Answer: Myofibroblasts

Fibroblasts are a type of cell which have mesenchymal origin and can exhibit either non-contractile or highly contractile phenotype. Under normal conditions, fibroblasts function to maintain tissue homeostasis by regulating the turnover of extracellular matrix (ECM). When tissues are injured, however, fibroblasts around the injured region differentiate into myofibroblasts, a type of highly contractile cells that produce abundant ECM proteins. While the mechanisms of wound healing are not completely understood, it has become clear that both fibroblasts and myofibroblasts play a critical role in the wound healing process. Specifically, the traction forces of fibroblasts and coordinated contraction of myofibroblasts are believed to be responsible for wound contraction and closure. However, excessive myofibroblast activity, accompanied by elevated levels of mechanical stress in the healing region, often causes scar tissue formation, and in the worst case, contracture of tissues (e.g. Dupuytren’s contracture), leading to local immobilization and loss of function.

Fractures of the distal tibia and fibula may result in loss of stability of the ankle joint. They may present as a fracture only, fracture and ligamentous injury, multiple fractures or a fracture dislocation.

Isolated fibular fractures at the level of the syndesmosis (Weber B) without associated medial injury should be placed in a short leg backslab (ankle at plantargrade) and remain NWB (non-weight bearing).

With medial malleolus fractures care should be taken to rule out any other fracture or injury around the ankle. The entire length of the fibula should be palpated and x-rayed to rule out any Maisonneuve type injuries. Any other fracture, ligament injury or talar shift indicate the fracture is likely to be unstable and should be reviewed by orthopaedics.

If medial malleolar injury is truly isolated then a short leg backslab (below knee plaster cast) should be applied and the patient is to remain NWB until orthopaedic review.

Achalasia is a failure of the lower oesophageal sphincter (LES) to relax that is caused by the degeneration of inhibitory neurons within the oesophageal wall. It is classified as either primary (idiopathic) or secondary (in the context of another disease). In patients with achalasia, the chief complaint is dysphagia to both solids and liquids, although regurgitation, retrosternal pain, and weight loss may also occur. Upper endoscopy, barium esophagram, and oesophageal manometry play complementary roles in the diagnosis of achalasia. While upper endoscopy and/or barium esophagram are often obtained initially, manometry usually confirms the diagnosis, and upper endoscopy is indicated to rule out a malignant underlying cause. In good surgical candidates, achalasia is usually treated with pneumatic dilation or myotomy. In most other cases, an injection of botulinum toxin is attempted. If these measures fail to provide relief, medical therapy (e.g., nifedipine) is indicated.

Lying on the palmer surfaces of the metacarpal bones are four palmar interossei which are smaller than the dorsal interossei. Arising from the entire length of the metacarpal bone of one finger, is a palmar interosseous, which is inserted into the side of the base of the first phalanx and the aponeurotic expansion of the extensor digitorum communis tendon to the same finger. All the interossei are innervated by the eighth cervical nerve, through the deep palmar branch of the ulnar nerve. The palmar interossei adducts the fingers to an imaginary line drawn longitudinally through the centre of the middle finger.

The lymphatics from the anus, skin of the perineum and the scrotum end in the superficial inguinal nodes. In case of a malignant growth of the anus, the superficial inguinal lymph nodes would most likely be enlarge.

The ‘nutcracker effect’ is only seen in one part of the alimentary canal, and that is in the third part of the duodenum. This can happen when the superior mesenteric artery that passes across the duodenum and the aorta, posteriorly to the third part of the duodenum enlarges and starts compressing the duodenum. The result is an obstructed duodenum that inhibits passage of food.

Pyrexia is a very common post operative finding and can most likely result from an infection. However, it is highly unlikely to occur as a result of ileus. Anastomotic leaks are uncommon after right sided colonic surgery. In this scenario atelectasis would be the most likely underlying cause, as open extended right hemicolectomies will necessitate a long midline incision.

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.

Hageman factor/factor XII in the intrinsic pathway activates prekallikrein and factor XI. Deficiency will not cause excessive bleeding as other coagulation factors will be utilized but the PTT will be greater than 200 seconds.
Thromboxane promotes platelet aggregation and causes vasoconstriction.
Plasmin, which is cleaved from plasminogen acts as an anticoagulant which breaks down thrombi.
Platelet activating factor promotes platelet aggregation and is also chemotactic to neutrophils.
Histamine acts as a vasodilator.
Platelet inhibiting factor acts an anticoagulant.
Renin is a hormone released from the kidney that causes vasoconstriction and water retention.

The rough endoplasmic reticulum is the factory for the manufacturing of proteins. It contains ribosomes attached to it and transports proteins that are destined for membranes and secretions. The rough ER is connected to the nuclear envelope and to the cisternae of the Golgi apparatus by vesicles that shuttle between the two compartments.

In a child 3 months to 12 years of age who is afebrile and well-appearing, it is reasonable to consider withholding empiric treatment if urine analysis (UA) is mildly positive or equivocal e.g.: leukocyte esterase (LE0 only, low WBC count) while awaiting culture results. Conversely, if the history is very consistent with UTI and positive UA, start treatment empirically.

Positive leukocyte esterase: very sensitive, but less specific for true infection (false positives are common)
Note: if no WBC on microscopy, more likely to be a false positive
Positive nitrite: high specificity for UTI, but lower sensitivity i.e. positive nitrite means likely UTI, but negative nitrite does not rule out UTI

Can also see positive nitrite in contaminated specimen if left at room temperature for too long
• Positive blood and protein: not specific for UTI
• Microscopy:>10 WBC/mm3 is suggestive of UTI

Management
– A single isolated UTI (in girls) may be managed expectantly.
– > 2 UTI’s (or 1 in males) in a 6 month period should prompt further testing.
– Voiding cystourethrograms show the greatest anatomical detail and is the ideal first line test in males; isotope cystography has a lower radiation dose and is the first line test in girls.
– USS should also be performed.
– Renal cortical scintigraphy should be performed when renal scarring is suspected.

Under the influence of oestrogen in pregnancy, there is an increase in the number of lobules which will facilitate lactation.
Steatocytes occur due to loss of weight and nutritional deficit.
Metaplasia is a normal physiological process which is due to a change in normal epithelium with another type.
Lobular atrophy will result in a decreased capacity to provide milk.

The sciatic nerve supplies both gemellae, quadratus femoris, semitendinosus, semimembranosus, both heads of the biceps femoris, the hamstring half of abductor magnus and obturator internus. Obturator externus is supplied by the obturator nerve.

Achalasia is an oesophageal motor disorder characterized by aperistalsis of the oesophageal body and lack of relaxation of the lower sphincter in response to swallows.
Achalasia cardia is one of the common causes of motor dysphagia. Pathophysiologically, achalasia cardia is caused by loss of inhibitory ganglion in the myenteric plexus of the oesophagus. In the initial stage, degeneration of inhibitory nerves in the oesophagus results in unopposed action of excitatory neurotransmitters such as acetylcholine, resulting in high amplitude non-peristaltic contractions (vigorous achalasia); progressive loss of cholinergic neurons over time results in dilation and low amplitude simultaneous contractions in the oesophageal body (classic achalasia).

Sputum cytology is a diagnostic test used for the examination of sputum under a microscope to determine if abnormal cells are present. It may be used as the first diagnostic procedure to help detect a suspected lung cancer or certain non-cancerous lung conditions.

The possible causes of post-operative pneumothorax after thoracotomy and esophagectomy include lung parenchymal leak/injury, bronchopleural fistula, ruptured bullae and malpositioned chest drains. When suction is applied to the chest drainage system, active and persistent bubbling may be seen. Although an anastomotic leak may produce a small pneumothorax, a large volume air leak is more indicative of lung injury.

The posterior humeral circumflex artery arises from the axillary artery and runs with the axillary nerve through the quadrangular space which is bounded laterally by the surgical neck of the humerus. After winding around the surgical neck of the humerus, it is distributed to the deltoid muscle and the shoulder joint. Thus fractures in the surgical neck of the humerus could result in an injury to this artery.

The ilioinguinal nerve doesn’t pass through the deep inguinal ring but enters the inguinal canal from the side and leaves by passing through the superficial ring thus it is at risk of injury during inguinal hernia repair.
The femoral branch of genitofemoral nerve travels lateral to the superficial inguinal ring.
The iliohypogastric nerve and the subcostal nerve travel superior to the inguinal canal and superficial inguinal ring.
The obturator nerve is a branch of the lumbar plexus that innervates the muscles of the thigh.

As most of the coagulation factors are synthesized in the liver, liver diseases like hepatitis or cirrhosis will depress the coagulation system. Vitamin K deficiency can also decrease the production of vitamin K dependent coagulation factors VII, XI, X and prothrombin.

Anterior cruciate ligament (ACL) injuries are most often a result of low-velocity, noncontact, deceleration injuries and contact injuries with a rotational component. Contact sports also may produce injury to the ACL secondary to twisting, valgus stress, or hyperextension all directly related to contact or collision.

Symptoms of an acute ACL injury may include the following:
– Feeling or hearing a “pop” sound in the knee
– Pain and inability to continue the activity
– Swelling and instability of the knee
– Development of a large hemarthrosis

Differential Diagnoses
A- Medial Collateral Knee Ligament Injury
Contact, noncontact, and overuse mechanisms are involved in causing MCL injuries.
Contact injuries involve a direct valgus load to the knee. This is the usual mechanism in a complete tear.
Noncontact, or indirect, injuries are observed with deceleration, cutting, and pivoting motions. These mechanisms tend to cause partial tears.
Overuse injuries of the MCL have been described in swimmers. The whip-kick technique of the breaststroke has been implicated. This technique involves repetitive valgus loads across the knee.

B- Posterior Cruciate Ligament Injury
Knowledge of the mechanism of injury is helpful. The following 4 mechanisms of PCL injury are recognized:
– A posteriorly directed force on a flexed knee, e.g., the anterior aspect of the flexed knee striking a dashboard, may cause PCL injury.
– A fall onto a flexed knee with the foot in plantar flexion and the tibial tubercle striking the ground first, directing a posterior force to the proximal tibia, may result in injury to the PCL.
– Hyperextension alone may lead to an avulsion injury of the PCL from the origin. This kind of injury may be amenable to repair.
– An anterior force to the anterior tibia in a hyperextended knee with the foot planted results in combined injury to the knee ligaments along with knee dislocation.

In chronic PCL tears, discomfort may be experienced with the following positions or activities:
– A semi flexed position, as with ascending or descending stairs or an incline
– Starting a run
– Lifting a load
– Walking longer distances
– Retro patellar pain symptoms may be reported as a result of posterior tibial sagging.
– Swelling and stiffness may be reported in cases of chondral damage.
– Individuals may describe a sensation of instability when walking on uneven ground
– Medial joint line pain may be reported.

The facial muscles generally originate from the facial bones and attach to the skin, in the same plane as the platysma muscle. They are all innervated by cranial nerve VII (the facial nerve). The occipitofrontalis muscle consists of two parts: The occipital belly, near the occipital bone, and the frontal belly, near the frontal bone.

Ligation of middle rectal artery is most likely to affect the blood supply of seminal vesicles since arteries supplying the seminal vesicles are derived from the middle and inferior vesical and middle rectal arteries.

Heparin is a natural highly-sulphated glycosaminoglycan that has anticoagulant functions. It is produced by the body basophils and mast cells.

Non-neoplastic proliferation of leucocytes causes an increase in leukocyte alkaline phosphatase (LAP). This is referred to as ‘leukemoid reaction’ because of the similarity to leukaemia with an increased white cell count (>50 × 109/l) with immature forms. Causes of leukemoid reaction includes haemorrhage, drugs (glucocorticoids, all-trans retinoic acid etc), infections such as tuberculosis and pertussis, and as a paraneoplastic phenomenon. Leukemoid reaction can also be seen in infancy as a feature of trisomy 21. This is usually a benign condition, but can be a response to a disease state. Differential diagnosis include chronic myelogenous leukaemia (CML).

Alpha-1 antitrypsin (A1AT) deficiency is a condition characterised by the lack of a protein that protects the lungs and liver from damage, called alpha1-antytripsin. The main complications of this condition are liver diseases such as cirrhosis and chronic hepatitis, due to accumulation of abnormal alpha 1-antytripsin and emphysema due to loss of the proteolytic protection of the lungs.

Answer: Mittelschmerz

Mittelschmerz is midcycle abdominal pain due to leakage of prostaglandin-containing follicular fluid at the time of ovulation. It is self-limited, and a theoretical concern is treatment of pain with prostaglandin synthetase inhibitors, which could prevent ovulation. The pain of mittelschmerz usually occurs in the lower abdomen and pelvis, either in the middle or to one side. The pain can range from a mild twinge to severe discomfort and usually lasts from minutes to hours. In some cases, a small amount of vaginal bleeding or discharge might occur. Some women have nausea, especially if the pain is very strong.
Diagnosis of pelvic pain in women can be challenging because many symptoms and signs are insensitive and nonspecific. As the first priority, urgent life-threatening conditions (e.g., ectopic pregnancy, appendicitis, ruptured ovarian cyst) and fertility-threatening conditions (e.g., pelvic inflammatory disease, ovarian torsion) must be considered.
Many women never have pain at ovulation. Some women, however, have mid-cycle pain every month, and can tell by the pain that they are ovulating.
As an egg develops in the ovary, it is surrounded by follicular fluid. During ovulation, the egg and the fluid, as well as some blood, are released from the ovary. While the exact cause of mittelschmerz is not known, it is believed to be caused by the normal enlargement of the egg in the ovary just before ovulation. Also, the pain could be caused by the normal bleeding that comes with ovulation.
Pelvic inflammatory disease can be ruled out if the patient is not sexually active.

Chylothorax is a potentially lethal condition characterized by fluid (chyle) accumulation in the pleural cavity, resulting from disruption of lymphatic drainage in the thoracic duct. Chyle is a fluid rich in triglycerides and chylomicrons and can originate from the thorax, the abdomen or both. Malignant tumours, especially lymphoma, are the most common causes of nontraumatic chylothorax. Bronchogenic carcinoma and trauma are the most common causes after lymphomas. Other rare causes of chylothorax are; granulomatous diseases, tuberculosis, congenital malformations, nephrotic syndrome, hypothyroidism, cirrhosis, decompensated heart failure and idiopathic chylothorax.

Colorectal cancer is one of the most common types of cancer in Western populations. The liver is the first location of metastatic disease; as the main mechanism of dissemination is through the portal system. In addition, the liver may be the sole site of metastasis in 30 to 40% of patients with advanced disease.

Unfortunately, 20% of these patients will develop metastasis in the lungs and >50% in liver. In 20 to 25% of patients at the time of diagnosis, hepatic metastatic disease can be identified clinically, and 40 to 50% will develop during the first 3 years after the primary tumour is diagnosed.
When metastatic lesions are localized in the liver, which corresponds to 30% of patients, there are several options for localized treatment, such as hepatic partial resection, localized ablative therapy, administration of chemotherapy by infusion of the hepatic artery, systemic chemotherapy, and isolated hepatic fusion for patients with high doses of chemotherapy. Surgical resection is the most effective treatment for hepatic metastasis in colorectal cancer, but only a few patients are candidates for initial surgery. Patients with hepatic metastasis that cannot be surgically resected are managed initially with chemotherapy and later are subject to surgery, and these patients present a similar survival rate to those undergoing surgery initially.
Prior to hepatic resection, patients with hepatic metastatic disease frequently receive neoadjuvant chemotherapy, which can aid in disappearing or hidden radiological lesions.
The 5-year survival rate after hepatic resection is 25-40%.

Desmopressin is useful in managing mild to moderate episodes of bleeding in von Willebrand disease (vWD).

vWD is the most common hereditary coagulopathy resulting from the deficiency or abnormal function of von Willebrand factor (vWF). vWF promotes platelet adhesion to damaged endothelium and other platelets and is also involved in the transport and stabilization of factor VIII.

There are seven subtypes of vWD. Type 1 vWD (autosomal dominant) is the most common and accounts for 80% of the cases. Type 2 vWD (autosomal dominant or recessive) accounts for 15% of the cases. There is a significant spectrum of severity ranging from spontaneous bleeding and epistaxis through to troublesome excessive bleeding following minor procedures.

Bleeding time is mostly used as a diagnostic test for vWD. Treatment options include administration of tranexamic acid for minor cases undergoing minor procedures. More significant bleeding or procedures respond well to desmopressin (DDAVP). It is most effective in type 1 vWD, less effective in type 2 and contraindicated in type 2B. Individuals who cannot have desmopressin or in whom it is contraindicated usually receive factor VIII concentrates containing vWF.

Answer: Undertake an open inguinal herniotomy

Inguinal hernia is a type of ventral hernia that occurs when an intra-abdominal structure, such as bowel or omentum, protrudes through a defect in the abdominal wall. Inguinal hernias do not spontaneously heal and must be surgically repaired because of the ever-present risk of incarceration. Generally, a surgical consultation should be made at the time of diagnosis, and repair (on an elective basis) should be performed very soon after the diagnosis is confirmed.

The infant or child with an inguinal hernia generally presents with an obvious bulge at the internal or external ring or within the scrotum. The parents typically provide the history of a visible swelling or bulge, commonly intermittent, in the inguinoscrotal region in boys and inguinolabial region in girls. The swelling may or may not be associated with any pain or discomfort.

Open herniotomy is its standard treatment against which all alternative modalities of treatment are evaluated. It is credited with being easy to perform, having a high success rate, and low rate of complications.
The use of prosthetic mesh in these patients is rare, however not uncalled for. Laparoscopic inguinal herniotomy is significantly associated with longer operative time for unilateral cases and a reduction in metachronous hernia development when compared to open inguinal herniotomy. There was a trend towards higher recurrence rate for laparoscopic repairs and shorter operative time for bilateral cases. A well conducted randomized controlled trial is warranted to compare both approaches.

Answer: Beta 2 transferrin assay

Beta-2-transferrin is a protein found only in CSF and perilymph. Since 1979, beta-2-transferrin has been used extensively by otolaryngologists in the diagnosis of CSF rhinorrhoea and skull-base cerebrospinal fluid fistulas. With sensitivity of 94% – 100%, and specificity of 98% – 100%, this assay has become the gold standard in detection of CSF leakage. CSF rhinorrhoea is characterized by clear or xanthochromic watery rhinorrhoea that may not become apparent until nasal packing is removed.

The Monteggia fracture refers to a dislocation of the proximal radio-ulnar joint (PRUJ) in association with a forearm fracture, most commonly a fracture of the ulna. Depending on the type of fracture and severity, they may experience elbow swelling, deformity, crepitus, and paraesthesia or numbness. Some patients may not have severe pain at rest, but elbow flexion and forearm rotation are limited and painful.
The dislocated radial head may be palpable in the anterior, posterior, or anterolateral position. In Bado type I and IV lesions, the radial head can be palpated in the antecubital fossa. The radial head can be palpated posteriorly in type II lesions and laterally in type III lesions.

Colles’ fractures have the following 3 features:
– Transverse fracture of the radius
– 1 inch proximal to the radio-carpal joint
– Dorsal displacement and angulation

Smith’s fracture (reverse Colles’ fracture)
– Volar angulation of distal radius fragment (Garden spade deformity)
– Caused by falling backwards onto the palm of an outstretched hand or falling with wrists flexed

Bennett’s fracture
– Intra-articular fracture of the first carpometacarpal joint
– Impact on flexed metacarpal, caused by fist fights
– X-ray: triangular fragment at ulnar base of metacarpal

Galeazzi fracture
– Radial shaft fracture with associated dislocation of the distal radioulnar joint

Pott’s fracture
– Bimalleolar ankle fracture
– Forced foot eversion

Barton’s fracture
– Distal radius fracture (Colles’/Smith’s) with associated radiocarpal dislocation
– Fall onto extended and pronated wrist
– Involvement of the joint is a defining feature

Ewing’s sarcoma is formed by small, round, blue cells, and is common in children. The usually develop in limbs, and clinical findings include pain and inflammation, with lytic destruction showing up on X-rays.

Dead space refers to inhaled air that does not take part in gas exchange. Because of this dead space, taking deep breaths slowly is more effective for gas exchange than taking quick, shallow breaths where a large proportion is dead space. Use of a snorkel by a diver increases the dead space marginally. Anatomical dead space refers to the gas in conducting areas such as mouth and trachea, and is roughly 150 ml (2.2 ml/kg body weight). This corresponds to a third of the tidal volume (400-500 ml). It can be measured by Fowler’s method, a nitrogen wash-out technique. It is posture-dependent and increases with increase in tidal volume. Physiological dead space is equal to the anatomical dead space plus the alveolar dead space, where alveolar dead space is the area in the alveoli where no effective exchange takes place due to poor blood flow in capillaries. This physiological dead space is very small normally (< 5 ml) but can increase in lung diseases. Physiological dead space can be measured by Bohr’s method. Total ventilation per minute (minute ventilation) is given by the product of tidal volume and the breathing rate. Here, the total ventilation is 600 ml times 12 breaths/min = 7200 ml/min. The problem mentions alveolar ventilation to be 6000 ml/min. Thus, the difference between the alveolar ventilation and total ventilation is 7200 – 6000 ml/min = 1200 ml/min, or 100 ml per breath at 12 breaths per min. This 100 ml is the dead space volume.

The internal auditory meatus provides a passage through which the vestibulocochlear nerve, the facial nerve, and the labyrinthine artery (an internal auditory branch of the basilar artery) can pass from inside the skull to structures of the inner ear and face.

Containment of fistula output and skin protection should be instituted as soon as the diagnosis is made as it will decrease local skin excoriation and inflammation, pain and infection. While low output fistulas may be controlled with a simple absorbent dressing, complex fistulas often require advanced techniques including barrier creams, powders, and sealants to protect the skin from auto-digestion as well as bridging for fistula isolation, topographical enhancements, and complex pouching systems with or without sump drainage
Fistulas arising from the oesophagus, duodenal stump after gastric resection, pancreaticobiliary tract, and jejunum are more likely to close without operative intervention. Additionally, those with long tracts and small enteric wall defects are associated with higher spontaneous closure rates. Fistulas in the colon show favourable rates of spontaneous resolution.

Seminoma is the most radiosensitive tumour and responds well to radiation therapy after unilateral orchidectomy. The ipsilateral inguinal areas are routinely not treated however, depending on the stage, the mediastinum and the left supraclavicular regions may also be irradiated.

High anion gap in metabolic acidosis is caused generally by the elevation of the levels of acids like ketones, lactate, sulphates in the body, which consume the bicarbonate ions. Other causes of a high anion gap include overdosing on salicylates, uraemia, rhabdomyolysis, hypocalcaemia, hypomagnesaemia, or ingestion of toxins such as ethylene glycol, methanol, propyl alcohol, cyanide and iron.

Cardiac notch: is an indentation on the left lung of the heart.
Coronary sinus: a venous sinus on the surface of the heart (the posterior aspect) that receives blood from the smaller veins that drain the heart.
Coronary sulcus: a groove on the heart between the atria and ventricles.
Transverse pericardial sinus: located behind the aorta and pulmonary trunk and anterior to the superior vena cava.
Oblique pericardial sinus: located behind the left atrium. Accessed from the inferior side (or the apex) of the heart upwards.
Horizontal pericardial sinus: this is a made-up term.

The pathogen that most likely causes recurrent urinary tract infection in young women are E. coli, Enterococcus and Staphylococcus saprophyticus.

Nimodipine, a calcium-channel antagonist with a relatively selective vasodilatory effect on cerebral blood vessels, has been approved for improvement of neurologic deficits due to spasm following subarachnoid haemorrhage. Oral nimodipine is the most studied calcium channel blocker for prevention of vasospasm after Subarachnoid haemorrhage.
An American Heart Association/American Stroke Association guideline recommends its use for this purpose (class I, level of evidence A). Calcium channel blockers have been shown to reduce the incidence of ischemic neurologic deficits, and nimodipine has been shown to improve overall outcome within 3 months of aneurysmal SAH. Calcium channel blockers and other antihypertensives should be used cautiously to avoid the deleterious effects of hypotension.

The muscles of the back of the leg are subdivided into two groups: superficial and deep. Superficial muscles include gastrocnemius, soleus and plantaris. Deep muscles include tibialis posterior, flexor hallucis longus, flexor digitorum longus and popliteus. The superficial ( calf muscles) which are responsible for plantarflexion of the foot are supplied by the tibial nerve as follows: the gastrocnemius and soleus muscles are supplied by the first and second sacral nerves and the plantaris by the fourth and fifth lumbar and first sacral nerve (the tibial nerve).

Adrenal adenomas are benign tumours of the adrenal glands, which can be either functioning or non-functioning. Though the majority are clinically silent, functional adenomas from the cortex of medulla can lead to overproduction of any of their associated hormones. Benign adenomas often have a lipid rich core that is readily identifiable on CT scanning. In addition the nodules are often well circumscribed.

Electroencephalography (EEG) is the neurophysiological measurement of the electrical activity of the brain. It is done by placing electrodes on the scalp or subdurally. In reality, the electrical currents are not measured, but rather the voltage differences between different parts of the brain. Four major types of EEG activity are recognized, which are alpha, beta, delta and theta.
Alpha waves, also known as Berger’s waves ranges in frequency from 8-12 Hz. Best detected with eyes closed, alpha waves are characteristic of a relaxed, alert state of consciousness. An alpha-like normal variant called mu is sometimes seen over the motor cortex (central scalp) and attenuates with movement or, rather, with the intention to move.

Penicillins and cephalosporins (e.g. cefuroxime, cefotaxime, ceftriaxone) inhibit bacterial cell wall synthesis through the inhibition of peptidoglycan cross-linking.
Macrolides (e.g. erythromycin), tetracyclines, aminoglycosides and chloramphenicol act by interfering with bacterial protein synthesis.
Sulphonamides (e.g. trimethoprim, co-trimoxazole) work by inhibiting the synthesis of nucleic acid

Flow in any vessel = Effective perfusion pressure divided by resistance, where effective perfusion pressure is the mean intraluminal pressure at the arterial end minus the mean pressure at the venous end. Thus, in the given problem, resistance = (60 − 20)/200 = 0.2 mmHg/ml per min.

Sodium bicarbonate is indicated in the management of metabolic acidosis, which may occur in severe renal disease, uncontrolled diabetes, circulatory insufficiency due to shock or severe dehydration, extracorporeal circulation of blood, cardiac arrest and severe primary lactic acidosis. Bicarbonate is given at 50-100 mmol at a time under scrupulous monitoring of the arterial blood gas readings. This intervention, however, has some serious complications including lactic acidosis, and in those cases, should be used with great care.

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.

A foreign body reaction Is characteristic of giant cells. Glass being the foreign object initiates an inflammatory response in this condition.
Mast cells are involved in allergic reactions.
Eosinophils are characteristic of a parasitic infection and allergic inflammatory process but are not due to foreign bodies.
Plasma cells are typical of chronic inflammation.
Lymphocytes are involved in viral infections.
Macrophages combine together to form giant cells.

Anal fissure is a tear in the anoderm distal to the dentate line. It is the most common cause of severe anal pain. It is equally one of the most common reasons for bleeding per anus in infants and young children. The pain of an anal ulcer is intolerable and always disproportionate to the severity of the physical lesion. It may be so severe that patients may avoid defecation for days together until it becomes inevitable. This leads to hardening of the stools, which further tear the anoderm during defecation, setting a vicious cycle. The fissures can be classified into 1] Acute or superficial and 2] Chronic fissure in ano.

Initial therapy for an anal fissure is medical, and more than 80% of acute anal fissures resolve without further therapy.
The goals of treatment are to relieve the constipation and to break the cycle of hard bowel movement, associated pain, and worsening constipation. Softer bowel movements are easier and less painful for the patient to pass.

First-line medical therapy consists of therapy with stool-bulking agents, such as fibre supplementation and stool softeners. Laxatives are used as needed to maintain regular bowel movements. Mineral oil may be added to facilitate passage of stool without as much stretching or abrasion of the anal mucosa, but it is not recommended for indefinite use. Sitz baths after bowel movements and as needed provide significant symptomatic relief because they relieve some of the painful internal sphincter muscle spasm.
Recurrence rates are in the range of 30-70% if the high-fibre diet is abandoned after the fissure is healed. This range can be reduced to 15-20% if patients remain on a high-fibre diet.

Second-line medical therapy consists of intra-anal application of 0.4% nitroglycerin (NTG; also called glycerol trinitrate) ointment directly to the internal sphincter.
Some physicians use NTG ointment as initial therapy in conjunction with fibre and stool softeners, and others prefer to add it to the medical regimen if fibre and stool softeners alone fail to heal the fissure. NTG ointment is thought to relax the internal sphincter and to help relieve some of the pain associated with sphincter spasm; it also is thought to increase blood flow to the anal mucosa.
Unfortunately, many people cannot tolerate the adverse effects of NTG, and as a result, its use is often limited. The main adverse effects are headache and dizziness; therefore, patients should be instructed to use NTG ointment for the first time in the presence of others or directly before bedtime.
Analogous to the use of NTG intra-anal ointment, nifedipine ointment is also available for use in clinical trials. It is thought to have similar efficacy to NTG ointment but with fewer adverse effects.

Botulinum toxin has been used to treat acute and chronic anal fissures. It is injected directly into the internal anal sphincter, in effect performing a chemical sphincterotomy. The effect lasts about 3 months, until nerve endings regenerate. This 3-month period may allow acute fissures (and sometimes chronic fissures) to heal and symptoms to resolve. If botulinum toxin injection provides initial relief of symptoms but there is a recurrence after 3 months, the patient may benefit from surgical sphincterotomy.

Surgical therapy is usually reserved for acute anal fissures that remain symptomatic after 3-4 weeks of medical therapy and for chronic anal fissures.
Sphincter dilatation
Lateral internal sphincterotomy