Internal Medicine Correlations and Clinical Scenarios (CCS) USMLE Step 3

CASE 3: Glomerulonephritis (Immunoglobulin A)

Setting: office

CC: “I have blood in my urine.”

VS: BP:143/92 mm Hg; T: 98°F

HPI: A 34-year-old man comes to your office after noticing what he thinks is blood in his urine off and on for the past few months. The first time he had it, his other physician gave him an antibiotic. Now it has recurred. He has a sore throat the day before each episode.

PMHx/Medications: none

PE: normal

Initial Order: UA

Hematuria Causes

• Stones

• Infection

• Glomerulonephritis

• Tumor (renal or bladder cancer)

• Trauma

The UA can be done immediately. There can be no meaningful discussion about dark urine or blood in the urine without the UA results.

Report:

Image RBCs 100 to 200

Image No white cells

Image No protein

Which is associated with necrotizing granulomas?

a. Wegener granulomatosis

b. Churg-Strauss syndrome

c. Goodpasture syndrome

d. Microscopic polyangiitis

e. Polyarteritis nodosa (PAN)

Answer a. Wegener granulomatosis

As the name Wegener granulomatosis implies, this disease is associated with granulomas. All of the listed disorders are systemic diseases and Wegener granulomatosis is a systemic vasculitis involving the skin, joints, eyes, brain, and gastrointestinal (GI) tract with special localization to the upper and lower respiratory tract.

Upper and Lower Respiratory Tract + Cytoplasmic Antineutrophil Cytoplasmic Antibody (cANCA) = Wegener = Steroids + Cyclophosphamide

PAN is associated with chronic hepatitis B and C.

With just some hematuria, but no protein, there is no immediate therapy needed. You can schedule the patient to follow up with you in a month to see if there is persistence and further evaluation is needed.

Which disease is associated with linear deposits in the glomerulus on biopsy?

a. Wegener granulomatosis

b. Churg-Strauss syndrome

c. Goodpasture syndrome

d. Microscopic polyangiitis

e. PAN

Answer c. Goodpasture syndrome

Only Goodpasture syndrome has linear deposits.

Lung + Kidney + Antibasement Membrane Antibodies = Goodpasture Syndrome

A month later the patient has a recurrence of hematuria. There is no pharyngitis this time.

Repeat UA:

Image RBCs 100 to 200

Image Dysmorphic RBCs

Image No protein

Which of the following has “dysmorphic” RBCs?

a. Stones

b. Infection

c. Glomerulonephritis

d. Tumor (renal or bladder cancer)

e. Trauma

Answer c. Glomerulonephritis

RBCs can become misshapen or “dysmorphic” as they pass through an abnormal glomerulus in glomerulonephritis. Nevertheless, any persistent or recurrent hematuria needs evaluation with a culture and ultrasound of the urinary system. You must exclude stones and anatomic problems with the urinary system with hematuria.

Orders:

Image Urine culture

Image Ultrasound of urinary system

Polycystic kidney disease most commonly presents with recurrent hematuria.

• Stones

• Recurrent pyelonephritis

Move the clock forward a week. Recurrent episodes of hematuria need investigation.

Report:

Image Urine culture: no growth

Image Ultrasound: normal; no stones; no hydronephrosis; no cysts

Which is most likely to present with recurrent abdominal pain that is worse on eating?

a. Wegener granulomatosis

b. Churg-Strauss syndrome

c. Microscopic polyangiitis

d. PAN

Answer d. PAN

PAN is a systemic vasculitis that spares the respiratory system. There is no single clear feature because, like Wegener granulomatosis, it is a systemic vasculitis involving the skin, joints, eyes, brain, and GI tract. Because of the presence of narrow vessels in the arterial system of the bowel, pain related to eating, or “intestinal angina” occurs. Look for an abnormal GI angiogram or sural nerve biopsy. Treat with steroids and cyclophosphamide as you would Wegener granulomatosis and Churg-Strauss syndrome.

Vasculitis + Asthma + Eosinophils = Churg-Strauss Syndrome = Steroids + Cyclophosphamide

The patient returns in a month. The UA now shows (Figure 6-2) the following:

Image RBCs 100 to 200

Image Dysmorphic RBCs

Image RBC casts

Image Mild proteinuria

Image

Figure 6-2. A. Fine granular casts. B. Red blood cell cast. (Reproduced with permission from Agnes B. Fogo, MD, Vanderbilt Collection.)

Immunoglobulin A (IgA) nephropathy is the most common glomerulonephritis.

What else besides the kidney is routinely involved in IgA nephropathy?

a. Nothing

b. GI tract

c. Joints

d. Skin

e. Lung

Answer a. Nothing

IgA nephropathy is monosymptomatic to the kidney alone. Henoch-Schönlein purpura involves the GI tract, joints, and skin. Oddly, although Henoch-Schönlein has a more serious systemic presentation at first, it nearly always resolves spontaneously and permanently in >95% of patients. It is IgA nephropathy that is much more dangerous. There is chronic and recurrent kidney disease in 60% to 70% of patients and a third will end up on dialysis with end-stage renal disease (ESRD).

A month later, the hematuria persists in the patient’s urinalysis. The BUN and creatinine levels are normal but start to slightly elevate after a few months.

Which test can confirm IgA nephropathy?

a. Renal biopsy only

b. Skin biopsy

c. GI biopsy

d. IgA level in blood

Answer a. Renal biopsy only

The difficulty of IgA nephropathy diagnosis is that only the renal biopsy can establish a diagnosis. Checking IgA levels in blood is unreliable.

See the patient at 1 month, 3 months and 6 months. If hematuria persists or the creatinine level stays elevated, order the kidney biopsy. Also order a nephrology consultation.

On CCS, if a consultation is felt to be needed prior to a procedure, the test will tell you. Just order the procedure you feel is necessary. Never wait for a consultant to tell you to do anything, it will not happen.

Which form of IgA-mediated disease has treatment that will reverse it?

a. IgA nephropathy

b. Celiac disease

c. Henoch-Schönlein purpura

d. None

Answer d. None

Stopping gluten and wheat in the diet is not the same as having a treatment that will reverse it. There is no therapy that will allow a person with celiac disease to eat wheat. No therapy reverses IgA-mediated disease. We have steroids for IgG- and IgE-mediated disease.

The renal biopsy shows IgA deposition in the kidney and the diagnosis is confirmed. There is no definitive therapy for IgA nephropathy. Over time, about a third of patients progress and proteinuria worsens. When this happens, order prednisone and ACE inhibitorsThere is a difference between the questions “What will you do?” and “What treatment stops the disease?”

There is no treatment that can stop IgA nephropathy.

Use ACE inhibitors and steroids.

If the case allows, move the clock forward 1 to 2 years. If the creatinine level starts to rise, refer the patient for renal transplant screeningThere is no cure for IgA nephropathy. You have to transplant the kidney.



If you find an error or have any questions, please email us at admin@doctorlib.info. Thank you!