Pathophysiology and Management of Community-Acquired Pneumonia in Geriatric Patients

Posted: March 18th, 2022

Pathophysiology and Management of Community-Acquired Pneumonia in Geriatric Patients | Clinical Insights into Bacterial Pneumonia: A Case Study Analysis of an Elderly Patient.

BACTERIAL PNEUMONIA

For the Disease Summary for this case study, see the CD-ROM.

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PATIENT CASE

Chief Complaints

Provided by the patient’s caregiver:
“Mrs. I. has been feeling very sick lately. She’s been coughing all night and seems confused. I’m really worried about her.”

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History of Present Illness (HPI)

Mrs. B.I. is an 84-year-old retired bank manager who lives at home with her caregiver. Over the past week, she has developed upper respiratory symptoms, including a persistent cough that has worsened in the last two days. The cough is now productive, with thick, greenish phlegm. Mrs. I. has also been feeling increasingly weak and fatigued. Last night, she became confused and nearly fell while trying to go to the bathroom. Her caregiver, who prepares her meals and helps with daily activities, noticed that Mrs. I. has been less active and is struggling to catch her breath. Despite these symptoms, Mrs. I. has not had a fever.

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Past Medical History (PMH)

• Chronic bronchitis for approximately 13 years
• Hypertension (HTN) for 6 years, well-controlled with medication
• Mild left hemiparesis following a stroke 4 years ago
• Depression for 2 years
• Constipation for 6 months
• Tobacco dependence for 64 years (currently smokes ½ pack per day)
• Influenza vaccine received 3 months ago

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Family History (FH)

• No family history of hypertension, cancer, coronary artery disease (CAD), asthma, or diabetes mellitus (DM).

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Social History (SH)

• Mrs. I. lives with her caregiver in her own home.
• She has a few friends who have recently been ill with “colds.”
• She occasionally drinks alcohol but has not done so recently.

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Review of Systems (ROS)

• Positive for: Persistent cough, difficulty sleeping due to coughing, decreased appetite, and weakness.
• Negative for: Fever, chills, nausea, vomiting, diarrhea, rashes, or blood in the stool.

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Medications

• Atenolol 100 mg po QD (for hypertension)
• Hydrochlorothiazide (HCTZ) 25 mg po QD (for hypertension)
• Aspirin 325 mg po QD (for cardiovascular protection)
• Nortriptyline 75 mg po QD (for depression)
• Combivent MDI 2 puffs QID (rarely used for chronic bronchitis)
• Albuterol MDI 2 puffs QID PRN (for bronchospasm)
• Docusate calcium 100 mg po HS (for constipation)

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Allergies

• Penicillin: Causes a rash.

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Physical Examination and Laboratory Tests

General Appearance

Mrs. I. is a frail, elderly woman who appears her stated age. She is lethargic, oriented only to herself, and uses a walker to ambulate. She is coughing frequently and using accessory muscles to breathe. Her respiratory effort is labored, and she appears uncomfortable.

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Vital Signs

• Blood Pressure (BP): 140/80 mmHg (no orthostatic changes)
• Pulse (P): 95 beats per minute (regular)
• Respiratory Rate (RR): 38 breaths per minute (labored)
• Temperature (T): 98.3°F
• Oxygen Saturation (SaO₂): 86% on room air
• Height (HT): 5’10½”
• Weight (WT): 124 lbs
• Body Mass Index (BMI): 17.6 (underweight)

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Skin

• Warm and clammy
• No rashes or lesions

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Head, Eyes, Ears, Nose, and Throat (HEENT)

• Pupils: Equal, round, and reactive to light (PERRLA)
• Extra-ocular movements (EOM): Intact
• Fundi: No hemorrhages or exudates
• Nares: Slightly flared with purulent discharge
• Oropharynx: Erythematous with purulent post-nasal drainage
• Mucous membranes: Inflamed but moist

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Neck

• Supple with mild bilateral cervical adenopathy
• No jugular venous distension (JVD) or carotid bruits

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Lungs/Thorax

• Breathing: Labored with tachypnea
• Auscultation: Crackles and diminished breath sounds in the right upper lobe (RUL) and left upper lobe (LUL); absence of breath sounds and dullness to percussion in the right lower lobe (RLL) and left lower lobe (LLL)
• No egophony

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Heart

• Regular rate and rhythm
• Normal S₁ and S₂
• No S₃, S₄, murmurs, or rubs

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Abdomen

• Soft and non-tender
• Normoactive bowel sounds
• No organomegaly or masses

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Musculoskeletal/Extremities (MS/Ext)

• No cyanosis, clubbing, or edema
• Strength: 4/5 on the right side, 1/5 on the left side (due to prior stroke)
• Peripheral pulses: 1+ bilaterally

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Neurological

• Orientation: Oriented to self only
• Cranial Nerves (CNs): II-XII intact
• Deep Tendon Reflexes (DTRs): 2+
• Babinski: Normal

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Laboratory Blood Test Results

• Sodium (Na): 141 meq/L
• Potassium (K): 4.5 meq/L
• Chloride (Cl): 105 meq/L
• Bicarbonate (HCO₃): 29 meq/L
• Blood Urea Nitrogen (BUN): 16 mg/dL
• Creatinine (Cr): 0.9 mg/dL
• Glucose (fasting): 138 mg/dL
• White Blood Cell Count (WBC): 15,200/mm³ (elevated)
• Neutrophils: 82% (elevated)
• Bands: 4% (elevated)
• Lymphocytes: 10% (low)
• Calcium (Ca): 8.7 mg/dL
• Magnesium (Mg): 1.7 mg/dL
• Phosphate (PO₄): 2.9 mg/dL

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Arterial Blood Gases (ABG)

• pH: 7.50 (alkalotic)
• PaO₂: 59 mm Hg (hypoxemic)
• PaCO₂: 25 mm Hg (low)

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Chest X-Ray

• Findings: Consolidation in the inferior and superior segments of the right lower lobe (RLL) and left lower lobe (LLL). Developing consolidation in the right upper lobe (RUL) and left upper lobe (LUL). No pleural effusion. Heart size within normal limits (WNL).

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Sputum Analysis

• Gram Stain: Too numerous to count (TNTC) neutrophils, few epithelial cells, no microbes identified.

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Sputum and Blood Cultures

• Pending results.

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Patient Case Questions

1. Is this infection community-acquired or nosocomial?
2. Define lethargy.
3. Match the medications to the patient’s conditions.
4. Calculate the Pneumonia Severity of Illness score.
5. Should the patient be hospitalized?
6. What is the 30-day mortality probability?
7. Identify signs of “double pneumonia.”
8. List risk factors for bacterial pneumonia.
9. Identify clinical manifestations of bacterial pneumonia.
10. Propose a likely causative microbe.
11. Suggest appropriate antimicrobial therapy.
12. Explain the elevated fasting glucose.
13. Why is the patient afebrile?
14. Could a urinary tract infection (UTI) have led to pneumonia?
15. Explain the high blood pH.
16. Interpret the chest x-ray findings.
17. Create a framework for understanding the challenges of diagnosing and managing bacterial pneumonia in elderly patients with comorbidities.

References

1. Jain, S., Self, W. H., Wunderink, R. G., et al. (2015). Community-Acquired Pneumonia Requiring Hospitalization among U.S. Adults. The New England Page Essay – Journal of Medicine, 373(5), 415-427. https://doi.org/10.1056/NEJMoa1500245
2. Metlay, J. P., Waterer, G. W., Long, A. C., et al. (2019). Diagnosis and Treatment of Adults with Community-Acquired Pneumonia: An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of America. American Page Essay – Journal of Respiratory and Critical Care Medicine, 200(7), e45-e67. https://doi.org/10.1164/rccm.201908-1581ST
3. Musher, D. M., & Thorner, A. R. (2014). Community-Acquired Pneumonia. The New England Page Essay – Journal of Medicine, 371(17), 1619-1628. https://doi.org/10.1056/NEJMra1312885

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