The first branch point in a skin infection is whether there is a drainable collection, because an abscess needs incision and drainage rather than antibiotics alone. These questions cover distinguishing cellulitis from abscess, when MRSA coverage is warranted, wound assessment and closure decisions, tetanus prophylaxis, and the systemic signs that change the plan. All 10 questions are written to Family Nurse Practitioner (FNP-BC / FNP-C) board standard, each with a full rationale.
Question 1
A 45-year-old male is being discharged after the repair of a simple laceration on the upper back using 4-0 nylon sutures.
- A) Instruct the patient to return in 4 days.
- B) Instruct the patient to return in 7 days.
- C) Instruct the patient to return in 14 days.✓
- D) Instruct the patient to return in 21 days.
💡 Key Takeaway
Suture removal timing depends on anatomic location, with high-tension areas requiring 10 to 14 days.
Show rationale
The appropriate timing for suture removal is dictated by the anatomical location and the resting tension on the skin. Option C is correct because the upper back is a high-tension area subject to continuous stretching, requiring 10 to 14 days for adequate tensile strength to develop before removal. Option A is appropriate for low-tension facial lacerations, which are removed in 3 to 5 days to prevent scarring. Option B is appropriate for low-tension areas like the scalp or anterior arms, typically removed in 7 to 10 days. Option D is incorrect because leaving nonabsorbable sutures for 21 days significantly increases the risk of epithelialized suture tracks and localized infection.
Question 2
A 21-year-old female reports new-onset fever and chills four days into a five-day nitrofurantoin course for simple cystitis. Her dysuria has improved, but she now has right-sided back pain and nausea.
- A) Extend the current nitrofurantoin prescription for an additional week.
- B) Add oral phenazopyridine to manage her new urinary symptoms.
- C) Discontinue nitrofurantoin and initiate a fluoroquinolone for suspected pyelonephritis.✓
- D) Advise increased fluid intake and re-evaluate in three days.
💡 Key Takeaway
Systemic symptoms during cystitis treatment indicate pyelonephritis, requiring a medication with adequate renal tissue penetration.
Show rationale
The development of systemic symptoms like fever, chills, and flank pain during treatment for simple cystitis strongly indicates progression to acute pyelonephritis. Nitrofurantoin does not achieve adequate tissue concentration in the kidneys and is entirely ineffective for upper urinary tract infections. The provider must modify the regimen to an agent with excellent renal tissue penetration, such as a fluoroquinolone, pending further culture results. Extending the current nitrofurantoin prescription (Option A) will not treat the upper tract involvement. Adding phenazopyridine (Option B) only masks the superficial urinary symptoms without addressing the worsening systemic infection. Advising increased fluids and waiting three days (Option D) is dangerous and risks severe complications like sepsis or the formation of a renal abscess.
Question 3
A 50-year-old male with non-purulent cellulitis was started on oral cephalexin 48 hours ago. He now presents with increased erythema and new fluctuant purulence. His vital signs remain completely stable. Which intervention is most appropriate?
- A) Continue current cephalexin and add oral amoxicillin.
- B) Continue current cephalexin and add oral penicillin.
- C) Perform incision and drainage and prescribe doxycycline.✓
- D) Perform incision and drainage and prescribe dicloxacillin.
💡 Key Takeaway
The development of purulence during cellulitis treatment indicates a staphylococcal shift requiring source control and MRSA coverage.
Show rationale
The development of new fluctuant purulence while on cephalexin indicates clinical failure and a shift from a presumed streptococcal infection to a staphylococcal abscess. Cephalexin lacks efficacy against methicillin-resistant Staphylococcus aureus (MRSA), which is a leading cause of purulent skin infections. The appropriate management requires incision and drainage for source control, coupled with a transition to an antibiotic that reliably covers MRSA, such as doxycycline. Continuing cephalexin and simply adding amoxicillin or penicillin is incorrect because neither agent provides the necessary MRSA coverage.
Question 4
While repairing a superficial 3-cm forearm laceration, the nurse practitioner notices a tendency for the wound edges to invert during closure.
- A) Take a deeper bite of subcutaneous tissue.✓
- B) Take a shallower bite of subcutaneous tissue.
- C) Tie the suture knots with greater tension.
- D) Tie the suture knots with lesser tension.
💡 Key Takeaway
Taking a wider, deeper bite at the base of the wound ensures proper epidermal edge eversion.
Show rationale
Proper wound edge eversion is critical for optimal healing and minimizing scar depression. Option A is correct because taking a deeper and wider bite at the base of the wound creates a flask-shaped tissue loop that naturally forces the epidermal edges upward and outward. Option B is incorrect because a shallow bite exacerbates edge inversion, leading to a depressed scar. Option C is incorrect because excessive tension causes tissue ischemia, necrosis, and prominent cross-hatching scars, rather than correcting the inversion. Option D is incorrect because while loose knots prevent ischemia, they do not mechanically correct the underlying inversion of the tissue planes.
Question 5
A patient with type 2 diabetes returns to the clinic 7 days post-excision of a benign cyst on the lower leg. The patient reports throbbing pain. The nurse practitioner observes a 3-mm separation of wound edges, surrounding induration, and thick purulent drainage. Which action is the most appropriate next step?
- A) Apply sterile adhesive strips to close the separated edges.
- B) Recommend warm compresses and continuous elevation of the leg.
- C) Obtain a wound culture and initiate systemic antibiotic therapy.✓
- D) Debride the wound bed and apply a hydrocolloid dressing.
💡 Key Takeaway
Purulent drainage with edge separation indicates active infection requiring culture and systemic antibiotics before other interventions.
Show rationale
The presence of purulent drainage, increasing pain, and wound dehiscence in a patient with diabetes strongly indicates an active surgical site infection. The standard of care requires obtaining a wound culture to guide targeted therapy while immediately initiating empiric systemic antibiotics. Applying adhesive strips to close the wound is contraindicated, as sealing an infected space can exacerbate an underlying abscess. Recommending warm compresses and elevation is insufficient for an active, purulent infection in a high-risk diabetic patient. While debridement might eventually be necessary, applying an occlusive hydrocolloid dressing over an actively infected, draining wound is contraindicated.
Question 6
A patient presents for a follow-up 48 hours post-procedure after a minor punch biopsy on the shoulder. The nurse practitioner notes a 1-mm rim of erythema around the intact sutures and a small amount of serosanguinous exudate on the dressing. The patient denies fever or worsening pain. Which action is most appropriate?
- A) Reassure the patient and continue daily wound cleansing.✓
- B) Prescribe oral cephalexin to treat the early infection.
- C) Remove the sutures to drain the underlying exudate.
- D) Apply topical mupirocin and cover with a bandage.
💡 Key Takeaway
Normal inflammatory wound healing features mild erythema and serosanguinous drainage within the first 48 hours.
Show rationale
The patient is exhibiting signs of the normal inflammatory phase of wound healing, which peaks around 48 hours post-procedure. A minimal rim of erythema and clear or serosanguinous drainage are expected physiological responses, not signs of infection. Therefore, reassuring the patient and continuing standard daily cleansing is the best action. Prescribing oral antibiotics or applying topical mupirocin is unnecessary and promotes antibiotic resistance since there is no clinical infection. Removing the sutures prematurely would disrupt normal healing and increase the risk of dehiscence, as the exudate described does not indicate an underlying abscess requiring drainage.
Question 7
A 9-month-old infant is evaluated in the urgent care center for acute onset of noisy breathing and a low-grade fever. During the focused physical examination, the nurse practitioner notes a respiratory rate of 48 breaths/minute, prolonged expiratory phase, and diffuse polyphonic wheezing heard predominantly at the lung bases.
- A) Assess for a barking cough indicative of viral croup.
- B) Evaluate for severe drooling suggestive of acute bacterial epiglottitis.
- C) Inspect the posterior pharynx for a large peritonsillar abscess.
- D) Monitor for worsening tachypnea indicative of acute viral bronchiolitis.✓
💡 Key Takeaway
Prolonged expiration and diffuse wheezing in infants strongly suggest lower airway bronchiolitis.
Show rationale
The presence of a prolonged expiratory phase and diffuse polyphonic wheezing are classic physical exam findings of lower airway obstruction, most commonly acute viral bronchiolitis in this age group. Option D is correct because bronchiolitis requires close monitoring for worsening respiratory distress, including tachypnea and retractions. Option A is incorrect because croup is an upper airway disease characterized by inspiratory stridor and a barking cough, not expiratory wheezing. Option B is incorrect as epiglottitis presents with high fever, drooling, and a toxic appearance, typically without wheezing. Option C is incorrect because a peritonsillar abscess presents with asymmetric tonsillar swelling and muffled voice, not diffuse lower airway wheezing.
Question 8
An 81-year-old female presents with a sharply demarcated, intensely red plaque on her right shin. She reports experiencing chills and a low-grade fever that started suddenly the previous evening.
- A) Acute deep vein thrombosis
- B) Chronic venous insufficiency flare
- C) Acute bacterial skin cellulitis✓
- D) Superficial venous thrombophlebitis
💡 Key Takeaway
Systemic symptoms combined with sharply demarcated erythema reliably differentiate infectious cellulitis from vascular etiologies.
Show rationale
The presence of a sharply demarcated red plaque combined with systemic infectious symptoms like chills and a low-grade fever is the hallmark presentation of acute bacterial skin cellulitis, specifically the erysipelas form. While differentiating between vascular and infectious causes in older adults can be tricky, an acute deep vein thrombosis does not cause sharply defined skin borders or acute systemic chills. A chronic venous insufficiency flare causes bilateral, poorly demarcated erythema and swelling without fever. Superficial venous thrombophlebitis causes localized tenderness along a vein, not a broad, demarcated plaque with systemic illness. The sudden onset of fever alongside these specific skin changes makes an infectious process the clear priority diagnosis.
Question 9
A 58-year-old male was diagnosed with uncomplicated diverticulitis and started on oral amoxicillin-clavulanate. He returns to the clinic reporting worsening pain after three days and an inability to tolerate oral fluids due to persistent vomiting. What is the most appropriate next step?
- A) Switch to oral ciprofloxacin and oral metronidazole.
- B) Prescribe oral ondansetron and continue current antibiotics.
- C) Refer to the emergency department for admission.✓
- D) Switch to oral trimethoprim-sulfamethoxazole and oral metronidazole.
💡 Key Takeaway
Inability to tolerate oral fluids or worsening symptoms on oral antibiotics requires emergency department referral.
Show rationale
Outpatient management of diverticulitis requires the patient to maintain adequate hydration. This patient's inability to tolerate oral fluids and worsening pain despite appropriate antibiotic therapy indicate a failure of outpatient management and potential progression to complicated diverticulitis. Option C is correct because intravenous hydration, intravenous antibiotics, and repeat imaging are now required to rule out a new abscess or perforation. Option A and Option D are incorrect because changing oral antibiotics will not resolve the immediate threat of dehydration or address the underlying complication. Option B is incorrect because merely treating nausea ignores the progression of the intra-abdominal infection.
Question 10
A 7-year-old child presents to establish care after being homeschooled. The parents report the child received only the birth hepatitis B vaccine. Which tetanus-containing vaccine should the APRN administer today?
- A) Diphtheria, tetanus, and acellular pertussis
- B) Tetanus, diphtheria, and acellular pertussis✓
- C) Tetanus and diphtheria toxoids formulation
- D) Diphtheria and tetanus toxoids formulation
💡 Key Takeaway
Unimmunized children aged 7 years and older should receive Tdap instead of DTaP for catch-up.
Show rationale
Children who are 7 years of age and older who are not fully immunized against pertussis, diphtheria, or tetanus should receive Tdap rather than DTaP. DTaP is only approved for children under age 7. Tdap provides the necessary primary catch-up dose for this older child. Td or DT formulations omit the pertussis component, which this unimmunized child still needs for comprehensive primary prevention against whooping cough. Therefore, Tdap is the only appropriate choice for initiating this catch-up series.
