Medical Quiz: SBA – Answers Question No. 1: Correct Answer – E and permanent neurological deficitmay occur without Streptococcus pneumoniae and Neisseria meningitidis urgent intervention. The shooting pain down the leftleg, account for80% of acute bacterial meningitis in adults. absence of ankle jerk reflex and urinary retention suggest Meningitis caused byNeisseria meningitidis is that the L5/S1 disk has prolapsed into the cauda equina calledmeningococcal meningitis. The presence ofa non- and nerve root. The patientmust be sent without delay blanching, petechial rash indicates that the meningitis for assessment,MRI of the spine and subsequent is caused byNeisseria meningitidis. While Varicella neurosurgical referral. Therefore, sendingthe patient Zoster Virus can cause viral meningitis, thepresence of home is inappropriate. Acomplete neurological the rash should indicate that this is not the correct answer.Neisseria gonorrhea causes gonorrhoea while examination is desirable, but should not delaytransfer Listeria monocytogenes is an important cause of to for MRI. Similarly, the patient willrequire a catheter neonatal meningitis. but this should not delay transfer to accident andemergency. It is important to note that while Question No. 2: Correct Answer - E intramuscular NSAIDanalgesia can be used for patients This patient is likely to be suffering from psychogenic with cauda equina syndrome, strongeropiate analgesia polydipsia. Thewater deprivation test is the most may be required. appropriate investigation to confirmthis diagnosis. In a normal patient, the serum osmolality remains withinthe Question No. 4: Correct Answer - E normal range (275–295 mOsm/kg), while the urine Since polycythaemiarubravera is a point mutation osmolality rises to>600 mOsm/kg as water is abnormality, the bonemarrow produces excess myeloid reabsorbed. In diabetes insipidus (DI), the lineage cells. This feeds back negativelyupon serumosmolality is elevated with no compensatory erythropoietin production from the renal cells, such that concentration of urineosmolality. If the patient responds a raised redcell mass but low erythropoietin level is to desmopressin, this confirms cranialDI rather than nephrogenic DI, hence a water deprivation test is the measured. In a renal cellcancer, erythropoietin levels mostappropriate answer. An MRI scan is most may be uncontrollably raised causing acorrespondent appropriate for investigatinga pituitary tumor. The increase in red cell mass. Conversely, renal failurecauses fastingplasma glucose would be appropriate for a reduction in erythropoietin therefore red cell mass can investigating a patient withsuspected diabetes mellitus, be lowered. In bone marrow failure raised erythropoietin however this is often accompanied by weightloss. Serum levels have no impact onincreasing red cell mass. In the osmolality would be useful in gauging how serious absence of disease, erythropoietin andred cell mass are thepatient’sdegree of dehydration is, but would not be at homeostatic levels. diagnostic. Urinaryelectrolytes and fastingplasma glucose would be useful in gauging theseverity of the Question No. 5: Correct Answer - D patient’s clinical state, but would not confirm the Acanthosis nigricans, as described above in the question diagnosis. stem, is commonlyassociated with gastric carcinoma, although it has also been seen inHodgkin’s lymphoma, Question No. 3: Correct Answer - C obesity, acromegaly, diabetes mellitus and thyroid The history and examination should raise the suspicion of cauda equinasyndrome. This is a medical emergency disease. 192.