A 42-year-old man presents to his doctor with complaints of left-sided flank pain radiating into his groin. The pain began suddenly and has increased in intensity. He had a similar problem several years ago, but he did not seek medical attention, and his symptoms resolved spontaneously. He denies fever, chills, nausea, or vomiting. He has had no diarrhea or difficulty urinating. Physical examination is remarkable for tenderness along the left flank and into the groin, but is otherwise normal. There are no inguinal hernias detected on examination. A urinalysis reveals microscopic hematuria without casts. Serum chemistry reveals: Sodium: 143 mEq/L Potassium: 2.4 mEq/L Bicarbonate: 17 mEq/L Chloride: 115 mEq/L Blood urea nitrogen: 12 mg/dL Creatinine: 1.0 mg/dL Glucose: 85 mg/dL Which of the following is MOST likely present in this patient?
A 42-year-old man presents to his doctor with complaints of left-sided flank pain radiating into his groin. The pain began suddenly and has increased in intensity. He had a similar problem several years ago, but he did not seek medical attention, and his symptoms resolved spontaneously. He denies fever, chills, nausea, or vomiting. He has had no diarrhea or difficulty urinating. Physical examination is remarkable for tenderness along the left flank and into the groin, but is otherwise normal. There are no inguinal hernias detected on examination. A urinalysis reveals microscopic hematuria without casts. Serum chemistry reveals: Sodium: 143 mEq/L Potassium: 2.4 mEq/L Bicarbonate: 17 mEq/L Chloride: 115 mEq/L Blood urea nitrogen: 12 mg/dL Creatinine: 1.0 mg/dL Glucose: 85 mg/dL Which of the following is MOST likely present in this patient?
💡 Explanation
## **Core Concept**
The patient's presentation of sudden onset flank pain radiating to the groin, along with microscopic hematuria, is suggestive of a **renal colic**, commonly caused by a **kidney stone**. The laboratory findings, particularly the serum chemistry results, also point towards an underlying issue related to the stone.
## **Why the Correct Answer is Right**
The patient's symptoms of flank pain radiating to the groin and microscopic hematuria are classic for nephrolithiasis (kidney stones). The presence of **hypokalemia (low potassium)**, **metabolic acidosis (low bicarbonate and high chloride)**, and **hyperchloremia**, along with a history suggestive of a previous episode, supports the diagnosis of a **stone causing a urinary obstruction**. This obstruction can lead to a **post-renal cause of acute kidney injury** but in this case, doesn't seem to have significantly elevated the creatinine. The acid-base disturbance is consistent with a **renal tubular acidosis (RTA) type 1**, which is associated with **kidney stones**, particularly those composed of **calcium phosphate**.
## **Why Each Wrong Option is Incorrect**
- **Option A:** Without specific details on the options, we can't directly address why A, B, or D are incorrect, but we can infer based on common causes of similar presentations.
- Typically, conditions like **pyelonephritis** or **prostatitis** would present with symptoms like fever, chills, or urinary symptoms, which this patient does not have.
- **Option B:** If suggesting another cause of pain, it would need to be evaluated against the evidence for nephrolithiasis and associated electrolyte imbalances.
- **Option C:** If suggesting a different metabolic issue, it would need to align more closely with the patient's presentation and lab values.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **kidney stones** can cause **obstructive uropathy**, leading to **post-renal acute kidney injury**. Also, certain types of stones are associated with **systemic conditions**, such as **hyperparathyroidism** (associated with **calcium stones**) or **urinary tract infections** (associated with **struvite stones**). The presence of **RTA type 1** is a significant clue pointing towards **calcium phosphate stones**.
## **Correct Answer:** .
✓ Correct Answer: B. Metabolic acidosis
📤 Share this MCQ
Share Card Preview
👆 1080x1080 square card — fills the full width in WhatsApp and Telegram