The child is suffering from acute sickle cell crisis, a complication of sickle cell disease. It is characterised by a new segmental pulmonary infiltrate consistent with consolidation together with one or more new respiratory symptoms.The mainstay of treatment is oxygen support, (ventilation if required), hydration, antibiotics and analgesia.

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.

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

Hyposplenism is associated with thrombocytosis. Other features of hyposplenism are: – Howell-Jolly bodies and acanthocytosis, occurring secondary to haemolysis.- Pappenheimer bodies: These are granular deposits of iron found within the RBCs.- Lymphocytosis and monocytosis.Causes for hyposplenism include:- Congenital asplenia- Iatrogenic splenectomy: Following trauma or treatment for ITP, thalassemia or spherocytosis).- Autosplenectomy: Secondary to sickle cell anaemia, coeliac disease, dermatitis herpetiformis, essential thrombocythemia or splenic arterial thrombosis).

The diagnosis of a post-splenectomy/hyposplenism blood picture can be made reliably by identifying Howell Jolly bodies in routine Wright-Giemsa stained blood and target cells. These are round basophilic bodies in red blood cells that represent residual nuclear material from marrow nucleated red cell precursors that are usually culled out by the spleen.These do not occur in individuals with normally functioning splenic tissue and their presence indicates either 1) an asplenic state or 2) hypofunctioning splenic tissue as might be seen in a patient with late-stage sickle cell anaemia. Their presence in an individual with splenomegaly leads to a narrow differential diagnosis and their absence in a splenectomised individual indicates accessory splenic Heinz bodies and poikilocytosis typically increase in a splenectomised individual and care must be taken not to overdiagnose haemolysis in such an individual.

This history is suggestive of Henoch-Schönlein Purpura following a respiratory infection. A typical rash involving thighs and buttocks is often seen in this age group. Coagulation profile is the suitable answer from the given answers.

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.

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 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.

Acute lymphoblastic leukaemia (ALL) is an aggressive type of blood and bone marrow cancer which can appear in childhood. Signs of childhood ALL include: Fever, Easy bruising, Petechiae, Bone or joint pain, Painless lumps in multiple areas of the body, Weakness, fatigue or paleness, and Loss of appetite. Blood tests may show elevated white blood cells, decreased values of red blood cells and low platelet count.

Von Willebrand disease (VWD), a congenital bleeding disorder caused by deficient or defective plasma von Willebrand factor (VWF), may only become apparent on haemostatic challenge, and bleeding history may become more apparent with increasing age. Type 1 VWD (,30% of VWD) typically manifests as mild mucocutaneous bleeding. Type 2 VWD accounts for approximately 60% of VWD. Type 2 subtypes include: Type 2A, which usually manifests as mild-to-moderate mucocutaneous bleeding| Type 2B, which typically manifests as mild-to-moderate mucocutaneous bleeding that can include thrombocytopenia that worsens in certain circumstances| Type 2M, which typically manifests as mild-moderate mucocutaneous bleeding| Type 2N, which can manifest as excessive bleeding with surgery and mimics mild haemophilia A. Type 3 VWD (<10% of VWD) manifests with severe mucocutaneous and musculoskeletal bleeding.

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 differentials of the child’s condition are likely to include an Iron deficiency anaemia, or a hemoglobinopathy such as sickle cell disease or thalassemia based on the presentation of pallor, growth failure and easy fatiguability. While the full blood count and film present a hypochromic microcytic anaemia with reticulocytosis, the normal serum ferritin levels rule out iron deficiency anaemia. Thalassemia is to be suspected over sickle cell disease as the patient comes from the Mediterranean region known for a high incidence of thalassemia. Sickle cell anaemia also tends to present with normocytic normochromic red blood cells, with many sickled cells. Vitamin B12 deficiency and Aplastic anaemia are ruled out as they present with a macrocytic anaemia, and a decrease in white blood cells, platelets and red blood cells respectively.

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.

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.

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.

Hassall’s corpuscles are groups of epithelial cells within the thymic medulla. The physical nature of these structures differs between mammalian species. Although Hassall’s corpuscles have been proposed to act in both the removal of apoptotic thymocytes and the maturation of developing thymocytes within the thymus, the function of Hassall’s corpuscles has remained an enigma.

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.

Blood tests do not help in the diagnosis of jaundice except of course by telling the level of jaundice (bilirubin) and providing some corroborative evidence such as autoantibodies, tumour markers or viral titres in the case of hepatitis. Classifying causes of jaundice on the basis of ultrasound provides a quick and easy schema for diagnosing jaundice which is applicable in primary care as well as hospital based practice.

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.