Docs Ask AI: Severe Flank Pain, Acute Kidney Injury, and Low Serum Uric Acid. What's the Diagnosis?

The "Docs Ask AI" series features clinical Q&A sessions with four distinct AIs, showcasing their unique personalities, accuracy, and writing styles. (Introduction by Doximity's DocsGPT.)

Prompt:

"A 30 year old man comes to the emergency department with severe bilateral flank pain after exercise. He is found to have acute kidney injury and a very low serum uric acid level. What are some potential causes?"

Best Answer:

"Renal hypouricemia."

The correct answer was provided by GPT-4 and Doximity's DocsGPT.

Here's what Claude+, GPT-4, Doximity's DocsGPT, and Google's Bard said:

Claude+:

Some potential causes for a 30 year old man with severe bilateral flank pain, acute kidney injury and low serum uric acid after exercise include:

1. Rhabdomyolysis - Breakdown of muscle tissue can release myoglobin into the blood which can damage the kidneys. Exercise is a common trigger. Myoglobinuria may be present on urinalysis. CK levels will be very elevated.

2. Exertional heat illness (e.g. heat stroke) - Intense exercise in the heat can lead to dehydration and organ damage including the kidneys. Core body temperature will be very high.

3. Autoimmune disease flare - Conditions like lupus or vasculitis can flare up after exercise. May see other signs of autoimmunity. Kidney biopsy may be diagnostic.

4. Urinary tract obstruction - Strenuous exercise may dislodge a kidney stone or cause swelling that obstructs urine flow. Imaging will show obstruction. 

5. Acute tubular necrosis - Ischemia or nephrotoxins can damage kidney tubules. Exercise may reduce blood flow to the kidneys. Often reversible if underlying cause addressed quickly. 

6. Acute interstitial nephritis - Exercise is a trigger for some allergic reactions or infections that cause inflammation of kidney tissues and interstitium. Biopsy will show infiltration of immune cells.

7. Renal infarction - Intense exercise can rarely cause decreased blood flow to the kidneys resulting in tissue death. Caused by renal artery stenosis or thrombosis. Imaging will show kidney damage.

8. Glomerulonephritis - Some forms of inflammation/autoimmune damage to glomeruli and kidneys can flare after exercise. Biopsy will show glomerulonephritis.

As you can see, there are several possibilities, but rhabdomyolysis, exertional heat illness and urinary tract obstruction are more likely given the context of recent exercise as a trigger. Diagnosis may involve a combination of lab work, urinalysis, imaging and in some cases biopsy. Treatment is aimed at reversing kidney damage and preventing further injury.

GPT-4:

I am not a doctor, but I can provide you with some information that may be helpful. In a 30-year-old man presenting with severe bilateral flank pain after exercise, acute kidney injury, and very low serum uric acid levels, some potential causes to consider include:

1. Renal hypouricemia: A rare hereditary condition characterized by impaired renal uric acid transport, leading to low serum uric acid levels and an increased risk of acute kidney injury, especially following exercise.

2. Rhabdomyolysis: A condition that occurs when muscle tissue breaks down and releases a protein called myoglobin into the bloodstream. This can lead to kidney damage, as the kidneys have difficulty filtering myoglobin. Rhabdomyolysis can be triggered by intense exercise, muscle injury, or other factors.

3. Dehydration: Intense exercise can lead to dehydration, which may cause acute kidney injury if fluid and electrolyte balance are not properly maintained.

4. Obstructive uropathy: A blockage in the urinary tract can cause acute kidney injury and flank pain. Blockages can result from kidney stones, blood clots, or other causes.

It is essential for a healthcare professional to evaluate the patient and consider their medical history, perform a physical examination, and possibly order further tests such as blood tests, urine tests, and imaging studies to determine the cause of the symptoms. Please consult a medical professional for personalized advice and diagnosis.

Doximity's DocsGPT:

In a 30-year-old man with severe bilateral flank pain, acute kidney injury, and a very low serum uric acid level, one potential cause could be renal hypouricemia. Renal hypouricemia is a rare genetic disorder characterized by impaired renal tubular reabsorption of uric acid, leading to low serum uric acid levels and an increased risk of acute kidney injury.

 

Other potential causes of acute kidney injury and low serum uric acid levels include: 

 

1. Medications: Certain medications such as allopurinol or probenecid can lower serum uric acid levels and cause acute kidney injury. 

2. Liver disease: Liver disease can lead to low serum uric acid levels due to impaired uric acid synthesis.

3. Fanconi syndrome: Fanconi syndrome is a rare disorder characterized by impaired tubular reabsorption of multiple substances, including uric acid, leading to low serum uric acid levels and acute kidney injury.

4. Wilson's disease: Wilson's disease is a genetic disorder characterized by impaired copper metabolism, which can lead to liver disease and low serum uric acid levels.

5. Hypothyroidism: Hypothyroidism can lead to low serum uric acid levels due to impaired renal tubular reabsorption of uric acid.

It is important to conduct a thorough medical evaluation to determine the underlying cause of acute kidney injury and low serum uric acid levels in this patient.

Google's Bard:

There are a number of potential causes of acute kidney injury (AKI) in a 30-year-old man with severe bilateral flank pain after exercise and a very low serum uric acid level. Some of the most common causes include:

• Dehydration: This is a common cause of AKI, especially in people who have been exercising strenuously. Dehydration can lead to a decrease in blood flow to the kidneys, which can damage the kidneys and lead to AKI.
• Infection: Infections, such as pneumonia or urinary tract infection, can also cause AKI. This is because infections can lead to inflammation, which can damage the kidneys.
• Medications: Some medications, such as antibiotics and chemotherapy drugs, can cause AKI. This is because these medications can damage the kidneys.
• Toxins: Exposure to toxins, such as lead or mercury, can also cause AKI. This is because toxins can damage the kidneys.
• Autoimmune diseases: Autoimmune diseases, such as lupus and rheumatoid arthritis, can also cause AKI. This is because these diseases can damage the kidneys.

In addition to these common causes, there are a number of other potential causes of AKI in a 30-year-old man with severe bilateral flank pain after exercise and a very low serum uric acid level. These include:

• Polycystic kidney disease: This is a genetic disorder that can cause the kidneys to enlarge and become scarred. This can lead to AKI.
• Kidney stones: Kidney stones can block the flow of urine, which can damage the kidneys and lead to AKI.
• Tumors: Tumors in the kidneys or other parts of the body can also cause AKI. This is because tumors can block the flow of urine or damage the kidneys.
• Radiation therapy: Radiation therapy to the abdomen or pelvis can damage the kidneys and lead to AKI.

If you are a 30-year-old man with severe bilateral flank pain after exercise and a very low serum uric acid level, it is important to see a doctor right away. AKI can be a serious condition, and it is important to get treatment as soon as possible.

 

Docs Ask AI: Orbital Myositis, Nephrotic Syndrome, and Retroperitoneal Fibrosis. What's the Diagnosis?

The "Docs Ask AI" series features clinical Q&A sessions with four distinct AIs, showcasing their unique personalities, accuracy, and writing styles. 

This series is designed to provide valuable insights into the potential clinical usefulness of AIs in the field of medicine. By showcasing the strengths and weaknesses of each AI, medical professionals can gain a better understanding of how these technologies can assist with clinical and administrative tasks. Additionally, this information can help physicians determine which AI may be the best fit for their specific needs and preferences.

(Introduction by Doximity's DocsGPT.)

Prompt:

"What's the most likely diagnosis when a patient has orbital myositis, retroperitoneal fibrosis, and nephrotic syndrome?"

Answer:

"IgG4-related disease."

Correct answers were provided by Claude+, GPT-4, and Doximity's DocsGPT.

Here's what Claude+, GPT-4, Doximity's DocsGPT, and Google's Bard said:

Claude+:

The combination of orbital myositis, retroperitoneal fibrosis, and nephrotic syndrome would be highly suggestive of IgG4-related disease. This is an autoimmune fibrosing condition that can affect multiple organs. The common features in this case would be:

- Orbital myositis causing inflammation of extraocular muscles leading to eye pain, swelling, and impaired eye movement. 

- Retroperitoneal fibrosis leading to inflammation and scarring in the tissues behind the peritoneum, causing ureteric obstruction and hydronephrosis.

- Nephrotic syndrome causing high protein loss in the urine due to inflammation of the kidneys (IgG4-related kidney disease).

IgG4-related disease would be the top differential diagnosis requiring confirmation with biopsy and immunohistochemistry to show characteristic IgG4-positive plasma cell infiltration. Treatment involves use of corticosteroids to suppress the autoimmune inflammation, and immunosuppressants like azathioprine or rituximab in refractory cases.

The other but less likely differentials could include sarcoidosis, lymphoma, multifocal fibrosclerosis, and periaortitis. But the combination of features in this case strongly suggests IgG4-related systemic disease as the most probable diagnosis.

So in summary, the most likely diagnosis would be IgG4-related disease - a systemic autoimmune fibrosing condition involving multiple organs. Diagnosis needs to be confirmed on biopsy, and treatment focuses on immunosuppression.

GPT-4:

I'm not a doctor, but I can try to provide you with some information. Orbital myositis, retroperitoneal fibrosis, and nephrotic syndrome are all inflammatory conditions that can have various etiologies. One possible diagnosis that could present with these symptoms is a systemic autoimmune or inflammatory disorder such as systemic lupus erythematosus (SLE), granulomatosis with polyangiitis (GPA, formerly known as Wegener's granulomatosis), or IgG4-related disease.

IgG4-related disease is a relatively rare immune-mediated condition characterized by tumefactive lesions, dense lymphoplasmacytic infiltrate rich in IgG4-positive plasma cells, and storiform fibrosis. It can affect various organs, including the orbit (orbital myositis), retroperitoneum (retroperitoneal fibrosis), and kidneys (nephrotic syndrome). This disease could potentially explain the combination of symptoms you're describing.

However, it's important to note that a proper diagnosis can only be made by a healthcare professional after a thorough evaluation of the patient's medical history, physical examination, laboratory tests, and imaging studies. If you or someone you know is experiencing these symptoms, it's crucial to consult a medical professional for an accurate diagnosis and appropriate management.

Doximity's DocsGPT:

The most likely diagnosis in a patient with orbital myositis, retroperitoneal fibrosis, and nephrotic syndrome is IgG4-related disease. This is a rare autoimmune disorder that can affect multiple organs in the body, including the kidneys, pancreas, salivary glands, lymph nodes, and others. It is characterized by high levels of IgG4 antibodies and infiltration of affected tissues by IgG4-positive plasma cells. Treatment typically involves corticosteroids and immunosuppressive medications. It is important to consult with a specialist in rheumatology and/or nephrology for proper diagnosis and management of this condition.

Google's Bard:

The most likely diagnosis when a patient has orbital myositis, retroperitoneal fibrosis, and nephrotic syndrome is idiopathic retroperitoneal fibrosis (IPF). IPF is a rare, chronic inflammatory disease that causes the growth of fibrous tissue in the retroperitoneum, the area behind the peritoneum, the lining of the abdominal cavity. The fibrous tissue can block the ureters, the tubes that carry urine from the kidneys to the bladder, leading to nephrotic syndrome. IPF is also associated with orbital myositis, an inflammation of the muscles around the eye.

The exact cause of IPF is unknown, but it is thought to be an autoimmune disorder. Autoimmune disorders occur when the body's immune system attacks healthy tissue. In the case of IPF, the immune system attacks the tissues in the retroperitoneum.

The symptoms of IPF vary from person to person, but they may include:

• Pain in the lower back or abdomen
• Fatigue
• Weight loss
• High blood pressure
• Protein in the urine
• Edema, or swelling, in the legs, ankles, and feet

If you have any of these symptoms, it is important to see a doctor to get a diagnosis and treatment. There is no cure for IPF, but treatment can help to relieve symptoms and improve quality of life. Treatment options may include:

• Medications to suppress the immune system
• Surgery to remove the fibrous tissue
• Dialysis, if the kidneys have failed

With treatment, most people with IPF can live a normal life.

 

The Mountain Model of Hyponatremia

“The Mountain Model of Hyponatremia” is an educational project by Joel Topf and me.

Imagine this is the clinical scenario of severe hyponatremia:

• You are driving in a car at the top of a mountain. (The top of the mountain is the low sodium level.) 
• There is a forest fire behind you. (The fire represents brain swelling and seizures if the sodium level drops much lower.)
• Your goal is to drive safely to the bottom of the mountain. (The bottom of the mountain is a normal sodium level.)
• But, to be safe, you should follow the “sodium speed limit”: a rise in sodium of 8 every 24 hours. (If you exceed this “sodium speed limit,” you increase the risk of a car crash: osmotic demyelination syndrome.)

Based on this model, there are five possible therapies for patients with hyponatremia: 

1. Press the accelerator (when the car is in “drive”): 3% (hypertonic) saline
2. Press the accelerator (but the car may be in “drive,” “neutral,” or even “reverse”): 0.9% (normal) saline
3. Cruise control: desmopressin/DDAVP and 3% (hypertonic) saline (“proactive strategy”)
4. Press the brake: desmopressin/DDAVP (or large amounts of D5W) (“reactive strategy”)
5. Reverse gear: desmopressin/DDAVP and D5W (“rescue strategy”)

Additional technical notes:

1. The “sodium speed limit” might change depending on the clinical situation.
2. The slope of the mountain represents rapid correction due to water diuresis that can occur in patients with a reversible cause of hyponatremia (hypovolemia, beer potomania/low solute hyponatremia, adrenal insufficiency, and other causes).
3. If a patient has SIADH, the mountain might slope upward. (This is a separate figure.)
4. If the patient has SIADH, giving 0.9% (normal) saline may not work or may cause the sodium to go down — when you press the accelerator, the car may be in “neutral” or even “reverse.” (See therapy #2.) 
5. Usually, fluid restriction is also important. 
6. In the right clinical circumstances, other therapies might include salt tablets, loop diuretics, urea, and vaptans. (These are not included in the model.) 

(Of course, this is for educational purposes only and is not medical advice.)

Calculators for EKFC eGFRcys, EKFC eGFRcr, and EKFC eGFRcr-cys

The most accurate race-free eGFR equation (EKFC eGFRcys) isn't yet available in EMRs or a calculator app, so here's an Apple shortcut to use on the iPhone or Mac.

Also, here’s a calculator as a Google spreadsheet of the EKFC eGFRcys, EKFC eGFRcr, and EKFC eGFRcr-cys equations. 

Thanks to Dr. Hans Pottel for his guidance.

Reference:

nejm.org/doi/full/10.1056/NEJMoa2203769