10- Haematology (Lymphadenopathy and the spleen)) Flashcards
The lymphatic system background
- Series of vessels and nodes that collect and filter excess tissue fluid (lymph), before returning it to venous circulation
Lymph organs
- Spleen
- Thymus- development and maturation of T lymphocytes
- Red bone marrow- maturation of immature lymphocytes
Lymph nodes
1) Kidney shaped sturctures
2) Filter particles from the blood
3) Immune function
Each node contains:
- T cells, B cells and other immune cells
- They are exposed to fluid as it passes through the node and commence and immune response if they detect the presence of a pathogen
Lymphadenopathy background
- Swelling of lymph nodes
- When nodes accumulate an excessive amount of lymphocytes they can become swollen
causes of lymphadenopathy
Infective
Neoplastic
Others
infective causes of lyphadenopathy
- Infectious mononucleosis
- HIV, including seroconversion illness
- eczema with secondary infection
- rubella
- toxoplasmosis
- CMV
- tuberculosis
- roseola infantum
Neoplastic causes of lymphadenopathy
- Leukaemia
- Lymphoma
other causes of lymphadenopathy
Others
- Autoimmune conditions: SLE, rheumatoid arthritis
- Graft versus host disease
- Sarcoidosis
- Drugs: phenytoin and to a lesser extent allopurinol, isoniazid
Investigations for lymphadenopathy
- Imaging
o US
o CT scan or MRI - Lymph node biopsy
the spleen location
- Upper left abdomen
- Size of clenched fist
Function of the spleen
In an adult main function is to filter blood, removing old RBC. Also has a role in cell-mediated and humoral immune responses
- Red pulp
–> Recycles RBCs and metabolised Hb - White pulp
–> Antibody synthesis
–> Removal of opsonised bacteria/blood cells - Sequestration and phagocytosis of old/abnormal cells by macrophages
- Blood pooling -> so platelets and RBCs can be rapidly mobilised during bleeding
- Extramedullary haemopoiesis -> during haematological stress or if bone marrow fails e.g. myelofibrosis
- Immunological function
–> 25% of T cells and 15% of B cells are present in the spleen
Vasculature of the spleen
- Most of its arterial supply from the splenic artery, a vessel which arises from the coeliac trunk
- Venous drainage through splenic vein
Lymphatics of the spleen
Lymphatic vessels of the spleen follow the splenic vessels and drain into the pancreaticosplenic lymph nodes and then the coeliac nodes
Spleen rupture
- Common site of injury
- Splenic rupture occurs when there is a break in its fibroelastic capsule, disrupting underlying parenchyma
- Mode of injury
o Blunt or penetrating trauma
o Associated with left rib fracture - Results in profuse bleeding into the peritoneal cavity because it is highly vascular
management of spleen rupture
Splenectomy
- When injury and subsequent haemorrhage are life threatening
- Can be partial or total
- Liver and bone marrow take over some functions of the spleen
- Lifelong antibiotics
Complications of spleen rupture and splenectomy
- Higher risk of encapsulated bacterial infections
Splenomegaly background
- Abnormally large spleen >12cm
- Usually a result of secondary causes rather than primary disease of the spleen
- Massive splenomegaly - >20cm
causes of splenomegaly
1) Blood cancers
- Leukaemia’s
- Lymphomas
2) Infections (due to increased work of spleen)
- Infectious mononucleosis
- Parasitic infections e.g. malaria
- Bacterial endocarditis
- Viral hepatitis
3) Portal hypertension
- Cirrhosis
4) Less common conditions
* Haemolytic anaemics
* Sickle cell
* Thalassaemia
* Autoimmune
* SLE
* RA
* Metabolic
* Gaucher disease
Causes of massive splenomegaly
- Myelofibrosis
- Chronic myelogenous leukaemia
- Malaria
Causes of massive splenomegaly
myelofibrosis
CML
malaria
visceral leishmaniasis
causes of moderate splenomegaly
lymphoproliferative
portal hypertension
thalassaemia
causes of mild splenomegaly
PRV (polycythaemia vera)
Haemoloytis
Infection
Infiltration
Connective tissue disorders
Presentation of splenomegaly
- Abdominal pain/ distention
- Constitutional symptoms: night sweats, fever, weight loss, malaise
- Abnormal bruising/bleeding
- Anaemic symptoms
- Decreased appetite (stomach squishes by spleen)
splenomegaly investigations
- Bloods: FBC, blood film, LFTs, UEs, autoimmune screen, CRP, LDH
- Imaging
o US
o CT
o MRI (blood flow)
management of splenomegaly
treat underlying causes
1) Avoid source of abdominal injury to prveent rupture
2) Splenectomy
- vaccination
- prophylactic antibiotics
summary of splenomegaly
asplenia
absence of spleen due to congenital anomaly or surgical procedure
Hyposplenism
: reduced or absent function of spleen, impairing capacity to prevent bacterial infections
causes of hyposplenism
1) Planned, where prophylactic measures can be used to prevent later complications.
2) Traumatic, due to an accident or during surgery.
3) Autosplenectomy, which refers to the physiological loss of spleen function (hyposplenism) - eg, associated with sickle cell anaemia (chronic damage to the spleen results in atrophy), coeliac disease, dermatitis herpetiformis, essential thrombocythaemia and ulcerative colitis.
Indication for splenectomy
- Trauma
- Spontaneous rupture e.g. caused by splenomegaly due to infectious mononucleosis
- Hypersplenism – immune thrombocytopenia
- Neoplasia
Complication of splenectomy
- Thrombocytosis - increased risk of VTE, but prophylactic aspirin may be given if very high
- Infection by encapsulated bacteria (NHS)
o Streptococcus pneumonia
o Haemophilus influenzae
o Neisseria meningitis
Investigations for hyposplenism
- Blood film: features of hyposplenism include Howell-Jolly bodies, Pappenheimer bodies, target cells and irregular contracted red blood cells
- Imaging techniques: ultrasound, CT scanning, and MRI scanning.
- Other investigations, which will depend on the clinical context.
Complications of hyposplenism
- Increased risk of NHS encapsulated bacterial infections
- Increased risk of severe falciparum malaria
which immunisations are important for people without a spleen or hyposplenism
- H.influzenae type B
- Influenza virus
- Pneumococcal
- Meningococcal ACWY and B
antibiotic prohylaxis in hyposplenism
For those at high risk of pneumococcal infections
Types:
- Phenoxypenicillin
- Macrolides
Risk factors for high risk hyposplenism
- Age <16 years or >50 years.
- Poor response to pneumococcal vaccination.
- Previous invasive pneumococcal illness.
- Underlying haematological malignancy resulting in splenectomy (increased risk if immunosuppressed).
pancytopenia background
- Low levels of RBC, WBC and platelets
o RBC- oxygen delivery
o WBC- immune
o Platelets- haemostasis - Increases risk of infection and bleedings
Causes of pancytopenia
Usually unknown
- Cancer e.g. acute leukaemia’s, chemotherapy or radiation
- Genetic conditions
- Vitamin B12 and folate deficiency
- Autoimmune conditions which attack the bone marrow
- Some medicines e.g. antiseizure, antibiotics
presentation of pancyto penia
- Anaemic symptoms
- low WBC symptoms
- Thrombocytopenic symptoms
Anaemic symptoms
- Weakness
- Fatigue
- Rapid heart rate
- SoB
- Pale skin
Low WBC symptoms
Frequent infections
Thrombocytopenic symptoms
- Petechiae
- Bleeding from the gums or nose, blood in faeces or urine, heavy bleeding from cut
- Heavy menstruation in female
- Easy bleeding
Investigation for pancytopenia
- Bloods
o Full blood count
o Blood culture
o Clotting/coagulation studies
o Group and cross-match blood
o U&Es
o CRP - Bone marrow biopsy
management of pancytopenia
Management
- Treat underlying cause
o E.g. drugs which stimulate bone marrow
o Drugs which suppress immune system attacking bone marrow
- Blood transfusion
o May prevent bleeding or organ damage
o Does not treat pancytopenia
- Stem cell transplant
