Question 1

He develops a headache and nausea. His family report he is increasingly irritable.

His investigations show:

What is the most likely complication to cause his symptoms?

Syndrome of inappropriate ADH (SIADH) results from excess secretion of ADH (vasopressin). ADH causes water re-absorption in the distal tubule, and excess action of ADH causes an inappropriately high urine osmolality, with a low plasma osmolality and low serum sodium. There are multiple causes (see box below):

Diabetes incipidus (DI) presents with polyuria and polydipsia. The pattern of plasma and urine osmolality seen in DI is the reverse of SIADH. A water deprivation test with synthetic ADH is used to distinguish between cranial and nephrogenic DI. This may also be used to distinguish CDI and NDI from Psychogenic Polydipsia.

Cushing's syndrome rarely presents acutely and is due to high levels of steroids, which may be exogenous (e.g. long term prednisolone), or endogenous.

Dehydration may present with headache and irritability, but would cause a normal-high plasma osmolality, concentrated urine (high osmolality) and a high plasma urea.

Question 2

Which is the most likely drug to cause this?

In patients prescribed rifampicin it is important to warn patients about the red-secretions, as this can stain contact lenses, and cause undue worry.

Isoniazid may cause peripheral neuropathy, so prophylactic Pyridoxine (vit B6) is usually given. Isoniazid also may cause hepatitis.

Ethambutol is also used to treat TB, it causes the important side effect of retrobulbar neuritis, which presents with colour blindness and a central scotoma. Visual field testing is performed before commencement of ethambutol for baseline status.

Question 3

What is the most likely congenital cardiac defect?

Tetralogy of Fallot is an example of congenital cyanotic heart disease.

The initial investigation of congenital heart disease includes a chest x-ray, ECG and echocardiography.

Question 4

The clinical diagnosis given by the GP is acute gout.

Which is the most likely drug to have precipitated acute gout?

The differential diagnosis for an acute, red, hot swollen joint is:

• Septic arthritis
• Gout
• Pseudogout (CPDD arthropathy)
• Inflammatory monoarthritis
• Post-traumatic

Gout is an inflammatory arthritis due to the deposition of urate crystals in the joint. It is associated with a raised serum uric acid but is not required for the diagnosis to be made.

There are a number of causes of gout, including prescribed medications.

• Medications - in particular thiazide diuretics (eg, bendrofluazide)
• Excessive alcohol consumption
• High purine diet
• Leukaemia (high cell turnover)
• Obesity
• Polycythaemia

Treatment is divided into those medications for acute gout and those for chronic gout:

• Acute Gout:
  • NSAID's (Indomethacin is the drug of choice.)
  • Colchine (2nd line agent)
• Chronic Gout: Allopurinol (xanthine oxidase inhibitor). This is the drug of choice in the long term control of gout, but should not be commenced during acute gout.

Question 5

Which of the following is not a recognised complication of this condition?

Varicose veins are dilated, tortuous superficial veins in the lower limb. It is a common condition which most often prompts clinical advice for cosmetic reasons, although a small proportion of patients have symptoms or complications. Complications of varicose veins include:

• Bleeding
• Thrombophlebitis (inflammation of the superficial veins)
• Venous eczema
• Lipodermatosclerosis

There is no evidence from studies that having varicose veins leads to a DVT.