A 28-year-old woman comes to the emergency department due to persistent bilateral headaches. The patient was initially seen at an urgent care clinic for the same symptoms 4 weeks ago and had normal physical examination findings. The headache was attributed to a suspected upper respiratory illness, and ibuprofen as needed was advised. The headache has failed to improve, and now the patient also feels fatigued. She has had no fever, nausea, vomiting, cough, shortness of breath, chest or abdominal pain, or diarrhea. The patient has no chronic medical conditions but says she sunburns easily. She does not use tobacco, alcohol, or illicit drugs. Temperature is 37.2 C (99 F), blood pressure is 170/110 mm Hg, pulse is 82/min, and respirations are 14/min. Physical examination shows normal jugular venous pressure, clear lungs, normal heart sounds, and a nontender abdomen. There is 1+ pitting edema of the bilateral lower extremities. Laboratory results are as follows: Which of the following is the most likely diagnosis?

Question

A 28-year-old woman comes to the emergency department due to persistent bilateral headaches.  The patient was initially seen at an urgent care clinic for the same symptoms 4 weeks ago and had normal physical examination findings.  The headache was attributed to a suspected upper respiratory illness, and ibuprofen as needed was advised.  The headache has failed to improve, and now the patient also feels fatigued.  She has had no fever, nausea, vomiting, cough, shortness of breath, chest or abdominal pain, or diarrhea.  The patient has no chronic medical conditions but says she sunburns easily.  She does not use tobacco, alcohol, or illicit drugs.  Temperature is 37.2 C (99 F), blood pressure is 170/110 mm Hg, pulse is 82/min, and respirations are 14/min.  Physical examination shows normal jugular venous pressure, clear lungs, normal heart sounds, and a nontender abdomen.  There is 1+ pitting edema of the bilateral lower extremities.  Laboratory results are as follows:  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec25c8_d4ff_71bd_bc81_d7b3db0ebef4_MD0003_00 This patient with headache has hypertension, an elevated creatinine, proteinuria, hematuria, and red blood cell casts, consistent with glomerulonephritis. In association with fatigue, cytopenias, and hypocomplementemia, this suggests systemic lupus erythematosus (SLE) with lupus nephritis. SLE is a multisystem autoimmune disorder that presents with systemic (eg, fever, fatigue) and localized (eg, photosensitive malar rash, as suggested by recurrent "sunburns") findings. Headache is common among patients with SLE; it can be a manifestation of CNS lupus (along with cognitive abnormalities, seizures, and psychiatric changes) but can also be due to unrelated conditions (eg, migraine or tension-type headaches). Lupus nephritis occurs in half of patients with SLE; severity can range from asymptomatic hematuria to rapidly progressive glomerulonephritis and end-stage renal disease. Immune complexes composed of double-stranded DNA (dsDNA) and anti-dsDNA antibodies deposit in the mesangium and/or subendothelial space, triggering an intense inflammatory reaction with activation of the complement system, lowering C3 and C4 levels. Immune complexes may also deposit in the subepithelial space, leading to nephrotic syndrome without hypocomplementemia. (Choice A) Granulomatosis with angiitis can cause glomerulonephritis, often associated with ear, nose, throat, and pulmonary manifestations. However, the complement pathway is not activated and C3 level is normal. (Choice B) Hemolytic uremic syndrome typically occurs after infection with Shiga toxin-producing Escherichia coli and presents with microangiopathic hemolytic anemia, thrombocytopenia, and renal failure. However, renal injury is due to thrombotic angiopathy rather than glomerulonephritis, and erythrocyte casts are absent. This patient's other clinical features (eg, photosensitive rash) are more consistent with SLE. (Choice C) Hypertensive emergency is a severe or sudden rise in blood pressure with evidence of end-organ damage (eg, renal failure, myocardial ischemia); however, hypocomplementemia and casts are not seen. (Choice D) Drug-induced interstitial nephritis can cause acute kidney injury, but urinalysis shows white blood cell casts and eosinophiluria; thrombocytopenia and erythrocyte casts are unexpected. Patients may also have fever, rash, and eosinophilia. (Choice E) Poststreptococcal glomerulonephritis most commonly presents in children or adults age >60. Features include hypertension, acute renal failure, erythrocyte casts in urine, and a low serum C3 level, but thrombocytopenia and photosensitive rash are not typical. Educational objective: Systemic lupus erythematosus is an autoimmune disorder affecting multiple organ systems. Renal involvement may present with nephritic syndrome with low serum C3 and C4 levels. Nephrotic syndrome may also occur. References: Update on lupus nephritis. (http://www.ncbi.nlm.nih.gov/pubmed/27821390)

A 28-Year-Old Woman Comes to the Emergency Department Due to Persistent