The patient is a 78-year-old male with CKD Stage 4 (secondary to DM/HTN with minimal proteinuria and no hematuria in previous notes, baseline serum creatinine around 2 mg/dl), who presented with diffuse hypoxic respiratory failure, anemia and AKI.

Initially presented to family physician with complaints of fatigue, weakness, and 3 days of coughing, and feeling fatigue for many months. Chest X-ray showed multilobar opacities consistent with pneumonia, for which he was started on antibiotics. Further evaluation also revealed anemia with a hemoglobin of 5 mg/dl (baseline 11), AKI with BUN of 90 mg/dl and serum creatinine of 4.5 mg/dl (from baseline of 40 and 2 respectively).

Urinalysis found microscopic hematuria and proteinuria.  

He received blood transfusions (5 units of packed red blood cells).

One week later he developed hematemesis and worsening hypoxemia and was transferred to the ICU. CT chest found diffuse multifocal opacities; He was supported with 100% oxygen on a non-rebreather mask, and covered with empiric antibiotics for community acquired pneumonia coverage.  

ANCA testing returned positive (both PR3 and MPO) concerning for ANCA vasculitis involving the kidneys and lungs. Bronchoscopy was deferred due to tenuous respiratory status and a wish to never get intubated.

He was started on pulse dose methylprednisolone for presumed ANCA vasculitis. Respiratory status stabilized and on high flow oxygen the next day.

Medical history:
CKD Stage 4, resistant HTN (on 5 agents), NIDDM, cholecystectomy

Medications:
Aspirin, glipizide, lisinopril, simvastatin, terazosin, amlodipine, clonidine, hydralazine

Physical Exam:
Temperature 97F, HR 65, BP 170/70, RR 19, O2 saturation 91% on high flow nasal cannula, 8 hour UOP 500cc.
Lungs: bilateral fine occasional crackles, bilateral lower extremity trace edema

Laboratory and other data:
ESR and CRP both significantly elevated
PR3 >8.0 units (normal <0.4)
MPO Ab >4.0 units (normal <0.4)
Complement normal
BUN 110 mg/dl
Serum creatinine 5.5 mg/dl
Serum albumin: 3.1 g/dl
Hb 7.0 mg/dl
Urine chemistry:
Protein to creatinine ratio: 2.5 g/g
The majority of RBCs are isomorphic but there are 2-3 dysmorphic RBCs and 0-1 RBC casts/hpf. Does have occasional muddy brown cast as well.
IMAGING:  
CT chest: Diffuse dense consolidative opacities with surrounding ground glass, upper lobe predominant, worst in RUL.