Soru

A male patient, aged $48$, presents to an ambulatory care facility reporting a $6$-week history of a persistent cough and episodes of blood-tinged sputum. Over this same period, he has experienced recurrent nosebleeds, intermittent low-grade fevers, and profound fatigue. His medical history includes major depressive disorder, for which he has been taking citalopram for the last $3$ years. He does not smoke or use illicit drugs.

Vital signs show a temperature of $37.7^\circ\text{C}$ ($99.9^\circ\text{F}$), blood pressure of $152/96\text{ mm Hg}$, heart rate of $88/\text{min}$, and respiratory rate of $16/\text{min}$.

Examination of the nasal cavity reveals mucosal ulcerations and adherent crusts. Auscultation of the lungs demonstrates scattered crackles in the right middle lung field.

Laboratory studies reveal:
Hemoglobin: $10.2\text{ g/dL}$
Leukocyte count: $11,500/\text{mm}^3$
Blood urea nitrogen: $34\text{ mg/dL}$
Serum creatinine: $2.2\text{ mg/dL}$ (was $0.8\text{ mg/dL}$ during a routine checkup $8$ months ago)
Urinalysis: $2+$ protein, large blood, $>50\text{ red blood cells/hpf}$, and several red blood cell casts.

A radiograph of the chest demonstrates a $3.5\text{-cm}$ cavitary lesion in the right middle lobe with thick walls.

Based on the most likely diagnosis, which of the following is the most appropriate next step in evaluation or management?