Option D is correct: Cystic fibrosis

1. One Australian study suggested that colonisation rates for Aspergillus in patients with cystic fibrosis approach 19%.
2. Rates of ABPA however are much lower at around 5%.
3. Allergic bronchopulmonary aspergillosis (ABPA) rates are lower in patients with obstructive lung disease at around 1%.
4. HIV patients with a known history of P. jirovecii are at increased risk of aspergilloma.
5. Bronchial carcinoma is not particularly associated with Aspergillus positivity.

A 45-year-old woman solicitor presents with shortness of breath and a dry cough. She has been treated by her GP with a salbutamol inhaler but tells you that this has made no difference at all to her symptoms. In addition, she has an itchy raised rash on both shins. On examination her BP is 145/82 mmHg, pulse is 80 and regular. Her BMI is 28. Lungs appear normal on auscultation. There is a rash on her shins consistent with erythema nodosum.

Option E is correct: Transbronchial biopsy

1. A dry cough with the presence of erythema nodosum raises the possibility of sarcoidosis.
2. You are asked to specify the investigation most likely to confirm the diagnosis, as such only transbronchial biopsy will determine whether non-caseating granulomas are present or not.
3. AAFB staining would be confirmatory for a diagnosis of tuberculosis.
4. Given this woman is a solicitor, it is less likely she has had significant TB exposure versus sarcoidosis.
5. Bronchoalveolar lavage may demonstrate increased lymphocytes, although this is a non-specific finding.
6. Serum ACE is raised in 60% of patients with sarcoidosis.
7. Transbronchial biopsy is therefore the definitive route to confirming the diagnosis.

Option A is correct: Left optic tract

Explanation:
1. A positive Hoffmans sign is a sign of upper motor neuron dysfunction and points to a disease of the central nervous system – in this case from the history degenerative cervical myelopathy [DCM] affecting the cervical spinal cord is most likely.
2. To elicit it, the examiner should flick the patient's distal phalanx (usually of the middle finger) to cause momentary flexion.
3. A positive sign is exaggerated flexion of the thumb.
4. DCM is often missed initially and there is a delay in the diagnosis of this condition by >2 years in some studies.
5. This is a problem as delayed treatment limits recovery.
6. It is most commonly misdiagnosed as carpal tunnel syndrome and in one study, 43% of patients who underwent surgery for degenerative cervical myelopathy, had been initially diagnosed with carpal tunnel syndrome.
7. DCM is therefore an important differential in patients suspected to have Carpal Tunnel Syndrome [CTS].
8. CTS is a disease of the peripheral nervous system, resulting from median nerve compression at the wrist inside the carpal tunnel.
9. It therefore affects only the aspects of the hand innervated by the median nerve: Sensation; Thumb / Index / Middle Finger.
10. This typically manifests as intermittent pain or paraesthesiae.
11. Motor; LOAF Muscles (lateral lumbricals, opponens pollicis, abductor pollicis brevis and flexor pollicis brevis).
12. Motor signs are less commonly seen with presentations of CTS, but wasting of the thenar eminence may be present.
13. Tinels test and Phalens test can be positive, but not always.
14. Both tests aim to increase the pressure within the carpal tunnel, to try to exacerbate symptoms; Tinels test via tapping on it and Phalens test by sustained full flexion of the wrist.
15. In focal central nervous system disorders, like DCM, examination features are known to have low sensitivity but high specificity.
16. As a disease of the cervical spinal cord, DCM can affect the sensory, motor and autonomic nervous systems from the neck downwards.
17. Motor signs will be upper motor neuron signs such as increased toned, hyper-reflexia and pyramidal weakness.
18. Note that the neurological signs of DCM are often subtle initially and easily missed, but as a progressive condition they are likely to get worse.
19. Therefore, detecting early DCM can be challenging.
20. A high index of suspicion, alongside a comprehensive neurological examination and monitoring for progression is required.

A 32-year-old woman has been admitted to the emergency department after an accident with a car. As she was crossing the road she was hit by a car’s bumper which made forceful contact with her leg. On closer examination you notice that the injury has manifested a foot drop.

Option A is correct: Common peroneal nerve

1. Common peroneal nerve lesion can cause weakness of foot dorsiflexion and foot eversion.
2. The common peroneal nerve provides sensation and motor function to the lower leg.
3. When compressed or damaged it can cause foot drop.
4. This nerve crosses laterally to curve over posterior rim of the fibula.
5. It then divides into the superficial and deep branches.
6. It supplies the tibialis anterior, extensor hallucis longus, extensor digitorum longus and peroneus tertius.
7. Combined, these allow dorsiflexion of the foot.
8. It is more vulnerable to injury as it has a long course throughout the leg and is more superficial than other nerves.
9. It is more prone to injury after a direct insult. Median nerve and pudendal nerves are not located in the leg.

Common Peroneal Nerve Lesion
1. The sciatic nerve divides into the tibial and common peroneal nerves. Injury often occurs at the neck of the fibula.
2. The most characteristic feature of a common peroneal nerve lesion is foot drop.

Other features include:
1. Weakness of foot dorsiflexion
2. Weakness of foot eversion
3. Weakness of extensor hallucis longus
4. Sensory loss over the dorsum of the foot and the lower lateral part of the leg
5. Wasting of the anterior tibial and peroneal muscles

A 30-year-old lady presents with acute occipital headache associated with vomiting, photophobia and stiff neck. There is no history of rash or fever. She has a past medical history of phaeochromocytoma for which she had surgery. She reports that her father died of kidney cancer and her brother is blind in his right eye due to a bleed in the eye.

Option B is correct: Von Hippel Lindau disease

1. This patient has von Hippel Lindau disease which is characterised by retinal and cerebellar haemangiomas, renal cysts with transformation to renal cell carcinoma, and phaeochromocytoma.
2. Neurological signs can be due to compression by haemangiomas, or an acute headache due to intracerebral or subarachnoid haemorrhage as in this patient.