20.2 Vaso-Occlusive Crisis

CPHON TCO V.D.6 tests vaso-occlusive crisis (VOC) as a vascular emergency. This is not the hydroxyurea-and-penicillin disease chapter. VOC is the most common SCD emergency: deoxygenated hemoglobin S polymerizes, microvasculature obstructs, and the child has ischemic pain. The CPHON product is a nurse who treats pain now, does not flood, does not give meperidine, puts an incentive spirometer in the child’s hands every 1–2 hours while awake, and still searches for acute chest syndrome (ACS), osteomyelitis, and avascular necrosis (AVN).

An 8-year-old with HbSS whose usual VOC is lumbar and tibial pain; a 14-month-old with swollen, painful hands and feet (dactylitis—infant VOC); and a 15-year-old whose outside emergency department gave meperidine and ice packs are the same outline at different ages.

Recognition: this child’s pattern versus a different emergency

VOC pain lives in bones, back, chest, abdomen, and extremities. Infants show dactylitis—sausage fingers or toes—rather than a neatly localized femur. Many children have a personal pattern. Ask what this crisis feels like compared with the last one. A new location is a prompt to look again, not a reason to withhold analgesia.

Fever does not prove the pain is “only VOC.” Functionally asplenic children still get parenteral antibiotics and cultures for protocol-defined fever. Pain plus fever plus a new oxygen requirement is ACS until imaging and the team say otherwise—full ACS respiratory support belongs in the cardiopulmonary-emergencies chapter; this section’s job is not to miss the search.

Do not send severe VOC home after one oral dose without a plan. Do not lecture a writhing 8-year-old about “drug-seeking.” Pediatric SCD pain is ischemic. Believe the child, use an age-appropriate pain scale, and treat.

First-hour care: hydrate without flooding, treat pain, blow the spirometer

Hydration restores euvolemia. Oral fluid is fine if the child can drink. Intravenous isotonic fluid is used when intake is poor, vomiting is present, or the team wants a reliable line for opioids. Do not flood. Excess volume contributes to pulmonary edema and ACS. Maintenance-range replacement, not a four-times-maintenance “sickle flush,” is the usual CPHON frame. Hypotonic free-water floods are not a pain medicine.

Multimodal analgesia starts on arrival, not after the chemistry panel prints:

• Opioids promptly for moderate–severe pain: morphine or hydromorphone as the protocol lists. For older children who can use a button, patient-controlled analgesia (PCA) beats a q4-hour intramuscular lottery. Schedule or PCA-basal-plus-bolus plans for severe pain; as-needed-only dosing that leaves a child in tears between doses is under-treatment.
• Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or ketorolac if kidneys, gastritis, and bleeding risk allow. NSAIDs are adjuncts. They do not replace opioids for severe VOC. Skip or hold them when creatinine is rising, the child has known renal papillary injury, or gastrointestinal bleeding is in play.
• Heat, positioning, massage as tolerated, and distraction. Ice is the wrong first comfort in SCD VOC because cold promotes vasoconstriction and sickling. Heating pads (with burn precautions) match the physiology.
• Incentive spirometry (IS) every 1–2 hours while awake. This is ACS prevention and a test clue. Splinting from thoracic or abdominal pain plus opioids plus bed rest produces atelectasis; atelectasis plus SCD is the ACS on-ramp. Ten breaths an hour, while awake, with a toy or sticker chart for the preschooler who will not “be a good spirometry patient” without coaching. IS is not optional entertainment and not a clinic-only pulmonary function test.

Do not use meperidine. Its metabolite normeperidine lowers the seizure threshold—a historically documented problem in SCD and a CPHON trap. If an outside hospital started meperidine, convert to morphine or hydromorphone as ordered and say why.

Hydroxyurea is prevention, not acute rescue. It raises fetal hemoglobin over weeks to months and reduces future VOC and ACS. An extra hydroxyurea capsule in triage does not abort tonight’s crisis and does not replace PCA. Do not hold opioids “until hydroxyurea kicks in.” Do not stop chronic hydroxyurea during an uncomplicated VOC unless the prescriber holds it for another reason (for example, myelosuppression). The emergency hour is analgesia, fluid, and IS.

Oxygen is for hypoxemia, not a ritual for every pain score. Unneeded high-flow oxygen dries mucosa and does not treat ischemia. If oxygen saturation is falling, you are already on the ACS search.

Walk the 8-year-old. Typical lumbar and tibial VOC, afebrile, saturating 98% on air, drinking. Start intravenous or oral opioid per protocol, add an NSAID if the creatinine is acceptable, heat to the back, and put the incentive spirometer on the bedside table with a q1–2-hour while-awake schedule. Do not hang a hypotonic bolus three times maintenance “because sickle cell.” Do not apply ice “like a sports sprain.” Do not offer meperidine because it is in the Pyxis.

Walk the 15-year-old from an outside emergency department. Meperidine and ice packs, no spirometer, a bag of fluid running wide open, and a parent asking whether an extra hydroxyurea dose will “knock this out.” Convert the opioid, stop the ice, slow the fluid to euvolemia, start IS, and teach that hydroxyurea is the home prevention drug, not tonight’s rescue.

Search while you treat: ACS, osteomyelitis, AVN

Treating pain does not close the differential.

• ACS: new pulmonary infiltrate plus chest pain, fever, tachypnea, wheeze, cough, or hypoxia. A VOC admission that becomes hypoxic at 03:00 is ACS workup—oxygen, IS, transfusion or exchange as that chapter and the team direct—not “more PCA and see you at rounds.” IS is still in play; it is prevention and a bedside test that the child can still take a deep breath.
• Osteomyelitis: VOC is far more common than bone infection, but SCD raises Salmonella and Staphylococcus aureus osteomyelitis risk. Persistent fever, a single exquisitely point-tender bone, bacteremia, and imaging the team orders separate infection from infarct. Do not withhold analgesia until magnetic resonance imaging (MRI) finishes. Do not treat every tibial ache as osteomyelitis with a 6-week antibiotic default, and do not ignore a hot, isolated, febrile tibia as “just crisis.”
• Avascular necrosis: chronic or subacute hip or shoulder pain, limp, and decreased range—especially femoral or humeral heads. AVN is not a 2-hour rescue diagnosis for every VOC, but a 12-year-old who has been limping for months needs that search, not endless “crisis” labels.

Abdominal VOC versus cholecystitis, appendicitis, constipation from opioids, and splenic sequestration (previous section) completes the belly list. Priapism is corporal VOC; time it, give analgesia and hydration, and involve hematology and urology—the disease chapter named it; this emergency hour still treats pain and does not send a boy home with a 4-hour erection to “wait until morning.”

A 5-year-old with fever and pinpoint tibial tenderness still gets opioids and IS while blood cultures and the osteomyelitis path proceed. A teenager with new chest pain, a falling saturation, and a new infiltrate is not “VOC of the ribs” as the final answer.

The CPHON product for TCO V.D.6 is a child whose pain was treated without meperidine, whose fluids stayed at euvolemia, whose incentive spirometer was used every 1–2 hours while awake, and whose nurse still looked for ACS, osteomyelitis, and AVN.