organisms are likely to have caused this man’s illness? How would you expect the clinical signs to differ with different pathogens?

Q.5

How do you assess severity of pneumonia and level of risk to patient?

You assess him as having moderately severe pneumonia. His age, his mental state and the multilobar involvement are high-risk characteristics requiring admission to hospital, and you arrange a bed in the respiratory unit.

Q.6

How are you going to manage this patient?

The patient is placed on oxygen via nasal cannula at 4 L/min. An intravenous line is inserted and 1 L isotonic saline is set up running over 2 hours to rehydrate the patient. You check with the patient and his family to ensure he is not allergic to penicillin.

The nurse is kindly drawing up the antibiotics, and your IV fluids are running. His family have started asking you some questions.

Q.7

What complications may be expected to occur?

The patient was commenced on erythromycin 1 g 6-hourly and ceftriaxone 1 g intravenously. He was rehydrated using isotonic saline so as not to exacerbate the hyponatraemia. The hypokalaemia was corrected.

Sputum culture on special medium was positive for Legionella pneumophila after 3 days. Urine was positive for legionella antigen (specific for L. pneumophila 1). Blood cultures were negative. His respiratory status was closely monitored with the assistance of oximetry and serial blood gases. Initial serology for Legionella species by indirect fluorescent antibody was <1 : 4. At 16 days the L. pneumophila titre was 1 : 1024. Intravenous erythromycin was continued for 7 days and an oral dose of clarithromycin 500 mg 12-hourly was given for a further 2 weeks.

He improved after 72 hours and made a slow recovery over the following 10 days. The disease was notified to the Department of Health and L. pneumophila was subsequently isolated from a sprinkler system in the patient’s greenhouses. The water system was decontaminated. The patient was told that his cigarette smoking and alcohol intake had put him at increased risk of contracting this illness. He was advised to stop smoking and was given options to assist with this process.

Answers

A.1 The presentation of this case strongly suggests community-acquired pneumonia. The patient has fever, cough, dyspnoea and abnormal respiratory signs but no hard clinical signs of consolidation. His respiratory rate is markedly increased, which is an important sign of respiratory compromise. Gastrointestinal symptoms (vomiting and diarrhoea) are not uncommon in pneumonia and may be misleading features for site of infection. Audible crackles on respiratory examination is a frequent and an important sign not to miss. Signs of consolidation is present in only about 30% of patients.

However, some patients can present with fever without localizing symptoms.

Pneumonia can also be referred to anatomically as in right lower lobe pneumonia or on the basis of aetiology such as pneumococcal pneumonia.

Differential diagnoses include pulmonary embolism, pulmonary vasculitis, malignacy, and hypersensitivity pneumonitis.

A.2 The following investigations are required to confirm diagnosis, assess severity and investigate for causative organism:

• Complete blood examination, serum chemistry and coagulation studies to assess severity of illness and assist diagnosis.
• Arterial blood gas analysis on air to ascertain the degree of respiratory impairment that is present, and oximetry performed for ongoing assessment.
• Chest X-ray to confirm diagnosis, and may provide clue to severity.

To identify aetiology:

• Blood cultures (prior to any antibiotics).
• Sputum collection for Gram and acid-fast stains and for culture (including for Legionella, mycobacteria).
• Urinary pneumococcal and legionella antigen.
• Nasopharyngeal swabs for the respiratory viruses (influenza, parainfluenza, respiratory syncytial virus, adenovirus).
• Serology (acute and convalescent) for respiratory pathogens including:

– viral
– Mycoplasma pneumoniae
– Chlamydia pneumoniae.

A.3 There is only a mild leucocytosis (much lower than would be expected for pneumococcal pneumonia). The patient has hyponatraemia, which is not uncommon with some pneumonias. It may be the result of pulmonary production of ADH-like substances. A hyponatraemia of less than 130 mmol/L can be associated with legionella pneumonia, but is not diagnostic. There is mild renal impairment, which may be due to dehydration or the underlying illness. There is a hypokalaemia which needs correction.

• The liver enzymes are abnormal. This is often a feature in pneumonias caused by ‘atypical’ organisms such as Legionella and Mycoplasma.
• The urinalysis is abnormal, highlighting the systemic illness.
• The coagulation studies are normal and this excludes disseminated intravascular coagulation.
• The arterial blood gas shows moderate hypoxaemia with hyperventilation and respiratory alkalosis.

These findings are in keeping with a moderately severe pneumonia with systemic sepsis. They would be consistent with legionellosis but could still represent pneumonia caused by other pathogens.

The chest X-ray shows significant bilateral pulmonary infiltrate, consistent with a clinical diagnosis of pneumonia. The right lung is extensively involved, particularly the upper lobe with consolidation and atelectasis. The appearances suggest bronchopneumonic change without major lobar volume loss. There is also patchy infiltrate in the left mid and upper zones. The heart size is normal.

A.4 Community-acquired pneumonia in the immunocompetent host can be caused by a broad range of pathogens which differ from those seen in hospital-acquired pneumonias and pneumonias in immunocompromised hosts (Table 33.1).

Table 33.1 Aetiology of community-acquired pneumonia

Causative Oragnism Percentages
Streptococcus pneumoniae 42
Mycoplasma pneumoniae 9
Legionella species 3
Chlamydia species 2
Gram-negative 3
Haemophilus influenzae 5
Staph. aureus 1
Respiratory viruses 14
Other or unknown 21

A.5 You should always assess the severity of pneumonia in every patient. It predicts the risk and prognosis, and determines admission and the types of recommended empiric antibiotics (see Table 33.2). The 30-day mortality for low-risk or mild pneumonia is less than 1%, while the 30-day mortality for severe (high-risk) pneumonia is approximately 27%.

Table 33.2 Treatment of community-acquired pneumonia

Mild (Low-Risk) Pneumonia Moderate Severity Pneumonia Severe (High-Risk) Pneumonia
Outpatient treatment Hospital admission Hospital admission – consider intensive care assessment/admission
Oral amoxicillin plus doxycycline or
Oral macrolide (clarithromycin or roxithromycin, azithromycin)		 IV benzyl penicillin and gentamicin plus oral doxycycline or macrolide
or
IV ceftriaxone plus IV erythomycin/azithromycin		 IV ceftriaxone or Tazocin plus IV azithromycin

The severity of pneumonia can be graded and scored and is based on the following factors:

• Age >50 years.
• Co-existing illness (e.g. diabetes, renal disease, cardiac failure, splenectomy).
• Abnormal physical signs on examination (confused, pulse >125 bpm, respiratory rate >35 per minute, systolic blood pressure <90 mmHg, or temperature <35°C or >40°C).
• Abnormal investigations ( pH<7.35, PaO2<60 mmHg on air, extensive CXR changes).

A.6 The initial antibiotic selection should be empirical as clinical and chest X-ray findings are not sufficiently specific for causal organism. The antibiotic choice should cover both pneumococcus and other less common organisms such as Legionella, Mycoplasma and Chlamydia pneumonias (see Table 33.2).

In severe pneumonia, IV vancomycin may need to be added to the empiric regimen as community-acquired methicillin-resistant Staphylococcus aureus is a rare but emerging pathogen. In some tropical regions, empiric treatment for severe pneumonia in patients with diabetes or chronic renal failure may need to also cover Burkholderia pseudomallei and Acinetobacter baumanii.

A.7 Most patients respond well to treatment but complications can occur. If patients are not improving, consider the following:

• The diagnosis is incorrect (e.g. pulmonary malignancy or pulmonary oedema).
• The antibiotic does not cover the pathogen (e.g. Mycobacterium tuberculosis or methicillin-resistant Staphylococcus aureus, or HIV-associated Pneumocystis pneumonia).
• Parapneumonic effusion (common).
• Empyema or lung abscesses.
• Sputum plug causing lobar collapse.
• Development of pulmonary embolism.
• Development of ARDS or multi-organ failure.
• Drug fever.

Revision Points

Community-Acquired Pneumonia

Aims of Management at Presentation

• Assess severity and risk. Severe cases need admission to hospital.
• Identify aetiologic agent. This can guide subsequent antibiotic choice and duration.
• Remember that underlying illnesses that impair the patient’s immune system will extend the spectrum of possible infecting agents (so-called opportunistic infection).
• Exclude other diagnoses.
• Initiate treatment appropriately:

– high-flow oxygen
– intravenous rehydration and monitoring of fluid balance and renal function
– antibiotic therapy (after blood cultures taken) as guided by local policy and microbiology results; the initial antibiotic choice depends on assessment of severity
– severe cases require early admission to an intensive care unit for ventilatory support.

• Remember to consider the patient’s fitness. For the elderly, those with serious co-morbid conditions such as diabetes, COPD or cardiac failure or those with immune compromise, pneumonia may be rapidly life-threatening and may require specialized management.

Issues to Consider

• What are the implications of the widespread use of parenteral cephalosporins in the management of community-acquired pneumonia?
• What other respiratory disorders can be transmitted from environmental exposure?

Further Information

, www.brit-thoracic.org.uk. The website of the British Thoracic Society, with access to the excellent guidelines for the management of community-acquired pneumonia

, www.legionella.org. Public access website from the USA with plenty of information on this organism and the public health issues related to it

Related posts:

Rectal bleeding in a 45-year-old woman A 42-year-old woman with hypertension A listless 45-year-old man Acute respiratory failure in a 68-year-old man ‘Jack has leg weakness’ Default ThumbnailThe routine check-up