Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3063_Библиотеки_им_академика_М_И_Перельмана
.pdf
megakaryocytes in the bone marrow. The presence of antiplatelet antibodies in the serum is not
diagnostic because these are often found nonspecifically in nonimmune-related
thrombocytopenia. Bone marrow biopsy shows increased megakaryocytes and excludes
production problems.
The presentation usually consists of platelet-type bleeding such as petechiae, purpura, gingival
bleeding, and epistaxis. The patient’s platelets are young and effective, and patients can
tolerate low counts without bleeding. Spontaneous bleeding with platelets >30,000/mm
3
suggests a separate problem of platelet dysfunction. Bleeding is occasionally seen in the GI or
GU tracts. CNS bleeds are rare but can be fatal.
In children, antibody-mediated thrombocytopenia often follows an antecedent viral illness. The
disease is usually transient, resolving in 2 to 8 weeks, and therapy is needed only to help
temporarily. In adults, the disease often becomes chronic or relapsing.
Prednisone is the initial therapy and is given for 4–6 wks and then tapered. IV immunoglobulin
results in the more rapid improvement in the platelet count through the blockage of the RES
system. Its effect is transient, and because it is quite expensive, its use is limited to patients
who require an acute increase due to profoundly low counts or severe, life-threatening
bleeding. Thrombopoietin-stimulating agents such as eltrombopag can also be used. Anti-RhD
therapy is a less expensive alternative for Rh-positive patients. Adult patients typically relapse
during steroid tapering, and second-line therapy is splenectomy. This is particularly effective
in patients with an initial response to steroids. Adults have a lower risk of postsplenectomy
sepsis than do children. Those patients with platelets >20,000/mm
3
and those without clinical
symptoms may sometimes be followed without therapy. Splenectomy failures are treated with
rituximab, romiplostim, or eltrombopag. Less effective agents are danazol or cytotoxic agents,
such as vincristine or cyclophosphamide.
Follow-up Management and Prevention
One day after the start of steroids, repeat CBC
311
Final Diagnosis
Immune (idiopathic) thrombocytopenic purpura
Continue prednisone or dexamethasone until platelet count >50,000
IV gammaglobulin (IgG) if acute increase in platelet counts are required with severe
bleeding such as CNS or melena
Splenectomy if thrombocytopenia continues to recur
Treat recurrences after splenectomy with rituximab or thrombopoietin-stimulating agents
such as romiplostim or eltrombopag
Platelet transfusion is rarely effective since platelets are consumed as soon as they are
infused. This should be considered only in life-threatening bleeding.
312
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
Case 3
Chief Complaint
Shortness of breath with joint and back pain
History and Physical Examination
A 25-year-old man with a history of sickle-cell anemia comes to the emergency
department with acute onset of severe knee and back pain, typical of his vaso-occlusive
crises in the past. In addition, over the last few hours, he has had the acute onset of
pleuritic pain, severe shortness of breath, and fever. He typically suffers from a crisis
every 3 months.
He appears to be in acute distress. Vital signs are temperature 38.3 C (101.0 F), blood
pressure 180/100 mm Hg, pulse 120/min, and respirations 30/min. Physical examination
shows tachycardia with I/VI systolic murmur at the left lower sternal border. There is no
costovertebral-angle tenderness. The remainder of the physical examination is
unremarkable.
Differential Diagnosis
Initial Management Plan
Vaso-occlusive crisis of sickle-cell disease1.
Pulmonary infarction (acute chest syndrome)2.
Pulmonary infection3.
313
Setting: emergency department
Diagnostic/Therapeutic Plan
Test Results
CCS NOTE
Oxygen, IV normal saline
Morphine or hydromorphone
Ceftriaxone IV (or moxifloxacin or levofloxacin)
Blood cultures
CBC
Bilirubin
Urinalysis
Chest x-ray
ABG
Smear
Blood cultures negative
WBC 14,500/mm
3
(normal 4,000–11,000/mm
3
), hematocrit 25% (normal 37–44%),
platelets 480,000/mm
3
(normal 150,000–400,000/mm
3
), reticulocytes 15% (normal 1–2%)
Bilirubin 2.3 mg/dL (normal 0.2–1.0 mg/dL), 85% unconjugated
Urinalysis: hematuria, no WBC
Chest x-ray: focal infiltrate peripherally on the right
ABG: pH 7.5, PCO2 32 mm Hg, PO2 70 mm Hg
Smear: sickle cells present
314
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
All patients with an unexplained fever should have a chest x-ray, urinalysis, and blood
culture.
Assessment
The cause of the patient’s back and knee pain is most likely vaso-occlusive crisis, particularly
given the history of recurrent crises of a similar nature in the past. Other potential etiologies for
abdominal pain include cholecystitis and pancreatitis because patients often have gallstones
due to chronic hemolysis.
Vaso-occlusive crisis is often precipitated by dehydration, hypoxia, or infection. Patients are
particularly susceptible to dehydration because of an inability to concentrate their urine due to
ischemic damage to the renal medulla. Hematuria is usually the result of renal tubular damage
or papillary necrosis, but infection must be ruled out. The presence of dyspnea with exertion
may be due to severe anemia precipitated by worsening hemolysis or aplastic crisis, as seen in
parvovirus infection. However, the presentation above is suggestive of a primary pulmonary
process, most likely infection or the acute chest syndrome.
CLINICAL PEARL
With sickle crisis, give antibiotics for fever or WBC higher than usual.
Patients with sickle-cell disease are at increased risk for infection, particularly with
encapsulated organisms such as Pneumococcus, Haemophilus influenzae, Klebsiella
pneumoniae, and Neisseria meningitidis. The presence of fever or WBC higher than usual is
an indication for antibiotics. Pleuritic pain, fever, and shortness of breath are characteristic of
the acute chest syndrome. This is caused by sickling and vaso-occlusion of the capillaries of
315
the pulmonary bed with resultant infarction. Meperidine is NOT the right pain medication to
use. Repeated doses of meperidine can cause seizures.
Further Management Plan/Results
16%
HgS 86%, HgF 12% HgA 0% HgA2 2%
CCS NOTE
Sickle-cell disease is a perfect example where therapy should be initiated prior to
obtaining the results of specific tests. If the patient has a fever, add a 3rd or 4th
generation cephalosporine (cefotaxime, ceftriaxone, cefepime) to the initial set of
orders even if the chest x-ray and urinalysis give normal results.
Discussion
Repeated doses of morphine or
hydromorphone
Continued IV saline and oxygen
Continued ceftriaxone
Reticulocyte count
Hemoglobin electrophoresis
316
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
The cause of pulmonary symptoms may be infection and/or an infarction. In adults with
negative sputum, the latter is more common. Empiric antibiotics may be given during the acute
period. If the patient’s oxygenation does not improve with supplemental oxygen, exchange
transfusion should be considered.
Sickle-cell anemia is the result of a mutation in the beta-globin gene. Patients with sickle trait
are heterozygous for this mutation, whereas those with sickle-cell anemia are homozygous.
Eight percent of African Americans are heterozygous for HbS. In homozygous SS disease, RBC
with the abnormal hemoglobin become sickled upon deoxygenation due to the formation of
abnormal polymers of beta-globin strands within the cells. The sickled cells are
nondeformable and block capillary flow. This leads to tissue hypoxia and lowered oxygen
tension, further exacerbating the sickling process. The additional sickled cells are rapidly
destroyed, leading to hemolysis and reticulocytosis. Acidosis increases sickling, whereas fetal
hemoglobin helps prevent cells from sickling. Hemoglobin electrophoresis is used to make the
diagnosis. Patients typically have:
Vaso-occlusive crisis is a common presentation. It is associated with an increased population
of sickle cells and is probably due to tissue ischemia as a result of small-vessel obstruction. It
is often precipitated by a viral or bacterial infection or dehydration.
Patients rarely present with focal complications of tissue ischemia, such as bowel infarction or
central nervous system symptoms such as seizure or stroke. Acute chest syndrome is a common
presentation and may be precipitated by hypoxia due to infection. Hematuria is often seen and
is most commonly caused by renal tubular damage. Papillary necrosis of the kidneys sometimes
occurs. Infection is common because patients are functionally asplenic and are susceptible to
encapsulated organisms.
Hemoglobin F: 2–20%
Hemoglobin A2: 2–4%
Remainder hemoglobin S: remainder
317
Hematocrit does not routinely drop with a sickle-cell crisis. A sudden drop in hematocrit >3–4
points should make you think of either parvovirus B19 or folic-acid deficiency. Parvovirus can
be detected with an immunoglobulin M level or PCR for parvovirus DNA level. Parvovirus is
treated acutely with IV immunoglobulin infusion.
Chronic organ damage includes decreased pulmonary function, probably due to chronic
hypoxia and shunting. Bilirubin gallstones may occur owing to chronic hemolysis.
Concentrating ability is impaired in the kidney, causing the patient to be prone to dehydration.
Aseptic necrosis of the head of the femur and chronic skin ulcers are also seen.
Patients with a history of SS homozygous disease should be maintained on folate to support the
increased RBC. Infections should be treated promptly. Care of vaso-occlusive crises is
supportive with emphasis on pain management and hydration. Supplemental oxygen is used for
respiratory symptoms. Exchange transfusions can be used to mitigate symptoms and are used
particularly for severe hypoxemia, pulmonary infarction or acute chest syndrome, stroke, visual
disturbance, and priapism. Long-term therapy concentrates on increasing the proportion of
hemoglobin F with agents such as hydroxyurea. Increased hemoglobin F levels prevent sickling
and decrease the frequency of crises.
Follow-up Management and Prevention
CLINICAL PEARL
Exchange transfusion if the hypoxia does not correct with supportive measures (to treat
possible acute chest syndrome)
Hydroxyurea to decrease frequency of crisis in future
Pneumococcal vaccine if not previously given
Folate supplementation chronically
If reticulocyte drops test for parvovirus
318
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
Parvovirus B19 causes a sudden drop in both hematocrit and reticulocyte count.
Final Diagnosis
Sickle-cell anemia with vaso-occlusive crisis
PCR for parvovirus DNA is more accurate than IgM or IgG for parvovirus
Marrow shows giant pro-normoblasts
Treat with IV immunoglobulin
319
Case 4
Chief Complaint
Bleeding
History and Physical Examination
A 70-year-old woman was hospitalized last week for pneumonia and was treated with
ceftriaxone and azithromycin. She was initially lethargic but has slowly improved. This
morning she had an episode of coffee-ground emesis which appeared to be self-limiting.
The patient has a history of peptic ulcer disease for which she takes pantoprazole. CBC
shows WBC 5,000/mm
3
(normal 4,500–11,000/mm
3
), hemoglobin 12 g/dL (normal 12–16
g/dL), platelets 250,000/mm
3
(normal 50,000–400,000/mm
3
), and coagulation studies: PT
22 sec (normal <14 sec) and PTT 45 sec (normal <35 sec).
Her temperature is 37.0 C (98.6 F), BP is 120/80 mm Hg, and pulse is 90/min. In general,
she is anicteric and appears somewhat debilitated. Physical examination shows that the
eyes, ears, nose, and throat are normal, lungs are clear, and abdomen is soft with no
hepatosplenomegaly. Rectal examination shows brown, guaiac-positive stool.
Differential Diagnosis
Vitamin K deficiency
1.
Factor deficiency
2.
Factor inhibitor
3.
Disseminated intravascular coagulation (DIC)
4.
320
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
Соседние файлы в папке Библиотека им академика М.И. Перельмана