In mild-to-moderate heroin overdoses, arterial blood gas (ABG) analysis reveals respiratory acidosis. In more severe overdoses, tissue hypoxia is common, leading to mixed respiratory and metabolic acidosis.

The normal range for PaCO2 is 35-45 mmHg (4.67 to 5.99 kPa). Respiratory acidosis can be acute or chronic. In acute respiratory acidosis, the PaCO2 is elevated above the upper limit of the reference range (i.e., >45 mm Hg) with an accompanying academia (i.e., pH < 7.35). In chronic respiratory acidosis, the PaCO2 is elevated above the upper limit of the reference range, with a normal or near-normal pH secondary to renal compensation and an elevated serum bicarbonate levels (i.e., >30 mEq/L).

Arterial blood gases with pH = 7.31; pCO2 = 7.4 kPa; pO2 = 8.1 kPa would indicate respiratory acidosis.

The empty boxes indicate that the patient has run out of his medication.
Chronic administration of high doses of glucocorticoids (GCs) (e.g., prednisone or prednisolone) and also other hormones such as oestrogens, progestins, androgens and growth hormone induce varying degrees of tolerance, resulting in a progressively decreased response to the effect of the drug, followed by dependence and rarely addiction.
The glucocorticoid withdrawal syndrome (GWS) has been considered a withdrawal reaction due to established physical dependence on supraphysiological GC levels.
The severity of GWS depends on the genetics and developmental history of the patient, on his environment, and on the phase and degree of dependence the patient has reached. Its management should include a temporary increase in the dose of GCs followed by gradual, slow tapering to a maintenance dose.

Difficulty in initiating movement (bradykinesia), postural instability and unilateral symptoms (initially) are typical of Parkinson’s. Essential tremor symptoms are usually worse if arms are outstretched and eased by rest and alcohol.

The given history suggests a small fibre painful peripheral sensory neuropathy, the most common cause of which is diabetes. Joint position sense and vibratory sensation are carried through large fibres, and therefore are not currently affected. Sensory nerves are affected more often than motor, so reflexes usually remain in tact.

Vitamin B12 deficiency causes impairment of joint position and vibratory sensation.

Chronic inflammatory demyelinating polyneuropathy (CIPD) causes a large fibre peripheral neuropathy with areflexia.

In syringomyelia there is impaired pain and temperature noted in the upper limbs.

Finally, with alcoholic polyneuropathy, all fibre types are affected (sensory and motor loss). It is usually gradual with long term alcohol abuse and may be accompanied by a nutritional deficiency. In addition, pain is a more dominant feature.

The phrenic nerve provides the primary motor supply to the diaphragm, the major respiratory muscle.
Phrenic nerve paralysis is a rare cause of exertional dyspnoea that should be included in the differential diagnosis. Fluoroscopy is considered the most reliable way to document diaphragmatic paralysis. During fluoroscopy a patient is asked to sniff and there is a paradoxical rise of the paralysed hemidiaphragm. This is to confirm that the cause is due to paralysis rather than unilateral weakness.

Narrow complex tachycardia with hypotension is a medical emergency. Immediate synchronized cardioversion is the ideal management.

Herpes zoster oticus is a viral infection of the inner, middle, and external ear. It manifests as severe otalgia with associated cutaneous vesicular eruption, usually of the external canal and pinna. When associated with facial paralysis, the infection is called Ramsay Hunt syndrome.

In hereditary non-polyposis colonic carcinoma (HNPCC), mutations in MSH2, MSH6, PMS2 or MLH1 genes are found.
Ataxia telangiectasia – ATM gene is affected.
Familial adenomatous polyposis – APC gene is affected.
Li-Fraumeni syndrome – mutation of the TP53 tumour suppressor gene. Neurofibromatosis – mutation in or a deletion of the NF1 gene

In spinal anaesthesia, the needle parts the dura rather than tears it. In an epidural, however, the needle is meant to inject around the dura but may penetrate it by accident. Maternal hypotension is most likely to be caused by dural penetration during an epidural, as this is the generally intended procedure. Postdural puncture headache appears to be associated higher with a spinal than an epidural.

Interleukin 1 alpha and interleukin 1 beta (IL1 alpha and IL1 beta) are cytokines that participate in the regulation of immune responses, inflammatory reactions, and hematopoiesis. It is secreted mainly by macrophages and monocytes and acts as a costimulator of T cell and B cell proliferation.

IV calcium gluconate is the drug of choice in hyperkalaemia, as it is a life threatening condition and prompt management is required.

Cardiac myxomas are the most common type of primary tumour of the heart. They are usually benign and arise from primary connective tissue. Most cardiac myxomas arise sporadically; however, 10% are hereditary (following an autosomal dominant pattern). Even though they may develop in any chamber of the heart, most (+-75 %) cardiac myxomas arise in the left atrium, usually from the interatrial septum, while the rest occur in the right atrium (ventricular myxomas are rare). Clinical features are primarily caused by obstruction of the blood flow through the heart and include dyspnoea on exertion, palpitations, syncope, weight loss, or even sudden death. Rarely, life-threatening conditions (e.g., stroke) may result from an embolization from the myxoma. Typical examination findings include abnormal heart sounds, such as a rumbling diastolic murmur over the apex or a characteristic tumour plop.
The diagnosis is not easily established clinically because of the nonspecific nature of symptoms. Echocardiography is the diagnostic procedure of choice. Surgical resection of the tumour is the curative treatment of choice. The prognosis is usually favourable, but tumours can recur after inadequate resection.

Methemoglobinemia is a rare condition in which the haemoglobin iron is in oxidized or ferric state (Fe3+) and cannot reversibly bind oxygen. Normally, the conversion of ferrous form of iron (Fe2+) to its ferric form (Fe3+) is regulated by NADH methaemoglobin reductase, which results in the reduction of methaemoglobin to haemoglobin. Disruption in the enzyme leads to increased methaemoglobin in the blood. There is tissue hypoxia as Fe3+ cannot bind oxygen, and hence the oxygen-haemoglobin dissociation curve is shifted to the left.

Methemoglobinemia can occur due to congenital or acquired causes. Congenital causes include haemoglobin variants such as HbM and HbH, and deficiency of NADH methaemoglobin reductase. Acquired causes are drugs (e.g. sulphonamides, nitrates, dapsone, sodium nitroprusside, and primaquine) and chemicals (such as aniline dyes).

The features of methemoglobinemia are cyanosis, dyspnoea, anxiety, headache, severe acidosis, arrhythmias, seizures, and loss of consciousness. Patients have normal pO2 but oxygen saturation is decreased. Moreover, presence of chocolate-brown coloured arterial blood (colour does not change with addition of O2) and brown urine also point towards the diagnosis of methemoglobinemia.

Alveolar haemorrhage (AH) is a rare, but serious manifestation of SLE. It may occur early or late in disease evolution. Extrapulmonary disease may be minimal and may be masked in patients who are already receiving immunosuppressants for other symptoms of SLE.

DLCO or TLCO (diffusing capacity or transfer factor of the lung for carbon monoxide (CO)) is the extent to which oxygen passes from the air sacs of the lungs into the blood.
Factors that can increase the DLCO include polycythaemia, asthma (can also have normal DLCO) and increased pulmonary blood volume as occurs in exercise. Other factors are left to right intracardiac shunting, mild left heart failure (increased blood volume) and alveolar haemorrhage (increased blood available for which CO does not have to cross a barrier to enter).

Free T4 levels or the free T4 index is usually elevated, as is the free T3 level or free T3 index
– Assays for thyrotropin-receptor antibodies (particularly TSIs) almost always are positive.
– Detection of TSIs is diagnostic for Graves disease.
– Other markers of thyroid autoimmunity, such as antithyroglobulin antibodies or antithyroid peroxidase antibodies, are usually present.
– Other autoantibodies that may be present include thyrotropin receptor-blocking antibodies and anti-sodium-iodide symporter antibody.
The presence of these antibodies supports the diagnosis of autoimmune thyroid disease.
– The radioactive iodine uptake is increased and the uptake is diffusely distributed over the entire gland.

The patient has spinal cord compression until proven otherwise. Urgent assessment is required.

Spinal cord compression is an oncological emergency and affects up to 5% of cancer patients. Extradural compression accounts for the majority of cases, usually due to vertebral body metastases. One of the most common causes of spinal cord compression is osteoarthritis. It is also more commonly seen in patients with lung, breast, or prostate cancer.

Clinical features include:
1. Back pain: the earliest and most common symptom, may worsen on lying down or coughing
2. Lower limb weakness
3. Sensory changes: sensory loss and numbness
4. Neurological signs: depending on the level of the lesion.
Lesions above L1 usually result in upper motor neurone signs in the legs. Lesions below L1 usually cause lower motor neurone signs in the legs and perianal numbness. Tendon reflexes are increased below the level of the lesion and absent at the level of the lesion.

Management options are:
1. High-dose oral dexamethasone
2. Urgent MRI for consideration of radiotherapy or surgery

Cyclizine and prochlorperazine are both used for the treatment of Meniere’s disease.

Thrombolytic therapy is indicated in patients with evidence of ST-segment elevation MI (STEMI) or presumably new left bundle-branch block (LBBB) presenting within 12 hours of the onset of symptoms if there are no contraindications to fibrinolysis. STEMI is defined as new ST elevation at the J point in at least two contiguous leads of 2 mm (0.2 mV) or more in men or 1.5 mm (0.15 mV) in women in leads V2-V3 and/or 1 mm (0.1 mV) or more in other contiguous limb leads.

Class I indications (i.e., the benefit greatly outweighs the risk, and the treatment should be administered): -Structural heart disease, sustained VT
-Syncope of undetermined origin, inducible VT or VF at electrophysiologic study (EPS)
-Left ventricular ejection fraction (LVEF) ≤35% due to prior MI, at least 40 days post-MI, NYHA class II or III
-LVEF ≤35%, NYHA class II or III
-LVEF ≤30% due to prior MI, at least 40 days post-MI
-LVEF ≤40% due to prior MI, inducible VT or VF at EPS

Class IIa indications (i.e., the benefit outweighs the risk and it is reasonable to administer the treatment):
-Unexplained syncope, significant LV dysfunction, nonischaemic cardiomyopathy
-Sustained VT, normal or near-normal ventricular function
-Hypertrophic cardiomyopathy with 1 or more major risk factors
-Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) with 1 or more risk factors for sudden cardiac death (SCD)
-Long QT syndrome, syncope or VT while receiving beta-blockers
-Nonhospitalized patients awaiting heart transplant
-Brugada syndrome, syncope or VT
-Catecholaminergic polymorphic VT, syncope or VT while receiving beta-blockers
-Cardiac sarcoidosis, giant cell myocarditis, or Chagas disease

Absolute contraindications for fibrinolytic use in STEMI

Prior intracranial haemorrhage (ICH)
Known structural cerebral vascular lesion
Known malignant intracranial neoplasm
Ischemic stroke within 3 months
Suspected aortic dissection
Active bleeding or bleeding diathesis (excluding menses)
Significant closed head trauma or facial trauma within 3 months
Intracranial or intraspinal surgery within 2 months
Severe uncontrolled hypertension (unresponsive to emergency therapy)
For streptokinase, prior treatment within the previous 6 months

A surgeon will observe the patient and will decide which procedure he needs.

The patients high morning blood sugar levels are suggestive to Somogyi Phenomenon which suggests that hypoglycaemia during the late evening induced by insulin could cause a counter regulatory hormone response that produces hyperglycaemia in the early morning.
Substitution of regular insulin with an immediate-acting insulin analogue, such as Humulin lispro, may be of some help.

Autosomal recessive polycystic kidney disease (ARPKD) is less common than ADPKD (dominant form) but can already present with symptoms and be diagnosed on prenatal ultrasound.

The history is suggestive of acute Epididymo-orchitis. The treatment option is antibiotics.

This patient has presented with a thromboembolic event most probably secondary to nephrotic syndrome (nephrotic-range proteinuria). Hypercoagulability is due to urinary loss of anticoagulant proteins, such as antithrombin III and plasminogen and an increase in clotting factors, especially factors I, VII, VIII, and X.

Cervical cancer results from genital infection with HPV. PV infections can be transmitted via nonsexual routes, but the result from sexual contact. So the best contraceptive method in relation to prevention of cervical cancer is the barrier method. But it will not prevent cervical cancer a 100%.

CMV infection is usually asymptomatic in adults. However, if the mother is infected for the first time during pregnancy then there is high chances of this infection passing on to the foetus. CMV infection can cause blindness, deafness, learning difficulties, restricted growth etc. Hepatitis B, herpes simplex, syphilis and HIV do not present with these classical signs of CMV infection in new-borns. It is estimated that 10 stillbirths occur in England and Wales every year due to CMV infection. The foetus is most at risk in early pregnancy. There is no effective prevention.

Conn’s disease is a condition in which excessive amounts of aldosterone are secreted from the adrenal glands. Because aldosterone increases the reabsorption of sodium, it leads to a very high blood pressure.

The most likely diagnosis with anaemia, raised erythrocyte sedimentation rate (ESR), hypercalcaemia, renal impairment, and raised total protein with low albumin is multiple myeloma (MM). Protein electrophoresis will confirm the presence of monoclonal band of paraprotein. Of note, a radioisotope bone scan is not a good test for picking up the lytic lesions of MM.

Diagnosis of MM is based on the confirmation of (a) one major criterion and one minor criterion or (b) three minor criteria in an individual who has signs or symptoms of multiple myeloma.

Major criteria:
1. >30% plasma cells on bone marrow biopsy
2. Monoclonal band of paraprotein on electrophoresis: >35g/L for IgG, 20g/L for IgA, or >1g of light chains excreted in the urine per day

Minor criteria:
1. 10-30% plasma cells on bone marrow biopsy
2. Abnormal monoclonal band but levels less than listed above
3. Lytic bone lesions observed radiographically
4. Immunosuppression