Acute respiratory distress syndrome (ARDS) is an inflammatory process in the lungs that induces non-hydrostatic protein-rich pulmonary oedema. The immediate consequences are profound hypoxemia, decreased lung compliance, and increased intrapulmonary shunt and dead space. The clinicopathological aspects include severe inflammatory injury to the alveolar-capillary barrier, surfactant depletion, and loss of aerated lung tissue.

The most recent definition of ARDS, the Berlin definition, was proposed by a working group under the aegis of the European Society of Intensive Care Medicine. It defines ARDS by the presence within 7 days of a known clinical insult or new or worsening respiratory symptoms of a combination of acute hypoxemia (PaO2/FiO2 ≤ 300 mmHg), in a ventilated patient with a positive end-expiratory pressure (PEEP) of at least 5 cmH2O, and bilateral opacities not fully explained by heart failure or volume overload i.e. the heart pressure is norma. The Berlin definition uses the PaO2/FiO2 ratio to distinguish mild ARDS (200 < PaO2/FiO2 ≤ 300 mmHg), moderate ARDS (100 < PaO2/FiO2 ≤ 200 mmHg), and severe ARDS (PaO2/FiO2 ≤ 100 mmHg).
Most cases of ARDS in adults are associated with pulmonary sepsis (46 percent) or nonpulmonary sepsis (33 percent). Risk factors include those causing direct lung injury (e.g., pneumonia, inhalation injury, pulmonary contusion) and those causing indirect lung injury (e.g., nonpulmonary sepsis, burns, transfusion-related acute lung injury)

Most patients with ARDS need sedation, intubation, and ventilation while the underlying injury is treated. Any ventilator mode may be used, according to the Surviving Sepsis Clinical Practice Guideline and the National Heart, Lung, and Blood Institute’s ARDS Network (ARDSNet). Respiratory rate, expiratory time, positive end-expiratory pressure, and FiO2 are set following ARDSNet protocols. Settings are adjusted to maintain an oxygen saturation of 88 to 95 percent and a plateau pressure of 30 cm H2O or less to avoid barotrauma. Clinical practice guidelines recommend maintaining an arterial pH of 7.30 to 7.45, although patients in some research trials have tolerated permissive hypercapnia and a pH as low as 7.15

The anterior pituitary gland (adenohypophysis or pars distalis) synthesizes and secretes:
1. FSH (follicle-stimulating hormone)
2. LH (luteinizing hormone)
3. Growth hormone
4. Prolactin
5. ACTH (adrenocorticotropic hormone)
6. TSH (thyroid-stimulating hormone).
The posterior pituitary gland (neurohypophysis) stores and secretes 2 hormones produced by the hypothalamus:
1. ADH (antidiuretic hormone or vasopressin)
2. Oxytocin

The iliohypogastric nerve comes from L1 and emerges from the upper part of the lateral border of the psoas major. It then crosses obliquely in front of the quadratus lumborum to the iliac crest where it perforates the posterior part of transversus abdominis and divides between that muscle and the internal oblique into a lateral and an anterior cutaneous branch. This provides sensory innervation to the skin of the lower abdominal wall, upper hip and upper thigh.
The genitofemoral nerve also comes from the lumbar plexus that innervates the skin of the anterior scrotum or labia majora and upper medial thigh.
The subcostal nerve is the ventral primary ramus of T12 providing sensory innervation to the anterolateral abdominal wall in an area superior to the pubic region.
A spinal nerve owing to their deep location would not have been injured in the procedure.

Answer: Inflammatory bowel disease

Inflammatory bowel disease (IBD) is an idiopathic disease caused by a dysregulated immune response to host intestinal microflora. The two major types of inflammatory bowel disease are ulcerative colitis (UC), which is limited to the colonic mucosa, and Crohn disease (CD), which can affect any segment of the gastrointestinal tract from the mouth to the anus, involves skip lesions, and is transmural. There is a genetic predisposition for IBD, and patients with this condition are more prone to the development of malignancy.

Generally, the manifestations of IBD depend on the area of the intestinal tract involved. The symptoms, however, are not specific for this disease. They are as follows:

Abdominal cramping

Irregular bowel habits, passage of mucus without blood or pus

Weight loss

Fever, sweats

Malaise, fatigue

Arthralgias

Growth retardation and delayed or failed sexual maturation in children

Extraintestinal manifestations (10-20%): Arthritis, uveitis, or liver disease

Grossly bloody stools, occasionally with tenesmus: Typical of UC, less common in CD

Perianal disease (e.g., fistulas, abscesses): Fifty percent of patients with CD

The World Gastroenterology Organization (WGO) indicates the following symptoms may be associated with inflammatory damage in the digestive tract [1] :

Diarrhoea: mucus or blood may be present in the stool; can occur at night; incontinence may occur

Constipation: this may be the primary symptom in ulcerative colitis, when the disease is limited to the rectum; obstipation may occur and may proceed to bowel obstruction

Bowel movement abnormalities: pain or rectal bleeding may be present, as well as severe urgency and tenesmus

Abdominal cramping and pain: commonly present in the right lower quadrant in Crohn disease; occur peri umbilically or in the left lower quadrant in moderate to severe ulcerative colitis

Nausea and vomiting: occurs more often in Crohn disease than in ulcerative colitis

The nocturnal diarrhoea and incontinence are important symptoms in diagnosis IBD.

Pulmonary embolism (PE) is a blockage of an artery in the lungs by an embolus that has travelled from elsewhere in the body through the bloodstream. The change in cardiopulmonary function is proportional to the extent of the obstruction, which varies with the size and number of emboli obstructing the pulmonary arteries. The resulting physiological changes may include pulmonary hypertension with right ventricular failure and shock, dyspnoea with tachypnoea and hyperventilation, arterial hypoxaemia and pulmonary infarction. Consequent alveolar hyperventilation is manifested by a lowered pa(CO2). After occlusion of the pulmonary artery, areas of the lung are ventilated but not perfused, resulting in wasted ventilation with an increased ventilation/perfusion ratio – the physiological hallmark of PE – contributing to a further hyperventilatory state. The risk of blood clots is increased by cancer, prolonged bed rest, smoking, stroke, certain genetic conditions, oestrogen-based medication, pregnancy, obesity, and post surgery.

Jaundice can occur due to any of the possible causes and treatment depends upon diagnosing the correct condition. Mild hyperbilirubinemia with normal levels of aminotransferase and alkaline phosphatase is often unconjugated (e.g., due to haemolysis or Gilbert’s syndrome rather than hepatobiliary disease). Moderate or severe hyperbilirubinemia along with increased urinary bilirubin (bilirubinuria), high alkaline phosphatase or aminotransferase levels suggest hepatobiliary disease. Hyperbilirubinemia produced by any hepatobiliary disease is largely conjugated. In this case, other blood tests include hepatitis serology for suspected hepatitis, prothrombin time (PT) or international normalised ratio (INR), albumin and globulin levels, and antimitochondrial antibody levels (suspected primary biliary cirrhosis). Low albumin and high globulin levels suggest chronic rather than acute liver disease. In cases where there is only a an elevation of alkaline phosphatase, γ-glutamyl transpeptidase (GGT) levels should be checked – the levels of which will be found high in hepatobiliary disease, but not in bone disorder which can also lead to elevated alkaline phosphatase levels. In diseases of hepatobiliary origin, aminotransferase elevations > 500 units suggest a hepatocellular cause, whereas disproportionate increases of alkaline phosphatase (e.g., alkaline phosphatase > 3 times normal and aminotransferase < 200 units) suggest cholestasis. Because hepatobiliary disease alone rarely causes bilirubin levels > 30 mg/dl, higher levels are suggestive of a combination of severe hepatobiliary disease and haemolysis or renal dysfunction. Imaging is best for diagnosing infiltrative and cholestatic causes of jaundice. Liver biopsy is rarely needed, but can be of use in intrahepatic cholestasis and in some types of hepatitis.

Chronic hypocalcaemia is mostly seen in patients with hypoparathyroidism as a result of accidental removal or damage to parathyroid glands during thyroidectomy.

Answer: Adrenaline 1:1000 IM

Early treatment with intramuscular adrenaline is the treatment of choice for patients having an anaphylactic reaction. IM Injection:

Adults: The usual dose is 500 micrograms (0.5ml of adrenaline 1/1000). If necessary, this dose may be repeated several times at 5-minute intervals according to blood pressure, pulse and respiratory function.

Additional measures

Beta2-agonists for bronchospasm: administer salbutamol or terbutaline by aerosol or nebuliser.

Antihistamines: administer both H1and H2receptor blockers slowly intravenously:
promethazine 0.5-1 mg/kg
and
ranitidine 1 mg/kg or famotidine 0.4 mg/kg or cimetidine 4 mg/kg
Corticosteroids: administer intravenously: hydrocortisone 2-6 mg/kg or dexamethasone 0.1-0.4 mg/kg
Nebulised adrenaline (5 mL of 1:1000) may be tried in laryngeal oedema and often will ease upper airways obstruction. However, do not delay intubation if upper airways obstruction is progressive.

Anaphylaxis is an acute, potentially fatal, multiorgan system reaction caused by the release of chemical mediators from mast cells and basophils. The classic form involves prior sensitization to an allergen with later reexposure, producing symptoms via an immunologic mechanism.

Anaphylaxis most commonly affects the cutaneous, respiratory, cardiovascular, and gastrointestinal systems. The skin or mucous membranes are involved in 80-90% of cases. A majority of adult patients have some combination of urticaria, erythema, pruritus, or angioedema. However, for poorly understood reasons, children may present more commonly with respiratory symptoms followed by cutaneous symptoms. It is also important to note that some of the most severe cases of anaphylaxis present in the absence of skin findings.

Initially, patients often experience pruritus and flushing. Other symptoms can evolve rapidly, such as the following:

Dermatologic/ocular: Flushing, urticaria, angioedema, cutaneous and/or conjunctival injection or pruritus, warmth, and swelling

Respiratory: Nasal congestion, coryza, rhinorrhoea, sneezing, throat tightness, wheezing, shortness of breath, cough, hoarseness, dyspnoea

Cardiovascular: Dizziness, weakness, syncope, chest pain, palpitations

Gastrointestinal: Dysphagia, nausea, vomiting, diarrhoea, bloating, cramps

Neurologic: Headache, dizziness, blurred vision, and seizure (very rare and often associated with hypotension)

Other: Metallic taste, feeling of impending doom

Answer: Yersinia enterocolitica

Yersinia enterocolitica (see the image below) is a bacterial species in the family Enterobacteriaceae that most often causes enterocolitis, acute diarrhoea, terminal ileitis, mesenteric lymphadenitis, and pseudo appendicitis but, if it spreads systemically, can also result in fatal sepsis. Symptoms of Y enterocolitica infection typically include the following:

Diarrhoea – The most common clinical manifestation of this infection; diarrhoea may be bloody in severe cases

Low-grade fever

Abdominal pain – May localize to the right lower quadrant

Vomiting – Present in approximately 15-40% of cases

Mesenteric adenitis, mesenteric ileitis, and acute pseudo appendicitis
These manifestations are characterized by the following symptoms (although nausea, vomiting, diarrhoea, and aphthous ulcers of the mouth can also occur):

Fever

Abdominal pain

Tenderness of the right lower quadrant

Leucocytosis

Pseudo appendicitis syndrome is more common in older children and young adults. Patients with Y enterocolitica infection often undergo appendectomy; several Scandinavian studies suggested a prevalence rate of 3.8-5.6% for infection with Y enterocolitica in patients with suspected appendicitis.

Analysis of several common-source outbreaks in the United States found that 10% of 444 patients with symptomatic, undiagnosed Y enterocolitica infection underwent laparotomy for suspected appendicitis.

Human clinical Y enterocolitica infections ensue after ingestion of the microorganisms in contaminated food or water or by direct inoculation through blood transfusion.

Y enterocolitica is potentially transmitted by contaminated unpasteurized milk and milk products, raw pork, tofu, meats, oysters, and fish. Outbreaks have been associated with raw vegetables; the surface of vegetables can become contaminated with pathogenic microorganisms through contact with soil, irrigation water, fertilizers, equipment, humans, and animals.

Pasteurized milk and dairy products can also cause outbreaks because Yersinia can proliferate at refrigerated temperatures.

Animal reservoirs of Y enterocolitica include swine (principle reservoir), dogs, cats, cows, sheep, goats, rodents, foxes, porcupines, and birds.

Reports of person-to-person spread are conflicting and are generally not observed in large outbreaks. Transmission via blood products has occurred, however, and infection can be transmitted from mother to new-born infant. Faecal-oral transmission among humans has not been proven.

Answer: Lanz

The Lanz and Gridiron incisions are two incisions that can be used to access the appendix, predominantly for appendectomy.

Both incisions are made at McBurney’s point (two-thirds from the umbilicus to the anterior superior iliac spine). They involve passing through all of the abdominal muscles, transversalis fascia, and then the peritoneum, before entering the abdominal cavity.

The Lanz incision is a transverse incision, whilst the Gridiron incision is oblique (superolateral to inferomedial). Due to its continuation with Langer’s lines, the Lanz incision produces much more aesthetically pleasing results with reduced scarring.

The bronchial circulation is part of the systemic circulation and receives about 2% of the cardiac output from the left heart. Bronchial arteries arise from branches of the aorta, intercostal, subclavian or internal mammary arteries. The bronchial arteries supply the tracheobronchial tree with both nutrients and O2. It is complementary to the pulmonary circulation that brings deoxygenated blood to the lungs and carries oxygenated blood away from them in order to oxygenate the rest of the body.

Bacterial meningitis (including meningococcal meningitis, Haemophilus influenzae meningitis, and staphylococcal meningitis) is a neurologic emergency that is associated with significant morbidity and mortality. Initiation of empiric antibacterial therapy is therefore essential for better outcomes. The patient appears to be suffering from meningitis caused by Staphylococcus aureus. Methicillin would be the drug of choice . It is bactericidal and unlike streptomycin and chloramphenicol it is not associated with toxicity

CA-125 is a protein that is used as a tumour marker. This substance is found in high concentration in patients with ovarian cancer. It is the only tumour marker recommended for clinical use in the diagnosis and management of ovarian cancer.

Hypospadias is the condition where the urethra opens along the underside or ventral aspect of penile shaft. First-degree hypospadias is seen in 50-75% cases, where the urethra open on the glans penis. Second-degree hypospadias is seen in 20% cases where the urethra opens on the shaft, and third-degree in 30% cases with the urethra opening on the perineum. The severe cases are usually associated with undescended testis (cryptorchidism) or chordee, where the penis is tethered downwards and not completely separated from the perineum.
It is a common male genital birth defect but varying incidences are noted in different countries. There is no obvious inheritance pattern noted. No exact cause has been determined, however several hypotheses include poor response to androgen, or interference by environmental factors.

The lateral medullary syndrome or Wallenberg’s disease is also known as posterior inferior cerebellar artery syndrome (PICA). This syndrome is a clinical manifestation of the occlusion of the posterior cerebellar artery that results in symptoms of infarction of the lateral medullary oblongata. Other arteries that contribute to blood flow in to this region such are the vertebral artery, superior middle cerebellar and inferior medullary arteries can also result to this syndrome when occluded.

The goal of fluid management in major burn injuries is to maintain the tissue perfusion in the early phase of burn shock, in which hypovolemia finally occurs due to steady fluid extravasation from the intravascular compartment.

Burn injuries of less than 20% are associated with minimal fluid shifts and can generally be resuscitated with oral hydration, except in cases of facial, hand and genital burns, as well as burns in children and the elderly. As the total body surface area (TBSA) involved in the burn approaches 15–20%, the systemic inflammatory response syndrome is initiated and massive fluid shifts, which result in burn oedema and burn shock, can be expected.

The ideal burn resuscitation is the one that effectively restores plasma volume, with no adverse effects. Isotonic crystalloids, hypertonic solutions and colloids have been used for this purpose, but every solution has its advantages and disadvantages. None of them is ideal, and none is superior to any of the others.
Crystalloids are readily available and cheaper than some of the other alternatives. RL solution, Hartmann solution (a solution similar to RL solution) and normal saline are commonly used. There are some adverse effects of the crystalloids: high volume administration of normal saline produces hyperchloremic acidosis, RL increases the neutrophil activation after resuscitation for haemorrhage or after infusion without haemorrhage. d-lactate in RL solution containing a racemic mixture of the d-lactate and l-lactate isomers has been found to be responsible for increased production of ROS. RL used in the majority of hospitals contains this mixture. Another adverse effect that has been demonstrated is that crystalloids have a substantial influence on coagulation. Recent studies have demonstrated that in vivo dilution with crystalloids (independent of the type of the crystalloid) resulted in a hypercoagulable state.
Despite these adverse effects, the most commonly used fluid for burn resuscitation in the UK and Ireland is Hartmann’s solution (adult units 76%, paediatric units 75%). Another study has revealed that RL is the most popular type of fluid in burn units located in USA and Canada.

This is transfusion-associated graft-versus-host disease (GvHD) occurring in an immunosuppressed patient. It can occur 4–30 days after a transfusion and follows a subacute pathway. Patients may also have diarrhoea and abnormal liver function tests. Management involves steroid therapy.

Acute transfusion reactions present during or within 24 hours of a blood transfusion. The most frequent clinical features are fever, chills, pruritus, or urticaria, which typically resolve promptly without specific treatment or complications. Other signs occurring in temporal relationship with a blood transfusion such as severe dyspnoea, pyrexia, or loss of consciousness may be the first indication of a more severe, potentially fatal reaction.

Transfusion reactions may be immune-mediated and non-immune-mediated. GvHD is a condition that might occur after an allogeneic transplant. The donated blood cells view the recipient’s body as foreign and attacks it. Immunosuppressed patients who receive white blood cells from another person are at increased risk of developing GvHD.

There are two forms of the disease:
1. Acute graft-versus-host disease (aGvHD): usually presents with skin and/or liver and/or gut involvement.
2. Chronic graft-versus-host disease (cGvHD).

The diagnosis is clinical and usually one of exclusion; however, biopsy of affected tissues may be helpful in unclear cases.

The medial umbilical fold is made by the medial umbilical ligament-which is the obliterated portion of the umbilical artery, while the lateral umbilical fold is a fold of peritoneum over the inferior epigastric vessels. The median umbilical fold is a midline structure made by the median umbilical ligament i.e. the obliterated urachus. The medial inguinal fossa is the space on the inner abdominal wall between the medial umbilical fold and the lateral umbilical fold. It is place in the abdominal wall where there is an area of weak fascia i.e. the inguinal triangle through which direct inguinal hernias break through. The lateral inguinal fossa on the other hand is a space lateral to the lateral umbilical fold. Indirect inguinal hernias push through this space.

The left colic flexure is the bend of the transverse colon as it continues to form the descending colon on the left upper quadrant. The spleen is located on the superior aspect of the left colic flexure. It is commonly referred to as the splenic flexure because of its relation o the spleen superiorly.

Oblique fissure: is found on both the left and the right lungs. It separates the upper from the lower lobes in both lungs and the middle lobe from the lower lobe in the right lung(which has three lobes.)
The superior lobar bronchus is found in both lungs.
Cardiac notch: found only on the left lung.
Horizontal fissure: a deep groove separating the middle lobe from the upper lobe of the right lung is absent on the left lung.
Diaphragmatic surface: refers to the part of the lung, both the left and the right, that is in contact with the diaphragm.

Iron deficiency anaemia is the most common type of anaemia. It can occur due to deficiency of iron from decreased intake, increased loss or inadequate absorption. An MCV less than 80 will indicated iron deficiency anaemia. On the smear the RBCs will be microcytic hypochromic and will also show poikilocytosis. Iron profile tests are important to make a diagnosis. Clinically the patient will be pale and lethargic.

The posterior drawer test is a physical exam technique that is done to assess the integrity of the posterior cruciate ligament (PCL). The PCL is attached to the posterior intercondylar area of the tibia and passes anteriorly, medially, and upward to attach to the lateral side of the medial femoral condyle.
This ligament prevents backward displacement of the tibia or forward sliding of the femur. Injury to the ligament allows displacement of the tibia

Epstein-Barr virus is the causative agent for infectious mononucleosis leading to presence of atypical lymphocytes in blood. Usually symptomatic in older children and adults, the incubation period is 30-50 days. Symptoms include fatigue, followed by fever, adenopathy and pharyngitis. Fatigue can last for months and is maximum in first few weeks. Fever spikes in the afternoon or early evening, with temperature around 39.5 – 40.5 °C. The ‘typhoidal’ form where fatigue and fever predominate has a low onset and resolution. Pharyngitis resemble that due to streptococcus and can be severe and painful. Lymphadenopathy is bilaterally symmetrical and can involve any nodes, specially the cervical ones. Mild splenomegaly is seen in 50% cases, usually in 2-3rd week. Mild tender hepatomegaly can occur. Less common manifestations include maculopapular eruptions, jaundice, periorbital oedema and palatal enanthema. Diagnostic tests include full blood count and a heterophil antibody test. Morphologically abnormal lymphocytes account for 80% cells and are heterogenous, unlike leukaemia.

The patient has a primary psoas abscess.

Psoas (or iliopsoas) abscess is a collection of pus in the iliopsoas muscle compartment. It may arise via contiguous spread from adjacent structures or by the haematogenous route from a distant site. Psoas abscesses may be either primary or secondary. Primary cases often develop in the immunosuppressed and may occur as a result of haematogenous spread. Secondary cases may occur as a complication of intra-abdominal diseases such as Crohn’s disease.

Patients usually present with lower back pain and if the abscess is extensive, a mass that may be localised to the inguinal region or femoral triangle. In most cases, the diagnosis can be made clinically. Where it is not clear, an ultrasound scan is often the most convenient investigation.

Smaller collections may be percutaneously drained. If the collection is larger, or the percutaneous route fails, then surgery (via a retroperitoneal approach) should be performed.

Gap junctions are attachments between cells that permit intercellular communication e.g. they permit current flow and electrical coupling between myocardial cells. They allow direct electrical transmission among cells and also permit certain substance to pass through as well. They are either homotypic, formed by two identical hemichannels or heterotypic, formed by different hemichannels.

Langhans giant cells are characteristically seen in granulomatous inflammation. They form when epithelioid cells fuse together. They usually contain a nuclei with a horseshoe-shaped pattern in the periphery of the cell.

Gram-positive rods include Clostridia, Listeria and diphtheroids.
Gram-negative rods include Escherichia coli, Klebsiella, Yersinia, Haemohilus, Pseudomonas, Shigella, Legionella, proteus and Salmonella

The most common cause of hypovolaemic hyponatraemia include: liver cirrhosis, congestive heart failure and nephrotic syndrome. In hypovolaemic hyponatraemia, both sodium and water content increase: Increase in sodium content leads to hypervolemia and water content to hyponatraemia.

The wound of this patient should be packed with alginate dressing. Abscess wounds should not undergo primary closure. Moreover, use of gauze is inappropriate and would be difficult to redress.

Alginate dressings are absorbent wound care products that contain sodium and calcium fibres derived from seaweed. An individual dressing is able to absorb up to 20 times its own weight. These dressings, which are easy to use, mold themselves to the shape of the wound, which helps ensure that they absorb wound drainage properly. In abscesses requiring incision and drainage, alginate dressings are well-tolerated and their removal causes minimal pain.

Craniopharyngiomas (also known as Rathke pouch tumours, adamantinomas or hypophyseal duct tumours) affect children mainly between the age of 5 and 10 years. It constitutes 9% of brain tumours affecting the paediatric population. These are slow-growing tumours which can also be cystic, and arise from the pituitary stalk, specifically the nests of epithelium derived from Rathke’s pouch. Histologically, this tumour shows nests of squamous epithelium which is lined on the outside by radially arranged cells. Calcium deposition is often seen with a papillary type of architecture.
ACTH-secreting pituitary adenomas are rare and mostly microadenomas. Paediatric astrocytoma’s usually occur in the posterior fossa. Although null cell adenomas can cause mass effect and give rise to the described symptoms, they are not suprasellar. Prolactinomas can also show symptoms of headache and disturbances in the visual field, however they are known to be small and slow-growing.