Pharmacotherapy Lecture on Acute Tubular Necrosis

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Questions and Answers

What symptom is specifically associated with postrenal acute kidney injury (AKI)?

Weight gain

Pulmonary oedema

Anuria alternating with polyuria (correct)

Nausea and vomiting

Which physical examination finding suggests systemic venous congestion and volume overload?

Cold extremities

Rash

Tachycardia

Jugular venous distention (JVD) (correct)

Which of the following signs is NOT typically associated with hypovolaemia?

Increased blood pressure (correct)

Hypotension

Reduced skin turgor

Postural hypotension

What is a common symptom of intrinsic acute kidney injury due to acute interstitial nephritis?

Rash Signup and view all the answers

Which condition can be indicated by the presence of crackles in the lungs during a physical examination?

Pulmonary oedema Signup and view all the answers

What could a high blood urea nitrogen (BUN) to serum creatinine (SCr) ratio indicate?

Prerenal acute kidney injury (AKI) Signup and view all the answers

In prerenal AKI, what happens to the fractional excretion of sodium (FENa)?

FENa decreases below 1% Signup and view all the answers

Which laboratory finding is NOT typically associated with prerenal AKI?

Brown, muddy granular casts in urine Signup and view all the answers

Which condition can cause an increase in blood urea nitrogen (BUN) levels besides prerenal AKI?

Excessive protein intake Signup and view all the answers

What would a FENa value above 2% indicate?

Intrinsic renal failure Signup and view all the answers

What is the reference range for serum creatinine (SCr) levels?

53 to 106 𝜇mol/L Signup and view all the answers

Which urinalysis finding is most consistent with allergic interstitial nephritis?

Eosinophiluria Signup and view all the answers

What is a common laboratory test for identifying metabolic acidosis?

Arterial blood gases Signup and view all the answers

What is the most common cause of intrinsic acute kidney injury (AKI)?

Acute tubular necrosis (ATN) Signup and view all the answers

Which of the following is NOT a typical nephrotoxin that can lead to acute tubular necrosis?

Corticosteroids Signup and view all the answers

What can happen to prerenal acute kidney injury (AKI) if the underlying cause is not addressed?

It can progress to acute tubular necrosis Signup and view all the answers

Which condition is associated with postrenal AKI due to obstruction?

Benign prostatic hyperplasia (BPH) Signup and view all the answers

What determines the signs and symptoms of acute kidney injury (AKI)?

The underlying aetiology Signup and view all the answers

What can lead to the necrosis of tubular epithelial cells in acute tubular necrosis?

Nephrotoxins and poor renal blood flow Signup and view all the answers

Which of the following is a cause of postrenal AKI?

Urinary tract obstruction Signup and view all the answers

What consequence does the necrosis of tubular epithelial cells lead to in acute tubular necrosis?

Blockage of tubules with debris Signup and view all the answers

What laboratory test is essential for evaluating kidney function in this patient?

BUN and SCr Signup and view all the answers

Which medication combination poses the highest risk of acute kidney injury (AKI) in this patient?

ARB, diuretic, and NSAID Signup and view all the answers

What history would be most relevant to assess for a risk of prerenal AKI?

Recent gastroenteritis Signup and view all the answers

Which additional lab test could help rule out infection in this patient?

WBC count Signup and view all the answers

Which question is least likely to provide relevant information for pharmacotherapy assessment?

What is your favorite food? Signup and view all the answers

Which symptom is a specific indicator of acute kidney injury (AKI) in this patient?

Bilateral 2+ pitting edema Signup and view all the answers

What is a concerning change in this patient's weight relevant to her kidney condition?

She weighs 70.5 kg, an increase of 2.5 kg Signup and view all the answers

Which medication in her regimen is primarily used to manage hypertension?

Losartan/Hydrochlorothiazide Signup and view all the answers

Which laboratory value would be crucial for further assessing the patient's kidney function?

Serum creatinine (SCr) Signup and view all the answers

Which of the following is a condition this patient has that increases her risk for AKI?

Stage 2 chronic kidney disease Signup and view all the answers

What symptom might indicate fluid overload in this patient?

Crackles on auscultation Signup and view all the answers

Which question is relevant to ask regarding her current pharmacotherapy?

Have you recently increased your sodium intake? Signup and view all the answers

What nonspecific symptom is this patient exhibiting that could be associated with AKI?

Nausea Signup and view all the answers

Study Notes

Acute Tubular Necrosis (ATN)

Acute Tubular Necrosis (ATN) is the primary cause of intrinsic acute kidney injury (AKI).
ATN involves necrosis of tubular epithelial cells due to nephrotoxins (e.g., aminoglycosides, contrast media) and conditions like sepsis and ischaemia.
Damage leads to tubular blockage by debris, increasing tubular pressure and hindering the elimination of sodium, water, and metabolic waste.
If untreated, prerenal AKI may progress to ATN.

Postrenal Acute Kidney Injury

Postrenal AKI results from obstruction of urinary outflow, affecting the ureters, urinary bladder, or urethra.
Common causes include benign prostatic hyperplasia (BPH), pelvic tumors, and kidney stones (nephrolithiasis).

Clinical Presentation & Diagnosis of AKI

Signs and symptoms of AKI vary based on underlying causes and can include:
- Weight gain or loss (prerenal)
- Gastrointestinal symptoms like nausea, vomiting, and diarrhea
- Fatigue and shortness of breath
- Pruritus and edema
- Anuria with alternating polyuria (postrenal)
- Colicky abdominal pain radiating to the groin (postrenal)
- Electrolyte disturbances
Signs of hypovolaemia: tachycardia, hypotension, postural hypotension, dry skin, sunken eyes, collapsed peripheral veins, and cold extremities.

Physical Examination Findings

Increased blood pressure and peripheral edema may be observed.
Changes in mental status, jugular venous distention, and pulmonary edema can indicate severity.
Physical indicators include crackles in the lungs and asterixis (involuntary jerking).
Hypotension or orthostatic hypotension might present in prerenal AKI, along with rashes from intrinsic causes.

AKI Staging System

Based on serum creatinine changes as per South African Renal Society (SARS) guidelines from 2015.
BUN-to-creatinine ratio > 10:1 can suggest prerenal AKI due to increased urea reabsorption at lower urine flow rates.
FENa (fractional excretion of sodium) differentiates AKI types; < 1% indicates prerenal AKI due to enhanced sodium reabsorption.

Laboratory Tests

Full blood count (FBC) may show elevated white blood cell count indicative of infection.
Arterial blood gases can reveal metabolic acidosis.
Urea & Electrolytes (U & E):
- Elevated serum creatinine (SCr) reference range: 53 to 106 µmol/L.
- Elevated BUN (reference range: 2.9 to 8.9 mmol/L).
- Hyperkalaemia might be present.
Urinalysis findings:
- Different appearances can indicate specific underlying conditions, such as brown muddy casts for intrinsic ATN or eosinophiluria for acute interstitial nephritis.

Case Study Findings

Example patient is a 65-year-old woman with stage 2 chronic kidney disease and presenting symptoms including nausea, vomiting, and weight gain due to edema.
Her blood pressure is elevated at 170/94 mmHg, and crackles are observed on auscultation.
Medications include losartan, hydrochlorothiazide, ibuprofen, and others, which may contribute to AKI risk.

Questions for Further Assessment

Signs and symptoms of AKI:
- Bilateral pitting edema, weight gain, elevated blood pressure, crackles, and general weakness suggest AKI.
Risk factors for developing AKI include age, history of diabetes and chronic kidney disease, and medication use (especially NSAIDs).
Additional laboratory information needed includes comprehensive blood chemistry tests (BUN, SCr, bicarbonate, potassium), WBC count, previous lab results to assess baseline kidney function, urinalysis, and results related to glucose management.
Key pharmacotherapy questions include duration and dosages of ibuprofen and other medications, adherence to prescriptions, and use of additional medications.

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Description

This quiz focuses on kidney-related conditions, particularly Acute Tubular Necrosis (ATN), a common cause of intrinsic acute kidney injury (AKI). It examines the nephrotoxic agents responsible for ATN and the implications for treatment in pharmacy practice.