Hematology and oncology red flags
A neutrophil curve falling into a shaded nadir trough between roughly days seven and fourteen after treatment, with a lighter platelet curve recovering slightly later and three event flags rising from the axis.
Six events in this domain change outcomes within hours. In each one, the sentinel cue is mild and the patient often looks well.
1 · Fever in neutropenia With too few neutrophils there is no pus, no redness, and no swelling, because those signs are made of neutrophils. A temperature elevation may be the only evidence of overwhelming infection. Cultures and antibiotics are started within about an hour, and this patient outranks every other assignment on the unit.
2 · The nadir Counts fall to their lowest point roughly seven to fourteen days after a chemotherapy dose, and that window is when the patient is most vulnerable. Infection-prevention teaching is timed to the nadir, not to the infusion day, which is exactly the discrimination the exam tests.
3 · Tumor lysis Cells destroyed in bulk dump potassium, phosphate, and uric acid into the blood while calcium falls, typically within one to three days of starting treatment for a bulky, rapidly dividing tumor. The killer is the potassium. Hydration is the prevention.
4 · Spinal cord compression New or worsening back pain in a patient with known malignancy precedes weakness, sensory change, and bladder or bowel dysfunction. The pain is the emergency, because function lost before treatment often does not come back.
5 · Superior vena cava obstruction Facial and upper body swelling, distended neck and chest veins, and dyspnea that worsens when lying flat. Raise the head of the bed and avoid venipuncture in the upper extremity on the affected side.
6 · Low platelets Bleeding precautions mean a soft toothbrush, an electric razor, no rectal temperatures or suppositories, avoidance of intramuscular injections, and prolonged pressure after any puncture. A new headache or a change in mentation in a thrombocytopenic patient is an intracranial bleed until imaging says otherwise.
7 · Sickle cell crisis Vaso-occlusion causes severe pain. Management is hydration, oxygenation, warmth, and adequate analgesia. Cold and cooling measures worsen sickling, and undertreated pain is the single most commonly tested error in this population.
Margin noteno neutrophils, no pus, only fever.
Watch outfever in a neutropenic patient is a medical emergency even when the patient looks entirely well.
TakeawayIn oncology the sentinel cue is often mild, so escalate on the cue rather than on the appearance of the patient.
→ BOOK 11 · P7 for anemias and transfusion reactions · → BOOK 07 · P5 for the counts