Adult Sickle Cell Disease

This essay is has two main foci - to discuss the ED treatment of pain crisis and how to recognize the most serious complications of SSD. Another essay will follow discussing some unique pediatric aspects of sickle cell disease (SSD). The motivation for including it is also two fold: SSD in common here in Buffalo and in all cities with a significant African-American population; and because I find many of the treatment recommendations lacking evidence, common sense, or often both.

Identifying a Pain Crisis
Pain crisis (PC) is by far the commonest reason for SSD patient to present to the ED. The H+P is diagnostic, which is a good thing because there is no lab test which can diagnose SSD PC. None! In fact, lab testing in a patient with clinically diagnosed SSD PC is almost never useful. The common sites for pain in SSD PC are as follows.
  • ribs
  • spine
  • pelvis
  • abdomen
  • sternum 
  • long bones in the legs and arms
Each patient has a different pattern which tends to be repetitive. Thus the most important question is along the lines of "is this like your usual crisis". A different pattern from usual is a red flag and should direct attention to the organ system or anatomic area which is symptomatic. When the usual pattern is present, a brief PE should be performed to confirm the lack of other alarming findings. When none are present you have made the diagnosis of SSD PC and can proceed to treatment. Note that no lab tests have been recommended, nor should they be done at this point. This is discussed further below.

Treating a Pain Crisis
The standard way to treat SSD PC involves parenteral narcotics. The IV route is almost universally talked about. This certainly seems appropriate but has one major issue - over time with frequent blood draws and IV's SSD patients develop increasingly difficult IV access. Then, when an IV is really needed it is difficult or impossible to obtain. This has lead me to try SQ morphine or SQ dilaudid. I have had, at best, mixed results with this. While a study we did locally and some other data suggests that the SQ and IV routes provide equal pain relief at 30 minutes with fewer adverse effects from the SQ route, this was not a study in SSD patients. Most SSD patients have come to expect and anticipate the "rush" from IV narcotics. Many aren't even willing to try the SC route. When they are willing, it is often sucessful and avoids the moridity of repeated IV access.

Standard treatment also includes IV fluids. The logic is that this some how reduces the concentration of sickle cells in the microvasculature enough to decrease sickling. Frankly, I question that with a lot of scepticism. About 1/3 of isotonic fluid stays in the intravascular compartment. If you gave a liter of saline  to a 70kg person here's what would happen. The 5L blood volume would be increased by about 300cc, about 6%. If the baseline Hct was 30, it would decrease to about 28. Is this enough to make a difference? I don't know. However, we have a great alternative to IV hydration that avoids the morbidity of repeated IV sticks - the PO route. My strong preference, unless an IV was already started or (as with the route of analgesia) the patient is not willing to try, is the po route.

 Another time honored treatment with little to back it up is supplemental oxygen. However, unlike IV meds and fluids there is little to no downside to O2 therapy. So I recommend O2 by nasal cannula even for non-hypoxic patients.

Summary of Recommendations for Sickle Cell Pain Crisis
  • The diagnosis is clinical, no lab tests are routinely needed.
  • If the patient is willing to try, give SC narcotics and PO fluids and avoid an IV start.
  • Give all patients oxygen via nasal cannula
  • Use higher than usual narcotic doses in the non-naive patient.
    • Consult old records and or discuss with the patient which meds and doses have worked before.
    • A resonable starting dose in most patients is 10mg of morphine or 2mg of dilaudid, SQ or IV.
      • Wait at least 30 minutes between doses of narcotics to avoiding "stacking".
  • Look for signs and symptoms suggesting this is not just a simple pain crisis.
More on Lab Tests and SSD PC
Almost every clinician you will meet, except me, orders a CBC on SSD PC patients. I have NEVER heard of one good reason for this. The comonest reason given is that "I want to see how anemic they are". The irrationality of this is that lower Hct is associated with LESS sickling and lower incidence of PC. OTOH, if a patient c/o symptoms suggesting more severe anemia than baseline, such as dyspnea on exertion, fatigue, pallor, etc. it IS logical to get a CBC.

Reticulocyte counts are also routinely advocated. The rationale is "what if they have an aplastic crisis". This is also quite illogical - an aplastic crisis does not cause bony and muscle pain. It is largely a disease of children with SSD and in any case presents as signs/symptoms of severe anemia, not with pain. I have also heard clinicians say the want a reticulocyte count to establish if there is a "real" pain crisis. Completely illogical: there is no relationship between the two.

Acute Complications of SSD
Besides painful crisis patients with SSD are prone to a number of complications that are less common but more serious.
  • Thrombotic stroke is very common is SSD patients (~25% by age 45). ICH is also increased. Suspect these when the are neuro deficits, unusual headache, or altered MS and order a CT scan.
  • Infections by Strep. pneumoniae and H. flu are much more common in SCD patients. The ones to watch out for are meningitis, pneumonia, and osteomyelitis. All are more common in younger patients. They should be suspected when there are the usual signs/symptoms of the respective diseases.
    • Infection, in general, is the commonest cause of death in SCD patients.
      • E. coli sepsis from UTI also seems to be increased
  • MI can occur in the absence of CAD. When a SCD patient has CP different from their usual pain, get an EKG.
  • Symptomatic cholelithiasis/cholecystitis is common and manifests and  treated in the usual way. 
  • Priapism is common.
    • Initiate treatment as for a PC
    • If priapism persists the patient will need cavernosal irrigation and instiallation of an adrenergic agent (typically phenylephrine)
  • Acute chest crisis (ACC) is a common cause of death in SCD patients. It presents with: 
    • fever
    • chest pain
    • cough
    • hypoxemia
    • infliltrate(s) on CXR. 
Admission is required for ACC. If there are infiltrates on the CXR, antibiotic treatment does not differ from other patients with pneumonia (e.g. ceftriaxone and and a macrolide for CAP). Get blood cultures and give oxygen in the ED. Hydrate and treat pain.

Admission for SSD PC
In theory, SCD PC can be treated on an outpatient basis. However, the ED sees only a subset of the SSD population. This group includes people who have already tried OP treatment. If you can relieve the symptoms in the ED consider DC especially if their OP medication regimen can be adjusted upward. However, many will expect hospital admission by this point. The basic reason to admit is that the patient decides their symptoms can't be managed at home.
  • The admitting physician/team will usually require a bunch of lab tests before admitting a SSD patient. It's "interesting" to see that during hospitalization there is ritual daily blood testing, even when nothing has been discovered other than a painful crisis and there has been no clinical deterioration.. 
    • I have given up trying to "educate" inpatient providers about these issues. They just don't listen. Some become angry when orthodoxy is questioned. So bow to the inevitable and be sure the patient is getting IV fluids, IV analgesics, and has a set of labs drawn before you try to admit them. The admitting team will probably also want a CXR and a UA. 

To access the individual essays, clink on the links on the left.