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)

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.

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.

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.

Breast milk jaundice is a type of jaundice associated with breast-feeding. It typically occurs one week after birth. The condition can sometimes last up to 12 weeks, but it rarely causes complications in healthy, breast-fed infants. The exact cause of breast milk jaundice isn’t known. However, it may be linked to a substance in the breast milk that prevents certain proteins in the infant’s liver from breaking down bilirubin. The condition may also run in families. Breast milk jaundice is rare, affecting less than 3 percent of infants. When it does occur, it usually doesn’t cause any problems and eventually goes away on its own. It’s safe to continue breast-feeding.

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.

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.

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 clinical picture suggests that the baby has Beckwith-Wiedemann Syndrome, which predisposes the individual to cancer. The most common childhood tumour that a person with Beckwith-Wiedemann Syndrome may develop is Wilms’ tumour. Typical features include: macrosomia, asymmetric limb growth, macroglossia, neonatal hypoglycaemia, umbilical hernias or other abdominal wall deformities.

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.

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.

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.

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.

Red blood cells (RBC) have a life span of 120 days in humans.Aging of RBC includes changes in many properties: decreased metabolic activity, morphological alterations, including decreased cell volume and changes in cell shape, and quantitative and qualitative modulations of the surface.

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.

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 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.

Burkitt lymphoma is associated with the c-myc gene translocation, usually t(8|14). Burkitt lymphoma is a rare high-grade non-Hodgkin lymphoma endemic to west Africa and the mosquito belt. It has a close association with the contraction of Epstein-Barr virus (EBV). Burkitt lymphoma often presents with symmetrical painless lymphadenopathy, systemic B symptoms (fever, sweats, and weight loss), central nervous system involvement, and bone marrow infiltration. Classically in the textbooks, the patient also develops a large jaw tumour.Other aforementioned options are ruled out because:1. t(9|22)—Chronic myeloid leukaemia2. t(15|17)—Acute promyelocytic leukaemia3. t(14|18)—Follicular Lymphoma4. t(11|14)—Mantle Cell Lymphoma

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.