Long Case - Approach to a case with Left Lumbar Pain

This patient presented with a history of left flank pains for 1 week associated with fever. The patient has history of Type 2 Diabetes Mellitus and Hypertension both of which were uncontrolled. 

This scenario is a common occurrence in the medical ward. And likelihood of it appearing for the MBBS Final Exams are also high. And the diagnosis is pretty straightforward, if tackled systematically. 

Based on the above information alone, students should be able to draw up a list of differentials. In order to form a sensible list of differential diagnoses, I would suggest the student to use the patient's anatomy as a source of inspiration. 

Potential causes of the left flank pain (in anatomical order from superficial to deep):

Skin: Herpes zoster

Subcutaneous tissue and Muscle: Hematoma or abscess/ cellulitis

Colon: Colitis

Kidney: Pyelonephritis, Renal colic, Obstructive uropathy, Renal abscess, Renal tumours

Adrenal: Adrenal tumours 

Lymph Nodes: Lymphadenitis

Muscle: Psoas muscle abscess or intramuscular hematomas

Spine: Prolapsed intervertebral disc with nerve impingement

Based on the differentials above, the student can sit down to exclude each differential by taking a thorough history as well as examine the patient in detail.

In real life, the case above was diagnosed by the Emergency Doctor as having left sided pyelonephritis based on the symptom of fever and left flank pain. This is not wrong as patient has Uncontrolled Type 2 Diabetes Mellitus which predisposes the patient to ascending urinary tract infection. 

From history taking done by Medical Officer from Internal Medicine unit, there was no chills or rigors accompanying the fever and there was no vomiting that usually accompany pyelonephritis. There was also no dysuria/ hematuria/ incomplete voiding sensation. Patient had no diarrhoea or hematochezia to suggest colitis. There was no injury to the abdomen to suggest hematoma. Patient had no history of fall and no limb weakness to suggest a spinal cord or sciatica issue. Patient did report numbness affecting BOTH lower limbs particularly the feet in stocking distribution, up to both shins. This is likely due to diabetic peripheral neuropathy rather than related to spine issue. 

During systemic review, patient mentioned having rash over the left side of abdomen which appeared 2 days prior to presentation to the Emergency Department. The rash was not itchy but painful to touch. 

The patient did not have any abdominal distension, no significant anorexia and no unexplained weight loss to suggest a malignant pathology. 

After taking the above history to rule in and rule out the possible differentials, the next step was to do a complete physical examination to confirm the findings as what is usually required in the final MBBS examination. 

However, take a look at the photo below which was taken by the Internal Medicine Physician attending the patient. 

Multiple vesicles with crusting over the left lumbar region...lateral view

Similar lesions were also seen at the left loin region extending all the way to the midline posteriorly

The photos show herpes zoster of the left T8 or T9 dermatome. This diagnosis can easily be made if the patient has been adequately exposed. Therefore it can only be concluded that the diagnosis of left pyelonephritis was made without exposing the patient properly. In this patient, the left renal punch was "positive" because it was tender over the herpes zoster site at the left loin region. Deeper palpation revealed no kidney enlargement and no tenderness. 

Urine analysis also did not show features of urinary tract infection.

Thus the diagnosis of left pyelonephritis was changed to left T8/ T9 dermatome herpes zoster.

IV antibiotics that was started for pyelonephritis was stopped and oral acyclovir was started as the rash onset was just 2 days old. Analgesics was started as well to help reduce the pain.

This is how a student is expected to approach any long case. Based on the chief or presenting complaint, the student should draw up a list of differentials (preferably according to anatomical distribution to avoid missing any possibilities). Then go ahead with taking a complete history (history of presenting illness, past medical history, past surgical history, drug history, obstetric or gynae history for females, family history, allergy history, social history and last but not least, the systemic review). And then proceed with physical examination to further narrow down the differential list and verify the provisional diagnosis. I cannot help but re-emphasize the importance of adequate exposure when performing the physical examination. Without adequate or proper exposure, the student risks missing out on important signs and making an accurate diagnosis. Worse still, the student may be penalized by the examiner for improper examination technique (adequate exposure is important part of physical examination technique).

CCE.