9.2 Immunocompromise & Oncologic Emergencies

The Immunocompromised Critical-Care Patient

Immunocompromise in the ICU arises from chemotherapy, hematologic malignancy, stem-cell or solid-organ transplant with immunosuppressants, high-dose corticosteroids, biologic agents, asplenia, and advanced HIV. These patients present two recurring challenges the CCRN tests: blunted signs of infection and atypical or opportunistic pathogens. Because the inflammatory response is suppressed, the usual markers may be muted - a neutropenic patient may mount fever as the only sign of overwhelming infection, without the expected leukocytosis, purulence, or infiltrate. Nurses must therefore treat subtle changes (a single fever spike, new tachycardia, mild hypotension, altered mentation) as potential sepsis and escalate early.

Protective (neutropenic) precautions

Neutropenia is defined by the absolute neutrophil count (ANC); profound neutropenia is an ANC below 500 cells/uL (severe risk below 100). Core protective measures:

Neutropenic sepsis (febrile neutropenia)

Febrile neutropenia - a single temperature at or above 38.3 C (101 F), or at or above 38.0 C sustained one hour, in a patient with an ANC below 500 - is an oncologic emergency. The evidence-based sequence is to draw blood cultures (peripheral and from each lumen) and administer a broad-spectrum anti-pseudomonal beta-lactam (cefepime, piperacillin-tazobactam, or a carbapenem) within 1 hour - do not wait for the ANC or cultures to result. Add vancomycin for suspected line, skin, or soft-tissue infection or for hemodynamic instability, and antifungals for persistent fever. Because vasodilated warm septic shock can develop rapidly with minimal exam findings, monitor MAP, lactate, and perfusion closely and resuscitate per Surviving Sepsis principles.

Opportunistic infection and cytopenias

Suppressed immunity opens the door to organisms a normal host resists: Pneumocystis jirovecii pneumonia (PCP), invasive Aspergillus and Candida, cytomegalovirus (CMV), reactivated herpes, and Clostridioides difficile. Suspect fungal disease when fever persists despite broad antibacterials, and remember that steroids and calcineurin inhibitors further mask fever and localizing signs. Chemotherapy also produces anemia and thrombocytopenia, so these patients tolerate hemorrhage poorly; transfuse red cells for symptomatic anemia and platelets for counts below roughly 10,000/uL (or higher with active bleeding), while continuing meticulous barrier and line care to protect the few remaining defenses.

Oncologic Emergencies

Tumor lysis syndrome (TLS)

Tumor lysis syndrome occurs when large volumes of tumor cells lyse - spontaneously or, more often, shortly after starting chemotherapy in bulky, rapidly proliferating cancers (acute leukemias, high-grade lymphomas). Intracellular contents flood the blood, producing the classic tetrad: hyperkalemia, hyperphosphatemia, hyperuricemia, and hypocalcemia (calcium falls as phosphate binds it). Consequences are lethal dysrhythmias (hyperkalemia), seizures and tetany (hypocalcemia), and acute kidney injury from urate and calcium-phosphate deposition.

Management centers on aggressive IV hydration to maintain urine output, rasburicase (recombinant urate oxidase) for high uric acid or allopurinol for prevention, plus treating hyperkalemia and hyperphosphatemia. Correct calcium only if symptomatic, because repleting calcium into a high-phosphate state risks precipitation. Continuous ECG monitoring and frequent electrolytes are mandatory; dialysis may be needed for refractory derangements.

Superior vena cava (SVC) syndrome

SVC syndrome is obstruction of venous return from the head and upper body, usually by mediastinal tumor (lung cancer, lymphoma) or a central-line thrombus. Signs include facial and upper-extremity edema, distended neck and chest veins, dyspnea, and facial plethora, worse when supine or bending forward. Priorities: elevate the head of the bed, give oxygen, avoid upper-extremity IVs (use lower-extremity access), and secure the airway if edema threatens it. Definitive therapy is radiation, chemotherapy, or stenting/thrombolysis. Although often subacute, SVC syndrome becomes a true emergency when it produces stridor, laryngeal edema, or cerebral edema with altered consciousness - situations that demand immediate airway protection and rapid oncologic intervention.

Malignant spinal cord compression

Epidural tumor or a collapsing vertebral metastasis compresses the cord. The cardinal early symptom is new or worsening back pain, often preceding weakness - followed by motor weakness, sensory loss, and, late, bowel and bladder dysfunction (urinary retention). Time is cord: high-dose corticosteroids (dexamethasone) are started immediately to reduce edema, with urgent MRI and radiation or surgical decompression. Neurologic recovery correlates with function at the time of treatment, so early recognition of back pain in a cancer patient is a tested nursing priority.

Hypercalcemia of malignancy

The most common metabolic oncologic emergency, driven by PTH-related peptide or osteolytic bone metastases. Symptoms follow the phrase stones, bones, groans, thrones, and psychiatric overtones - renal stones and polyuria, bone pain, abdominal and GI upset, frequent urination with dehydration, and confusion progressing toward coma; the ECG shows a shortened QT interval. Treatment order: aggressive isotonic saline rehydration first, then IV bisphosphonates (zoledronic acid) or calcitonin for faster short-term lowering. Loop diuretics are used only after volume repletion if overload develops, and dialysis for severe refractory cases. Note the sequence trap the exam sets: giving a loop diuretic before restoring intravascular volume worsens the dehydration that hypercalcemia already causes, so saline always comes first. Across all four emergencies, the CCRN rewards early recognition and the first correct action - hydration in TLS and hypercalcemia, steroids in cord compression, and airway/positioning in SVC syndrome.