Bernard- Soulier Syndrome results from a deficiency of platelet glycoprotein protein Ib, which mediates the initial interaction of platelets with the subendothelial components via the von Willebrand protein. It is a rare but severe bleeding disorder. Platelets do not aggregate to ristocetin. The platelet count is low, but, characteristically, the platelets are large, often the size of red blood cells, and may be missed on complete blood counts because most automatic counters do not count them as platelets.

The clinical features and the presentation of this child and the MRI findings are highly suggestive of acute lymphoblastic leukaemia.Anaemia and neutropenia, with a borderline platelet count as well as the tumour infiltration on both femurs on the MRI scan, are suggestive of a widespread Marrow disorder. Based on the age of the patient, acute lymphoblastic leukaemia is more appropriate as it is more common than acute myeloid leukaemia in children and can present with bony pain in this age group.Other options:- Acute myeloid leukaemia: Although this is the most common leukaemia that is seen in adults, it rarely presents in children. – Ewing’s sarcoma: This would usually present in a more unilateral manner, and would only be associated with cytopenia if there was direct bone marrow involvement.- HIV infection: It would be very rare in this group. HIV infection can cause a wide array of signs and symptoms, but we are told that the MRI scan is highly suggestive of tumour infiltration, which would be uncommon in this condition. – Juvenile arthritis: It is much less common. There is also nothing to find on examination, such as swollen or painful joints, which would usually be seen in this condition.

The organisms most likely to cause post-splenectomy sepsis include:- Streptococcus pneumoniae- Haemophilus influenzae- MeningococciEncapsulated organisms carry the most significant pathogenic risk following splenectomy. Hyposplenism:It may complicate certain medical conditions where splenic atrophy occurs or maybe the result of medical intervention such as splenic artery embolization and splenectomy for trauma. The diagnosis of hyposplenism is difficult, and while there may be peripheral markers of the splenectomised state (e.g. Howell-Jolly bodies), these are neither 100% sensitive or specific. The most sensitive test is a radionucleotide labelled red cell scan.It dramatically increases the risk of post-splenectomy sepsis, particularly with encapsulated organisms. Since these organisms may be opsonized, but this then goes undetected at an immunological level due to loss of the spleen. For this reason, individuals are recommended to be vaccinated and have antibiotic prophylaxis.Key recommendations:- All those with hyposplenism or prior to an elective splenectomy should receive pneumococcal, Haemophilus type b and meningococcal type C vaccines. These should be administered two weeks before or two weeks following splenectomy. The vaccine schedule for meningococcal disease primarily consists of a dose of Men C and Hib at two weeks and then a dose of the MenACWY vaccine one month later. Those aged under two may require a booster at two years. A dose of pneumococcal polyvalent polysaccharide vaccine (PPV) is given at two weeks. A conjugate vaccine (PCV) is offered to young children. The PCV is more immunogenic but covers fewer serotypes. Boosting PPV is either guided by serological measurements (where available) or by routine boosting doses at five-yearly intervals.Annual influenza vaccination is recommended in all cases- Antibiotic prophylaxis is offered to all. The risk of post-splenectomy sepsis is highest immediately following splenectomy. Individuals with an inadequate response to pneumococcal vaccination are another high-risk group. High-risk individuals should be counselled to take penicillin or macrolide prophylaxis. Those at low risk may choose to discontinue therapy. All patients should be advised about taking antibiotics early in the case of intercurrent infections.- Asplenic individuals travelling to malaria-endemic areas are at high risk and should have both pharmacological and mechanical protection.

Based on the studies, genetic factors are responsible for approximately 60 % DVT cases. Factor V (FV) Leiden which is the most common cause of inherited thrombophilia, predisposes patients to DVT because of resistance to protein C.The heritable causes of deep vein thrombosis, from most to least common are:Factor V LeidenProthrombin G20210A variantProtein C deficiencyProtein S deficiencyAntithrombin deficiencyVon Willebrand disease and thalassaemia are not causes of DVT.

Haemophilia B (also known as Christmas disease) is due to a deficiency in factor IX. Haemophilia A is due to a deficiency in factor VIII.

The anti-B antibodies in a patient with blood group A belong to the IgM class of immunoglobulins.Note:IgM is the largest antibody formed of 5 antibodies attached together. This functions to agglutinate or clump antigens. The associated anti-A and anti-B antibodies are usually IgM produced in the first years of life by sensitisation to environmental substances such as food, bacteria, and viruses.Other options:- IgG is the most common antibody. It is a single antibody complex.- IgD is found on the surface of B-lymphocytes.- IgE is bound to tissue cells, especially mast cells and eosinophils.

Bone marrow failure syndromes are characterized by the bone marrow’s inability to produce cells of different lineage. They can be classified as those affecting one or two cell lineages or those affecting all three of them. Fanconi syndrome, along with dyskeratosis congenita, is one of the inherited bone marrow failure syndromes that causes pancytopenia. Other inherited disorders affecting hematopoietic lineage include Diamond-Blackfan anaemia, Schwachman-Diamond syndrome, congenital amegakaryocytic thrombocytopenia (CAMT) and Thrombocytopenia absent radii (TAR) syndrome. Acquired causes of bone marrow failure that lead to pancytopenia include aplastic anaemia, drugs, nutritional deficiencies, and viral infections. Kostmann syndrome is an autosomal recessive form of severe neutropenia, most likely due to excessive neutrophil apoptosis.

Aplastic anaemia causes a deficiency of all blood cell types: red blood cells, white blood cells, and platelets. It is more frequent in people in their teens and twenties, but is also common among the elderly. It can be caused by heredity, immune disease, or exposure to chemicals, drugs, or radiation. However, in about one-half of cases, the cause is unknown.The definitive diagnosis is by bone marrow biopsy| normal bone marrow has 30–70% blood stem cells, but in aplastic anaemia, these cells are mostly gone and replaced by fat.First-line treatment for aplastic anaemia consists of immunosuppressive drugs, typically either anti-lymphocyte globulin or anti-thymocyte globulin, combined with corticosteroids, chemotherapy and ciclosporin. Hematopoietic stem cell transplantation is also used, especially for patients under 30 years of age with a related matched marrow donor.

From the options mentioned here, the closest diagnosis is haemophilia. This is a mixed picture, as a purpuric rash on the buttocks does not correlate with this diagnosis. However, the most appropriate diagnosis is haemophilia.

The presentation of the child is highly suggestive of Henoch-Schonlein purpura (HSP). It is an IgA-mediated, autoimmune hypersensitivity vasculitis that targets the small vessels of the skin, GI tract, kidneys, and joints.It is most commonly seen in children aged 3 – 6 years old and is twice as common in boys than girls. Preceding viral URTI with low-grade pyrexia is common. The most common organism associated with HSP is, however, Group A streptococcal infection.A purpuric rash is seen on the back of the legs and buttocks and can less frequently affect the arms. Arthralgia is common (usually knees/ankles) in these patients.Abdominal pain and bloody diarrhoea may occur. And half of the children with HSP have renal involvement. Rarely, it can lead to end-stage renal failure.Treatment includes adequate hydration, occasionally steroids, and other immunosuppressants. The disease can recur in 1 in 3 children.

Jaundice is considered pathologic if it presents within the first 24 hours after birth. Although up to 60 percent of term new-borns have clinical jaundice in the first week of life, few have significant underlying disease.1,2 However, hyperbilirubinemia in the new-born period can be associated with severe illnesses such as haemolytic disease, metabolic and endocrine disorders, anatomic abnormalities of the liver, and infections. The risk factors here is the mothers blood ground which suggests the cause is fetal-maternal blood group incompatibility.

Acute lymphoblastic leukaemia (ALL) is a cancer of the lymphoid line of blood cells characterized by the development of large numbers of immature lymphocytes. Symptoms may include feeling tired, frequent infections with fever as well as anaemia with thrombocytopenia. As an acute leukaemia, ALL progresses rapidly and is typically fatal within weeks or months if left untreated. The patient’s age also favours the diagnosis of ALL as it occurs most commonly in children, particularly those between the ages of two and five.

Transfusion with blood products carries a risk of acute and more chronic adverse reactions. These reactions can either be immune mediated due to a component mismatch, or non immune, underpinned by bacterial or viral contamination. Reactions range from very mild such as urticaria, to life threatening in the case of transfusion-related acute lung injury. In transfusion with packed red blood cells, the most common adverse event is pyrexia, while urticaria is the most common adverse event that follows infusion with FFP.

A peripheral blood film in iron deficiency anaemia can reveal the following morphologically variant RBCs:- Microcytic cells- Hypochromic cells- Pencil cells- Target cellsOther options:- Schistocytes can be caused by mechanical heart valves. – Rouleaux can be seen in chronic liver disease and malignant lymphoma. – Tear-drop poikilocytes can be seen in myelofibrosis. – Acanthocytes can be seen in liver disease and McLeod blood group phenotype.Pathological red cell forms include:- Target cells: Sickle-cell/thalassaemia, iron-deficiency anaemia, hyposplenism, and liver disease.- Tear-drop poikilocytes: Myelofibrosis- Spherocytes: Hereditary spherocytosis and autoimmune haemolytic anaemia- Basophilic stippling: Lead poisoning, thalassaemia, sideroblastic anaemia, and myelodysplasia- Howell-Jolly bodies: Hyposplenism- Heinz bodies: G6PD deficiency and alpha-thalassaemiaSchistocytes (‘helmet cells’): Intravascular haemolysis, mechanical heart valve, and disseminated intravascular coagulation- Pencil poikilocytes: Iron deficiency anaemia- Burr cells (echinocytes): Uraemia and pyruvate kinase deficiency – Acanthocytes: Abetalipoproteinemia

Carbon monoxide is a colourless gas, which is toxic to animals. It has a high affinity for haemoglobin (around 250 times greater than oxygen). It combines with haemoglobin forming carboxyhaemoglobin, which decreases the oxygen-carrying capacity of the blood, leading to a left-shift in the oxygen-dissociation curve. CO is produced endogenously in limited amounts (0.4ml per hour), but the toxic levels are higher.

Factors V and VIII are consumed most rapidly in a patient with disseminated intravascular coagulation.Simultaneous coagulation and haemorrhage caused by initially formation of thrombi which consume clotting factors (factors 5,8) and platelets, ultimately leading to bleeding.Causes include:- Infection- Malignancy- Trauma e.g. major surgery, burns, shock, dissecting aortic aneurysm- Liver disease- Obstetric complicationsClinically bleeding is usually a dominant feature, bruising, ischaemia and organ failure.Blood tests reveal prolonged clotting times, thrombocytopenia, decreased fibrinogen and increased fibrinogen degradation products.Treatment of DIC involves treating the underlying cause and supportive management.Mnemonic:D-I-S-S-E-M-I-N-A-T-E-DD- D dimerI-Immune complexesS-Snakebite, shock, heatstrokeS-SLEE-Eclampsia, HELLP syndromeM-Massive tissue damageI-Infections: viral and bacterialN-NeoplasmsA-Acute promyelocytic leukaemiaT-Tumour products: Tissue Factor (TF) and TF-like factors released by carcinomas of pancreas, prostate, lung,colon, stomachE-Endotoxins (bacterial)D-Dead foetus (retained)

Reed-Sternberg cells are classically associated with Hodgkin lymphoma.Classical diagnostic Reed-Sternberg cells are large (15 to 45 micrometres), have abundant slightly basophilic or amphophilic cytoplasm and have at least two nuclear lobes or nuclei. Diagnostic Reed-Sternberg cells must have at least two nucleoli in two separate nuclear lobes. The nuclei are large and often rounded in contour with a prominent, often irregular nuclear membrane, pale chromatin and usually one prominent eosinophilic nucleolus, with perinuclear clearing (halo), resembling a viral inclusion.

Due to breakdown of the red blood cell membrane in haemophilic patients, cholesterol crystals are formed by the lipids. On the other hand lipofuscin deposition does not occur in haemolysis or haemorrhage. Neutrophil accumulation suggests acute inflammation. Anthracotic pigment is an exogenous carbon pigment that deposits in the lung from dust. Russell bodies are intracellular accumulations of immunoglobins in plasma cells. Curschmann’s spirals and Charcot Leyden crystals are pathognomonic of asthma.

Haemophilia A and haemophilia B are inherited in an X-linked recessive pattern. The genes associated with these conditions are located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition.

The most probable diagnosis based on the scenario provided above is hereditary spherocytosis.While jaundice and abdominal pain might make you think of hepatitis or cholecystitis in the first instance, the lack of fever suggests otherwise. The apyrexial presentation is against acute cholecystitis, and the past medical history reveals a chronic type of fatigue and two previous episodes of hepatitis. Furthermore, it is unlikely that the child has contracted infective hepatitis twice and now a third time! The most common cause of hepatitis in childhood is hepatitis A, however the lack of travel history to endemic areas makes this less likely. Hepatitis A is usually a mild, self-limiting disease that never presents with chronic symptoms. The chronicity of his fatigue and the blood results lead towards a haematological diagnosis. This is further substantiated by his low haemoglobin levels, high MCV and high reticulocyte count. Chronic haemolytic anaemia is the most likely cause, and the negative Coombs excludes autoimmune haemolytic anaemia (AIHA). Thus, leaving us with the answer as hereditary spherocytosis.Hereditary spherocytosis is a disorder that makes the cytoskeleton of red cells more fragile and therefore leads to red cell death and splenomegaly. Gallstones are a result of this red cell destruction and increased haem metabolism.