20.3 Stroke, Thrombosis, and Joint Bleed

CPHON TCO V.D.7–9 tests three related emergencies: ischemic stroke in SCD, thrombosis (especially asparaginase-associated cerebral venous thrombosis and line-associated deep-vein thrombosis), and hemophilia joint and muscle bleed, including iliopsoas and head trauma. This is not a rewrite of the sickle-cell prevention chapter or the factor-product clinic chapter. Those sections named genotypes, transcranial Doppler (TCD) screening, emicizumab, and desmopressin. This section is the hour you call apheresis, treat a clot in a child on asparaginase, or infuse factor before the magnet finishes a knee protocol.

A 10-year-old with HbSS who cannot move the right arm; a 6-year-old on pegaspargase with a new headache and seizure; a toddler with a swollen port-arm; a 7-year-old with severe hemophilia A and a hot knee; and a 12-year-old who will not straighten the hip after a stumble are the outline in pediatric clothes. Generic names only: asparaginase, pegaspargase, factor VIII, factor IX.

SCD ischemic stroke: exchange now, TCD is prevention

Overt ischemic stroke in SCD is a vascular emergency. Rigid, adherent cells and a chronic cerebral vasculopathy occlude large arteries. The child has acute focal neurologic change: hemiparesis, facial droop, aphasia or sudden speech change, visual loss, severe headache, seizure with a residual deficit, or a new inability to walk. Toddlers may only look “wrong on one side” or stop using a hand. Silent cerebral infarction exists on MRI in many children with HbSS; it is not the CPHON shock-hour script. The emergency item is the child who changed neurologically tonight.

Emergency exchange transfusion is the disease-specific rescue. Exchange lowers the hemoglobin S fraction and restores oxygen-carrying hemoglobin A without the viscosity spike of stacking simple transfusions on an already high-normal hemoglobin. Call hematology and the apheresis or manual-exchange team as soon as stroke is the working diagnosis. Imaging (MRI/MRA when feasible; CT if you must exclude hemorrhage quickly) runs in parallel. Do not hold exchange for a 72-hour radiology queue. If exchange will be delayed and the child is severely anemic, a simple transfusion can bridge, but do not overshoot hemoglobin—hyperviscosity worsens cerebral ischemia. Adult “normal” hemoglobin targets are wrong here.

TCD screening is prevention, not treatment. Abnormal TCD velocities in HbSS and similarly severe genotypes identify children who need a chronic transfusion discussion to prevent a first stroke. A completed TCD from last spring does not treat tonight’s hemiparesis. After an overt stroke, chronic transfusion is the usual secondary-prevention path; that is a discharge and clinic plan, not a reason to skip emergency exchange.

Hemorrhagic stroke is less common in young children with SCD than ischemic stroke but is still a neurologic emergency: factor-agnostic airway and blood-pressure protection, imaging, and intensive care. Do not give exchange as a reflex without a picture if the story is sudden collapse with meningismus—get the scan in parallel and let the team name ischemia versus blood.

Walk the 10-year-old. Right-arm weakness for 40 minutes, HbSS, last TCD normal. This is emergency exchange, neuro checks, NPO, and imaging in parallel—not hydroxyurea by nasogastric tube as “stroke rescue,” not a simple transfusion to 14 g/dL, and not a waiting-room observation because “TCD was fine.”

Thrombosis: asparaginase, cerebral veins, and the line

Pediatric oncology clots. Asparaginase and pegaspargase deplete antithrombin and other liver-made anticoagulants. Corticosteroids, immobility, and central venous catheters add risk. Two CPHON pictures:

• Cerebral venous thrombosis (CVT), including cerebral sinuses: new or progressive headache, seizure, papilledema, visual change, or focal signs during acute lymphoblastic leukemia (ALL) induction or another asparaginase-containing block. This is a clotting event in the head, not “leukemic headache” to sleep off. Image as the team directs (often MRI with MR venography). Anticoagulate as hematology orders when the bleed risk is acceptable.
• Line-associated deep-vein thrombosis (DVT): a fatter arm or leg, pain, discoloration, or a line that will not draw. Ultrasound the limb. Do not automatically pull every port at the first swollen arm; removal is a team decision. Anticoagulation, line management, and a search for pulmonary symptoms follow protocol.

Platelets and coagulopathy still matter. An ALL patient can be both thrombocytopenic (marrow, chemotherapy) and prothrombotic (asparaginase). A platelet count of 8,000/µL with wet purpura is a bleed pathway; a platelet count of 80,000/µL, recent pegaspargase, and a thunderclap headache is a CVT pathway. Do not assume every neurologic change in ALL is a clot, and do not assume asparaginase only causes bleeding because fibrinogen is low. Check the labs in front of you, image, and call hematology. Hold further asparaginase until the prescriber decides. Incentive spirometry does not prevent CVT.

Walk the 6-year-old on day 12 of ALL induction after pegaspargase: headache, vomiting, then a 2-minute seizure. Platelets 92,000/µL, fibrinogen lowish, line in the right internal jugular. Think CVT, protect the airway, obtain urgent imaging, and start the anticoagulation conversation—not a playroom observation with acetaminophen.

Walk the toddler whose port arm is suddenly twice the size of the other. Think line DVT, compare circumferences, notify, and image. Do not massage the arm “to move the clot” and do not declare the swelling “just a tape allergy” without a look at the vein.

Hemophilia joint bleed, iliopsoas, and head trauma: factor first

A known child with hemophilia and a swollen, warm, painful joint has hemarthrosis until proven otherwise. Factor replacement FIRST, then imaging. Do not wait for MRI to treat. MRI is useful later for target-joint damage and selected muscle bleeds; it is not a gate that delays factor. Infuse the disease-specific product (factor VIII for hemophilia A, factor IX for hemophilia B, or the hemophilia-center breakthrough plan if the child is on a mimetic). Then rest, ice, compression, and elevation (RICE). Ice is appropriate after replacement in hemophilia; it is not the SCD VOC heat story from the previous section.

Iliopsoas bleed is a hidden-volume muscle emergency. The child holds the hip flexed, reports groin or flank pain, and may show femoral neuropathy: quadriceps weakness, trouble extending the knee, and sensory change on the anterior thigh. A large iliopsoas hematoma can produce hypovolemia without a spectacular external bruise. Treat as a serious bleed: factor immediately, serial vital signs, hemoglobin, and imaging after replacement. Do not stretch the hip or send the 12-year-old to walk off a “pulled muscle.”

Head trauma in hemophilia: factor then CT. Infuse on the way to the scanner. Do not hold factor so that “product is not wasted if CT is normal.” Early CT can be falsely reassuring; delayed factor cannot unbleed a subdural hematoma. A 9-year-old with hemophilia B who struck a coffee table gets factor IX, then computed tomography (CT), then observation as the center directs—not intramuscular ketorolac for headache and a ride home.

This emergency hour does not rebuild emicizumab, aPCC-thrombosis caution, or desmopressin hyponatremia from the coagulopathy chapter. Breakthrough bleeds on a mimetic still need a hemostatic plan. The TCO V.D.9 behaviors are replace first, name iliopsoas, and never queue factor behind MRI or CT.

The CPHON product for TCO V.D.7–9 is an exchange that started before the MRI playlist finished, an asparaginase headache that was imaged as CVT rather than ignored, a port-arm that was scanned as DVT, a hemophilia knee that received factor before MRI, an iliopsoas that was not stretched, and a head bump that got product on the way to CT.