Thirst is the basic need or instinct to drink. It arises from a lack of fluids and/or an increase in the concentration of certain osmolites such as salt. If the water volume of the body falls below a certain threshold or the osmolite concentration becomes too high, the brain signals thirst. Excessive thirst, known as polydipsia, along with excessive urination, known as polyuria, may be an indication of diabetes. Angiotensin II is a hormone that is a powerful dipsogen (i.e. it stimulates thirst) that acts via the subfornical organ. It increases secretion of ADH in the posterior pituitary and secretion of ACTH in the anterior pituitary.

The complications of central vein catheterization (CVC) include infection, thrombosis, occlusion, and, in particular, mechanical complications which usually occur during insertion and are closely related to the anatomic location of the central veins. Infectious complications are reported to occur in 5% to 26% of patients, mechanical complications in 5% to 19%, and thrombotic complications in 2% to 26%. Mechanical complications associated with the insertion of central lines include arterial puncture, hematoma, haemothorax, pneumothorax, arterial-venous fistula, venous air embolism, nerve injury, thoracic duct injury (left side only), intraluminal dissection, and puncture of the aorta
Pneumothorax is one of the most common CVC insertion complications, reportedly representing up to 30% of all mechanical adverse events of CVC insertion.
Clinician-performed bedside US allows the diagnosis of pneumothorax to be made immediately, with a high degree of sensitivity and with better accuracy than supine chest films and equal to that of CT scan.
Tension pneumothorax is classically characterized by hypotension and hypoxia. On examination, breath sounds are absent on the affected haemothorax and the trachea deviates away from the affected side. The thorax may also be hyper resonant; jugular venous distention and tachycardia may be present.
If a pneumothorax is diagnosed the treatment strategy should be determined by the following factors: (I) size; (II) symptoms; (III) spontaneous breathing or use of mechanical ventilation; (IV) clinical diagnosis of a tension pneumothorax.

Treatment consisted of: (I) observation; (II) outpatient insertion of a Heimlich valve; (III) inpatient tube thoracostomy.

The inferior epigastric artery comes from the external iliac artery just above the inguinal ligament to curve forward in the subperitoneal tissue and then ascend obliquely along the medial margin of the deep inguinal ring. It continues to ascend between the rectus abdominis and the posterior lamella of its sheath after piercing the fascia transversalis and passing anterior to the linea semicircularis. Finally it gives off numerous branches that anastomose above the umbilicus with the superior epigastric branch of the internal mammary artery and with the lower intercostal arteries. As this artery ascends obliquely upwards from its origin it lies along the lower medial margins of the deep inguinal ring and posterior to the start of the spermatic cord. It is found in the preperitoneal fat of the abdomen lying just superficial to the peritoneum and forms the lateral umbilical fold. Hernias that pass lateral to this are indirect and medial to this, direct hernias.
The deep circumflex artery travels along the iliac crest on the inner surface of the abdominal wall. It is very lateral to the abdominal wall and hernias would pass medial to it.
The superficial circumflex iliac, superficial epigastric, superficial external pudendal arteries are all superficial arteries found in the superficial fascia.

Superficial burns are confined in the depth of the epidermis, and all dermal appendages and nerve endings are intact. Superficial burns generally heal in 3 to 5 days with minimal intervention and do not leave significant scarring as they typically heal by re epithelialization. Therefore the sweat glands will be intact.

The boundaries of the posterior mediastinum are: the superiorly through the sternal angle and T4/5, inferiorly, the diaphragm, anteriorly, by the middle mediastinal structures and posteriorly by the spinal cord. Structures in the posterior mediastinum include the descending thoracic aorta, the azygos system, oesophagus, thoracic duct and lymph nodes. The great vessels and structures at the root of the lung are part of the middle mediastinum. The oesophagus is the only structure in the posterior mediastinum among the choices.

Early ECG changes of hyperkalaemia, typically seen at a serum potassium levels of 5.5-6.5 mEq/L, include the following:
– Tall, peaked T waves with a narrow base (best seen in precordial leads)
– Shortened QT interval
– ST-segment depression

Capillaries are the smallest of the body’s blood vessels, measuring 5–10 μm and they help to enable the exchange of water, oxygen, carbon dioxide, and many other nutrients and waste substances between the blood and the tissues surrounding them. The walls of capillaries are composed of only a single layer of cells, the endothelium. Ion channels are pore-forming proteins that help to establish and control the small voltage gradient that exists across the plasma membrane of all living cells by allowing the flow of ions down their electrochemical gradient. An ion channel is an integral membrane protein or more typically an assembly of several proteins. The archetypal channel pore is just one or two atoms wide at its narrowest point. It conducts a specific ion such as sodium or potassium and conveys them through the membrane in single file.

The muscles of the superficial posterior compartment of the leg form the characteristic ‘calf’ shape of the posterior leg and include the gastrocnemius, soleus and plantaris. The gastrocnemius and soleus together form a muscular mass which is occasionally described as the triceps surae; its tendon of insertion is the tendo calcaneus. The tendo calcaneus is the thickest and strongest in the body and together with the tendon of the plantaris muscle is inserted into the posterior part of the calcaneus.

Virginal breast hypertrophy’ is the term assigned to excessive growth of breasts during puberty and is a common phenomenon. It is also known as ‘juvenile macromastia’ or ‘ juvenile gigantomastia’. The breast hypertrophy often starts with menarche and occasionally occurs in growth spurts. These spurts can cause physical discomfort, red and itchy skin or pain in the breasts. The breasts can also grow continuously over several years and lead to overdevelopment of a normal breast. Nipples also undergo enlargement along with the breasts.

The pain could have been caused by the urinary bladder, uterus/cervix/vagina or rectum as it involves the pelvic viscera.

Iron deficiency anaemia (IDA) is the most common form of anaemia worldwide and can be due to inadequate intake, decreased absorption (e.g., atrophic gastritis, inflammatory bowel disease), increased demand (e.g., during pregnancy), or increased loss (e.g., gastrointestinal bleeding, menorrhagia) of iron. Prolonged deficiency depletes the iron stores in the body, resulting in decreased erythropoiesis and anaemia.
Symptoms are nonspecific and include fatigue, pallor, lethargy, hair loss, brittle nails, and pica. Diagnostic lab values include low haemoglobin, microcytic, hypochromic red blood cells on peripheral smear, and low ferritin and iron levels. Once diagnosed, the underlying cause should be determined. Patients at risk for underlying gastrointestinal malignancy should also undergo a colonoscopy.
Iron deficiency anaemia is treated with oral (most common) or parenteral iron supplementation. Severe anaemia or those with concomitant cardiac conditions may also require blood transfusions. The underlying cause of IDA should also be corrected. IDA may manifest as Plummer-Vinson syndrome (PVS): triad of postcricoid dysphagia, upper oesophageal webs, and iron deficiency anaemia

Adductor canal compression syndrome most commonly presents in young males, and it is important to differentiate it from acute limb ischaemia on exertion. Of the listed options, popliteal fossa entrapment is the main differential diagnosis. However, the popliteal pulse disappears when the knee is fully extended in popliteal fossa entrapment.

Adductor canal compression syndrome is caused by compression of the femoral artery by the musculotendinous band of adductor magnus muscle. The treatment consists of division of the abnormal band and restoration of the arterial circulation.

Epidural hematoma (EDH) is a traumatic accumulation of blood between the inner table of the skull and the stripped-off dural membrane. EDH results from a traumatic head injury, usually with an associated skull fracture and arterial laceration. The inciting event often is a focused blow to the head, such as that produced by a hammer or baseball bat. In 85-95% of patients, this type of trauma results in an overlying fracture of the skull. Blood vessels in close proximity to the fracture are the sources of the haemorrhage in the formation of an epidural hematoma. Because the underlying brain has usually been minimally injured, prognosis is excellent if treated aggressively. Outcome from surgical decompression and repair is related directly to patient’s preoperative neurologic condition.

This is likely a case of epididymo-orchitis which usually occurs due to infection with gonorrhoea or chlamydia in this age group (<35 years). Epididymo-orchitis is an acute inflammation of the epididymis and often involves the testis. It is usually caused by bacterial infection which spreads from the urethra or bladder. Amiodarone is a recognised non-infective cause of epididymitis, which resolves on stopping the drug. On examination, tenderness is usually confined to the epididymis, which may facilitate differentiating it from torsion where pain usually affects the entire testis.

An inguinal hernia is a common condition requiring surgical repair in the paediatric age group.
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. More commonly, no pain is associated with a simple inguinal hernia in an infant. The parents may perceive the bulge as being painful when, in truth, it causes no discomfort to the patient.
The bulge commonly occurs after crying or straining and often resolves during the night while the baby is sleeping.
Indirect hernias are more common on the right side because of delayed descent of the right testicle. Hernias are present on the right side in 60% of patients, on the left is 30%, and bilaterally in 10% of patients.
Physical examination of a child with an inguinal hernia typically reveals a palpable smooth mass originating from the external ring lateral to the pubic tubercle. The mass may only be noticeable after coughing or performing a Valsalva manoeuvre, and it should be reduced easily. Occasionally, the examining physician may feel the loops of intestine within the hernia sac. In girls, feeling the ovary in the hernia sac is not unusual; it is not infrequently confused with a lymph node in the groin region. In boys, palpation of both testicles is important to rule out an undescended or retractile testicle.
In boys, differentiating between a hernia and a hydrocele is not always easy. Transillumination has been advocated as a means of distinguishing between the presence of a sac filled with fluid in the scrotum (hydrocele) and the presence of bowel in the scrotal sac. However, in cases of inguinal hernia incarceration, transillumination may not be beneficial because any viscera that is distended and fluid-filled in the scrotum of a young infant may also transilluminate. A rectal examination may be helpful if intestine can be felt descending through the internal ring.
A femoral hernia can be very difficult to differentiate from an indirect inguinal hernia. Its location is below the inguinal canal, through the femoral canal. The differentiation is often made only at the time of operative repair, once the anatomy and relationship to the inguinal ligament are clearly visualized. The signs and symptoms for femoral hernias are essentially the same as those described for indirect inguinal hernias.

Severe abdominal pain tends to favour infection with Campylobacter jejuni.

Infection with Campylobacter jejuni is one of the most common causes of gastroenteritis worldwide. In developed countries, the incidence of Campylobacter jejuni infections peaks during infancy and, again, during early adulthood. Most infections are acquired by the consumption and handling of poultry. A typical case is characterized by diarrhoea, fever, and severe abdominal cramps. Obtaining cultures of the organism from stool samples remains the best way to diagnose this infection. Complications of C. jejuni infections are rare, and most patients do not require antibiotics. Careful food preparation and cooking practices may prevent some Campylobacter infections.

Primary aldosteronism, also known as primary hyperaldosteronism or Conn’s syndrome, is excess production of the hormone aldosterone by the adrenal glands resulting in low renin levels. Most patients with primary aldosteronism (Conn’s syndrome) have an adrenal adenoma. The increased plasma aldosterone concentration leads to increased renal Na+ reabsorption, which results in plasma volume expansion. The increase in plasma volume suppresses renin release from the juxtaglomerular apparatus and these patients usually have low plasma renin levels. Salt restriction and upright posture decrease renal perfusion pressure and therefore increases renin release from the juxtaglomerular apparatus. Secondary aldosteronism is due to elevated renin levels and may be caused by heart failure or renal artery stenosis.

Acute aortic dissection is a serious condition in which the inner layer of the aorta tears and the blood flows in between the inner and middle layers of the aorta causing their separation (dissection). Aortic dissection can lead to rupture or decreased blood flow to organs. Clinical manifestations most often include the sudden onset of severe, tearing or ripping chest pain that can radiate to the shoulder, back or neck; syncope; altered mental status; dyspnoea; pale skin; stroke symptoms etc. The diagnosis of acute aortic dissection is based on clinical findings, imaging studies, electrocardiography and laboratory analysis.

Benign giant-cell tumours tend to affect adults in their twenties and thirties, occur in the epiphyses and can erode the bone and extend into the soft tissues. These tumours have a strong tendency to recur.

Mesenteric venous thrombosis (MVT) is a blood clot in one or more of the major veins that drain blood from the intestine. The superior mesenteric vein is most commonly involved. The exact cause of MVT is unknown. However, there are many diseases that can lead to MVT. Many of the diseases cause swelling (inflammation) of the tissues surrounding the veins, and include:
Appendicitis
Cancer of the abdomen
Diverticulitis
Liver disease with cirrhosis
High blood pressure in the blood vessels of the liver
Abdominal surgery or trauma
Pancreatitis
Inflammatory bowel disorders
Heart failure
Protein C or S deficiencies
Polycythaemia vera
Essential thrombocythemia
People who have disorders that make the blood more likely to stick together (clot) have a higher risk for MVT. Birth control pills and oestrogen medicines also increase risk.

MVT is more common in men than women. It mainly affects middle aged or older adults. Symptoms may include any of the following:
Abdominal pain, which may get worse after eating and over time; Bloating; Constipation; Bloody diarrhoea; Fever; Septic shock; Lower gastrointestinal bleeding; Vomiting and nausea.
Blood thinners (most commonly heparin or related medicines) are used to treat MVT when there is no associated bleeding. In some cases, medicine can be delivered directly into the clot to dissolve it. This procedure is called thrombolysis. Less often, the clot is removed by thrombectomy.

The latissimus dorsi receives blood from the thoracodorsal artery, the supraspinatus receives its blood from the suprascapular artery, the levator scapulae and the rhomboids are supplied by the dorsal scapular artery and the transverse cervical artery supplies blood to the trapezius.

Crohn’s disease is a chronic, inflammatory disease that can affect any part of the gastrointestinal tract but is usually seen in the distal ileum and colon. It is transmural and symptoms include chronic diarrhoea, abdominal pain, fever, anorexia and weight loss. On examination, there is usually abdominal tenderness with a palpable mass or fullness seen occasionally. Rectal bleeding is uncommon (except in isolated colonic involvement) which manifests like ulcerative colitis. Differential diagnosis includes acute appendicitis or intestinal obstruction. 25%-33% patients also have perianal disease in the form of fissure or fistulas.
Extra intestinal manifestations predominate in children, and include: arthritis, pyrexia, anaemia or growth retardation. Histologically, the disease shows crypt inflammation and abscesses initially, which progress to aphthoid ulcers. These eventually develop into longitudinal and transverse ulcers with interspersed mucosal oedema, leading to the characteristic ‘cobblestoned appearance’. Transmural involvement leads to lymphoedema and thickening of bowel wall and mesentery, leading to extension of mesenteric fat on the serosal surface of bowel and enlargement of mesenteric nodes. There can also be hypertrophy of the muscularis mucosae, fibrosis and stricture formation, which can cause bowel obstruction. Abscesses are common and the disease can also leas to development of fistulas with various other organs, anterior abdominal wall and adjacent muscles. Pathognomonic non-caseating granulomas are seen in 50% cases and they can occur in nodes, peritoneum, liver, and in all layers of the bowel wall. The clinical course does not depend on the presence of granulomas. There is sharp demarcation between the diseased and the normal bowel (skip areas).
35% cases show only the ileal involvement, whereas in 45% cases, both the ileum and colon are involved with a predilection for right side of colon. 20% cases show only colonic involvement, often sparing the rectum (unlike ulcerative colitis). In occasional cases, there is jejunoileitis – involvement of the entire small bowel. The stomach, duodenum and oesophagus are rarely involved, although there has been microscopic evidence of disease involving the gastric antrum in younger patients. The affected small bowel segments show increased rick of cancer. Moreover, patients with colonic disease show a long-term risk of cancer similar to that seen in ulcerative colitis.

Hashimoto thyroiditis is part of the spectrum of autoimmune thyroid diseases (AITDs) and is characterized by the destruction of thyroid cells by various cell- and antibody-mediated immune processes.
The thyroid gland may become firm, large, and lobulated in Hashimoto’s thyroiditis, but changes in the thyroid can also be nonpalpable. Enlargement of the thyroid is due to lymphocytic infiltration and fibrosis, rather than tissue hypertrophy.

Laboratory studies and potential results for patients with suspected Hashimoto thyroiditis include the following:
– Serum thyroid-stimulating hormone (TSH) levels: Sensitive test of thyroid function; levels are invariably raised in hypothyroidism due to Hashimoto thyroiditis and in primary hypothyroidism from any cause
– Free T4 levels: Needed to correctly interpret the TSH in some clinical settings; low total T4 or free T4 level in the presence of an elevated TSH level further confirms diagnosis of primary hypothyroidism
– T3 levels: Low T3 level and high reverse T3 level may aid in the diagnosis of nonthyroidal illness

Thyroid autoantibodies: Presence of typically anti-TPO (anti-thyroid peroxidase) and anti-Tg (anti-thyroglobulin) antibodies delineates the cause of hypothyroidism as Hashimoto thyroiditis or its variant; however, 10-15% of patients with Hashimoto thyroiditis may be antibody negative.
While their role in the initial destruction of the follicles is unclear, antibodies against thyroid peroxidase (TPO) (also called TPOAb) or thyroglobulin are relevant, as they serve as markers for detecting the disease and its severity. They are hypothesized to be the secondary products of the T cell mediated destruction of the gland.

Hirschsprung’s disease is characterized by congenital absence of the autonomic plexus (Meissner’s and Auerbach’s plexus) in the intestinal wall. Usually limited to the distal colon, it can occasionally involve the entire colon or even the small bowel. There is abnormal or absent peristalsis in the affected segment, resulting in continuous spasm of smooth muscle and partial/complete obstruction. This causes accumulation of intestinal contents and dilatation of proximal segment. Skip lesions are highly uncommon. This disease is seen early in life with 15% patients presenting in first month, 60% by 1 year of age and 85% by the age of 4 years. Symptoms include severe and complete constipation, abdominal distension and vomiting. Patients with involvement of ultra-short segments might have mild constipation with intervening diarrhoea. In older children, symptoms include failure to thrive, anorexia, and lack of an urge to defecate. On examination, an empty rectum is revealed with stool palpable high up in the colon. If not diagnosed in time, it can lead to Hirschsprung’s enterocolitis (toxic megacolon), which can be fulminant and lead to death. Diagnosis involves a barium enema or a rectal suction biopsy. Barium enema shows a transition in diameter between the dilated, normal colon proximal to the narrowed, affected distal segment. It is to be noted that barium enema should be done without prior preparation, which can dilate the abnormal segment, leading to a false-negative result. A 24-hour post-evacuation film can be obtained in the neonatal period – if the colon is still filled with barium, there is a high likelihood of Hirschsprung’s disease. Full-thickness rectal biopsy is diagnostic by showing the absence of ganglion cells. Acetylcholinesterase staining can be done to highlight the enlarged nerve trunks. Abnormal innervation can also be demonstrated by rectal manometry.

Chronic obstructive pulmonary disease (COPD) is a type of obstructive lung disease characterized by long-term poor airflow. The main symptoms include shortness of breath and cough with sputum production. The best diagnostic test for evaluating patients with suspected chronic obstructive pulmonary disease (COPD) is lung function measured with spirometry. Key spirometrical measures may be obtained with a portable office spirometer and should include forced vital capacity (FVC) and the normal forced expiratory volume in the first second of expiration (FEV1). The ratio of FEV1 to forced vital capacity (FEV1/FVC) normally exceeds 0.75. Patients with COPD typically present with obstructive airflow. Complete pulmonary function testing may show increased total lung capacity, functional residual capacity and residual volume. A substantial loss of lung surface area available for effective oxygen exchange causes diminished carbon monoxide diffusion in the lung (DLco) in patients with emphysema. Tobacco smoking is the most common cause of COPD, with factors such as air pollution and genetics playing a smaller role.

Renal cell carcinoma is a kidney cancer that originates in the lining of the proximal convoluted tubule. It is the most common type of kidney cancer in adults, responsible for approximately 90–95% of cases. Renal cell carcinomas can be staged by using the American Joint Committee on Cancer (AJCC) TNM (tumour-node-metastasis) classification, as follows: Stage I: tumours that are 7 cm or smaller and confined to the kidney, Stage II: tumours that are larger than 7 cm but still confined to the kidney, Stage III: tumours extending into the renal vein or vena cava, involving the ipsilateral adrenal gland and/or perinephric fat, or which have spread to one local lymph node and Stage IV: tumours extending beyond Gerota’s fascia, to more than one local node, or with distant metastases Recent literature has questioned whether the cut-off in size between stage I and stage II tumours should be 5 cm instead of 7 cm. The patient’s cancer in this case is stage III.

Sarcoidosis is an inflammatory disease of unknown aetiology that affects multiple organs but predominantly the lungs and intrathoracic lymph nodes. Systemic and pulmonary symptoms may both be present. Pulmonary involvement is confirmed by a chest X-ray and other imaging studies. The main histological finding is the presence of non-caseating granulomas.

Suspected penile fractures should be surgically explored and the injury repaired.

Penile fractures are a rare type of urological trauma. The injury is usually in the proximal part of the penile shaft and may involve the urethra. A classical history of a snapping sensation followed by immediate pain is usually given by the patient (usually during vigorous intercourse). On examination, a tense haematoma is most commonly noted, and if the urethra is injured, blood may be seen at the meatus.

The correct management involves surgical exploration and repair of the injury. A circumferential incision is made immediately inferior to the glans and the penile shaft is inspected. Injuries are usually sutured and the urethra is repaired over a catheter.

Thrombomodulin is a protein cofactor expressed on the surface of endothelial cells. Thrombomodulin binds with thrombin forming a complex which activates protein C, initiating the anticoagulant pathway.

The sartorius muscle arises from tendinous fibres from the superior iliac spine. It passes obliquely across the thigh from lateral to medial and is inserted into the upper part of the medial side of the tibia. When the sartorius muscle contracts it will flex the leg at the knee joint.