Central nervous system leukemia

Introduction to central nervous system leukemia Central nervous system leukemia (CNS-L) is a common complication of leukemia caused by extramedullary infiltration of leukemia cells into the arachnoid or arachnoid adjacent nerve tissue, which has an important impact on prognosis. The patient is presented with corresponding neurological and/or psychiatric symptoms. Brain white can be seen at any stage of the course of leukemia. basic knowledge The proportion of illness: 0.005% Susceptible people: no specific population Mode of infection: non-infectious Complications: headache, nausea and vomiting

Causes of central nervous system leukemia

Chemical factors (26%):

Some chemicals have a leukemia effect. The incidence of leukemia in people exposed to benzene and its derivatives is higher than in the general population. There are also reports of nitrosamines, phenylbutazone and its derivatives, chloramphenicol and other induced leukemia. Certain anti-tumor cytotoxic drugs, such as nitrogen mustard, cyclophosphamide, procarbazine, VP16, VM26, etc., have leukemia effects.

Radiation factor (20%):

There is evidence that various ionizing radiation can cause human leukemia. The occurrence of leukemia depends on the dose of radiation absorbed by the body, and the whole body or part of the body can induce leukemia after being exposed to medium or large doses of radiation. Whether small doses of radiation can cause leukemia remains uncertain. The incidence of leukemia is significantly increased in people exposed to radiation (such as cobalt-60). High-dose radiation diagnosis and treatment can increase the incidence of leukemia.

Virus factor (20%):

The leukemia effect of RNA viruses in animals such as mice, cats, chickens and cattle has been confirmed. Leukemias caused by such viruses are mostly T cell types.

Genetic factors (15%):

The incidence of leukemia in people with chromosomal aberrations is higher than in normal people.

Central nervous system leukemia prevention

(1) Do a good job in the patient's ideological work, eliminate mental stress, and let the patient rest in bed and avoid visiting.

(2) The ward should be cleaned and disinfected, smoking is prohibited, and the diet should be light and clean to keep the stool smooth.

(3) Pay attention to the patient's mental state and changes in consciousness, and closely observe changes in body temperature, pulse, respiration and blood pressure.

Central nervous system leukemia complications Complications, headache, nausea and vomiting

CNS-L is the main source of leukemia recurrence and drug resistance.

Symptoms of central nervous system leukemia Common symptoms Unclear intracranial hemorrhage Spinal cord hemorrhage coagulopathy Cervical strong facial nerve sputum Increased intracranial pressure Thyroid thrombocytopenia Trigeminal nerve one or two...

Clinically, the main manifestations are headache, nausea, vomiting, papilledema, visual impairment, convulsions, coma, hemiplegia and meningeal irritation. Cerebrospinal fluid examination can increase the intracranial pressure, increase the number of proteins and white blood cells, reduce sugar and chloride, and find leukemia cells. Central nervous system leukemia can occur at any stage of acute leukemia, but most occur during remission. Because many chemotherapeutic drugs do not easily penetrate the blood-brain barrier, leukemia cells hidden in the central nervous system cannot be effectively killed, and become a shelter for leukemia cells, which is the primary cause of recurrence of extramedullary leukemia. Central nervous system leukemia is most common in acute lymphoblastic leukemia, especially in children. The incidence of acute lymphoblastic leukemia is 26% to 80%, and the incidence of acute myeloid leukemia is 7% to 38%.

Similar to meningitis, there are intracranial hypertension, such as headache, vomiting, optic nerve head edema. Lumbar puncture cerebrospinal fluid pressure increased, white blood cell count and protein in cerebrospinal fluid increased, sugar decreased, leukemia cells can be detected. Invasion of the brain can cause symptoms such as visual impairment, pupillary changes, and facial nerve spasm. The latter is more common in patients with ALL.

CNSL can occur in all stages of acute leukemia, which can be the first symptom of leukemia, or it can occur many years after the remission of leukemia treatment. It is more common in the complete remission period of about half a year after onset, and ALL is significantly more than AML. CNSL has occurred in patients with white blood cells above 50x109/L and with liver, spleen and lymph nodes. Leukemia cells entering the central nervous system can be caused by blood flow, infiltration of skull bone marrow leukemia cells or intracranial punctiform hemorrhage. General chemotherapy drugs are difficult to pass the blood-brain barrier, and the central nervous system becomes a "refuge" for leukemia cells, which is one of the causes of leukemia recurrence.

The leukemia of the central nervous system causes the patient to exhibit corresponding neurological and/or psychiatric symptoms due to infiltration of leukemia cells into the meninges or brain parenchyma. Brain white can be seen at any stage of the course of leukemia. When leukemia patients have unexplained headache, nausea and vomiting, blurred or double vision, strabismus, facial paresthesia, facial paralysis, tongue deviation or paraplegia, dysfunction or mental behavior disorder, and disturbance of consciousness during the course of the disease ( When you are sleepy, lethargic, or coma, you need to be alert to the brain.

Central nervous system leukemia examination

CSF examination is the most important means of diagnosing CNS-L, often accompanied by elevated intracranial pressure, ie >200mmH2O, CSF routinely shows white blood cell count>0.005×10 ⁹ /L, mainly mononuclear cells, protein qualitative positive, a few patients with sugar Reduced (ie less than 1/2 of the blood glucose level detected at the same time), the diagnosis needs to be found in the CSF smear leukemia cells, the current CSF natural sedimentation method is recommended for the filming test, the positive rate is high, should pay attention to the lumbar puncture should be avoided Injury of blood vessels, the significance of detecting leukemia cells after mixed blood in CSF is difficult to be confirmed, platelet is significantly reduced or leukemia cell infiltration leads to rupture of intracranial tube, brain parenchymal hemorrhage or subarachnoid hemorrhage, CSF can be bloody, or microscopic cells under microscope Significantly increased, at this time leukemia cell examination, also lost meaning.

Skull imaging studies, including CT, MRI, usually have no positive findings because leukemia cells are diffusely infiltrated and do not form tumor mass.

Diagnosis and diagnosis of central nervous system leukemia

diagnosis

1. Diagnostic criteria and according to domestic standards are as follows.

(1) There are symptoms and signs of CNS, especially the symptoms and signs of increased intracranial pressure.

(2) CSF changes:

1 increased intracranial pressure >200mmH2O.

2 white blood cells > 0.01 × 109 / L.

3 smear with leukemia cells.

4 protein > 0.45g / L, or qualitative test positive.

(3) Exclude similar changes in CNS or CSF caused by other causes.

In short, any of the above-mentioned items (3) and (2) is suspicious CSN-L; 3 of the above-mentioned items (3) and (2), or any other 2 items, Can be diagnosed as CNS-L.

Need to pay attention to:

1 No clinical manifestations, only CSF meet the criteria, can also be diagnosed.

2 simple intracranial pressure increase, temporarily not diagnosed, but should be treated according to CNS-L, such as short-term intracranial pressure after treatment to restore normal, can also be diagnosed.

3 There are clinical symptoms and signs of the aforementioned CNS-L, and those without CSF change can also be diagnosed if other causes and improvement after CNS-L treatment are improved.

2. Diagnostic evaluation

(1) Leukemia patients, mainly AL, should always think of the possibility of combining CNS-L, even if there are no symptoms and signs, lumbar puncture and CSF should be performed immediately after the diagnosis of AL is confirmed, to see if CNS-L is present. The presence and routine injection of prophylactic drugs.

(2) Lumbar puncture measurement of intracranial pressure and CSF examination is the key to the diagnosis of CNS-L: the discovery of leukemia cells in CSF is a basis for diagnosis, but leukemia patients have no clinical manifestations of CNS-L, as long as there is an increase in intracranial pressure, or Any abnormality in the CSF examination should be highly alert to the presence of CNS-L and begin treatment and dynamic observation. In short, the standard should be flexible and the treatment should be timely and decisive.

(3) Patients with symptoms and signs of CNS: Although there is no intracranial pressure and abnormal CSF, the vast majority can still be clearly identified as CNS-L.

1 Leukemia patients: mainly AL, should always think of the possibility of combining CNS-L, even if there are no symptoms and signs, lumbar puncture and CSF should be performed immediately after the diagnosis of AL is clear to understand the presence or absence of CNS-L. And routine injection of preventive drugs.

2 lumbar puncture measurement of intracranial pressure and CSF examination is the key to the diagnosis of CNS-L: the discovery of leukemia cells in CSF is certainly the basis for diagnosis, but the clinical manifestations of leukemia patients without CNS-L, as long as there is elevated intracranial pressure, or CSF examination Anyone with an abnormality should be highly alert to the existence of CNS-L and begin treatment and dynamic observation. In short, the standard should be flexible and the treatment should be timely and decisive.

3 The symptoms and signs of CNS appear: Although there is no intracranial pressure and abnormal CSF, the vast majority can still be clearly identified as CNS-L.

Differential diagnosis

1. The most important need to identify is CNS-L is the first manifestation of leukemia, the proportion of missed diagnosis is high, causing increased intracranial pressure and CSF similar to CNS-L changes, mainly viral meningitis or encephalitis , tuberculous meningitis, cerebral cysticercosis (cysticercosis) and brain metastases, identification points:

1 The positive signs of leukemia were found, and peripheral blood or bone marrow examination confirmed the presence of leukemia.

2 As long as the possibility of leukemia is thought, the CSF should be cytologically examined, but in most cases it is easily overlooked and missed.

3 virus serological detection of related antibodies, CSF found acid-fast bacilli, cystic skin test positive and serum antibody detection and the discovery of primary tumors are conducive to the diagnosis of non-CNS-L, in addition, tuberculous meningitis Often accompanied by pulmonary miliary tuberculosis, imaging examination can assist diagnosis, patients with leukemia have been identified, clinical manifestations of CNS and abnormal CSF changes during the course of the disease, and occasionally need to be differentiated from tuberculous or fungal meningitis:

1 In tuberculosis or fungal infection, the increase in protein and sugar in CSF is much greater than CNS-L.

2 pathogen examination, infected people can sometimes find fungi, in a few cases, acid-fast bacilli can also be found, while CNS-L can detect leukemia cells.

3 Intrathecal injection of anti-leukemia drugs, CNS-L often quickly improved, and infected people are ineffective.

2. After treatment with high-dose cytarabine, it can produce neurotoxicity, especially the clinical manifestations of cerebellar damage. It is not difficult to identify according to medication and CSF. In addition, repeated intrathecal injection causes chemical arachnoiditis and cranial radiotherapy. After the leukoencephalopathy, sometimes it needs to be differentiated from CNS-L, and it is difficult to distinguish. If CSF is used to detect leukemia cells negative, the recurrence of CNS-L may be small. After stopping intrathecal injection, it will gradually improve, and CNS- can be basically excluded. L relapse.

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