A patient presents with flank pain and chills. After assessment, pyelonephritis is diagnosed. What is the most likely cause of this condition?

Appeared in: NORCET 7 Prelims -2024

Explanation

Pyelonephritis is defined as an infection of the kidney's functional tissue (parenchyma) and its collecting system (renal pelvis), making it an upper urinary tract infection (UTI).
The most common cause is an ascending infection, where pathogenic bacteria, typically from a bladder infection (cystitis), travel up the ureters to the kidneys.
This option accurately describes the entire pathogenic process, differentiating it from a simple bladder infection or a risk factor.

Option B: Chronic kidney disease (CKD) is a potential long-term consequence of recurrent or poorly treated pyelonephritis, which can cause permanent kidney scarring. It is a result, not a cause of the acute infection.
Option C: A bladder infection (cystitis) is the most common origin of the bacteria. However, pyelonephritis specifically refers to the condition where this infection has ascended to the kidneys. Therefore, 'extending UTI' is a more precise description of the cause of pyelonephritis.
Option D: Dehydration is a significant risk factor that impairs the body's ability to flush bacteria from the urinary tract. However, it is not the direct infectious cause; bacteria are the causative agents.

Clinical Relevance

Nursing practice connection: Safe nursing care depends on performing Pathophysiology and cause of acute pyelonephritis in the correct sequence, documenting the action clearly, and monitoring for the expected response.
Nurses must recognize that prompt diagnosis and antibiotic treatment of pyelonephritis are crucial to prevent serious complications like urosepsis (sepsis originating from the urinary tract) and permanent kidney damage.
Key nursing roles include monitoring for signs of worsening infection (e.g., persistent fever, hypotension), managing pain, encouraging fluid intake, and educating the patient on the importance of completing the full course of antibiotics to prevent recurrence and resistance.
What if? If the patient was pregnant, the risk of complications from pyelonephritis (like preterm labor) would be much higher, necessitating hospitalization and intravenous antibiotics as a standard of care.

How to Approach the Question

First, identify the key diagnosis in the question stem: 'pyelonephritis'.
Recall the definition of pyelonephritis. The prefix 'pyelo-' refers to the renal pelvis, and '-nephritis' means inflammation of the kidney.
Consider the pathophysiology. The most common way infections reach the kidney is by traveling upward from the lower urinary tract.
Evaluate the options based on this understanding. 'Urinary tract infection extending to the kidneys' directly describes this ascending pathway.
Differentiate this direct cause from risk factors (dehydration), precursor conditions (bladder infection), and potential complications (chronic kidney disease) to select the most precise answer.

Concept Tested & Keywords

Concept Tested: Pathophysiology and cause of acute pyelonephritis
Stem keywords: pyelonephritis, flank pain, chills, cause
Lead-in keywords: most likely
Clinical cues: The combination of flank pain and chills is a classic presentation for pyelonephritis, pointing towards a systemic infection originating in the kidney.
Negative lead-in flag: false

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E6 Medicine Davidson Principles Practice 24e p. 450-452

E6 PATHOLOGY QUICK REVIEWBased on Harsh Mohan Textbook of PATHOLOGY p. 212-214

E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 927-929

Practise the full NORCET 7 Prelims -2024

Attempt every question from this paper in a timed mock, then review the full solution for each one.