An emergency medical team evaluates a 62-year-old male who presents with rapidly worsening… — USMLE Step 2 CK

An emergency medical team evaluates a $62$ -year-old male who presents with rapidly worsening facial fullness, a "stuffy" head sensation, and difficulty breathing over the past $48$ hours. The patient has a $40$ -pack-year history of smoking and was recently found to have a large right upper lobe pulmonary mass on a chest radiograph. Four days ago, he underwent a video-assisted thoracoscopic biopsy of the lesion; pathology results are pending. His past medical history is notable for chronic obstructive pulmonary disease (COPD) and Hashimoto thyroiditis.

Vital signs show a blood pressure of $145/88$ mmHg, a heart rate of $110$ /min, a respiratory rate of $24$ /min, and a temperature of $38.0^\circ\text{C}$ ( $100.4^\circ\text{F}$ ). Pulse oximetry is $91\%$ on room air.

Physical examination reveals striking plethora and edema involving the face, neck, and upper extremities. The jugular veins are prominently distended and do not collapse during inspiration. Auscultation of the lungs demonstrates distant breath sounds on the right and mild diffuse expiratory wheezing.

Laboratory and arterial blood gas (ABG) results are as follows:

Test	Result	Reference Range
Thyroid-stimulating hormone (TSH)	$1.5$ µU/mL	$0.4$ – $4.0$ µU/mL
Free thyroxine (T4)	$0.6$ ng/dL	$0.9$ – $1.7$ ng/dL
pH	$7.33$	$7.35$ – $7.45$
pCO2	$48$ mmHg	$35$ – $45$ mmHg
pO2	$60$ mmHg	$75$ – $105$ mmHg
HCO3-	$25$ mEq/L	$22$ – $28$ mEq/L

Which of the following is the most appropriate initial intervention for this patient's acute symptoms?

Initiate intravenous dexamethasone and keep the patient in a semi-upright positionCevap
B
Administer inhaled bronchodilators and an oral macrolide antibiotic
C
Obtain blood cultures and start empiric intravenous piperacillin-tazobactam
D
Administer a high-dose bolus of intravenous levothyroxine
E
Administer a continuous intravenous sodium bicarbonate infusion

Cevap

Initiate intravenous dexamethasone and keep the patient in a semi-upright position

The correct answer involves the immediate symptomatic management of Superior Vena Cava (SVC) syndrome, a classic oncologic emergency. This patient presents with the hallmark triad of facial plethora, upper extremity edema, and elevated jugular venous pressure that does not collapse on inspiration. These findings strongly suggest that his right upper lobe pulmonary mass is compressing the SVC. The most appropriate initial medical intervention includes elevating the head of the bed (to decrease venous hydrostatic pressure) and administering intravenous glucocorticoids, such as dexamethasone (to reduce peritumoral edema and relieve the mechanical obstruction). This buys crucial time for definitive management, which usually involves endovascular stenting or radiation therapy.

Adım Adım Çözüm

Analyze the physical examination findings in the context of the patient's recent pulmonary diagnosis.

The triad of facial plethora, upper body edema, and non-collapsing jugular venous distention points to Superior Vena Cava (SVC) syndrome.

The right upper lobe mass is mechanically compressing the SVC, impeding venous return from the head and upper extremities.

Evaluate the laboratory and ABG findings to rule out alternative diagnoses.

The low free T4 with normal TSH indicates euthyroid sick syndrome, ruling out myxedema. The ABG shows a mild respiratory acidosis, consistent with hypoventilation, ruling out a primary metabolic derangement.

Careful lab interpretation ensures that secondary phenomena (euthyroid sick syndrome) are not mistakenly treated as the primary life-threatening issue.

Determine the most appropriate immediate therapeutic intervention.

Select elevation of the head of the bed and administration of intravenous glucocorticoids (e.g., dexamethasone).

These interventions act rapidly to decrease venous hydrostatic pressure and reduce peritumoral edema, stabilizing the patient prior to definitive endovascular stenting or radiation therapy.

Anahtar Kavram

Diagnosis and acute medical management of Superior Vena Cava (SVC) syndrome

Tahmini Süre:1m 30s

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