17.4 Respiratory Infections, Asthma & Urinary Tract Infection

Ambulatory primary care in midwifery requires high clinical competence across a diverse spectrum of common outpatient presentations. Certified nurse-midwives routinely evaluate and manage acute respiratory infections, asthma exacerbations, urinary tract complaints, gastrointestinal disturbances, and dermatologic eruptions. Simultaneously, nurse-midwives serve on the front lines of mental and behavioral healthcare, identifying major depression, generalized anxiety, substance use disorders, intimate partner violence, and human trafficking. Applying rigorous diagnostic criteria, observing strict antibiotic stewardship, and providing trauma-informed psychological and safety interventions are vital skills tested on the AMCB examination.

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Upper Respiratory & ENT Infections

Respiratory tract complaints represent the most frequent cause of inappropriate antibiotic prescribing in ambulatory healthcare. Midwives must distinguish self-limiting viral pathogens from bacterial infections requiring targeted antimicrobial therapy.

Acute Rhinosinusitis: Viral vs. Bacterial

Over 90% to 98% of acute rhinosinusitis episodes are viral. Acute Bacterial Rhinosinusitis (ABRS) should be diagnosed only when clinical presentation fulfills at least one of the following three criteria:

1. Persistent Symptoms (Duration ≥10 days): Nasal discharge, facial pressure, or congestion lasting 10 or more days without any evidence of clinical improvement.
2. "Double Sickening" (Biphasic Illness): Acute worsening of symptoms (new-onset fever, increased nasal discharge, intensified headache/facial pain) after 5 to 6 days of initial improvement following a typical viral upper respiratory infection.
3. Severe Onset: High fever (temperature >39.0°C / 102.2°F) accompanied by purulent (thick, opaque, discolored) nasal discharge and intense facial pain lasting for at least 3 to 4 consecutive days at disease onset.

Acute Rhinosinusitis Diagnostic Cascade
├── Symptoms <10 Days & Improving ──> Acute Viral Rhinosinusitis (AVRS)
│   └── Treatment: Symptomatic Care (Saline irrigation, Intranasal steroids, Analgesics)
└── ABRS Criteria (≥10 Days Without Improvement OR Double Sickening OR Severe Onset)
    ├── First-Line: Amoxicillin-Clavulanate 875/125 mg PO BID x 5–7 Days
    └── Penicillin Allergy (Non-Pregnant Adults):
        ├── Doxycycline 100 mg PO BID x 5–7 Days (Preferred)
        └── Respiratory Fluoroquinolone (Levofloxacin 500 mg daily - if alternatives fail)

Acute Pharyngitis: Modified Centor (McIsaac) Criteria

The primary clinical objective in acute pharyngitis is identifying Group A Streptococcus (GAS; Streptococcus pyogenes) to prevent nonsuppurative complications, specifically acute rheumatic fever and peritonsillar abscess (note: antibiotic therapy does not prevent post-streptococcal glomerulonephritis).

• Score 0 to 1: Very low risk of GAS (<10%). Do not test; provide supportive symptomatic care.
• Score 2 to 3: Moderate risk (15%–30%). Perform Rapid Antigen Detection Test (RADT). Treat with antibiotics only if RADT is positive.
• Score ≥4: High risk (50%). Perform RADT; treat if positive (or treat empirically if testing unavailable).
• First-Line Pharmacotherapy: Penicillin V potassium 500 mg PO BID or TID for 10 days, or Amoxicillin 500 mg PO BID for 10 days (or 1,000 mg once daily x 10 days). In patients with non-severe penicillin allergy, prescribe Cephalexin 500 mg PO BID x 10 days; for severe/anaphylactic penicillin allergy, prescribe Azithromycin 500 mg on day 1, then 250 mg daily for days 2–5, or Clindamycin 300 mg PO TID x 10 days.

Acute Uncomplicated Bronchitis

Acute bronchitis is an inflammation of the large airways characterized by cough (with or without sputum production) lasting 1 to 3 weeks (mean duration: 18 days). More than 90% of cases are caused by respiratory viruses (influenza, parainfluenza, respiratory syncytial virus, rhinovirus, adenovirus). Sputum purulence (yellow or green color) is caused by sloughed bronchial epithelial cells and inflammatory myeloperoxidase enzymes—it does not indicate bacterial infection. Physical examination reveals clear lung fields or scattered rhonchi and wheezing that clear with coughing. Vital signs are normal, and focal consolidative signs (rales, egophony, fremitus) are absent.

• Midwifery Practice Rule: Antibiotics are NOT indicated for acute uncomplicated bronchitis in healthy adults. Routine antibiotic use does not shorten illness duration and promotes antimicrobial resistance. Prescribe supportive care: hydration, humidified air, honey, dextromethorphan or guaifenesin, and an inhaled short-acting beta-agonist (albuterol) only if objective bronchospasm is documented.

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Lower Respiratory: Asthma Management Across the Lifespan & Pregnancy

Asthma is a chronic inflammatory disorder of the conducting airways characterized by episodic bronchial hyperresponsiveness and reversible airflow obstruction. Spirometry demonstrates airflow limitation (FEV1/FVC ratio <0.70) with significant bronchodilator reversibility (≥12% and ≥200 mL increase in FEV1 following administration of 4 puffs of albuterol).

GINA and NAEPP Asthma Classification

• Intermittent Asthma: Symptoms ≤2 days/week; nighttime awakenings ≤2 times/month; SABA use ≤2 days/week; no interference with normal activities; normal FEV1/FVC between exacerbations.
• Mild Persistent Asthma: Symptoms >2 days/week but not daily; nighttime awakenings 3–4 times/month; SABA use >2 days/week but not daily; minor activity limitation; FEV1 ≥80% predicted.
• Moderate Persistent Asthma: Daily symptoms; nighttime awakenings >1 time/week (not nightly); daily SABA use; some activity limitation; FEV1 60% to 80% predicted.
• Severe Persistent Asthma: Continuous symptoms throughout the day; nightly awakenings; SABA use several times daily; extreme physical limitation; FEV1 <60% predicted.

Stepwise Management & Pharmacotherapy

• GINA Track 1 (Preferred Strategy): Utilizes as-needed low-dose Inhaled Corticosteroid (ICS) combined with formoterol (a rapid-onset, long-acting beta-2 agonist) as the preferred reliever across all severity steps. This strategy delivers a dose of anti-inflammatory corticosteroid every time bronchospasm occurs, dramatically reducing severe exacerbation risk compared to SABA monotherapy.
• Traditional NAEPP Strategy: Step 1 (SABA as-needed); Step 2 (Daily low-dose ICS + SABA prn); Step 3 (Daily low-dose ICS-LABA combination); Step 4 (Medium-dose ICS-LABA); Step 5 (High-dose ICS-LABA ± biologic therapy).

Asthma Management in Pregnancy: The "Rule of Thirds"

During pregnancy, asthma follows the clinical rule of thirds: approximately one-third of patients improve, one-third remain unchanged, and one-third experience clinical worsening (most commonly between 24 and 36 weeks gestation).

• Critical Midwifery Principle: Maternal hypoxia directly induces fetal hypoxia. Uncontrolled asthma significantly elevates the risks of preeclampsia, low birth weight, intrauterine growth restriction (IUGR), and preterm birth. The risks of uncontrolled asthma to both pregnant individual and fetus vastly exceed any theoretical risk of standard asthma controller and rescue medications.
• Preferred Agents in Pregnancy:
  • Preferred Inhaled Corticosteroid (ICS): Budesonide (Pulmicort) is the preferred maintenance ICS due to the largest body of reassuring human gestational safety data.
  • Preferred Short-Acting Beta-Agonist (SABA): Albuterol (ProAir, Ventolin) remains the preferred, safe rescue bronchodilator for acute symptoms.

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Urinary Tract Infections: Cystitis vs. Pyelonephritis

Urinary tract infections (UTIs) are among the most common bacterial infections encountered in ambulatory midwifery practice. The predominant pathogen is uropathogenic Escherichia coli (responsible for 75%–90% of uncomplicated cases), followed by Staphylococcus saprophyticus (5%–15%), Klebsiella pneumoniae, and Proteus mirabilis.

Acute Uncomplicated Cystitis (Non-Pregnant Women)

• Clinical Presentation: Acute dysuria, urinary frequency, urgency, suprapubic tenderness, and gross hematuria. The presence of vaginal discharge or vaginal irritation strongly suggests vaginitis or an STI rather than a UTI.
• Urinalysis (Dipstick & Microscopy): Positive leukocyte esterase indicates pyuria (neutrophil presence); positive nitrites indicates presence of nitrate-reducing Gram-negative enterobacteriaceae (E. coli, Klebsiella, Proteus; Enterococcus and S. saprophyticus are nitrite-negative). Urine culture is not required for first-line treatment of acute uncomplicated cystitis in non-pregnant individuals but should be ordered if symptoms are recurrent or atypical.
• First-Line Empiric Antimicrobial Regimens:
  1. Nitrofurantoin monohydrate/macrocrystals (Macrobid): 100 mg PO BID for 5 days. (Contraindicated if eGFR <30 mL/min; avoid at term 38–42 weeks in pregnancy due to theoretical risk of neonatal hemolytic anemia/hyperbilirubinemia in G6PD deficiency).
  2. Trimethoprim-Sulfamethoxazole (TMP-SMX DS): 160/800 mg (1 double-strength tablet) PO BID for 3 days. (Use strictly if local community E. coli resistance is <20%; avoid during the first trimester of pregnancy due to antifolate teratogenicity and at term due to newborn kernicterus).
  3. Fosfomycin trometamol: 3 g single-dose oral packet dissolved in 3 to 4 ounces of water.
• Second-Line Regimens: Oral beta-lactams (e.g., Amoxicillin-clavulanate 500/125 mg BID x 5–7 days, Cephalexin 500 mg BID x 5–7 days, Cefpodoxime 100 mg BID x 5–7 days).
• Fluoroquinolones (Ciprofloxacin, Levofloxacin): Strictly reserved as last-line agents for uncomplicated cystitis. Fluoroquinolones carry FDA Boxed Warnings for severe, potentially permanent adverse reactions involving tendons (tendonitis, tendon rupture), muscles, joints, peripheral neuropathy, central nervous system toxicities, and aortic aneurysm/dissection.

Acute Pyelonephritis

Pyelonephritis represents an ascending infection of the renal parenchyma and renal pelvis.

• Clinical Presentation: Fever (temperature >38.0°C / 100.4°F), rigors, chills, unilateral or bilateral flank pain, pronounced costovertebral angle (CVA) tenderness, nausea, vomiting, and malaise, with or without concurrent lower urinary tract symptoms.
• Diagnostic Workup: Clean-catch or catheterized urine specimen for urinalysis, microscopy (white blood cell casts are pathognomonic), and urine culture with antimicrobial susceptibility testing (mandatory in all cases of pyelonephritis).
• Outpatient Management (Mild-to-Moderate Uncomplicated Non-Pregnant Adults): Patient must be hemodynamically stable, able to tolerate oral hydration and medications, and reliable for close follow-up within 24 to 48 hours. Prescribe Ciprofloxacin 500 mg PO BID for 7 days (or Ciprofloxacin ER 1,000 mg daily x 7 days), OR an initial single parenteral dose of Ceftriaxone 1 g IV/IM, followed by oral TMP-SMX DS BID for 14 days.
• Inpatient Hospitalization Criteria:
  • Pregnancy (Mandatory Admission): Pyelonephritis during pregnancy requires immediate hospital admission for intravenous hydration, intravenous broad-spectrum antimicrobials (e.g., Ceftriaxone 1 g IV every 24 hours or Cefazolin 1–2 g IV every 8 hours), continuous maternal monitoring, and tocodynamometry surveillance due to high risks of sepsis, acute respiratory distress syndrome (ARDS), and preterm labor.
  • Severe sepsis, hemodynamic instability, intractable nausea and vomiting, dehydration, suspected urinary tract obstruction/nephrolithiasis, or immunocompromised status.

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