Steps involved in leukocyte arrival and function include:
1. margination: cells migrate from the centre to the periphery of the vessel.
2. rolling: selectins are upregulated on the vessel walls.
3. adhesion: upregulation of the adhesion molecules ICAM and VCAM on the endothelium interact with integrins on the leukocytes. Interaction of these results in adhesion.
4. diapedesis and chemotaxis: diapedesis is the transmigration of the leukocyte across the endothelium of the capillary and towards a chemotactic product.
5. phagocytosis: engulfing the offending substance/cell.

Branchial cleft cysts are congenital anomalies that usually arise from second cleft/pouch, with remnants of the third and fourth pouch are rare. Children are typically born with these congenital lesions; however, they may not be evident for weeks, months, or possibly years. The lesions present as fistulae, cyst, sinus tracts, or cartilaginous remnants due to incomplete obliteration during embryogenesis.

They are often asymptomatic, but can often become tender, enlarged, or inflamed with possible abscess formation during episodes of upper respiratory tract infections.
The patient can present with purulent drainage of the sinus to skin or pharynx from spontaneous rupture of branchial cleft cyst abscess. The most concerning symptoms include dysphagia, dyspnoea, and stridor due to cyst compression of the upper airway.

The physical examination will differ depending on the location of the branchial cleft cyst:
– A primary branchial cleft cyst is typically smooth, non-tender, fluctuant mass found between the external auditory canal and submandibular area. It is usually with the parotid gland and facial nerve. Two types of lesions exist. Type 1 is rare and characterized as duplication of the membranous external auditory canal. Type 2 lesions contain both ectoderm and mesoderm elements including cartilage. The patient usually presents with soft tissue mass or draining sinus located on the angle of the mandible or otorrhea, making an otologic exam critical in these cases.
– A secondary branchial cleft cyst is located between the lower anterior border of the sternocleidomastoid and the tonsillar fossa of the pharynx. It can be in proximity to the glossopharyngeal and hypoglossal nerve as well as carotid vessels. Compared to the primary branchial cleft cysts, secondary cysts are tender if secondarily inflamed or infected. If it is associated with a sinus tract, a mucoid or purulent discharge may be present on the skin or into the pharynx.

The treatment of a branchial cleft cyst is typically elective excision due to the risk of infection or present infection, further enlargement, or malignancy.

– Carotid Body Tumour: Painless oropharyngeal or upper anterior triangle of the neck; pulsatile, compressible with a bruit or thrill, mobile from medial to lateral direction.
– Bartonella henselae infection is Isolated, mobile, fluctuant, tender, warm, erythematous, > 2 cm near the site of inoculation.
– Thyroglossal duct cyst: In the Midline, adjacent to the hyoid bone; rises with deglutition.

Extension of the humerus is a function of the latissimus dorsi. This muscle is supplied by the thoracodorsal nerve which is a branch of the posterior cord of the plexus whose fibres are derived from cranial nerves V, VI and VII.

The seminal vesicles are two lobulated membranous pouches situated between the fundus of the bladder and rectum and act as a reservoir for the semen and secrete a fluid that is added to the seminal fluid. Each sac is pyramidal in shape but they all vary in size not only in different individuals but also in the same individuals. The anterior surface is in contact with the fundus of the bladder, extending from near the termination of the ureter to the base of the prostate. Each vesicle consist of single tube, which gives off several irregular caecal diverticula. These separate coils and the diverticula are connected by fibrous tissue.

Gout is a rheumatic disease caused by the precipitation of monosodium urate crystals into tissues, usually joints. This causes acute or chronic pain; the acute illness initially affects only one joint, often the first metatarsophalangeal joint. The diagnosis of the disease requires the identification of crystal in the synovial fluid. These crystals are needle-shaped and strongly negatively birefringent.

The duodenum is connected to the diaphragm by the suspensory ligament called the ligament of Treitz. It is a slip of skeletal muscle from the right crus of the diaphragm and a fibromuscular band of smooth muscle from the 3rd and 4th parts of the duodenum. It is an important landmark, used to divide the gastrointestinal tract into the upper and lower parts. Contraction of this ‘ligament’ leads to opening of the duodenojejunal flexure allowing the flow of chyme.

Answer: Inflammatory bowel disease

The inflammatory bowel diseases (IBDs), including ulcerative colitis and Crohn disease, are chronic inflammatory disorders of the gastrointestinal tract most often diagnosed in adolescence and young adulthood, with a rising incidence in paediatric populations. Inflammatory bowel disease is caused by a dysregulated mucosal immune response to the intestinal microflora in genetically predisposed hosts. Although children can present with the classic symptoms of weight loss, abdominal pain, and bloody diarrhoea, many present with nonclassical symptoms of isolated poor growth, anaemia, or other extraintestinal manifestations.

Colorectal Carcinoma (CRC) is rare in patients less than 20 years of age.

Pelvic fractures may cause laceration of the urethra. Urinary retention, blood at the urethral meatus, and a high-riding prostate on digital rectal examination are the typical features of urethral injury.

Up to 10% of male pelvic fractures are associated with urethral or bladder injuries. Urethral injury occurs mainly in males. It has two types.
1.Bulbar rupture:
a. most common
b. mostly associated with straddle-type injury, e.g. from bicycles
c. presentation with a triad of urinary retention, perineal haematoma, and blood at the meatus

2. Membranous rupture:
a. can be extra- or intraperitoneal
b. occurs commonly due to pelvic fracture
c. symptomology may include penile or perineal oedema/haematoma
d. prostate displaced upwards (high-riding prostate)

Ascending urethrogram is carried out in patients of suspected urethral injury. Suprapubic catheter is surgically placed and is indicated in:
1. External genitalia injuries (i.e. the penis and the scrotum)
2. Injury to the urethra caused by penetration, blunt trauma, continence- or sexual pleasure–enhancing devices, and mutilation.

Anaemia refers to a decrease in the circulating levels of haemoglobin in the blood resulting in a reduced ability of the body to transport oxygen effectively. Anaemia from blood loss results in the body further compensating by releasing stored RBCs and immature RBCs from the bone marrow. Thus resulting in a high reticulocyte count.

Osteomyelitis is most commonly caused by S. aureus in all age groups.

Lymphadenitis is the inflammation or enlargement of a lymph node. Lymph nodes are small, ovoid nodules normally ranging in size from a few millimetres to 2 cm. They are distributed in clusters along the course of lymphatic vessels located throughout the body. The primary function of lymph nodes is to filter out microorganisms and abnormal cells that have collected in lymph fluid. Lymph node enlargement is a common feature in a variety of diseases and may serve as a focal point for subsequent clinical investigation of diseases of the reticuloendothelial system or regional infection. The majority of cases represent a benign response to localized or systemic infection. The red streaks that are noted along the line of lymphatics are indicative of lymphadenitis.

Groin masses are common and include:
Herniae
Lipomas
Lymph nodes
Undescended testis
Femoral aneurysm
Saphena varix

The inferior rectus muscle is a muscle in the orbit. As with most of the muscles of the orbit, it is innervated by the inferior division of oculomotor nerve (Cranial Nerve III). It depresses, adducts, and helps laterally rotate the eye.

The described features suggest acute bowel obstruction. The scar described points toward previous surgery, which suggests development of peritoneal adhesions that could lead to obstruction. Hepatitis does not lead to dilated bowel loops. Amoebiasis could lead to inflammatory bowel disease, however, occult blood in stool is usually positive. Ileal adenocarcinoma is rare. Meckel’s diverticulum can possibly lea to obstruction but the findings described here are more consistent with obstruction due to peritoneal adhesions from a past surgery.

Viral infections will cause necrosis of the hepatocytes with characteristic changes of karyorrhexis and cell fragmentation.
Brown atrophy of the heart is due to accumulation of lipofuscin in the myocardium.
Tissue destruction associated with transplant rejection leads to widespread loss of structural integrity.
Single cell necrosis is not characteristically seen in chronic alcoholic liver.
Barbiturate overdose will result in hypertrophy of the smooth endoplasmic reticulum.
Carcinoma insitu will cause dysplastic cells without the overall structural integrity being disrupted.
Atrophy is due to apoptosis with ordered cellular fragmentation and phagocytosis and will not induce an inflammatory process unlike necrosis.

Answer: Infection with Staphylococcus aureus

Surgical site infections (SSIs) are among the most common healthcare-associated infections, and contribute significantly to patient morbidity and healthcare costs. Staphylococcus aureus is the most common microbial cause. The epidemiology of S. aureus is changing with the dissemination of newer clones and the emergence of mupirocin resistance. Pre-operative screening, using culture- or molecular-based methods, and subsequent decolonization of patients who are positive for methicillin-susceptible S. aureus and methicillin-resistant S. aureus (MRSA) reduces SSIs and hospital stay. This applies especially to major clean surgery, such as cardiothoracic and orthopaedic, involving the insertion of implanted devices. However, it requires a multi-disciplinary approach coupled with patient education. Universal decolonization pre-operatively without screening for S. aureus may compromise the capacity to monitor for the emergence of new clones of S. aureus, contribute to mupirocin resistance, and prevent the adjustment of surgical prophylaxis for MRSA (i.e. replacement of a beta-lactam agent with a glycopeptide or alternative).

A surgical site infection is an infection that occurs after surgery in the part of the body where the surgery took place. Surgical site infections can sometimes be superficial infections involving the skin only. Other surgical site infections are more serious and can involve tissues under the skin, organs, or implanted material.

Symptoms include:
Redness and pain around the area where you had surgery
Drainage of cloudy fluid from your surgical wound
Fever

Haemorrhagic lesions of the temporal lobe are typical of Herpes simplex encephalitis (HSE). It tends to affect patients aged under 20 or over 40 years, and is often fatal if left untreated. In acute encephalitis, cerebral oedema and petechial haemorrhages occur and direct viral invasion of the brain usually damages neurones. The majority of cases of herpes encephalitis are caused by herpes simplex virus-1 (HSV-1), and about 10% of cases of herpes encephalitis are due to HSV-2, which is typically spread through sexual contact.

Vesicovaginal fistula (VVF) is an abnormal opening between the bladder and the vagina that results in continuous and unremitting urinary incontinence. It is one of the most distressing complications of gynaecologic and obstetric procedures. Vesicovaginal fistulae should be suspected in patients with continuous dribbling incontinence after prolonged labour.

Ileal resection may lead to bile acid malabsorption and an altered biliary lipid composition. A “bile acid deficiency” in the enterohepatic circulation with a relative excess of cholesterol and cholesterol supersaturated bile might ensue, causing cholesterol gallstone formation.

In patients with Crohn’s disease involving the small
intestine, the prevalence of gall-bladder stones is higher
than that in the general population. One hypothesis
for this increased risk is that bile acid malabsorption,
secondary to impaired active bile acid transport as a
consequence of ileal disease/resection, leads to a
reduction in the total bile acid pool size and an increase
in biliary cholesterol saturation. In patients with
ulcerative or Crohn’s colitis, or who have undergone
colectomy, the bile acid malabsorption is less than that
in those with ileal dysfunction or resection, but the risk
of gallstone formation is still increased, allegedly by the
same mechanism.

The patient has Denis B fracture, unstable fracture requiring open reduction and internal fixation (ORIF)
open reduction internal fixation indications:
– any talar displacement
– displaced isolated medial malleolar fracture
– displaced isolated lateral malleolar fracture
– bimalleolar fracture and bimalleolar-equivalent fracture
– posterior malleolar fracture with > 25% or > 2mm step-off
– Bosworth fracture-dislocations
– open fractures
– malleolar non-union

Danis-Weber classification:
type A
below the level of the talar dome
usually transverse
tibiofibular syndesmosis intact
deltoid ligament intact
medial malleolus occasionally fractured
usually stable if medial malleolus intact
type B
the distal extent at the level of the talar dome; may extend some distance proximally
usually spiral
tibiofibular syndesmosis usually intact, but a widening of the distal tibiofibular joint (especially on stressed views) indicates syndesmotic injury
medial malleolus may be fractured
the deltoid ligament may be torn, indicated by a widening of the space between the medial malleolus and talar dome
variable stability, dependent on the status of medial structures (malleolus/deltoid ligament) and syndesmosis; may require ORIF
Weber B fractures could be further subclassified as 9
B1: isolated
B2: associated with a medial lesion (malleolus or ligament)
B3: associated with a medial lesion and fracture of the posterolateral tibia
type C
above the level of the ankle joint
tibiofibular syndesmosis disruption with a widening of the distal tibiofibular articulation
medial malleolus fracture or deltoid ligament injury often present
a fracture may arise as proximally as the level of the fibular neck and not visualized on ankle films, requiring knee or full-length tibia-fibula radiographs (Maisonneuve fracture)
unstable: usually requires ORIF
Weber C fractures can be further subclassified as 6
C1: diaphyseal fracture of the fibula, simple
C2: diaphyseal fracture of the fibula, complex
C3: proximal fracture of the fibula
a fracture above the syndesmosis results from external rotation or abduction forces that also disrupt the joint
usually associated with an injury to the medial side

Usually a parasitic infection will be associated with a type I hypersensitivity reaction.
Amyloid deposition will not cause an immune reaction.
Organic dust will lead to a type III hypersensitivity reaction.
Cell mediated as well as humoral immune mechanism play a part in syphilis, but they are do not specifically cause a type I reaction.
Malaria is cause by plasmodium and is not cause of a hypersensitivity reaction.
Atopic dermatitis will not be accompanied by eosinophilia.

The anterior drawer test is an important orthopaedic test that is used to test weakness of the anterior cruciate ligament. The test is done by having the patient sit in a supine position with his/her knees flexed at 90 degrees. An examiner stabilises the patients feet and softly pulls or pushes on the proximal tibia. The test is positive if there is translational movement of the tibia in relation to the femur, indicating a weakened anterior cruciate ligament. The anterior cruciate ligament prevents the tibia from sliding out in front of the femur.

Diarrhoea is defined as having three or more loose or liquid stools per day, or as having more stools than is normal for that person. Severe diarrhoea, causing fluid loss and loss of bicarbonate, will result in marked dehydration and metabolic acidosis.

Achalasia is a rare neurological deficit of the oesophagus that produces an impaired relaxation of the lower oesophageal sphincter and decreased motility of the oesophageal body. Achalasia is generally accepted to be a pre-malignant disorder, since, particularly in the mega-oesophagus, chronic irritation by foods and bacterial overgrowth may contribute to the development of dysplasia and carcinoma.
When oesophageal cancer develops in patients with underlying achalasia, diagnosis tends to be in the more advanced stages of cancer, compared to cases with no achalasia, because both physicians and patients often regard symptoms such as dysphagia and chest discomfort as attributable to the achalasia, rather than to other causes. Therefore, additional approaches that would lead to earlier diagnosis might be pursued less aggressively.
Achalasia is a predisposing factor for oesophageal squamous cell carcinoma.

Erection is a function of the parasympathetic nerves. Of the nerves listed, only the pelvic splanchnic nerves have parasympathetic fibres that innervate the smooth muscles and glands of the pelvic viscera.

A 1 day history suggests the purulent discharge is due to acute inflammation. Acute inflammation has 3 features:
1) the affected area is occupied by a purulent discharge composed of proteins, fluids and cells from local blood vessels
2) the infective agent i.e. bacteria is present in the affected area
3) the damaged tissue can be liquified and the debris removed from the site.
If the inflammation lasts over weeks or months, then it is termed as chronic inflammation.
Granulomatous inflammation is characterised by the presence and formation of granulomas.
Exudate is not a feature of resolution or a complication of inflammation.
Abscess formation takes more than 1 day to form and is usually within a capsule/cavity.

Polymyalgia rheumatica (PMR) affects older adults, with an acute or subacute onset. Symptoms include severe pain and stiffness of the neck and pectoral or pelvic girdles, which is worse in the morning or after a period of inactivity and is usually bilateral. Other symptoms can include fatigue, weight loss, depression and fever. The erythrocyte sedimentation rate is usually elevated, and normochromic normocytic anaemia can occur. Other tests are usually normal in this disease.

The drainage of cerebral spinal fluid from the third ventricle to the fourth ventricle is carried out by the cerebral aqueduct. The cerebral aqueduct is the narrowest passageway in the entire ventricular system and thus forms the most common site of blockage of flow of cerebrospinal fluid. The interventricular foramen allows passage of CSF to the third ventricle. The foramen of Luschka and Magendie are located on the fourth ventricle and allow passage of CSF to the subarachnoid space from the ventricular system. The pontine cistern is a space located on the ventral aspect of the pons. The cisterna magna is an opening on the subarachnoid space between the pia matter and the arachnoid.

Necrosis and ulcers of the colon are a feature of infection with enteroinvasive E. coli (EIEC). It presents with a dysentery-type illness similar to shigellosis.

E. coli have different strains that cause a wide range of conditions. The four main types are:

1. Enteropathogenic E. coli—cause watery diarrhoea, vomiting, and low-grade fever

2. Enteroinvasive E. coli—cause dysentery, large bowel necrosis, and ulcers

3. Enterotoxigenic E. coli—cause traveller’s diarrhoea

4. Enterohaemorrhagic E. coli 0157:H7—cause haemorrhagic colitis, haemolytic uremic syndrome, and thrombotic thrombocytopenic purpura

Hypoxic pulmonary vasoconstriction is a local response to hypoxia resulting primarily from constriction of small muscular pulmonary arteries in response to reduced alveolar oxygen tension. This unique response of pulmonary arterioles results in a local adjustment of perfusion to ventilation. This means that if a bronchiole is obstructed, the lack of oxygen causes contraction of the pulmonary vascular smooth muscle in the corresponding area, shunting blood away from the hypoxic region to better-ventilated regions. The purpose of hypoxic pulmonary vasoconstriction is to distribute blood flow regionally to increase the overall efficiency of gas exchange between air and blood.

The patient has a right groin hernia since he has a reducible lump and a history of carrying heavy objects.
Inguinal hernias present with a reducible lump in the groin.
A third of patients scheduled for surgery have no pain, and severe pain is uncommon (1.5% at rest and 10.2% on movement).
Inguinal hernias are at risk of irreducibility or incarceration, which may result in strangulation and obstruction; however, unlike with femoral hernias, strangulation is rare.
Inguinal hernias are often classified as direct or indirect, depending on whether the hernia sac bulges directly through the posterior wall of the inguinal canal (direct hernia) or passes through the internal inguinal ring alongside the spermatic cord, following the coursing of the inguinal canal (indirect hernia).

Surgery is the only curative treatment.
If patients with asymptomatic inguinal hernia are medically fit, they should be offered repair
Mesh repair is associated with the lowest recurrence rates of hernia
Laparoscopic repair is suggested for recurrent and bilateral inguinal hernias, though it may also be offered for primary inguinal hernia repair
The EuraHS recommendations:
– For Primary unilateral Hernia: Mesh repair, Lichtenstein or endoscopic repair are recommended. Endoscopic repair only if expertise is available.
– Primary bilateral: Mesh repair, Lichtenstein or endoscopic.
– Recurrent inguinal hernia: Mesh repair, modifying the technique with respect to the previous technique.
– If previously anterior: Consider open preperitoneal mesh or endoscopic approach (if expertise is present).
– If previously posterior: Consider an anterior mesh

In inguinal hernia tension-free repair, synthetic non-absorbable flat meshes (or composite meshes with a non-absorbable component) should be used.